ROOTSTOCK - Plant Physiology · PLANT PHYSIOLOGY Methods Thechemical methodsused were those previously employed (4). Total nitrogen was determined by the Kjeldahl method, total sulfur

EFFECT OF THE ROOTSTOCK ON THE COMPOSITIONOF CITRUS TREES AND FRUIT

A. R. C. HAAS

Received October 6, 1947

Introduction

In previous studies (3), it was shown that the amount of boron thataccumulates in citrus leaves is influenced by the rootstock variety. Therelative order or type of boron accumulation in the leaves of seedling treesof different varieties is the same as that impressed or imposed upon theleaves of the scion variety by these seedling varieties when used as root-stocks. This rootstock influence was found to affect many of the other in-organic constituents of Valencia orange leaves and rootlets (4). Recentlyit was pointed out (5) that the rootstock variety may affect the content oftotal phosphorus in citrus flowers.

The effect of rootstocks on fruit quality, for the most part, has dealtwith the organic constituents of the fruit. As a result of a seven-year in-vestigation on the effects of the rootstock on the composition of oranges andgrapefruit (9), considerable data are now available regarding the totalsoluble solids, total and reducing sugars, pH, titratable acidity, dry matter,ash, and inorganic constituents of the peel, pulp, and juice of these fruits.Scarcely any data are available regarding the effect of the rootstock on theaccumulation of inorganic constituents in the vegetative portions of lemontrees or in lemon fruit, and further data of this kind for orange and grape-fruit trees and fruit are very desirable.

It is reported (2) that rootstocks affect the prevalence of lemon tree de-cline as well as the yields of fruit. In certain areas in the United Statesand abroad, the use of sweet orange scions on sour orange as the rootstockmay be accompanied by a rapid tree decline (10, 12).

The present paper deals largely with differences in the inorganic com-position of the peel of citrus fruits and of the leaves and rootlets of trees inwhich the scions (buds) of any one variety were obtained from a singleparent tree and in which the seedlings used as rootstocks were carefullyselected (11). The soil and other environmental factors were quite similarfor each row of trees and frequent use was made of plot replications inorder to make more accurate comparisons. The results presented in thispaper add emphasis to the care required in the collection of citrus treesamples in order not to have the frequently unknown factor of rootstockvariety nullify the results of careful chemical analysis. Thus in cases inwhich the fertilizer requirements or status of a soil are sought by means ofcompositional variations in various portions of citrus trees or fruit, it be-comes most necessary to know that the observed chemical differences are notdue instead to the nature of the rootstock varieties involved.

309

Copyright (c) 2020 American Society of Plant Biologists. All rights reserved.

PLANT PHYSIOLOGY

MethodsThe chemical methods used were those previously employed (4). Total

nitrogen was determined by the Kjeldahl method, total sulfur by weighingas barium sulfate after incineration with magnesium nitrate, whereas sugarswere estimated iodometrically (8). In most cases only the peel of the fruitwas utilized on account of the lack of sufficient drying facilities to caresimultaneously for both the peel and pulp portions and the possibility of,variation in the number of seeds in the pulp of some scion varieties. Asample consisting of fifteen fruits was collected from each plot tested. Allof the fruit samples of a given scion variety were picked the same day.The stem and calyx (button) was discarded and each fruit was lightlyscrubbed in running distilled water and wiped dry. Fresh and dryweights of whole fruit and peel were obtained. One hundred and fiftyhealthy mature leaves of a given scion variety were collected the same dayfrom each plot tested. The leaves were individually washed or lightlyscrubbed in running distilled water and wiped dry. Several handfuls ofrootlets obtained by digging about the roots of the trees of the plots tested,were repeatedly washed by immersion in jars of tap water, followed by simi-lar treatment with distilled water and shaking off the excess water. Asany of the samples became dry in the large ventilated oven maintained at650 C., they were finely ground in various-sized Wiley mills. Ground sam-ples were placed in envelopes made of folded heavy brown wrapping paperand each envelope was placed in a heavy brown paper bag bearing the datadescriptive of the sample. These bags were stored in an oven maintained at500 C. and were removed temporarily during the weighing of duplicatealiquots.

In the presentation of the data the rootstock varieties are arranged inthe order of their descending values. This enables one to note whether theresults for the same rootstock variety plots from different locations in theorchard showed any agreement as regards their positions in the list.

Peel of navel orange fruitThe Washington navel orange fruits were collected in C.E.S. field Si on

January 29, 1946. When the calcium values were arranged (table I), thesour orange and trifoliate orange rootstock varieties were found near thetop of the list, rough lemon rootstock was intermediate, whereas sweetorange and grapefruit rootstocks were lowermost. Trifoliate orange root-stock is also near the top of the list for magnesium whereas the Washingtonnavel orange cuttings and the grapefruit rootstock are at the bottom of thelist. The grapefruit (pomelo) rootstock variety being low in the list asregards both calcium and magnesium may be of interest here and in othertables because of the occurrence in Florida of magnesium deficiency espe-cially in grapefruit trees.

When the percentages of calcium or magnesium are high, it oftenfollows that the values for potassium may be low, as when sour orange root-

310


HAAS: EFFECT OF ROOTSTOCK

TABLE ICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF PEELOF WASHINGTON NAVEL ORANGE FRUITS FROM TREES ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. FIELD S) IN DRY

Block Row Trees MATTER

CALCIUM

Brazilian sour orange ............................. A 43 6-10 0.864Rubidoux sour orange ............................. A 37 1-5- 0.813Brazilian sour orange ............................. A 38 1-5 0.801Trifoliate orange ............................. B 43 11-15 0.762Trifoliate orange ............................. B 41 1-5 0.761Siamese shaddock............................. A 40 1-5 0.734Rubidoux sour orange ............................. A 43 11-15 0.714Rough lemon ............................ A 45 11-15 0.712Rough lemon ............................ A 42 1-5 0.688C.E.S. 362 sweet orange ........................... B 38 1-5 0.685C.E.S. 362 sweet orange ........................... B 48 1-5 0.664Koethen sweet orange ............................. A 39 6-10 0.629(None) Washington Navel orange

(cuttings) ............................ B 38 6-10 0.604C.E.S. 343 grapefruit ............................. A 41 1-5 0.528

MAGNESIUM

Brazilian sour orange ............................. A 43 6-10 0.111C.E.S. 362 sweet orange ........................... B 38 1-5 0.109Trifoliate orange ............................. B 43 11-15 0.108Trifoliate orange ............................. B 41 1-5 0.103Rubidoux sour orange ............................. A 43 11-15 0.103Rough lemon ............................ A 45 11-15 0.103Koethen sweet orange ............................. A 39 6-10 0.101Rubidoux sour orange ............................. A 37 1-5 0.097Brazilian sour orange ............................. A 38 1-5 0.097Siamese shaddock............................. A 40 1-5 0.097Rough lemon ............................ A 42 1-5 0.094C.E.S. 362 sweet orange ........................... B 48 1-5 0.093(None) Washington Navel orange

(cuttings) ............................ B 38 6-10 0.092C.E.S. 343 grapefruit ............................. A 41 1-5 0.076

POTASSIUM

Trifoliate orange .............................. B 43 11-15 0.677C.E.S. 343 grapefruit .............................. A 41 1-5 0.577Trifoliate orange ..............................B 41 1-5 0.553Siamese shaddock.............................. A 40 1-5 0.528(None) Washington Navel orange

(cuttings) ............................. B 38 6-10 0.512C.E.S. 362 sweet orange ........................... B 48 1-5 0.511Koethen sweet orange ............................. A 39 6-10 0.504Rubidoux sour orange .............................. A 43 11-15 0.495C.E.S. 362 sweet orange ........................... B 38 1-5 0.404Rubidoux sour orange .............................. A 37 1-5 0.395Brazilian sour orange .............................. A 38 1-5 0.391Brazilian sour orange ............................. A 43 6-10 0.382Rough lemon ............................. A 45 11-15 0.336Rough lemon ............................. A 42 1-5 0.309

311


PLANT PHYSIOLOGY

TABLE I (Cont.)

LoCATION INT ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. FIELD S1) IN DRY


TOTAL PHOSPHORUS (P)

p.p.m.Trifoliate orange ............................. B 43 11-15 770Rubidoux sour orange ............................. A 43 11-15 700Trifoliate orange ............................. B 41 1-5 690C.E.S. 343 grapefruit ............................. A 41 1-5 680Siamese shaddock ............................. A 40 1-5 630Rubidoux sour orange ............................. A 37 1-5 630C.E.S. 362 sweet orange ........................... B 48 1-5 610Rough lemon ........... ................. A 42 1-5 610Koethen sweet orange ............................. A 39 6-10 600(None) Washington Navel orange

(cuttings) ........... ................. B 38 6-10 600C.E.S. 362 sweet orange ........................... B 38 1-5 590Brazilian sour orange ............................. A 38 1-5 580Rough lemon ........... ................. A 45 11-15 570Brazilian sour orange ............................. A 43 6-10 550

stocks were high in the calcium list and low in that of potassium or aswhen cuttings or grapefruit rootstock were low in the calcium and magne-sium lists and high in that of potassium. That this- reciprocal relation of-ten does not take place is seen in table I in which trifoliate orange root-stock is near the top in each of the lists. This rootstock is reported asbeing a dwarfing rootstock for Marsh grapefruit (7) and as producing thehighest soluble solids content (6) in citrus juice. The best quality fruitof navel orange, Valencia orange, and grapefruit was obtained (6) fromtrees on trifoliate orange rootstock although yield is a factor that cannotbe overlooked. Rough lemon rootstock, which is lowest in the potassiumlist, is reported (7) as being a most vigorous rootstock and as producingthe lowest soluble solids in fruit juice.

Valencia orange trees and fruit

PEEL OF VALENCIA ORANGE FRUIT

The Valencia orange fruit was collected on May 24, 1945i from trees inC.E.S. field SlA. Trifoliate orange rootstock occurs near the top of thelists for calcium and magnesium values in the dry matter of the peel(table II). Duncan grapefruit rootstock was associated with the highestpotassium (table III), followed by lemon shaddock, Sampson tangelo, tri-foliate orange, grapefruit, and Savage citrange rootstocks. Rough lemonrootstock is low in the list and most sweet or sour orange rootstocks occurin the lower half of the list. Total phosphorus values for the peel of fruitfrom trees on the same rootstock in different plots lack much agreement(table IV) except in a few cases such as Duncan grapefruit and Savage

312


313HAAS: EFFECT OF ROOTSTOCK

TABLE IICALCIUM AND MAGNESIUM CONTENT OF PEEL OF VALENCIA ORANGE FRUITS

FROM TREES ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD CALCIUM MAGNESIUMROOTSTOCK VARIETY (C.E.S. FIELD SlA) IN DRY IN DRY

Row Trees MATTER MATTER

Trifoliate orange .............................................Trifoliate orange .............................................Standard sour orange .................................Savage citrange ................................................

Trifoliate orange.............................................Sampson tangelo ................................................African sour orange .......................................Rubidoux sour orange .................................

Siamese shaddock .............................................Savage citrange ................................................Homosassa sweet orange ...........................Rough lemon .........................................................

C.E.S. 362 sweet orange ..............................Rough lemon .........................................................Rubidoux sour orange .................................Sampson tangelo ................................................

C.E.S. 343 grapefruit ....................................Cleopatra mandarin .......................................Siamese shaddock .............................................Brazilian sour orange ....................................

African sour orange .......................................Cleopatra mandarin .......................................Brazilian sour orange ....................................C.E.S. 362 sweet orange ..............................

Koethen sweet orange .................................Standard sour orange .................................Duncan grapefruit ..........................................Homosassa sweet orange ...........................

C.E.S. 343 grapefruit .................................Duncan grapefruit .............Koethen sweet orange .................................Lemon shaddock ................................................

27 11-1521 1-526 1-523 6-10

22 6-1031 6-1027 1-528 1-5

32 1-522 1,2,4,523 1-530 1-5

36 1-532 6-1033 6-1030 6-10

33 1-531 11-1535 11-1529 1-5

30 11-1532 11-1529 11-1529 6-10

28 6-1023 11-1534 11-1527 6-10

36 11-1531 1-535 1-533 11-13

citrange rootstocks, the latter of which headed the list. Citrange rootstocksare reported (1) as having improved the quality of Marsh grapefruit.

Valencia orange fruit samples also were collected on May 25, 1944,from trees in C.E.S. field SlA. The dry matter of the peel (table V)contained the highest total nitrogen content when the fruit was obtained

0.8970.8800.8720.864

0.8510.8240.8170.807

0.8030.7990.7930.792

0.7820.7800.7560.745

0.7420.7400.7360.735

0.7150.7130.7080.682

0.6810.6740.6740.672

0.6720.6040.5880.539

0.1240.1120.1020.109

0.1110.1110.1090.110

0.1150.1000.1040.115

0.1090.1050.1000.113

0.1020.1080.1090.098

0.1020.1110.0990.097

0.0970.1000.1060.098

0.0950.0970.0950.116


314 PLANT PHYSIOLOGY

from trees on sour orange or rough lemon rootstocks and the lowest con-tent when trifoliate orange was the rootstock. Total sulphur in the peel waslow: trifoliate orange rootstock and Valencia orange cuttings being asso-ciated with the lowest percentages of sulfur. The reducing and total

TABLE IIIPOTASSIUM CONTENT OF PEEL OF VALENCIA ORANGE FRUITS FROM TREES

ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD POTASSIUMROOTSTOCK VARIETY (C.E.S. FIELD S1A) IN DRY

Row Trees MATTER

Duncan grapefruit ........... ............. 31 1-5 0.826Duncan grapefruit .......... ............. 34 11-15 0.754Lemon shaddock.33 11-13 0.733Sampson tangelo.30 6-10 0.686

Sampson tangelo.31 6-10 0.610Trifoliate orange.21 1-5 0.598Trifoliate orange.22 6-10 0.597Koethen sweet orange.35 1-5 0.586Trifoliate orange ..27 11-15 0.580C.E.S. 343 grapefruit.36 11-15 0.580Savage citrange ..23 6-10 0.553C.E.S. 343 grapefruit.33 1-5 0.539Siamese shaddock.35 11-15 0.531Cleopatra mandarin.32 11-15 0.504Siamese shaddock.32 1-5 0.493Savage citrange.22 1,2,4,5 0.489C.E.S. 362 sweet orange.36 1-5 0.471Koethen sweet orange ..28 6-10 0.465Brazilian sour orange ..29 11-15 0.459Cleopatra mandarin ..31 11-15 0.457African sour orange ..30 11-15 0.438Homosassa sweet orange ..27 6-10 0.437Brazilian sour orange ..29 1-5 0.435Standard sour orange ..23 11-15 0.432C.E.S. 362 sweet orange ..29 6-10 0.421Rubidoux sour orange ..28 1-5 0.397Homosassa sweet orange ..23 1-5 0.376Standard sour orange ..26 1-5 0.372Rough lemon ..32 6-10 0.363Rubidoux sour orange ..33 6-10 0.360African sour orange ..27 1-5 0.327Rough lemon 30 1-5 0.315

sugars were highest in the case of Valencia orange cuttings and lowestwhen trifoliate orange was the rootstock. In the pulp the reducing sugarswere highest when Siamese grapefruit and trifoliate orange were the root-stocks whereas the total sugars were highest with Valencia trange cuttingsand with the Siamese grapefruit as rootstock.

ROOTLETS OF VALENCIA ORANGE TREES

The rootlets were collected on July 31, 1946 from the rootstocks ofValencia orange trees in C.E.S. field SlA. Considerable variation oc-



TABLE IVTOTAL PHOSPHORUS CONTENT OF PEEL OF VALENCIA ORANGE FRUITS FROM

TREES ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD TOTAL PHOS-

ROOTSTOCK VARIETY (C.E.S. FIELD S1A) PHORUS (P)IN DRY

Row Trees MATTER

p.p.m.Savage citrange .................. .............. 23 6-10 940Savage citrange ............. .................. 22 1,2,4,5 910Cleopatra mandarin ............................... 32 11-15 880C.E.S. 362 sweet orange .................... 36 1-5 860C.E.S. 343 grapefruit ..................................... 33 1-5 840Standard sour orange ............................... 26 1-5 830Siamese shaddock ................. 32 1-5 830Trifoliate orange ................... 22 6-10 810Standard sour orange ............................... 23 11-15 800Rubidoux sour orange ............................... 28 1-5 800Homosassa sweet orange ........................... 27 6-10 780Rough lemon ...................... 30 1-5 770African sour orange ............................... 30 11-15 760Cleopatra mandarin ................ .... 31 11-15 760Trifoliate orange ................. .............. 27 11-15 760Koethen sweet orange ................. ..... 35 1-5 750Brazilian sour orange ............................... 29 1-5 740Koethen sweet orange ................. .... 28 6-10 740Siamese shaddock ................. .............. 35 11-15 740Trifoliate orange ................. .............. 21 1-5 740C.E.S. 343 grapefruit ............................... 36 11-15 740Sampson tangelo ............... ................ 30 6-10 740Rubidoux sour orange ............................... 33 6-10 730Brazilian sour orange ............................... 29 11-15 730Duncan grapefruit ................... ............ 31 1-5 730Duncan grapefruit ................... ............ 34 11-15 720African sour orange ............................... 27 1-5 720Rough lemon .......... ..................... 32 6-10 700C.E.S. 362 sweet orange ............................... 29 6-10 690Sampson tangelo ............... ................ 31 6-10 690Homosassa sweet orange ............................... 23 1-5 680Lemon shaddock ............... ................ 33 11-13 620

curred in the thickness of the rootlets and only the young and small-sizedrootlets were taken. Trifoliate orange, Savage citrange, and Brazilian sourorange rootstocks occur in the upper portion of the list of calcium values(table VI) whereas Sampson tangelo and Koethen sweet orange rootstocksoccur in the lower portion, the two portions of the list being markedlydifferent in calcium values. In table VI it is seen that the Sampson tangelorootstock is relatively low and the trifoliate orange rootstock relativelyhigh in the list of values for the various constituents.

Marsh grapefruit trees and fruitPEEL OF MARSH GRAPEFRUIT

The fruit samples were collected on May 26, 1945, from trees in C.E.S.field S1. In the list of values (table VII) for calcium the sour orange root-

315


PLANT PHYSIOLOGY

stocks rank fairly high whereas rough lemon and lemon shaddock root-stocks rank lower. All of the grapefruit rootstocks occur in the upper halfof the list of the values for magnesium. Grapefruit and lemon shaddockrootstocks rank high in the list of potassium values whereas sour orange

TABLE VTOTAL NITROGEN, TOTAL SULPHUR, REDUCING AND TOTAL (AS REDUCING) SUGARS IN VALENCIA

ORANGE FRUIT FROM TREES ON VARIOUS ROOTSTOCKS

LOCATIONIN ORCHARD CONTENT CONTENT

ROOTSTOCK VARIETY (C.E.S. FIELD IN DRY ROOTSTOCK VARIETY IN DRYS1A) MATTER MATTER

Row Trees

TOTAL NITROGEN IN PEEL TOTAL SULPHUR IN PEEL

African sour orange ............ 27 1-5 1.204 Rough lemon.0.082Brazilian sour orange 29 1-5 1.126 Koethen sweet orange 0.078Rough lemon. 30 1-5 1.042 Duncan grapefruit. 0.069C.E.S. 362 sweet orange 36 1-5 0.987 Brazilian sour orange 0.065Siamese grapefruit ............... 32 1-5 0.948 African sour orange 0.062(None) Valencia orange Siamese grapefruit. 0.055

(cuttings) .................... 18 6-10 0.930 C.E.S. 362 sweet orange 0.051Koethen sweet orange 35 1-5 0.840 Trifoliate orange. 0.038Duncan grapefruit .................. 34 11-15 0.825 (None) Valencia orangeTrifoliate orange 21 1-5 0.803 (cuttings) 0.027

REDUCING SUGARS IN PEEL REDUCING SUGARS IN PULP

(None) Valencia orange Siamese grapefruit. 32.00(cuttings) ..................... 18 6-10 16.08 Trifoliate orange ............... 29.35

Rough lemon .................... 30 1-5 14.00 C.E.S. 362 sweet orange 28.75Koethen sweet orange ......... 35 1-5 13.96 (None) Valencia orangeSiamese grapefruit ............... 32 1-5 13.58 (cuttings) ................... 28.55C.E.S. 362 sweet orange 36 1-5 13.38 Rough lemon t................... 28.40Brazilian sour orange 29 1-5 13.30 Brazilian sour orange 28.40African sour orange ............ 27 1-5 13.30 Duncan grapefruit ............ 26.95Duncan grapefruit .................. 34 11-15 11.28 African sour orange ........ 26.85Trifoliate orange .................... 21 1-5 8.78 Koethen sweet orange ... 25.80

TOTAL (AS REDUCING) SUGARS IN PEEL TOTAL (AS REDUCING)TOTAL(AS ~~~~~~~~SUGARSIN PULP

(None) Valencia orange (None) Valencia orange(cuttings) .................. 18 6-10 27.52 (cuttings) ...... 43.40

Siamese grapefruit ............... 32 1-5 24.86 Siamese grapefruit ............ 42.90C.E.S. 362 sweet orange ... 36 1-5 24.72 Koethen sweet orange ... 42.80Rough lemon .................... 30 1-5 24.40 Trifoliate orange ............... 41.50Koethen sweet orange ......... 35 1-5 24.16 Brazilian sour orange ... 41.20Duncan grapefruit .................. 34 11-15 23.39 C.E.S. 362 sweet orange 40.60Brazilian sour orange ......... 29 1-5 23.17 Rough lemon ................... 39.10African sour orange ............ 27 1-5 22.84 African sour orange ......... 37.00Trifoliate orange .................... 21 1-5 17.25 Duncan grapefruit ............ 36.00

and sweet orange rootstocks occur in the lower half of the list. The totalphosphorus values are low in the cases of rough lemon and lemon shaddockrootstocks. Trifoliate orange rootstocks were conspicuous for their lackof agreement in table VII although fair agreement of values were obtainedfor rootstocks of a given variety even though occurring in widely scatteredrows or plots.

316



TABLE VICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF

VALENCIA ORANGE TREES ON VARIOUS ROOTSTOCKSROOTLETS FROM

LOCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. ]FIELD S1A) IN DRY

Row Trees MATTER

CALCIUM

Trifoliate orange ................. ............... 27 11-15 2.723Savage citrange ............. ................... 23 6-10 2.594Trifoliate orange ................. ............... 22 6-10 2.544Brazilian sour orange ................................ 29 11-15 2.281Sa.vage citrange ............. ................... 22 4-5 2.243Brazilian sour orange ................................ 29 1-5 2.200Sampson tangelo ............... ................. 30 6-10 1.363Sampson tangelo ............... ................. 31 6-10 1.222Koethen sweet orange ................................ 28 6-10 1.064Koethen sweet orange ................................ 35 1-5 0.886

MAGNESIUM

Koethen sweet orange ................................ 28 6-10 0.343Trifoliate orange ................. ............... 27 11-15 0.317Brazilian sour orange ................................ 29 11-15 0.298Savage citrange ............ .................... 23 6-10 0.265Trifoliate orange ................. ............... 22 . 6-10 0.249Koethen sweet orange ................................ 35 1-5 0.228Sampson tangelo ............... ................. 31 6-10 0.175Sampson tangelo ............... ................. 30 6-10 0.168Savage citrange ............. ................... 22 4-5 0.166

POTASSIUM

Koethen sweet orange ................................ 28 6-10 1.661Savage citrange ............. ................... 23 6-10 1.550Trifoliate orange ................. ............... 22 6-10 1.425Trifoliate orange ................. ............... 27 11-15 1.416Brazilian sour orange ................................ 29 1-5 1.364Koethen sweet orange ................................ 35 1-5 1.218Savage citrange ............. ................... 22 4-5 1.098Sampson tangelo ............... ................. 30 6-10 1.038Sampson tangelo ............... ................. 31 6-10 0.832Brazilian sour orange ................................ 29 11-15 0.801


p.p.m.Trifoliate orange ................. ............... 27 11-15 1360Trifoliate orange ............. 22 6-10 1270Savage citrange ............. ................... 23 6-10 1230Koethen sweet orange ................................ 28 6-10 1180Cleopatra mandarin .......................... ...... 32 11-15 1090Rough lemon ........ ........................ 30 1-5 1070Duncan grapefruit .................... ............ 31 1-5 1010Brazilian sour orange ................................ 29 1-5 970Duncan grapefruit .................... ............ 34 11-15 900Rough lemon ........ 32 6-10 890Savage citrange ............. ................... 22 4-5 820Koethen sweet orange ................................ 35 1-5 810Cleopatra mandarin ........................... ..... 31 11-15 810Brazilian sour orange ................................ 29 11-15 770Sampson tangelo ............... ................. 30 6-10 770Sampson tangelo ............... ................. 31 6-10 720

317


PLANT PHYSIOLOGY

TABLE VIICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF

GRAPEFRUIT FROM TREES ON VARIOUS ROOTSTOCKSPEEL OF MARSH

LOCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. FIELD Si) IN DRY

Row Trees MATTER

CALCIUM

Trifoliate orange ................................ 33 6-10 0.637Homosassa sweet orange ............................... 29 6-10 0.587Duncan grapefruit ................................ 20 1-5 0.582Brazilian sour orange ................................ 28 6-10 0.573African sour orange ................................ 27 6-10 0.565African sour orange 34 1-5 0.565Brazilian sour orange ................................ 35 1-5 0.557C.E.S. 362 sweet orange ................................ 20 6-10 0.541Camulos grapefruit ................................ 17 1-5 0.541C.E.S. 362 sweet orange ................................ 37 1-5 0.537Lemon shaddock ................................ 32 6-10 0.536Rough lemon ...... .......................... 22 1-5 0.535Camulos grapefruit ................................ 16 1-5 0.533Homosassa sweet orange ................................ 36 1-5 0.490Rough lemon .......... ...................... 37 6-10 0.478Trifoliate orange ................................ 23 1-5 0.472Lemon shaddock ................................ 21 1-5 0.430

MAGNESIUM

Homosassa sweet orange ................................ 29 6-10 0.099Trifoliate orange ................................ 33 6-10 0.098Lemon shaddock ................................ 21 1-5 0.089C.E.S. 362 sweet orange ................................ 37 1-5 0.087Camulos grapefruit ................................ 16 1-5 0.086Brazilian sour orange ................................ 35 1-5 0.083Duncan grapefruit ................................ 20 1-5 0.082Camulos grapefruit ................................ 17 1-5 0.081Brazilian sour orange ................................ 28 6-10 0.081African sour orange ................:.27 6-10 0.081Rough lemon ............................... 37 6-10 0.078C.E.S. 362 sweet orange ............................... 20 6-10 0.077Homosassa sweet orange ............................... 36 1-5 0.077African sour orange ............................... 34 1-5 0.075Lemon shaddock ............................... 32 6-10 0.075Trifoliate orange ............................... 23 1-5 0.072Rough lemon ......... ...................... 22 1-5 0.069

POTASSIUM

Camulos grapefruit ............................... 16 1-5 0.861Lemon shaddock .............. ................. 21 1-5 0.833Lemon shaddock ............................... 32 6-10 0.833Duncan grapefruit ............................... 20 1-5 0.786Camulos grapefruit ............................... 17 1-5 - 0.768Trifoliate orange ............................... 23 1-5 0.746C.E.S. 362 sweet orange ............................... 37 1-5 0.700Rough lemon ......... ...................... 37 6-10 0.666Brazilian sour orange ............................... 35 1-5 0.665Homosassa sweet orange ............................... 36 -1-5 0.658C.E.S. 362 sweet orange ............................... 20 6-10 0.625Homosassa sweet orange ............................... 29 6-10 0.615Brazilian sour orange ............................... 28 6-10 0.574African sour orange ............................... 34 1-5 0.564African sour orange ............................... 27 6-10 0.536Tiifoliate orange ............................... 33 6-10 0.497Rough lemon ......... ...................... 22 1-5 0.444

318



TABLE VII (Cont.)

LOCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. FIELD Si) IN DRY

Row Trees MATTER


p.p.m.Homosassa sweet orange ............................... 36 1-5 850Camulos grapefruit ............................... 16 1-5 840Camulos grapefruit ............................... 17 1-5 830C.E.S. 362 sweet orange ............................... 20 6-10 830C.E.S. 362 sweet orange ............................... 37 1-5 820Duncan grapefruit ............................... 20 1-5 810Brazilian sour orange ............................... 28 6-10 800Brazilian sour orange ............................... 35 1-5 770African sour orange ............................... 27 6-10 760Trifoliate orange ............................... 23 1-5 750Marsh grapefruit ................ ............... 29 6-10 740Lemon shaddock ................ ............... 21 1-5 740Rough lemon ................ ............... 37 6-10 730African sour orange .......................... 34 1-5 710Rough lemon ................ ............... 22 1-5 680Lemon shaddock ............................... 32 6-10 650Trifoliate orange ............................... 33 6-10 620

LEAvEs OF MARSH GRAPEFRUIT TREES ON VARIOUS ROOTSTOCKS

The leaf samples were collected on August 7, 1945, from trees in blockB (with the exception of row 35 in block C) in C.E.S. field Si. Table VIIIclearly shows that the dry matter of the leaves of trees on trifoliate orangeor sour orange rootstocks contained more calcium than that of leaves oftrees on sweet orange, grapefruit, rough lemon, or lemon shaddock root-stocks. High magnesium values in Marsh grapefruit leaves was associatedwith the rough lemon rootstock whereas low values were associated withthe grapefruit rootstock. This may be of interest in situations in Floridawhere magnesium deficiency is prevalent over considerable areas. Thegrapefruit rootstock was associated with high potassium values. Lemonshaddock, trifoliate orange and Brazilian sour orange rootstocks were asso-ciated with low percentages of total phosphorus.

LJEAvEs OF MARSH GRAPEFRUIT TREES ON VARIOUS GRAPEFRUITROOTSTOCKS

All of these leaf samples were collected on February 26, 1947, fromtrees on grapefruit rootstocks in C.E.S. field Si. From the data (tableIX) it appears that the percentages of calcium, magnesium, and potassiumin the leaves of Marsh grapefruit trees vary according to the grapefruitrootstock variety. These results may be of considerable importance fortrees on Florida soils.

ROOTLETS OF MARSH GRAPEFRUIT TREES

The rootlets were collected on March 5, 1947, from trees in block B(with a few samples in block C) in C.E.S. field S1. The calcium pereen-

319



TABLE VIIICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF MATURE MA RSH

GRAPEFRUIT LEAVES FROM TREES ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD

ROOTSTOCK VARIETY (C.E.S. FIELD Si, B AND C*) IN DRY

Row Trees MATTER

CALCIUM

Brazilian sour orange ................................. 35* 1-5 6.748African sour orange ..........................3........ 1-5 6.513Trifoliate orange ................................ 23 1-5 6.442Brazilian sour orange ................................ 28 6-10 6.199Trifoliate orange ................................. 33 6-10 6.181African sour orange ................................. 27 6-10 5.916C.E.S. 362 sweet orange ................................. 37 1-5 5.866Homosassa sweet orange ............................... 36 1-5 5.571Duncan grapefruit ................................. 20 1-5 5.557Homosassa sweet orange ................................ 29 6-10 5.457Camulos grapefruit ............... 16 1-5 5.393Camulos grapefruit ................................ 17 1-5 5.383Rough lemon ............... .. ................ 37 6-10 5.319C.E.S. 362 sweet orange ................................. 20 6-10 5.270Lemon shaddock ................................. 21 1-5 4.927Rough lemon ................. ................ 22 1-5 4.795Lemon shaddock ................................. 32 6-10 4.792

MAGNESIUM

Rough lemon .......... ....................... 37 6-10 0.555Trifoliate orange ................................. 33 6-10 0.520Lemon shaddock ................................. 32 6-10 0.495Homosassa sweet orange ................................. 29 6-10 0.468Rough lemon .......... ....................... 22 1-5 0.452Homosassa sweet orange ................................. 36 1-5 0.451African sour orange ................................. 34 1-5 0.440African sour orange ................................. 27 6-10 0.439Brazilian sour orange ................................. 35* 1-5 0.430C.E.S. 362 sweet orange ................................. 37 1-5 0.427C.E.S. 362 sweet orange ................................. 20 6-10 0.426Trifoliate orange ................................ 23 1-5 0.426Lemon shaddock .............. .................. 21. 1-5 0.425Brazilian sour orange ................................. 28 6-10 0.400Camulos grapefruit................................................ 17 1-5 0.380Duncan grapefruit................................................ 20 1-5 0.350Camulos grapefruit................................................ 16 1-5 0.326

POTASSIUM

Camulos grapefruit ................................. 16 1-5 1.024Duncan grapefruit ................................. 20 1-5 0.910Camulos grapefruit ................................. 17 1-5 0.711Lemon shaddock ................................. 21 1-5 0.680Rough lemon ............... .. ................ 22 1-5 0.610Homosassa sweet orange ................................. 36 1-5 0.590African sour orange ................................ 27 6-10 0.578C.E.S. 362 sweet orange .................... 37 1-5 0.562Lemon shaddock ................................. 32 6-10 0.560C.E.S. 362 sweet orange ................................. 20 6-10 0.544Rough lemon ................. ................ 37 6-10 0.512Brazilian sour orange ................................. 28 6-10 0.506Trifoliate orange ................................. 23 1-5 0.503Homosassa sweet orange ................................ 29 6-10 0.496Brazilian sour orange ................................. 35* 1-5 0.446Trifoliate orange ................................. 33 6-10 0.439African sour orange ................................. 34 1-5 0.410



TABLE VIII (Cont.)

LOCATION IN ORCHARD


Row Trees MATTER


p.p.m.Rough lemon . ................................ 22 1-5 1400Duncan grapefruit ................................ 20 1-5 1290African sour orange................................. 27 6-10 1200C.E.S. 362 sweet orange ................................ 37 1-5 1190C.E.S. 362 sweet orange ................................ 20 6-10 1170Rough lemon ......... 37 6-10 1160Camulos grapefruit ................. 17 1-5 1160Africaln sour orange ................................ 34 1-5 1150Homosassa sweet orange .................. 36 1-5 1140Camulos grapefruit ......................... 16 1-5 1060Lemon shaddock..2.............. 1 1-5 1050Homosassa sweet orange .................. 29 6-10 1020rrifoliate orange ................... 33 6-10 1010Trifoliate orange .. 23............23 1-5 960Brazilian sour orange ................................ 35* 1-5 960Lemon shaddock................... 32 6-10 910Brazilian sour orange ..... 28 6-10 890

tages in the rootlets of grapefruit trees on various rootstocks (table X)were high when trifoliate orange and sour orange rootstocks were used,which is in agreement with the results obtained with Valencia orange onthese rootstocks (table VI). Considerable variation occurs in the rootletsof other rootstock varieties such as grapefruit. A comparisoni of the rela-tive order of the grapefruit rootstock varieties in the list of percentagesfor magnesium (tables IX and X) suggests that the order is approximatelythe same in both the rootlets and Marsh grapefruit leaves. Table X indi-cates the wide variation that occurs in the potassium content of the rootletsof Marsh grapefruit trees on various grapefruit rootstock varieties. Therootlets of Marsh grapefruit trees are high in calcium and low in potassiumwhen the rootstock is sour orange and are high in both calcium and potas-sium when the rootstock is trifoliate orange.

Eureka lemon trees and fruit

PEEL OF EUREKA LEMON FRUIT

The lemon fruit in the silver stage of maturity were collected on Novem-ber 28, 1945, from trees in C.E.S. field 3. Data for the effect of rootstockson the inorganic content of lemon peel is shown in table XI. Sour orangeand rough lemon rootstocks were associated with high calcium percentagesin the dry matter of the peel and sweet lemon rootstock with low percen-tages. The peel of fruits of trees on sour orange, sweet orange, or pomelorootstocks contained low percentages of magnesium. The range of the po-tassium content of lemon peel extended from 0.475 to 1.136 per cent accord-

321


PLANT PHYSIOLOGY

ing to the rootstock variety. Pomelo and tangelo rootstocks were highestin the list of potassium values whereas sweet lemon, rough lemon, andsour orange rootstocks were lowest. The pomelo rootstocks also were highin the list of values for total phosphorus.

TABLE IXCALCIUM, MAGNESIUM, AND POTASSIUM CONTENT OF MATURE MARSH

FROM TREES ON VARIOUS GRAPEFRUIT ROOTSTOCKSGRAPEFRUIT LEAVES

LOCATION IN ORCHARD CONTENTGRAPEFRUIT ROOTSTOCK VARIETY (CES IL i N )IN DRY

Block Row Trees MATTERCALCIUM

Camulos......................................................................B 16 1-5 4.879Camulos.B 17 1-5 4.741Pernambucon. 28 6-10 4.721Camulos.B 13 1-5 4.707Pernambueo.C 27 6-10 4.643Dunca n.B 2 1-5 4.614McCarty.C 24 6-10 4.577(None) Marsh (cuttings).B 18 1-10 4.564McCarty.C 23 6-10 4.410Tresa.C 25 6-10 4.366Tresca.C 26 6-10 4.346(None) Marsh (cuttings).B 19 6-10 4.341

MAGNESIUM

Tresea ... 25 6-10 0.365Tresca .. 26 6-10 0.362Camulos ..B 17 1-5 0.297Pernambuco .. 27 6-10 0.287Pernambuco ..C 28 6-10 0.281Camulos ..B 16 1-5 0.272Camulos ..B 13 1-5 0.264McCarty ....................a.24 6-10 0.264(None) Marsh (cuttings).B 19 6-10 0.262(None) Marsh (cuttings).B 18 1-10 0.260uncan ..B 20 1-5 0.253

McCarty............. C 23 6-10 0.252

POTASSIUM

(None) Marsh (cuttings).B 19 6-10 0.760Duncan.....B:...............B 20 1-5 0.704Pernambucon. 27 6-10 0.690(None) Marsh (cuttings).B 18 1-10 0.689McCarty ..................... .23 6-10 0.680Pernambuco.C 28 6-J0 0.665Camulos.B 13 1-5 .0.651McCarty.... 24 6-10 0.626Camulos.B 16 1-5 0.622Camulos.B 17 1-5 0.547Tresca.C 25 6-10 0.521-Tresa.C. 26 6-10 0.443

LrEAvES OF EUREKA LEMON TREES

Healthy mature Eureka lemon leaves were collected on July 18, 1945,from trees in C.E.S. field 3. The highest calcium content in the dry matter

322



of lemon leaves (table XII) was in those from trees on Cleopatra mandarinrootstock whereas the lowest was in leaves from trees on sweet lemon root-stock. The first ten rootstocks in the list for magnesium included: rough

TABLE XCALCIUM, MAGNESIUM, AND POTASSIUM CONTENT OF ROOTLETS FROM MARSH

GRAPEFRUIT TREES ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD CONTENT


Row Trees MATTERCALCIUM

Trifoliate orange ..................23..............2 1-5 2.517African sour orange ................................. 34 1-5 2.317Brazilian sour orange ................................ 35 1-5 2.211Tresca grapefruit .................. .............. 25* 6-10 2.009Pernambuco grapefruit ............................... 27* 6-10 1.877Rough lemon ...... ......................... 22 1-5 1.658Lemon shaddock ............... ................. 21 1-5 1.609Camulos grapefruit................................. 16 1-5 1.568(None) Marsh grapefruit (cuttings) 18 1-5 1.411Homosassa sweet orange ............................... 36 1-5 1.410McCarty grapefruit ............................... 23* 6-10 1.348C.E.S. 362 sweet orange ............................... 37 1-5 1.226Duncan grapefruit ...... ........ .. 20 1-5 1.194

MAGNESIUM

Homosassa sweet orange ............................... 36 1-5 0.382Lemon shaddock .............. ................. 21 1-5 0.326Camulos grapefruit ................... ............ 16 1-5 0.306C.E.S. 362 sweet orange ............................... 37 1-5 0.284Tresca grapefruit ............................... 25* 6-10 0.279Pernambuco grapefruit ............................... 27* 6-10 0.276Brazilian sour orange ............................... 35 1-5 0.271(None) Marsh grapefruit (cuttings) 18 1-5 0.264African sour orange ............................... 34 1-5 0.247Trifoliate orange ................ ............... 23 1-5 0.226Rough lemon ............ ................... 22 1-5 0.213McCarty grapefruit ............................... 23* 6-10 0.196Duncan grapefruit ................... ............ 20 1-5 0.181

POTASSIUM

Trifoliate orange ............. .................. 23 1-5 1.815Pernambuco grapefruit ............................... 27* 6-10 1.423Tresea grapefruit................................ 25* 6-10 1.412(None) Marsh grapefruit (cuttings) 18 1-5 1.161Camulos grapefruit ................... ............ 16 1-5 1.006Rough lemon ............. .................. 22 1-5 0.967Lemon shaddock ........... .................... 21 1-5 0.836McCarty grapefruit ............................... 23* 6-10 0.724Homosassa sweet orange ............................... 36 1-5 0.688Duncan grapefruit................................ 20 1-5 0.686C.E.S. 362 sweet orange ............................... 37 1-5 0.602Brazilian sour orange ............................... 35 1-5 0.537African sour orange ............................... 34 1-5 0.499

lemon, Cleopatra mandarin, Sampson tangelo, sweet lemon, and MadameVinus rootstock, whereas the lowest eleven rootstocks included: varioussour orange, various sweet orange, and pomelo rootstocks. Pomelo and

323


'r324 PLANT PHYSIOLOGY

Sampson tangelo rootstocks are associated with the highest potassium valuesin lemon leaves whereas rough lemon, sweet lemon, sour orange, and Cleo-patra mandarin rootstocks are associated with relatively low potassiumvalues. Pomelo, tangelo, and sweet orange rootstocks are high in the listof total phosphorus values whereas rough lemon and sour orange root-stocks are low.

TABLE XICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF PEEL

OF EUREKA LEMON FRUITS FROM TREES ON VARIOUS ROOTSTOCKS

LOCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. F!ELD 3) IN DRY


CALCIUM

Brazilian sour orange .............................. C 15 1-5 1.545Rubidoux sour orange .............................. C 11 1-5 1.481Brazilian sour orange .............................. B 28 1-5 1.353Rubidoux sour orange .............................. B 29 1-5 1.286Rough lemon .............................. C 14 1-5 1.249Rough lemon .............................. B 26 1-5 1.224Cleopatra mandarin .............................. B 35 6-10 1.114C.E.S. 343 pomelo .............................. B 36 6-10 1.093Bessie sweet orange ..............................B 10 1-5 1.087Koethen sweet orange .............................. B 16 1-5 1.071Madame Vinus ............................. B 28 6-10 1.040Madame Vinus ............................. B 13 1-5 1.040Sampson tangelo ...............C..............C 23 11-15 1.039Duncan pomelo ............................. B 23 1-5 1.032Cleopatra mandarin .............................. C 13 6-10 1.024C.E.S. 343 pomelo .............................. B 21 1-5 1.021Bessie sweet orange .............................. C 12 1-5 0.985Sweet lemon ......... ..................... C 17 6-10 0.977Sampson tangelo ............................. B 38 6-10 0.955Sweet lemon ......... ..................... C 34 11-15 0.944

MAGNESIUM

Rough lemon .............................. C 14 1-5 0.156Sampson tangelo .............................. C 23 11-15 0.143Sweet lemon .......... .................... C 34 11-15 0.135Rough lemon .............................. B 26 1-5 0.133Sampson tangelo .............................. B 38 6-10 0.131Sweet lemon ...... ........................ C 17 6-10 0.127Cleopatra mandarin .............................. B 35 6-10 0.124Bessie sweet orange ..............................B 10 1-5 0.122Cleopatra mandarini .............................. C 13 6-10 0.121Madame Vinius .............................. B 28 6-10 0.121Brazilian sour orange .............................. C 15 1-5 0.116Rubidoux sour orange .............................. C 11 1-5 0.115Madame Vinus .............................. B 13 1-5 0.114Rubidoux sour orange .............................. B 29 1-5 0.109Koethen sweet orange .............................. B 16 1-5 0.105C.E.S. 343 pomelo .............................. B 36 6-10 0.105Bessie sweet orange ..............................C 12 1-5 0.104Brazilian sour orange .............................. B 28 1-5 0.104Dunean pomelo.............................. B 23 1-5 0.099C.E.S 343 pomelo .............................. B 21 1-5 0.093



TABLE XI (Cont.)

LOCATION IN ORCHARD CONTENTRoOTSTOCK VARIETY (CES IL )IN DRY


POTASSIUM

Duncan pomelo .............................. B 23 1-5 1.136C.E.S 343 pomelo ............................. B 21 1-5 0.965Sampson tangelo ............................. C 23 11-15 0.911Sampson tangelo.............................. B 38 6-10 0.903Madame Vinus.............................. B 28 6-10 0.885C.E.S 343 pomelo .............................. B 36 6-10 0.865Cleopatra mandarin ............................. B 35 6-10 0.787Koethen sweet orange .............................. B 16 1-5 0.777Madame Vinus.............................. B 13 1-5 0.761Rubidoux sour orange ............................. B 29 1-5 0.742Bessie sweet orange ..............................B 10 1-5 0.726Cleopatra mandarin ............................. C 13 6-10 0.721Bessie sweet orange .............................. C 12 1-5 0.718Brazilian sour orange ............................. B 28 1-5 0.696Rubidoux sour orange .............................. C 11 1-5 0.628Brazilian sour orange .............................. C 15 1-5 0.568Rough lemon .............................. B 26 1-5 0.517Sweet lemon .............................. C 17 6-10 0.512Roughlemon.C............................. C 14 1-5 0.485Sweet lemon ......... .................... C 34 11-15 0.475


p.p.m.Sampson tangelo ............................. C 23 11-15 840Duncan pomelo .............................. B 23 1-5 830Cleopatra mandarin .............................. B 35 6-10 720C.E.S 343 pomelo .............................. B 21 1-5 710C.E.S. 343 pomelo ............................. B 36 6-10 670Madame Vinus.............................. B 13 1-5 670Brazilian sour oranige ............................. B 28 1-5 660Rubidoux sour orange ............................. B 29 1-5 640Sweet lemon .............................. C 17 6-10 640Sampson tangelo.............................. B 38 6-10 640Cleopatra mandarin .............................. C 13 6-10 630Madame Vinus ............................. B 28 6-10 620Bessie sweet orange ..............................B 10 1-5 620Bessie sweet orange .............................C 12 1-5 620Rough lemon .......... .................. B 26 1-5 610Rough lemon .............................. C 14 1-5 590Brazilian sour orange ............................. C 15 1-5 590Bessie sweet orange ..............................B 16 1-5 580Sweet lemon .......... .................... C 34 11-15 580Rubidoux sour orange .............................. C 11 1-5 580

ROOTLETS OF EUREKA LEMON TREES

Rootlets were dug on August 29, 1946, from the rootstocks of lemontrees in C.E.S. field 3. The number of samples is limited and there are noadditional data available. The rootlets of Siamese grapefruit and Africansour orange rootstocks (table XIII) contained the most calcium whereasthose of rough lemon and Sampson tangelo contained the least. Therootlets of Koethen sweet orange, Siamese grapefruit and rough lemon root-

325



stocks contained the most magnesium, whereas those of African sour orangeand Sampson tangelo rootstocks contained the least. Rootlets of theselatter rootstocks also contained the least potassium, whereas those of Cun-ningham citrange and rough lemon contained the most potassium and mosttotal phosphorus.

TABLE XIICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF MATURE

EUREKA LEMON LEAVES FROM TREES ON VARIOUS ROOTSTOCKS

LoCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. FIELD 3) IN DRY


CALCIUM

Cleopatra mandarin ...................... C 13 6-10 5.875Cleopatra mandarin ...................... B 35 6-10 5.661Bessie sweet orange.B 10 1-5 5.410Sampson tangelo ..C 23 11-15 5.272Bessie sweet orange.C 12 1-5 5.210Madame Vinus ..C 13 1-5 5.126Rubidoux sour orange ..C 11 1-5 5.102Bessie sweet orange.C 12 1-5 5.076Sampson tangelo ..B 38 6-10 5.071Duncan pomelo ..B 23 1-5 5.023Brazilian sour orange ..C 15 1-5 4.986Madame Vinus B 28 6-10 4.941C.E.S. 343 Pomelo B 21 1-5 4.813Brazilian sour orange ..B 28 1-5 4.708Rough lemon ..C 14 1-5 4.704Koethen sweet orange B 16 1-5 4.668C.E.S. 343 pomelo B 36 6-10 4.526Rough lemon ..B 26 1-5 4.436Rubidoux sour orange ..B 29 1-5 4.269Sweet lemon.C 17 6-10 4.182Sweet lemon.C 34 11-15 4.182

MAGNESIUM

Rough lemon.C 14 1-5 0.512Cleopatra mandarin ..C 13 6-10 0.443Sampson tangelo ..C 23 11-15 0.436Sweet lemon.C 17 6-10 0.430Sampson tangelo ..B 38 6-10 0.424Rough lemon.B 26 1-5 0.405Cleopatra mandarin ..B 35 6-10 0.382Madame Vinus ..B 28 6-10 0.377Sweet lemon.C 34 11-15 0.366Madame Vinus ..C 13 1-5 0.364Brazilian sour orange ..C 15 1-5 0.350Bessie sweet orange.B 10 1-5 0.339Bessie sweet orange.C 12 1-5 0.329Bessie sweet orange.C 12 1-5 0.322Koethen sweet orange ..B 16 1-5 0.304Rubidoux sour orange ..C 11 1-5 0.297C.E.S. 343 pomelo.B 36 6-10 0.285Brazilian sour orange ..B 28 1-5 0.283C.E.S. 343 pomelo.B 21 1-5 0.280Rubidoux sour orange ..B 29 1-5 0.256Duncan pomelo ..B 23 1-5 0.220


327HAAS: EFFECT OF ROOTSTOCK

TABLE XII (Cont.)

LOCATION IN ORCHARD CONTENTROOTSTOCK VARIETY (C.E.S. FIELD 3) IN DRY


POTASSIUM

Duncan pomelo ............................ B 23 1-5 1.073C.E.S. 343 pomelo .............................. B 21 1-5 1.036C.E.S. 343 pomelo .............................B 36 6-10 0.947Sampson tangelo .............................. B 38 6-10 0.831Sampson tangelo .............................. C 23 11-15 0.732Koethen sweet orange .............................. B 16 1-5 0.685Madame Vinus ..............C...............C 13 1-5 0.645Bessie sweet orange ..............................C 12 1-5 0.644Bessie sweet orange .............................C 12 1-5 0.603Rubidoux sour orange .............................. B 29 1-5 0.602Bessie sweet orange ..............................B 10 1-5 0.564Madame Vinus ............................. B 28 6-10 0.479Cleopatra mandarin ............................. C 13 6-10 0.476Cleopatra mandarin ............................. B 35 6-10 0.463Sweet lemon ............................. C: 17 6-10 0.462Brazilian sour orange .............................. B 28 1-5 0.454Brazilian sour orange .............................. C 15 1-5 0.448Rubidoux sour orange .............................. C 11 1-5 0.447Sweet lemon .......... .................... C 34 11-15 0.428Rough lemon ........... .................. B 26 1-5 0.407Rough lemon .............................. C 14 1-5 0.306


p.p.m.C.E.S. 343 pomelo .............................. B 21 1-5 1300Sampson tangelo....................................C.. 23 11-15 1280Koethen sweet orange .............................. B 16 1-5 1120Duncan pomelo .............................. B 23 1-5 1090Bessie sweet orange ............................. B 10 1-5 1090C.E.S. 343 pomelo .............................. B 36 6-10 1080Sweet lemon .......... .................... C 17 6-10 1080Bessie sweet orange ............................. C 12 1-5 1070Sampson tangelo.............................. B 38 6-10 1050Madame Vinus ............................. C 13 1-5 1050Rubidoux sour orange ............................. 3B 29 1-5 990Cleopatra mandarin .............................. C 35 6-10 970Sweet lemon .......... .................... C 34 11-15 960Madame Vinus ............................. B 28 6-10 950Cleopatra mandarin .............................. C 13 6-10 950Rough lemon .............................. B 26 1-5 890Rubidoux sour orange .............................. C 11 1-5 800Rough lemon .............................. C 14 1-5 760Brazilian sour orange .............................. B 28 1-5 760Brazilian sour orange .............................. C 15 1-5 700

Summary and conclusions

The peel of Washington Navel orange fruit contained high percentagesof calcium when the trees were on sour orange or on trifoliate orangerootstocks and low calcium values when on sweet orange or grapefruitrootstocks. Magnesium values were lowest when grapefruit rootstock wasused. The potassium percentages in navel orange peel were highest fortrifoliate orange and grapefruit rootstocks, followed in descending order


PLANT PHYSIOLOGY

by sweet orange, sour orange, and rough lemon rootstocks. Trifoliateorange rootstock ranked high as regards the calcium, magnesium, potassium,and total phosphorus values in the peel of navel oranges.

In Valencia orange peel the calcium content was high when the root-stocks were Duncan grapefruit, lemon shaddock, Sampson tangelo andtrifoliate orange and low when the rootstocks were sour orange or rough

TABLE XIIICALCIUM, MAGNESIUM, POTASSIUM, AND TOTAL PHOSPHORUS CONTENT OF ROOTLETS

FROM EUREKA LEMON TREES ON VARIOUS ROOTSTOCKS

ROOTSTOCK VARIETY CONTENT IN DRYMATTER

CALCIUM

Siamese grapefruit ................................................ 2.458African sour orange ................................................ 2.352Cunningham citrange ................................................. 2.157Koethen sweet orange ................................................ 1.966Rough lemon ............................................... 1.742Sampson tangelo ................................................ 1.430

MAGNESIUM

Koethen sweet orange 0.392Siamese grapefruit.0.375Rough lemon.0.355Cunningham citrange.0.291African sour orange.0.261Sampson tangelo.0.220

POTASSIUM

Cunningham citrange.1.990Rough lemon......... , 1.598Koethen sweet orange ................................................ 1.118African sour orange ................................................ 0.859Sampson tangelo ............................................... 0.842


P.p.m.Rough lemon ................................................ 1270Cunningham citrange ............ .................................... 1100Sampson tangelo ................................................ 890Koethen sweet orange ............ .................................... 880African sour orange ................................................ 720Siamese grapefruit ............................................... 690

lemon. The potassium percentages when the trees were on Duncan grape-fruit rootstock were double those found when rough lemon rootstock wasused. Duncan grapefruit, lemon shaddock, Sampson tangelo, trifoliateorange, grapefruit, and Savage citrange rootstocks were associated withhigh potassium values and rough lemon rootstock with low values. Mostsweet orange and sour orange rootstocks occurred in the lower portion ofthe list of potassium values. The total phosphorus content was highest

328



when the rootstock was Savage citrange. The peel of Valencia orangecontained high total nitrogen with sour orange and low total .nitrogenwith trifoliate orange rootstocks. Sugars were usually high in peel andpulp when Valencia orange cuttings or Siamese grapefruit rootstock wasused. Sugars were very low in the peel and high in the pulp when therootstock variety was trifoliate orange. The trifoliate orange rootstockwas associated with high values for calcium, magnesium, potassium, andtotal phosphorus in the rootlets of Valencia orange trees, whereas Samp-son tangelo rootstock was associated with low values.

The calcium percentages were high in the peel of Marsh grapefruitwhen sour orange rootstock was used and low when rough lemon and lemonshaddock rootstocks were used. The magnesium values were rather highwhen grapefruit rootstocks were used. The peel contained high potassiumvalues in fruits of trees on grapefruit and lemon shaddock rootstocks andlower values for trees on sour orange and sweet orange rootstocks.

The leaves of Marsh grapefruit trees contained higher percentages ofcalcium when the rootstocks were trifoliate orange or sour orange andlower values when the rootstocks were sweet orange, grapefruit, roughlemon, or lemon shaddock. In contrast to the magnesium content in thepeel of Marsh grapefruit, the leaves of grapefruit trees on grapefruitrootstock contained the lowest magnesium content among any of the root-stocks tested. Leaves of Marsh grapefruit trees on grapefruit rootstockcontained the highest percentages of potassium. The percentages of cal-cium, magnesium, and potassium in the dry matter of Marsh grapefruitleaves were found to vary according to the grapefruit rootstock variety.

The values for calcium in the rootlets of Marsh grapefruit trees onvarious rootstocks agree with those obtained for the rootlets of Valenciaorange trees on various rootstocks. Trifoliate orange and sour orangerootstocks rank high in the list for calcium percentages in the rootlets.Trifoliate orange rootstock also ranks high for the potassium values inthe rootlets whereas sour orange rootstock ranks low.

For the first time data on the effect of the rootstock variety on theinorganic composition of lemon trees and fruit have been made available.In lemon peel the high calcium values were associated with sour orangeand rough lemon rootstocks, and low values with sweet lemon rootstock.The high magnesium percentages in lemon peel were obtained with roughlemon, Sampson tangelo, sweet lemon, and Cleopatra mandarin rootstocks.Pomelo and tangelo rootstocks were associated with highi potassium percen-tages in the peel of lemons and sweet lemon, rough lemon, and sour orangerootstocks with the lowest percentages.

The leaves of lemon trees contained the highest calcium percentageswhen the rootstock was Cleopatra mandarin and the lowest when the root-stock was sweet lemon. The pomelo and sour orange rootstocks were asso-ciated with low percentages of magnesium in the leaves and the possibilityof magnesium as a limiting factor is suggested by the data presented.

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Leaves of trees on pomelo, and on Sampson tangelo rootstocks, containedthe highest percentages of potassium, whereas those of trees on roughlemon, sweet lemon, sour orange, and Cleopatra mandarin contained thelowest. Rootlets of lemon trees on Sampson tangelo rootstock containedthe least calcium, magnesium, and- potassium, whereas those of -trees onAfrican sour orange were high in calcium and low in magnesium, potas-sium, and total phosphorus content.

In chemical and other studies with citrus trees the determination ofthe rootstock variety is of considerable importance. Wide ranges in per-centages were found in the inorganic composition of the various portionsof citrus trees and fruits when the trees were grown on various rootstocksunder approximately the same environmental conditions.

CITRUS EXPERIMENT STATION,RIVERSIDE, CALIFCRNIA

LITERATURE CITED1. BATCHELOR, L. D., and BITTERS, W. P. Rootstocks for Marsh grape-

fruit in California. California Citrogr. 32: 282, 294, 296. 1947.2. , and ROUNDS, M. B. Effect of rootstocks on lemon

decline and yield in two experimental orchards. CaliforniaCitrogr. 29: 242-243, 165-269. 1944.

3. HAAS, A. R. C. Boron content of citrus trees grown on various root-stocks. Soil Sci. 59: 465-479. 1945.

4. . Influence of the rootstock on the composition of citrusleaves and rootlets. Soil Sci. 60: 445-461. 1945.

5. . Effects of fertilizer and rootstock on total phosphoruscontent of citrus flowers. Soil Sci. 64: 47-59. 1947.

6. HALL, E. G. Effect of stocks on citrus fruit quality. Trials withNavels, Valencias, and Marsh grapefruit. Agr. Gaz.'N. S. Wales54: 173-176. 1943.

7. HODGSON, R. W., and EGGERS, E. R. Rootstock influence on the com-position of citrus fruits. Calfornia Citrogr. 23: 499,7 531. 1938.

8. SHAFFER, P. A., and HARTMANN, A. F. The iodometric determina-tion of copper and its use in sugar analysis. II. Methods for thedetermination of reducing sugars in blood, urine, milk, and othersolutions. Jour. Biol. Chem. 45: 365-390. 1921.

9. SINCLAIR, W. B., and BARTHOLOMEw, E. T. Effects of rootstock andenvironment on the composition of oranges and grapefruit. Hil-gardia 16: 125-176. 1944.

10. SMOYER, K. M., and HALMA, F. F. The rootstock factor in quickdecline. California Citrogr. 31: 249, 282. 1946.

11 WEBBER, H. J. Variations in citrus seedlings and their relations torootstock selection. Hilgardia 7: 1-79. 1932.

12. WEBBER, H. J. The "Tristeza" disease of sour orange rootstock.Proc. Amer. Soc. Hort. Sci. 43: 160-168. 1943.

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ROOTSTOCK - Plant Physiology · PLANT PHYSIOLOGY Methods Thechemical methodsused were those previously employed (4). Total nitrogen was determined by the Kjeldahl method, total sulfur