Table 1 Mean values (N = 56) of leaf water potential, leaf gas exchange, chlorophyll fluorescence parameters and chlorophyll content determined at anthesis (A) and grain filling (soft dough-SD and hard dough-HD grain), of 14 genotypes growing in a glasshouse under well-watered (WW) and water-limited (WL) conditions (Experiment 1). G – genotype; W – water regime; P – phenology.

From: Genotypic variations in leaf and whole-plant water use efficiencies are closely related in bread wheat genotypes under well-watered and water-limited conditions during grain filling

Traita

WW

WL

ANOVA

A

SD

HD

A

SD

HD

G

W

P

Interactions

Ψ (Mpa)

−0.55

−0.58

−1.01

−0.73

−0.93

−1.82

n.s.

***

***

WxP

An (μmol CO2 m−2 s−1)

21.1

14.7

7.6

17.2

12.0

4.9

n.s.

***

***

n.s.

gs (mmol H20 m−2 s−1)

527.7

430.5

327.3

327.2

245.3

146.9

n.s.

***

***

n.s.

E (mmol H20 m−2 s−1)

6.4

5.7

4.0

4.5

3.8

2.0

*

***

***

n.s.

Ci (mmol CO2 mol−1)

271.7

287.4

320.5

252.2

267.1

311.3

***

***

***

GxW, WxP

An/E (μmol CO2 mmol H20−1)

3.4

2.7

1.9

3.9

3.3

2.3

***

***

***

GxW, GxP

An/gs (μmol CO2 mol H20−1)

43.0

38.9

24.2

58.0

53.8

33.9

***

***

***

GxW

F0 (mv)

1.55

1.72

1.74

1.54

1.69

1.64

***

***

***

GxP, WxP

Fm (mv)

6.89

6.90

6.47

6.90

6.90

6.36

***

n.s

***

GxP

Fv/Fm

0.80

0.76

0.72

0.80

0.76

0.75

***

n.s.

***

GxP

∼F0’ (mv)

1.39

1.46

1.30

1.37

1.45

1.23

***

**

***

GxP

Fm’ (mv)

3.35

3.58

2.64

3.33

3.60

2.54

***

n.s.

***

GxP

Alpha (e−/ photons)

0.37

0.37

0.41

0.36

0.38

0.40

n.s.

n.s.

***

n.s.

IK (μmol photons m−2 s−1)

286.7

195.9

137.8

296.5

208.8

150.4

n.s.

n.s.

***

n.s.

ETRmax (μmol e− m−2 s−1)

99.6

74.8

55.9

102.7

75.8

59.6

n.s.

n.s.

***

n.s.

Y(II)

0.16

0.13

0.10

0.16

0.13

0.09

*

n.s.

***

n.s.

Y(NPQ)

0.43

0.42

0.55

0.44

0.42

0.54

***

n.s.

***

n.s.

Y(NO)

0.41

0.46

0.38

0.41

0.46

0.37

n.s.

n.s.

***

GxP

Chl (Dualex units)

46.69

42.48

12.86

46.81

44.12

13.12

***

n.s

***

GxW, GxP

  1. aΨ: leaf water potential; An: leaf net CO2 assimilation; gs: stomatal conductance; E: transpiration rate; Ci: internal CO2 concentration; An/E: instantaneous water use efficiency; An/gs: intrinsic water use efficiency; F0 and Fm: minimum and maximum fluorescence in the dark-adapted state, respectively; Fv/Fm: maximum photochemical quantum yield of PSII; ∼F0’ and Fm’: respectively the calculated minimum and maximum chlorophyll fluorescence yield in PSII reaction centres in the open state; Alpha: initial slope of the light curve, related to maximum yield of photosynthesis; IK: PAR value of the point of intersection between the horizontal line ETRmax and the extrapolated initial slope; ETRmax: maximum rate of electron transport; Y(II) = (Fm’-F)/Fm’): effective photochemical quantum yield of photosystem II; Y(NPQ): quantum yield of non-photochemical energy conversion in PS II due to down-regulation of the light-harvesting function; Y(NO): quantum yield of non-photochemical energy conversion in PS II other than that caused by down-regulation of the light-harvesting function; Chl: chlorophyll content. Significance levels: *(P < 0.05), **(P < 0.01), ***(P < 0.001), n.s. (differences not significant; P > 0.05).
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