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Lower soil moisture threshold for transpiration decline under water deficit correlates with lower canopy conductance and higher transpiration efficiency in drought-tolerant cowpea

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Relation http://oar.icrisat.org/5786/
http://dx.doi.org/10.1071/FP11282
 
Title Lower soil moisture threshold for transpiration decline under water deficit correlates with lower canopy conductance and higher transpiration efficiency in drought-tolerant cowpea
 
Creator Belko, N
Zaman-Allah, M
Cisse, N
Vadez, V
et al, .
 
Subject Agriculture-Farming, Production, Technology, Economics
 
Description As water availability is critical for reproduction, terminal drought tolerance may involve water-saving traits. Experiments were undertaken under different vapour pressure deficit (VPD) and water regimes (water stress (WS) and well watered (WW)) to test genotypic differences and trait relationships in the fraction of transpirable soil water (FTSW) at which transpiration declines, canopy conductance (proxied by transpiration rate (TR, g H2O cm–2 h–1)), canopy temperature depression (CTD, °C), transpiration efficiency (TE, g kg–1) and growth parameters, using 15 contrasting cowpea (Vigna unguiculata (L.) Walp.) genotypes. Under WW conditions at the vegetative and early podding stages, plant mass and leaf area were larger under low VPD, and was generally lower in tolerant than in sensitive genotypes. Several tolerant lines had lower TR under WW conditions and restricted TR more than sensitive lines under high VPD. Under WS conditions, transpiration declined at a lower FTSW in tolerant than in sensitive lines. Tolerant lines also maintained higher TR and CTD under severe stress. TE was higher in tolerant genotypes under WS conditions. Significant relationships were found between TR, and TE, CTD and FTSW under different water regimes. In summary, traits that condition how genotypes manage limited water resources discriminated between tolerant and sensitive lines. Arguably, a lower canopy conductance limits plant growth and plant water use, and allows tolerant lines to behave like unstressed plants until the soil is drier and to maintain a higher TR under severe stress, as lower TR at high VPD leads to higher TE.
 
Publisher CSIRO Publishing
 
Date 2012
 
Type Article
PeerReviewed
 
Format application/pdf
application/pdf
 
Language en
en
 
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Identifier http://oar.icrisat.org/5786/5/FPB_2012.pdf
http://oar.icrisat.org/5786/31/Belko_et_al_2012-Funct_Plant_Biol-Manuscript.pdf
Belko, N and Zaman-Allah, M and Cisse, N and Vadez, V and et al, . (2012) Lower soil moisture threshold for transpiration decline under water deficit correlates with lower canopy conductance and higher transpiration efficiency in drought-tolerant cowpea. Functional Plant Biology. 17 pp.. ISSN 1445-4408