A Cryptic, Invasive, A Cryptic, Invasive, Haplotype of the Common Haplotype of the Common Reed Reed Phragmites australisPhragmites australis

Ed VasquezEd VasquezDr. Ed GlennDr. Ed Glenn

Dr. Stephen NelsonDr. Stephen Nelson

Phragmites australis Phragmites australis (common reed)(common reed)

• A tall (to over 4m), A tall (to over 4m), emergent wetland emergent wetland grass grass

• Invasive haplotype Invasive haplotype introduced to North introduced to North America from EurasiaAmerica from Eurasia

• Invasive to NE coastal Invasive to NE coastal salt-marshes within the salt-marshes within the past 30 years past 30 years

• Alters their ecological Alters their ecological functionsfunctions

Comparison of M-Haplotype Comparison of M-Haplotype (invasive) and F-Haplotype (invasive) and F-Haplotype (native)(native)

Research ObjectiveResearch Objective

Compare the salinity tolerance Compare the salinity tolerance and growth characteristics of the and growth characteristics of the introduced haplotype of introduced haplotype of P. P. australisaustralis with those of two native with those of two native haplotypeshaplotypes

Hypothesis: The physiological Hypothesis: The physiological characteristics of the introduced characteristics of the introduced haplotype differs from those of haplotype differs from those of

the native haplotypesthe native haplotypes

Materials and MethodsMaterials and Methods

Source of Germplasm and Initial Source of Germplasm and Initial Growout of PlantsGrowout of Plants

Rhizome sections of Rhizome sections of P. P. australisaustralis were collected were collected from reed populations from reed populations in Delaware and in Delaware and MarylandMaryland

Samples included two Samples included two native haplotypes (F native haplotypes (F and AC) and of the and AC) and of the introduced invasive introduced invasive haplotype (M)haplotype (M)

Rhizomes were Rhizomes were immediately shipped to immediately shipped to the U. of A. the U. of A. Environmental Environmental Research Lab (ERL)Research Lab (ERL)

Salinity ExperimentSalinity Experiment

Forty rhizome Forty rhizome sections (˜5g) of sections (˜5g) of haplotypes F, AC, haplotypes F, AC, and M were and M were plantedplanted

Irrigated for 12 Irrigated for 12 days under fresh days under fresh water water

Salinity StudySalinity Study

Propagated Propagated rhizomes were rhizomes were placed into 5 placed into 5 randomized blocksrandomized blocks

Plants were Plants were randomly assigned randomly assigned to irrigation to irrigation treatment : 0M, treatment : 0M, 0.9M, 0.18M, 0.9M, 0.18M, 0.27M, or 0.36M 0.27M, or 0.36M NaClNaCl

RESULTSRESULTS

Figure 1. Typical shoot growth produced from rhizomes of M, F, and AC haplotypes of

Phragmites australis

Table 1. Survival (%) of Phragmites australis haplotypes on different salinity treatments, calculated based on survival

after 56 days (initial n = 5)

Salinity (M NaCl) M F AC

0 80 80 80

0.09 100 20 30

0.18 100 0 20

0.27 100 0 30

0.36 100 0 0

Figure 2. Salinity (M) in the treatment pots compared to salinity of the irrigation water. Data were calculated for drainage water collected from pots following an

irrigation near the end of the experiment when plant water use was highest.

Pot Salinity vs. Irrigation Salinity

Solution Salinity (M)

0.0 0.1 0.2 0.3 0.4 0.5

Pot

Sal

inity

(M

)

0.0

0.1

0.2

0.3

0.4

0.5

Figure 3. Growth of shoots of P. australis haplotype at different salinities, showing plant height (a), number of shoots per pot (b), relative growth rate

(RGR) (c), and dry weight of rhizomes (d) over the experiment. F, M, and AC haplotypes are shown by solid circles, open circles, and triangles, respectively.

Error bars are SEMHeight vs. Salinity

Salinity (M NaCl)

0.0 0.1 0.2 0.3 0.4

Sh

oo

t H

eig

ht

(cm

)

0

20

40

60

80

100

No. Shoots vs. Salinity

Salinity (M NaCl)

0.0 0.1 0.2 0.3 0.4

No

. S

ho

ots

0

2

4

6

8

10

12

14

16

18

20

RGR vs. Salinity

Salinity (M NaCl)

0.0 0.1 0.2 0.3 0.4

RG

R (

% d

-1)

2

3

4

5

6

7

8

9

10

Rhizome Wt. vs. Salinity

Salinity (M)

0.0 0.1 0.2 0.3 0.4

Rh

izo

me

Dry

Wt.

(g

)

0

2

4

6

8

10

12

a b

c d

Figure 4. (a) Molar concentration of Na + K in the shoot tissues vs NaCl in the soil solution for haplotypes of Phragmites australis, and (b) water content grown at different salinities. F, M, and AC haplotypes are shown by solid circles, open

circles, and triangles, respectively. Error bar are SEM

Pot Salinity (M)

0.0 0.1 0.2 0.3 0.4 0.5

Tis

su

e N

a +

K (

M)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

y = 0.74 x + 0.28r2 = 0.86

Pot Salinity (M)

0.0 0.1 0.2 0.3 0.4 0.5

g H

2O p

er

g d

ry w

t.

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

a

b

CONCLUSIONCONCLUSION

M haplotype exhibited the characteristics of a M haplotype exhibited the characteristics of a halophytehalophyte

M haplotype exhibits a greater rate of shoot M haplotype exhibits a greater rate of shoot initiation and, subsequently, biomass accumulationinitiation and, subsequently, biomass accumulation

M haplotype appears to be adapted to a weedy M haplotype appears to be adapted to a weedy growth strategygrowth strategy

The M haplotype of The M haplotype of P. australis P. australis differs in differs in ecophysiology from the native haplotypesecophysiology from the native haplotypes

The genetic and enzymatic mechanisms underlying The genetic and enzymatic mechanisms underlying these differences remain to be explored these differences remain to be explored

AcknowledgementsAcknowledgements

AdvisorsAdvisors

Ed GlennEd Glenn

Stephen NelsonStephen Nelson

SponsorsSponsors

Jed BrownJed Brown

Glenn Guntenspergen Glenn Guntenspergen