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Introduction
GLOSSARY
FLOWER STRUCTURE
POLLINATION
POLLEN MECHANISM
POLLEN BIOLOGY
POLLEN VIABILITY
POLLEN STORAGE
FERTILIZATION
Review of research work
Conclusion 2
OPEN
CONTROL
Key words Angiosperms: (angios=container and sperms=seeds). The angiosperms are also
known as plants with flowers.
Bryophytes: these are minuscule plants, mostly land-based, which differ from
the other plants mainly because of the absence of true conductor vessels (xylem and
phloem).
Caatinga: it is the only exclusively Brazilian biome, formed by a typical flora
and fauna highly adapted to arid soils and climate.
Cerrado: it is a phytogeo graphical domain of the Savanna type that occurs in
approximately 23% of the Brazilian territory.
Dispersion: process that makes possible the settlement of individuals of a
species in places different from that where their parentals lived.
Nectar: aqueous substance produced by plants nectaries, like special glands and
tricomas. Nectar is constituted mainly by sugars and is an important and nutritive
food source to many animals.
Pollination: it is the transference of pollen from the anther to the stigma of the
same vegetal species.
Proboscis: long and narrow mouth apparatus, highly adapted, used to withdraw
nectar from flowers.
Dehiscent: fruit that naturally opens itself and releases the seeds.
Testa: part of the fruit originated from the wall of the ovary.
Pericarpum: external integument of the seed. 3
Floral organs are thought to have evolved from leaves.
A complete flower has four whorls
1.Calyx,
2.Corolla,
3.Androecium and
4.Gynoecium
An incomplete flower lacks one or more of these whorls.
4
Stamen Anther Filament
Carpel Stigma Style Ovary Ovule
Petal
Receptacle
Sepal
all stamens = androecium
all carpels = gynoecium
all petals = corolla
all sepals = calyx
5
Figure 1: Flower Structure
In a flowering plant the flower develops on the receptacle.
The buds of the flower are protected by sepals. Sepals are
small leaves.
The petals of many flowers are brightly coloured which
attracts insects.
These petals are often highly scented. Inside the flower there
are pin-like structures called stamens.
The top of the stamen produces pollen cells, which contain the
male sex cells. The club-like structure is the stigma.
6
In the base of the stigma is the ovary.
The ovary contains ovules.
Each ovule contains a female sex cell. The carpel is made up
of the stigma, style and ovary.
When the tip of the stigma is sticky it indicates that the carpel
is ripe and ready to receive grains of pollen.
Flowers differ in external colour, size and shape. However
they all have a similar internal structure. Some have carpels
with one ovule, others have rows of ovules.
CONTI…..
7
Flower types
8
Monoecious species present male and female flowers distributed in the
same plant or individual.
Dioecious species have male and female flowers disposed in separated
plants or individuals.
Hermaphrodite species possess hermaphrodite or bisexual flowers.
Gynomonoecious species bear female and bisexual flowers in the same
individual.
Gynodioecious species present female and bisexual flowers in
separated individuals.
Andromonoecious species have male as well as bisexual flowers
distributed along the same plant or individual.
Androdioecious species possess male and bisexual flowers, but in
different individuals.
Polygamous species bear male, female and bisexual flowers in the same
individual. Throughout the vegetal world, around 80% of the species bear hermaphrodite
flowers and approximately 10% present individuals with separated genders.
The remainder shows a lot of variation and some species have non-functional
organs.
9
Figure 2: Basic types of plants found in nature according to the
sexual expression of the flowers.
Polygamous plant. Dioecious plant Monoecious plant
10
pollen grains
Figure 3: Basic flower types found in nature
Pollen sac
filament
Male flower Female flower Hermaphrodite flower
Ovary Position
12
CONTI….
13
New plants can grow in several ways:
i. From seeds (sexual reproduction)
ii. Producing things such as bulbs or tubers (asexual reproduction).
Tropical tree improvement programs basically depend on genetically
superior seed crops that can be either obtained through open pollination
or by controlled crossing.
In classical tree breeding it is achieved by establishing breeding
populations such as clonal and seedling seed orchards.
Though in open pollinated conditions it appears easy to harvest an
optimal seed crop, under field conditions, it is difficult in most
species.
It is mainly due to the reasons such as asynchronous flowering,
flowering redundancy, self incompatibility, pollinator limitation and
most often harsh climatic conditions.
Obtaining seeds through controlled crossing is also difficult
because of inherent problems such as delicate flowers, high rates of
flower and fruit abortions (Bawa and Webb 1984).
13
14
Sexual Expression
Frequency of Species
Tropical forest Temperate forest
Hermaphrodite 68% 7%
Dioecious 10% 74%
Monoecious 22% 19%
Table 1: Sexual expression in species of Tropical and Temperate Forests.
Brasil Bawa (1974).
• Pollen biology is of significance in tree improvement programmes as they decide
gene flow and heterozygosity of populations which in turn decides genetic
variability.
• Pollens are reduced male gametophytes, upon pollination they produce tubes that
grow through pistil tissues bringing in fertilization and seed set.
• Pollen production and dispersal has both biological and genetic ramifications for
the quantity and genetic quality of the seed produced.
• Pollen grains differ in shape, number and position of germination pores.
• These features are employed in identification and quantification of the pollen on
the stigmas of open pollinated species, a measure to know effectiveness of
pollination.
15
Knowledge on pollen movement helps in determination of isolation distances and
in establishment and management of seed orchards.
Quality of pollen is assessed by its viability and vigour.
Viability is the ability of pollen to deliver functional sperm cells to the embryosac
following compatible pollination.
The period over which the pollen grain retains viability after release is highly
variable as they are exposed to a wide range of environmental stresses particularly
of temperature and humidity.
The time and rate of pollen shedding are also under the control of both external
and internal factors.
In many species pollens get hydrated due to rain and causes loss of viability,
bursting and precocious germination (Linskens et al. 1991). 16
CONTI…..
• Pollen viability is one measure of male fertility, they are generally conducted
in breeding experiments and for monitoring the condition of stored pollen
(Heslop- Harrison et al. 1989).
• They are also used in identification of sterile hybrids where pollen is shrunk
and infertile.
• The method of collection and storage period affect viability (Shivanna and
Johri 1985) and therefore any work requiring maximum viability of pollen
should be conducted shortly after anther dehiscence.
• Best results in controlled pollinated fruit set about < 90% can be obtained
when fresh (1 day old) pollen is used.
17
Since most tropical produce very sticky pollen, both collection as
well storing is extremely difficult.
Till date controlled crossing using processed pollen have been
performed only in Eucalyptus and Tectona grandis with varying
success rates.
Extended period of pollen storage directly depends upon its
nucleation.
Binucleate pollen have longer stored life when compared to
trinucleate type.
Teak and Tamarind are typical binucleate pollens with one
vegetative and a generative nuclei.
Using simple air drying method or silicate dessication and cold
storage in 5° C allows Teak, Tamarind and Casuarina pollen to be
viable and fertile up to 6 months. However there is a considerable
fertility reduction when compared to fresh pollen.
18
Pollination is the process by which pollen is placed on the stigma.
This must occur before a male sex cell can fuse with a female sex
cell. There are a number of ways pollination can happen.
Self-pollination = Pollen from a flower’s anther pollinates
stigma of the same flower.
Cross-pollination = Pollen from anther of one flower pollinates
another flower’s stigma.
-Also termed outcrossing.
19
Wind pollination = wind blows pollen from anthers of one plant to the
stigmas of others. Plants that are wind pollinated are not usually brightly
coloured, for example grasses. They do, however, have long filaments with
anthers that hang down in the wind. They produce millions of pollen grains.
The pollen is very light, some grains even have small air sacs to help them
stay in the air longer.
Insect pollination = when insects like bees carry pollen on their bodies as
they move from flower to flower. The insects are attracted to the plants
because the plants produce a sugary liquid called nectar which the insects
like. The flowers of plants that are insectpollinated tend to be brightly
coloured, which makes it easy for the insects to find them. The pollen of
these types of plant have large pollen grains and is a good food supply for the
insects. Some pollen grains have spikes, which stick to the hair of insects.
CONTI…..
20
Figure 4: Successful pollination in many angiosperms depends on regular
attraction of pollinators. 21
22
Figure 5: There are pollinators, as the "carpenter" bees (genus
Xylocopa), which can fly more than 20 km. Being so, the gene flow
among distant populations is incremented due to the search for a
flower resource.
23
Melittophily (Bees) Cantharophily
(Coleoptera)
Psychophily
(Butterflies)
Phalaenophily,
Sphingophily
(Moths)
Myophily
(Flies)
Sapromyophiy
(Carrion Flies)
Ornithophily
(Birds)
Chiropterophily
(Bats)
Anthesis diurnal diurnal diurnal diurnal or
nocturnal
Diurnal diurnal diurnal nocturnal
Color vivid colors, blue,
white, yellow,
orange, red, rose
white, hues of
very light green
or yellow
Red, blue,
orange,
yellow,
pink (vivid
colors)
White or weakly
colored
Variable purple, color of
exposed fleshy
tissue
scarlet, blue
(vivid colors)
light shades from
white to cream
Scent sweetish,
refreshing
strong, fruity weak,
fresh,
pleasant
strong,
sometimes
sweetish
imperceptible decaying
animal
protein
weak, fresh,
pleasant
rancid, may
resemble
fermentation Flower
shape standard, tube,
campanula (bell-
flower), brush,
gorge,
mechanically
strong
bowl, generally
large
or in numerous
inflorescences,
with many
stamens and
pistils
tube,
standard,
gorge, brush,
sometimes
hanging
tube, gorge,
brush,
sometimes
hanging
campanula
(bell-flower),
bowl, shallow
or moderately
concave
dish or trap-
like tubular
tube, standard,
gorge, brush,
the ovary is
protected by a
solid wall
brush, campanula
(bell-flower),
bowl, with one
big single flower
or many small
flowers in
strong
inflorescences Symmetry
plan radial or
zygomorphic
generally radial generally
radial
generally
zygomorphic
generally radial generally radial radial generally radial
Nectar moderately
hidden
absent hidden in a
long,
thin tube
with
medium
quantity
hidden in a long,
thin tube with
medium
quantity
absent or
present in
small
amounts
absent in large
amounts,
moderately
exposed
in large
amounts,
moderately
exposed
Nectar
guides present absent present,
sometime
complex
usually absent present absent absent or
simple
absent
Floral characteristics of the main pollination syndromes.
INSECT (Entomophily)
Bees:
fly showy, colorful, fragrant, with:
nectar guides
landing platforms
Butterflies:
fly showy, colorful, fragrant
no nectar guides
long tubes or spurs 24
Flies (Sapromyiophily)
maroon / brown in color
foul smelling (like rotting flesh)
25
Birds (Ornithophily): red (often) tubular
26
Figure 6: Examples of ornithophily. A: Aratinga aurea (Psittacideae) eating fruits of
Oratea hexasperma (Ochnaceae); B: Aratinga ararauna Psittacideae) eating fruits
of Brazilian Palmae.
Bats (Cheiropterophily):
nocturnal anthesis
large, colorful or white
produce copious nectar or pollen
27
Figure 7: Bat pollination during the consumption of nectar.
Siphocampylus sulfureus visited by Anoura caudifer
Wind (Anemophily):
flowers small, numerous, often unisexual
perianth absent or non-showy
flowers often produced in mass
28
Figure 8: Examples of dispersion syndromes. Anemophily: A- seeds involved in silk cotton
(Eriotheca gracilipes, Bombacaceae) and B- samaras (Peixotoa tomentosa,
Malpighiaceae); Zoochory: C- fleshy fruit (Brosimum gaudichaudii, Moraceae).
29
Figure 9: Generalist flower of the Cerrado cherry (Myrtaceae), exposing large
quantities of anthers, accessible to all floral visitors. (Picture by Kleber Del Claro)
30
Figure 10: Some example of the diversity of shapes, colors and floral resources available for
the attraction of visitors and pollinators. Pollen flowers: A - Eriotheca gracilipes
(Bombacaceae): B - Senna velutina (Caesalpiniaceae); Oil flower: C -Banisteriopsis malifolia
(Malpighiaceae); Nectar flower: D - Jacaranda sp. (Bignoniaceae); compound flowers: E -
Catlleya walkeriana and F -Schomburgkia crispa (Orchidaceae).
31
Figure 11: An example of morphological features acting as a selective force upon pollinators.
The flower of Odontadenia lutea (Apocynaceae) has a gamosepal corolla in a bottle-neck-
like shape in the inferior part of the corolla (indicated under the arrow).
32
Figure 12: Distribution of flowers from six species of the Malpighiaceae family
along time in an area of Brazilian savanna. Each color represents a species of plant
offering oil and pollen to the flower visitors. The consecutive flowerings provide
the necessary resources to the maintenance of a guild of pollinators in the area in a
determined time span.
April
Open pollination refers to the mating and reproductive success
that happens in natural conditions.
Flower to fruit ratio and fruit to seed ratio are very low in most
tropical trees (Bawa and Webb, 1984).
It is an inherent problem even in common species like Teak,
(Kumar 1992) and Eucalypts (Moncur et al, 1995).
Attempts to enhance fruit and seed yield in Teak through
application of growth regulators and insecticides have proved to
be commercially non-viable.
Since Teak is a insect pollinated species introduction of apiaries
was suggested (Nagarajan et al, 1996) as pollinator limitation is
quite common in monocultures.
It has been proven to be successful in Phyllode Acacias and
Eucalypts (Moncur et al, 1995). Based on the teak plantation
targets and seed availability from breeding populations.
33
Though successful controlled crossings have been carried out in many
tropical trees (Bawa and Webb, 1984) only a few practically successful
hybrid programmes have been reported so far (Eldridge and Griffin, 1983)
due to technical difficulty.
Standardizing tree hybridization depends on a series of activities such as
recording flowering phenology, knowing peak stigma receptivity, pollen
collection and transfer.
Performance of controlled crossing on trees depends on the circadian rhythm
exhibited by the trees.
Most tropical trees either flower in the early or late night.
Trees like Albizia lebbeck need to controlled pollinated 7.00PM to 2.00 AM,
while teak can be worked between 8.00 - 11.00 am. 34
Species like Tamarind should be emasculated during late nights and can be
pollen dusted in early mornings.
Technical precision matters much in controlled pollinating tropical trees. For
example fruit set increases in Eucalypts when cotton bags are used instead of
paper bags for caging operated flowers.
In species like Teak that have high rates of flower abortion with 6-7 hours of
stigma receptivity bags can be removed on the same day of dusting shows
higher fruit set.
In species like Eucalyptus regnans the time between emasculation and
dusting could be even eighteen days (Eldridge and Griffin, 1983).
Using standardized controlled crossing techniques fruit set from 20 - 90 %
can be obtained for any given species.
CONTI…..
35
36 Figure 13: plant pollinator mutualisms
Breeding systems How is it promoted?
1) Plant sex: dioecy (incl. gynodioecy, androdioecy, trioecy)
Outbreeding = outcrossing / allogamy / xenogamy:
2) Difference in timing of floral parts = dichogamy
protandry - male first
protogyny - female first
37
Breeding systems Outbreeding = allogamy (outcrossing, xenogamy):
3) Spatial separation of anthers and stigmas = hercogamy
38
4) Self-incompatibility
Inability for fertilization to occur between gametes derived from one individual.
39
Inbreeding = selfing
autogamy (within 1 flower) & geitonogamy (between fls. of 1 indiv.)
Selective advantage: ensures propagule production
Disadvantage: reduced to absent genetic variability
allautogamy: both outcrossing & inbreeding
e.g., Viola, Clarkia: two flower types:
chasmogamous flowers - normal, open
cleistogamous flowers - remain closed
40
Gamete Production:
Plant sexual life cycles are characterized by an alternation of generations
-Diploid sporophyte haploid gametophyte
In angiosperms, the gametophyte generation is very small and is completely
enclosed within the tissues of the parent sporophyte
-Male gametophyte = Pollen grains
-Female gametophyte = Embryo sac
Gametes are produced in separate, specialized structures of the flower.
41
• Angiosperms undergo a unique process called double fertilization.
• A pollen grain that lands on a stigma forms a pollen tube that pierces the style.
• While the pollen tube is growing, the generative cell divides to form 2 sperm
cells.
• When pollen tube reaches the ovule, it enters one of the synergids and releases the
two sperm cells.
• Then double-fertilization occurs.
• One sperm cell nucleus fuses with the egg cell to form the diploid (2n) zygote.
• Other sperm cell nucleus fuses with the two polar nuclei to form the triploid (3n)
endosperm nucleus.
• Eventually develops into the endosperm that nourishes embryo.
42
Growth of pollen tube
Pollen tube
Double fertilization Release of sperm cells
Zygote (2n)
Antipodals
Polar nuclei
Egg cell
Synergids
Endosperm nucleus (3n)
43
Figure 14: Structure of double fertilisation
44
45
Terminalia arjuna
Floral characters Observations
Flowering period April-july
Inflorescence Spike
No. of flowers/ Inflorescence 45 ± 3.5
Flower Hermaphrodile, actinomorphic,
epigynous
No. of stamens 10
Perianth Gamotepalous with five tepals
Time of flower opening 05:00-06:30 h
Time of anther dehiscence 06:00-07:30 h
Mode of anther dehiscence Longitudinal slit
Pollen grains/anther 2120 ± 265
Pollen grains/flower 21200 ± 530
Pistil type Monocarpellary, unilocular
Time of stigma receptivity 08:00-14:00 h
No. of ovules/ovary 2
Ovule type Anatropous
Table: 2 Floral characters of Terminalia arjuna
46 B.R. Ambedkar University Agra Seema Chauhan et al. (2008)
Pollination
mechanism
No. of
flowers
pollinated
No. of
flowers set
fruit
Fruit-set (%) No. of fruits
dropped off
prematurely
Fruit drop (%)
1. Autogamy
(i) Unmanipulated 50 0 0 0 0
(ii) Manipulated 50 21 42 15 71
2. Geitonogamy 50 40 82 18 45
3. Xenogamy 50 48 96 0 0
Table: 3 Results of breeding systems in T. arjuna
47
B.R. Ambedkar University Agra Seema Chauhan et al. (2008)
Visitor
species
No. flowers visits/min. Length of a visit/sec. Pollen grains observed on
different body parts
N R ∑ SD N R ∑ SD N R ∑ SD
Apis indica 10 12-18 15.0 4.5 10 1 - 4 2.5 1.2 10 740-
1750
1256 795
Apis florea 10 9-15 12.0 4.0 10 2-5 3.5 1.5 10 525-
1395
972 386
Pieris
brassicae
10 7-11 9.0 3.0 10 4-13 8.5 2.0 10 436-
844
643 280
Danaus
plexippus
10 6-10 8.0 2.5 10 5-14 9.5 2.2 10 405-
795
608 225
Vespa
species
10 4-8 6.0 1.5 10 8-14 11.0 3.0 10 338-
610
480 175
Musca
domestica
10 4-7 5.4 1.0 10 6-18 12.0 3.5 10 270-
325
299 128
Camponotus
species 10 2-6 4.0 0.7 10 10-
16
13.0 4.0 10 190-
295
245 107
Table: 4 Foraging efficiency and pollen pick-up by insect species on T. arjuna.
48
N – No. of insects observed, R- Range, Ʃ Mean, SD- Standard deviation
B.R. Ambedkar University Agra Seema Chauhan et al. (2008)
49
Casuarina equisetifolia
50
Table: 5 Variation in total Cone and seed production in single tree of C.equisetifolia population Seed source Cones Seeds
Natural provenances
Viti Levu, Fiji 1556.0 42,214
Cotonou, Benin 1239.0 40,150
Sarawak, Malaysia 1129.0 22,012
Ranong, Thailand 1070.0 28,135
Danger Piont, Australia 576.0 15,455
Kolombangara, Solomon
Islands
451.7 12,960
Mariana Island, Guam 403.3 15,600
Wangetti Beach, Australia 196.0 5,944
Landraces
Rameswaram, India 5817.3 2,02,132
Beihai, China 3446.6 1,59,320
Orissa, India 2819.0 1,04,788
Malindi, Kenya 633.7 23,029
Montazah, Egypt 214.0 7,785
Mean 1341.0 57,275
SE 561.0
CV % 72.4 Pondicherry Nagaranjan et al.(2001)
51
Table: 6 Cone size and seed production in C. equisetifolia Seed
source
Cone size (cm) Seeds per Cone 1000 seed weight
(gm) Width Length
J O Mean J O Mean J O Mean J O Mean
Cotonou 1.48 1.49 1.48 1.78 1.64 1.70 25.47 25.84 25.65 1.43 1.27 1.35
Danger Point 1.45 1.45 1.45 1.68 1.32 1.50 29.41 29.29 29.35 2.12 2.27 2.19
Wangetti
Beach
1.10 1.18 1.14 0.90 0.94 0.92 25.20 26.33 25.77 1.12 1.32 1.22
Ranong 1.03 1.08 1.05 1.22 1.28 1.25 26.35 30.67 28.51 1.07 1.12 1.10
Sarawak 1.43 1.40 1.41 1.45 1.43 1.44 25.57 27.91 26.74 1.07 1.20 1.13
Solomon
Island
1.14 1.13 1.14 1.04 1.04 1.04 29.36 31.75 30.55 1.05 1.13 1.09
Viti Levu,
Fiji
1.14 1.18 1.16 1.22 1.40 1.31 26.53 29.63 28.08 1.01 1.14 1.08
Guam 1.21 1.16 1.19 1.44 1.39 1.41 33.04 36.91 34.98 1.45 1.10 1.27
Beihai,
China
1.38 1.39 1.39 1.65 1.67 1.66 46.38 46.08 46.23 1.06 1.33 1.19
Malindi,
Kenya
1.25 1.22 1.24 1.35 1.36 1.36 39.49 36.56 38.02 1.08 1.19 1.14
Egypt 1.07 1.06 1.07 1.21 1.24 1.22 31.68 31.99 31.83 0.78 0.82 0.80
Orissa, India 1.28 1.27 1.28 1.50 1.45 1.47 37.17 41.30 39.24 0.50 1.14 0.82
Rameswaram
, India
1.498 1.49 1.49 2.05 2.01 2.03 45.40 48.29 46.85 1.36 1.57 1.47
Mean 1.27 1.27 1.27 1.42 1.40 1.41 32.39 34.04 33.22 1.163 1.276 1.219
SEd LSD CV % SEd LSD CV % SEd LSD CV % SEd LSD CV %
Provenance 0.735 1.51 19.0 1.13 2.26 13.8 3.641 7.28 19 0.146 0.29 20.8
Season 0.295 0.59 0.44 0.89 1.428 2.86 0.057 0.11
Pondicherry Nagaranjan et al.(2001)
52
Table: 7 Seed set and reproductive success in C. equisetifolia under open and
controlled pollination
Clone Pollination Seeds per
Cone
Seed felling (%) Germination
(%)
PERS
TNIPT 7
open 48.4 90.2 61.5 0.805
cross 46.6 86.6 38.50 0.772
self 34.3 63.49 37.25 0.575
PY 119 open 42.8 93.0 90.17 0.855
cross 34.3 74.56 47.5 0.685
PY 42 open 67.4 90.59 67.5 0.846
cross 41.1 55.24 49.0 0.513
PY 75 open 34.8 93.29 83.5 0.868
cross 33.0 88.47 68.6 0.823
TNRM 2 open 44.7 87.13 78.2 0.744
cross 34.3 66.86 54.3 0.571
Pondicherry Nagaranjan et al.(2001) PERS = Pre-emergent reproductive success
53
54
Table :8 Reproductive attributes of Dalbergia sissoo Roxb.
S. No. Component Average Range
1. Number of inflorescences per tree 14450 3,200- 20,000
2. Number of flower in an inflorescence 45 20- 75
3. Number of pollen grains per flower 3550 2,500- 4,000
4. Number of ovules per flower 5.0 3-8
5. Number of flowers in a tree 6,50,000 1,44,000- 9,00,000
6. Number of fruits/pods in an
inflorescence
6.72 2- 26
7. Number of fruits /pods per tree 97,500 21,000- 1,35,000
8. Number of seeds per pod 1.30 1- 4
9. Number of seeds per tree 1,26,750 27,300- 1,75,500
Punjab University Chandigarh Vasudeva and Sareen (2011)
55
Table: 9 Fruit and Seed formation as a result of Experimental pollinations and that
formed in nature in D. sissoo Roxb.
S. No. Type of
Pollination
No. of
flowers
Pollinated
No. of pods
formed
Percentage
pod
formation
No. of seeds
formed per
pod
1. Self-pollination 50 3 6 0.5
2. Crossing 50 22 44 2.4
3. Mixture crossing 50 24 48 2.6
4. In Nature 400 60 15 1.3
Punjab University Chandigarh Vasudeva and Sareen (2011)
56
S. No. Branches
Average
number of
flowers
Average
number of
pods formed
Average
number of
seeds formed
1. Upper 49.2 (30- 75) 7.4 (5- 9) 1.50 (1- 4)
2. Middle 45.4 (25- 72) 6.8 (5- 12) 1.30 (1- 4)
3. Lower 40.4 (20- 60) 6.0 (2- 12) 1.20 (1- 4)
Average 45 6.72 1.30
Table :10 Production of flowers, pods and seeds in different canopies of middle
aged tree of D. sissoo Roxb.
Punjab University Chandigarh Vasudeva and Sareen (2011)
57
58
S. No. Time (hrs) Pollen viability (%)
1. 06.00 12.50
2. 07.00 25.00
3. 08.00 37.50
4. 09.00 56.25
5. 10.00 75.00
6. 11.00 75.00
7. 12.00 68.75
8. 13.00 62.50
9. 14.00 60.20
10. 15.00 56.25
11. 16.00 54.82
12. 17.00 50.00
13. 18.00 48.50
lsd (P<0.05) 10.00494
Table: 11 Pollen viability in different day time in Acacia nilotica (L.) Wild.
Tamil Nadu Ganesan and Chandra (2009).
59
Sucrose
concentrations (%)
% of pollen
germination
Pollen tube length
(micrometer)
1 6.25 5
2 12.50 8
4 25.00 15
8 56.25 40
10 31.25 30
20 25.00 18
40 12.50 6
Table: 12 Optimum sucrose concentration for pollen in Acacia nilotica (L.) Wild.
Tamil Nadu Ganesan and Chandra (2009).
60
61
Table: 13 Details of floral foragers, duration of flower handling, peak time of
foraging and pollen load on their bodies
Pollinator/
forager species
Family Peak time of
visitation (120 h)
Flower handling
time (s)
(n = 20)
Pollen load
(n = 50)
Thysanoptera
Thrips hawaiensis Thripidae — 2 ± 1
Hymenoptera
Apis dorsata
Apidae
07. 30-08.30 hours 4.5 ± 1.8 254 ± 49
Apis indica 08.30-09.30 hours 4 ± 1.8 191 ± 32
Apis florea 07.30-08.30 hours 4.2 ± 2.1 179 ± 20
Apis cerana 07.30-08.30 hours 3.6 ± 1.6 196 ± 29
Apis mellifera 07.30-08.30 hours 2 ± 1.4 182 ± 49
Trigona sp 08.30-09.30 hours 5.8 ± 1.7 89 ± 23
Ceratina sp 08.30-09.30 hours 5.9 ± 1.6 76 ± 14
Lepidoptera
Danaus chrysippus Danaidae 10.30-11.30 hours 4.5 ± 1.6 30 ± 17
Junonia almana Nymphalidae 10.30-11.30 hours 4 ± 1.7 12 ± 5
Pieris sp Pieridae 11.30-12.30 hours 4 ± 1.6 49 ± 22
Diptera
Syrphid fly Syrphidae 09.30-10.30 hours 4.2 ± 0.6 80 ± 12
Unidentified insect — 09.30-10.30 hours 2 ± 0.4 32 ± 16
Delhi Vikas and Tandon (2011).
62
Table: 14 Fruit set as a result of open and xenogamous pollination in the three
populations.
Population
Fruit set (%)
Open pollination Xenogamous Poliination
NDU 4.8 12.1
NBW 3.7 14.4
NSO 4.1 11.8
Delhi Vikas and Tandon (2011).
63
Jatropha curcas
64
Table: 15 Time and occurrence of different phenological stages of Jatropha curcas
Phenological stage First flowering span Second flowering span
Flowering span April third week till
June forth
July second week till November second
week
Fruit initiation May third week July fourth week
Opening of male
flower
7.8 ± 0.31 days after
bud formation
7.78 ± 0.69 days after bud formation
Opening of female
flower
9.7 ± 0.75 days after
bud formation
10.9 ± 0.34 days after bud formation
Fruit formation 26.5 ± 1.22 days after
bud formation,
7- 9 days after anthesis
30.20 ± 2.00 days after bud formation,
7- 9 days after anthesis
Fruit set (%) 37.0* 61.6*
No. of
fruits/inflorescence
5.2* ± 1.15, range 2- 14 10.6* ± 0.96, range 6- 16
No. of seeds per fruit 1.97* ± 0.16 2.7* ± 0.19
Unit seed weight (g) 0.22* ± 0.01 0.51* ± 0.05
Kernel wight (g) 0.10* ± 0.02 0.29* ± 0.01
Oil content (%) 25.4* 31.1*
*Significant t value (p< 0.05) between two flowering seasons
PAU, Punjab Kaur et al. (2011)
65
Parameter Range Mean
Male flower
Length (cm) 1.10 – 1.40 1.20 ± 0.01
Breadth (cm) 0.60 – 0.90 0.76 ± 0.01
Female flower
Length (cm) 1.10 – 1.90 1.60 ± 0.06
Breadth (cm) 0.71 – 1.1 1.01 ± 0.02
Male flower/inflorescence 86.5 – 151.4 117.4 ± 7.98
Female
flower/inflorescence
6 – 16.6 13.5 ± 1.5
Male/female flower ratio 10.4 : 1 – 16.4 : 1 13.4 : 1
Pollens/anther 61.9 – 195.1 122.3 ± 11.5
Pollen size (µm) 80.2 – 89.5 85.5
Pollen viability (%) 58.2 – 79.4 71.6 ± 10.4
Table: 16 Morphology of flowers and pollens of J. Curcas
PAU,Punjab Kaur et al. (2011)
66
Table: 17 Fruit set in different breeding systems in controlled pollinations of
Jatropha curcas
Breeding
system
Fruit set (%) Number of seeds/fruit
Cross
pollination
93.2 2.4
Self
pollination
72.2 1.3
Apomixes 36.3 1.6
Open
pollination
79.2 2.6
CD 5 % 11.4 0.5
PAU Punjab Kaur et al. (2011)
67
Pterocarpus santalinus (Fabaceae)
Figure 17: Pollinator bees of P. santalinus. a, Apis dorsata; b, A. cerana and
c, A. florea.
68
Table: 18 Foraging efficiency and pollen pick-up by honeybees on P. Santalinus
Visitor
species
No. of flowers visited Length of a visit Pollen grains found in
body washings
N R Ʃ SD N R Ʃ SD N R Ʃ SD
Apis
dorsata
10 12-18 15 2.56 10 1-6 3 1.4 10 850–
1860
1346 365
A.
cerana
10 4-14 8 3.17 10 2-13 6 3.0 10 472–
1420
914 553
A. florea 10 6-12 9 1.92 10 4-15 7 3.9 10 340–
985
726 240
Tamilnadu Thangaraja and Ganesan (2008).
N= Normal, R=Range, Ʃ = Mean.
69
Figure 18: Day-to-day flower production of P. santalinus. Arrows
indicate total absence or very less flowering.
70
Table :19 Results of breeding systems in P. Santalinus
Pollination
mechanism
No. of
flowers
Pollinated
No. of
flowers
set fruit
Fruit
set
(%)
No. of
seeds
produced
Seed
set
(%)
No. of fruits
dropped-off
prematurely
Fruit
drop
(%)
Autogamy
Unmanipulated
Manipulated
50 0 0 0 0 0 0
50 12 24 12 50 10 83
Geitonogamy 50 34 68 34 50 20 59
Xenogamy 50 42 84 48 57 0 0
Tamilnadu Thangaraja and Ganesan, (2008).
71
72
Table: 20 Deposition of pollen grains on the stigma of T. paniculata
S.
No The day on
which / after
flower opening
observation
Range of
pollen
depositio
n
No. of pollen
grains
deposited on
stigma
Pollination
efficiency Pollination
success (in
%)
1 The day on
which flower
opened
0 - 3 1.24 + 0.2182 0.000076 8
2 First day after
flower opening
3 - 10 6.40 + 0.5363 0.00039 54
3 Second day
after flower
opening
6 - 26 13.48 +
1.2920
0.00083 72
4 Third day after
flower opening
0 -1 0.98 + 0.26 0 0.2
Andhra University Rao and Solomon Raju (2002)
73
Table: 21 Effect of different sucrose concentration along with BKM on
the pollen germination and length of pollen tube in T. paniculata.
S. No Sucrose with
BKM (in %) Percentage
of pollen
germination
Pollen tube length
(mm)
1 Distilled Water 0 0
2 05 15.00 23.50 + 1.26
3 10 20.00 31.20 + 0.81
4 15 34.00 32.20 + 1.34
5 20 46.70 42.10 + 1.34
6 25 65.30 44.10 + 1.86
7 30 90.10 62.40 + 1.57
8 35 76.50 52.50 + 2.25
9 40 40.80 34.80 + 1.90
Andhra University Rao and Solomon Raju (2002)
74
Gmelina arborea Roxb. Gmelina arborea is a dry season bloomer.
It produces large, brownish-yellow, bisexual and zygomorphic nectariferous
flowers.
The breeding system involves both self- and cross-pollination, but most of the
self-pollinated flowers abort after two weeks of growth.
The floral characteristics suggest bee-floral syndrome, but bees, especially
Xylocopa bees and passerine birds, pollinated the flowers.
Figure 1. Gmelina arborea – A. Inflorescence; B. Mature bud; C. Open flower; D. Positions
of sex organs.
A B C D
75
A B C
D E F
Figure 15. Gmelina arborea – A. Flower visitors: Xylocopa latipes; B. Redwhiskered
Bulbul; C. Thickbilled flowerpecker;D. Initial fruit; E. Young fruit; and F. Ripe fruit.
76
Table 22. Results of breeding systems in Gmelina arborea
Pollination
mechanism
No. of
flowers
pollinated
No. of
flowers set
fruit
Fruit set
(%)
No. of fruits
dropped-off
prematurely
Fruit drop
(%)
Autogamy
Unmanipulated
Manipulated
50 2 4 0 100
50 24 48 20 83.3
Geitonogamy 50 38 76 24 63.2
Xenogamy 50 46 92 0 0
NOTE- Hand-pollination results indicated that G. Arborea fruits through self- and cross-
pollination. Even simply bagged mature buds without any manipulation for pollination
produced fruit but fruit set rate is low.
Andhra University Solomon Raju and Rao (2006)
77
Figure 16. Natural fruit set rate in G. arborea.
NOTE- However, most of the fruits that resulted from self-pollination were aborted
after two weeks of growth. The natural fruit set rate at initial and young stage (after
two weeks) is 14.5% and at fruit maturity 8.5%.
Tectona grandis
78
seeds
Table 23. Reproductive success rate in Teak.
79
Field of investigation Finding Reference
Pollen fertility 99% fertility Nagarajan et al. (1996 b)
Breeding system Weakly
protandrous
Rawat et al. (1992)
Mating system analysis 98% out crossing Kertadikera and Prat (1995).
Natural selfing rate 1.67% Nagarajan et al. (unpublished data)
Controlled selfing rate 2.49% Tangmitcharoen and Owens (1996)
Controlled crossing success
rate
14.0% Tangmitcharoen and Owens (1996)
Index of self incompatibility 0.17% Tangmitcharoen and Owens (1997)
Pre-emergent reproductive
success (PERS)
0.5% Palupi and Owens (1996)
in open pollination
PERS in open pollination 0.04% Nagarajan et al. (unpublished data)
TNAU,Coimbatore Nagarajan et al. (2001)
80
Insect visitors Order Family Species Relative*amount of
teak pollen /insect
Estimated number of
insects observed
Time of visitation
Hymenoptera
Anthophoridae Ceratina sp. 4 3 0800h—1700h
Vespidae Polistes sp. 2 2 1000h—1400h
Polistes sagitarrius Sauss. 2 2 1000h—1200h
Polistes stigma Fabr. 2 2 1000h—1200h
Vespa affinis (L.) 2 2 0800h—1000h
Vespa velutina Lepeltier 2 2 1200h—1400h
Formicidae — 0 1 1000h—1600h
Apidae Apis mellifera 3 2 0800h—1200h
Eumennidae Eumenes conica Fabricius. 2 2 1400h—1600h
Eumennes esuriens Fabricius. 2 2 1400h—1600h
Eumenes orchitectus Smith. 2 2 1400h—1600h
Eumenes petiolata Fabricius. 2 2 1400h—1600h
Eumenes sp. 2 2 1200h—1600h
Diptera
Calliphoridae Stomorhina lunata (Fab.) 4 0800h—1700h
Lucilia sp. 3 1000h—1600h
Tachinidae Dolichocolon sp. 3 1000h—1600h
Sarcophagidae Sarcophaga sp. 3 1000h—1600h
Syrphidae Eristalinus arvorum (Fab.) 2 1000h—1600h
Otitidae Chrysomyza sp. 2 1000h—1600h
Lepidoptera
Hesperidae Iambrix salsala salsala Moore. 0 1 1400h—1600h
Oriens sp. 0 1 1400h—1600h
Pelopides sp. 0 1 1400h—1600h
Lycaenidae Euchrysops paudava Horsf. 0 1 1400h—1600h
Nacaduba sp. 0 1 1400h—1600h
Nymphalidae Naptis columella martabana Moore. 0 1 1000h—1600h
Precis almana almana (L.). 0 1 1400h—1600h
Papilionidae Precis lemonias L. 0 2 1000h—1200h
Atrophaneura aristolochiae aristolochiae Fabr. 0 1 0800h—1600h
Pieridae Catopsilia pomona pomona-f hilaria stoll. 0 1 1400h—1600h
Catopsilia pomona pomona-f pomona Fabr. 0 1 1200h—1400h
Satyridae Delias hyparate ciris Fruhst. 1 1 0800h—1000h
Eurema sp. 1 2 0800h—1200h
Table :24 Insect visitors to Tectona grandis flowers collected at ASEAN Forest Tree
Seed Centre, Saraburi, Thailand during 4 observation in July
TNAU,Coimbatore Nagarajan et al. (2001)
81
Fig. 17. Teak (Tectona grandis) the corolla abscised. Bar 5 mm.,six stamens and petals and
straight style at receptivity (A); and (B) 1 d after receptivity after artially open anther at
13:00h, showing swelling of the epidermal cells which appear to contain secretory substances.
Bar 0±4 mm. Fig. 3. Transverse section of anther as in Fig. 2 showing two microsporangia,
each bearing two chambers. Bar 0±3 mm.
EP: epidermal cell M: microsporangia;
Scanning electron micrographs (SEM))
Corrola Microsporangia Anther
82
Fig. 4. Inside of dehisced anther showing pollen and the secretion (*). Bar¯0±04 mm. Fig. 5.
SEM of stigma papillae during receptivity with germinated pollen showingvarying degrees of
hydration. Pollen tubes appear to have entered between the loose papillae. Bar 50 lm.
. P: pollen, PT: pollen tubes
83
Fig. 6. Floral nectaries at the base of the ovary. Bar 0±4 mm. Fig. 8. Nectariferous tissue
during post-receptive period. Starch has been hydrolyzed leaving large vacuolate cells.
Bars 0±03 mm. NE: nectary, SY: style , TT: hollow transmitting tissue ; OV: ovule.
Fig. 7. Nectariferous tissue during the pre-receptive
period characterized by darkly staining cells
containing large amounts of starch (arrowhead).
Bar0±03 mm.
84
SEM micrographs during receptivity when style is relatively straight.
Fig. 9. Forked stigma but lobes remain together. Bar 0±3 mm. Fig. 10. Splayed
stigma. Bar 0±3 mm. ST: stigma, SY: style.
85
From the forgoing presentation, it can be concluded that breeding
characters viz., flowering period, inflorescence, time of flower
opening, time of anther dehiscence, time of stigma receptivity,
pollinating agent ,time of visitor of pollinating agent and fruit set
(%) in tropical species are required to be studied as they are vital for
any improvement and eco-environmental planning purposes. It also
throws light on how species adopts itself along with the phenomenon
of speciation and reproductive isolation. From these characters we
can introduce new variety which is essential for further evaluation
and also the identification of the interactions between biological
factors, such as animal, plant species, and non-biological factors,
like temperature, RH, rain and wind, helps us to elaborate
management and conservation plans for the ecosystems of the
planet, which have become more and more necessary due to highly
increased rate of deterioration of different ecosystems during the last
few decades.
