Leaf chlorophyll concentration relates to transpiration efficiency in peanut

Abstract

Two pot experiments were conducted in two different seasons at the University of Agricultural Science, Bangalore, India, to study (a) the relationship between chlorophyll concentration (by measuring the leaf light-transmittance characteristics using a SPAD metre) and transpiration efficiency (TE) and (b) the effect of leaf N on chlorophyll and TE relationship in peanut. In Experiment (Expt) I, six peanut genotypes with wide genetic variation for the specific leaf area (SLA) were used. In Expt II, three non-nodulating isogenic lines were used to study the effect of N levels on leaf chlorophyll concentration-TE relationship without potential confounding effects in biological nitrogen fixation. Leaf N was manipulated by applying N fertiliser in Expt II. Chlorophyll concentration, TE (g dry matter kg 21 of H 2 O transpired, measured using gravimetric method), specific leaf nitrogen (g N m 22 , SLN), SLA (cm 2 g 21 ), carbon isotope composition (Á 13 C) were determined in the leaves sampled during the treatment period (35-55 days after sowing) in the two experiments. Results showed that the leaf chlorophyll concentration expressed as soil plant analytical development (SPAD) chlorophyll metre reading (SCMR) varied significantly among genotypes in Expt I and as a result of N application in Expt II. Changes in leaf N levels were strongly associated with changes in SCMR, TE and Á 13 C. In both the experiments, a significant positive relationship between SCMR and TE with similar slopes but differing intercepts was noticed. However, correction of TE for seasonal differences in vapour pressure deficit (VPD) between the two experiments resulted in a single and stronger relationship between SCMR and TE. There was a significant inverse relationship between SCMR and Á 13 C, suggesting a close linkage between chlorophyll concentration and Á 13 C in peanut. This study provides the first evidence for a significant positive relationship between TE and leaf chlorophyll concentration in peanut. The study also describes the effect of growing environment on the relationships among SLA, SLN and SCMR.

Management of crop water under drought: a review

“…The latter would combine water saving with high yield potential, but is considered to be less variable in plants beyond different photosynthetic pathways. Leaf chlorophyll concentration (Rao et al 2001;Sheshshayee et al 2006) and specific leaf area (Rao et al 1995;Richards 2000), however, are proxies for selection of genotypes with high intrinsic water-use efficiency mediated by superior photosynthetic capacity. Measurement of leaf temperature has been used as a screening trait for sustained plant water supply (Blum et al 1982) instead of direct measurement of stomata conductance.…”

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

“…Whether these thresholds relate to the canopy conductance under well-watered conditions is an important question to resolve. Whether these canopy conductance differences would also relate to genotypic differences in transpiration efficiency [TE], which is a major source of crops yield variation under drought stress (Condon et al 2004;Sheshshayee et al 2006;Krishnamurthy et al 2007), is another one. None of these questions has been tested in cowpea and they are addressed in here.…”

Association and Path Coefficient Studies for Traits Related to Water Use Efficiency, Yield and Its Components in RILs of Groundnut (Arachis hypogaea L.)

“…A strong and positive relationship between SCMR and WUE was reported (Sheshshayee et al, 2006). SCMR and SLA are negatively correlated (Nageswara Rao et al, 2001;Upadhyaya, 2005) and genetic variation for SCMR has also been reported (Upadhyaya, 2005).…”