Effects of water-deficit stress on photosynthesis, its components and component limitations, and on water use efficiency in wheat (Triticum aestivum L.)
Martin, B.
Effects of water-deficit stress on photosynthesis, its components and component limitations, and on water use efficiency in wheat (Triticum aestivum L.) - 1992 - Printed
references US (DNAL 450 P692)
It is of theoretical as well as practical interest to identify the components of the photosynthetic machinery that govern variability in photosynthesis rate (A) and water-use efficiency (WUE), and to define the extent by which the component processes limit A and WUE during developing water-deficit stress. For that purpose, leaf exchange of CO2 and H2O was determined in two growth-chamber-grown wheat cultivars (Triticum aestivum L. cv TAM W-101 and cv Sturdy), and the capacity of A was determined and broken down into carboxylation efficiency (c.e.), light- and CO2-saturated A, and stomatal conductance (gs) components. The limitations on A measured at ambient CO2 concentration (A350) were estimated. No cultivar difference was observed when A350 was plotted versus leaf water potential. Light- and CO2-saturated A, c.e., and gs decreased with decreasing leaf water potential but of the corresponding photosynthesis limitations only those caused by insufficient c.e. and gs increased. Thus, reduced stomatal a perture and Calvin cycle activity, but not electron transport/photophosphorylation, appeared to be major reasons for drought stress-induced inhibition of A350-WUE measured as A350/gs first increased with stomatal closure down to a gs of about 0.25 mol H2O m-2 s-1 (water potential = -1.6 MPa). However, it was predicted that A350/gs would decrease with more severe stress due to inhibition of c.e
English
0032-0889
Biochemical pathways
Biochemical reactions
Biosynthesis
Chemical reactions
Energy metabolism
Epidermis
Gramineae
Metabolism
Miscellaneous plant disorders
Oxides
Physiological functions
Plant anatomy
Plant physiology
Plant physiology and biochemistry
Plant tissues
Plant vegetative organs
Resource management
Stress
Water
Water balance
Triticum
94-107860
Effects of water-deficit stress on photosynthesis, its components and component limitations, and on water use efficiency in wheat (Triticum aestivum L.) - 1992 - Printed
references US (DNAL 450 P692)
It is of theoretical as well as practical interest to identify the components of the photosynthetic machinery that govern variability in photosynthesis rate (A) and water-use efficiency (WUE), and to define the extent by which the component processes limit A and WUE during developing water-deficit stress. For that purpose, leaf exchange of CO2 and H2O was determined in two growth-chamber-grown wheat cultivars (Triticum aestivum L. cv TAM W-101 and cv Sturdy), and the capacity of A was determined and broken down into carboxylation efficiency (c.e.), light- and CO2-saturated A, and stomatal conductance (gs) components. The limitations on A measured at ambient CO2 concentration (A350) were estimated. No cultivar difference was observed when A350 was plotted versus leaf water potential. Light- and CO2-saturated A, c.e., and gs decreased with decreasing leaf water potential but of the corresponding photosynthesis limitations only those caused by insufficient c.e. and gs increased. Thus, reduced stomatal a perture and Calvin cycle activity, but not electron transport/photophosphorylation, appeared to be major reasons for drought stress-induced inhibition of A350-WUE measured as A350/gs first increased with stomatal closure down to a gs of about 0.25 mol H2O m-2 s-1 (water potential = -1.6 MPa). However, it was predicted that A350/gs would decrease with more severe stress due to inhibition of c.e
English
0032-0889
Biochemical pathways
Biochemical reactions
Biosynthesis
Chemical reactions
Energy metabolism
Epidermis
Gramineae
Metabolism
Miscellaneous plant disorders
Oxides
Physiological functions
Plant anatomy
Plant physiology
Plant physiology and biochemistry
Plant tissues
Plant vegetative organs
Resource management
Stress
Water
Water balance
Triticum
94-107860