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Carbon and water economy of Australian NAD-ME and NADP-ME C4 grasses

Geijer, Paulina; von Caemmerer, Susanne; Conroy, Jann P

Description

C4 grasses are grouped into three biochemical subtypes, NAD malic enzyme (NAD-ME), NADP malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PCK), possessing characteristic leaf anatomy, biochemistry and physiology. This study investigates the physiological implications of these differences by comparing growth, water use efficiency (WUE, dry matter gain per unit water transpired) and gas exchange characteristics of NAD-ME and NADP-ME C4 grasses belonging to three taxonomic groups (main...[Show more]

dc.contributor.authorGeijer, Paulina
dc.contributor.authorvon Caemmerer, Susanne
dc.contributor.authorConroy, Jann P
dc.date.accessioned2015-12-13T23:22:20Z
dc.date.available2015-12-13T23:22:20Z
dc.identifier.issn0310-7841
dc.identifier.urihttp://hdl.handle.net/1885/91400
dc.description.abstractC4 grasses are grouped into three biochemical subtypes, NAD malic enzyme (NAD-ME), NADP malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PCK), possessing characteristic leaf anatomy, biochemistry and physiology. This study investigates the physiological implications of these differences by comparing growth, water use efficiency (WUE, dry matter gain per unit water transpired) and gas exchange characteristics of NAD-ME and NADP-ME C4 grasses belonging to three taxonomic groups (main Chloroid assemblage, Paniceae and Andropogoneae). We grew 28 C4 grasses from seeds for 6 weeks in a glasshouse under ample water and nutrients in winter and summer. The inter-specific variation in plant dry mass (30-fold) was much greater than that in WUE (2-fold). There was no significant difference in average WUE between NAD-ME and NADP-ME grasses. Average plant dry mass and WUE were highest in the Paniceae (mostly NADP-ME), lowest in the Andropogoneae (NADP-ME) and intermediate in the Chloroid (NAD-ME). CO2 assimilation rate (A), stomatal conductance (g) and the ratio of intercellular to ambient CO2 partial pressure (pi/pa) were measured under standard conditions at high light. Average A and g were slightly higher in NADP-ME than NAD-ME grasses, but pi/pa was similar for the two subtypes. A did not differ between winter and summer experiments in spite of a 3-fold difference in maximal daily irradiance. Dry matter accumulation correlated positively with leaf area ratio (LAR; plant leaf area per unit plant dry mass) and specific leaf area (SLA; leaf area per unit leaf dry mass) in NAD-ME, but not NADP-ME, grasses. Variation in A (expressed on a per area basis) did not correlate with biomass accumulation or SLA. When expressed on a dry mass basis, A correlated with SLA in all C4 grasses. This study shows that there is large inter-specific variation in growth among the C4 grasses, but average WUE and A/g are similar for NAD-ME and NADP-ME species under well-watered conditions.
dc.publisherCSLI Publications
dc.sourceAustralian Journal of Plant Physiology
dc.titleCarbon and water economy of Australian NAD-ME and NADP-ME C4 grasses
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume28
dc.date.issued2001
local.identifier.absfor060104 - Cell Metabolism
local.identifier.ariespublicationMigratedxPub22128
local.type.statusPublished Version
local.contributor.affiliationGeijer, Paulina, Lund University
local.contributor.affiliationvon Caemmerer, Susanne, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationConroy, Jann P, University of Western Sydney
local.bibliographicCitation.startpage213
local.bibliographicCitation.lastpage223
dc.date.updated2015-12-12T09:10:39Z
local.identifier.scopusID2-s2.0-0035090010
CollectionsANU Research Publications

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