Variation in leaf photosynthetic response of rice genotypes to post-anthesis water deficit

Abstract

Variation in the response of six diverse rice genotypes to imposed water stress was investigated in terms of leaf photosynthetic traits and leaf water potential measurements (W leaf ) during and following a period of water stress. The W leaf reduced from 0 days up to 6th day of irrigation deprivation and the reduction in W leaf was more pronounced in Swarna and minimum in PA-6201. A gradual recovery in W leaf was observed in all the tested varieties after re-irrigation. Similarly, water stress significantly reduced rate of photosynthesis (P N ), stomatal conductance (g s ), transpiration (E) and internal CO 2 concentration (C i ). Significant differences were noticed amongst the varieties in their response to water stress. The P N partially recovered in all tested varieties after re-irrigation. Vandana recorded greater recovery (65 %), where as the recovery was only 32 % in Sugandha Samba. Water stress (6 days of irrigation deprivation) significantly decreased the mean Chl a, Chlb, total chlorophyll and total carotenoid content. However, a marginal increase in total chlorophyll was observed under water stress in Vandana and N-22. Water stress had no significant effect on maximum photochemical efficiency (F v /F m ) for all the tested varieties. However, in Sugandha Samba and Swarna a significant reduction was noticed. Water stress reduced the efficiency of excitation capture (U e ), in vivo quantum yield of PSII photochemistry (U PSI ), coefficient of photochemical quenching (qP) and increased the coefficient of nonphotochemical quenching (qN). The data on photosynthetic traits and chlorophyll fluorescence parameters indicate that Vandana, N-22, DRR-Dhan-38 and PA-6201 which maintained relatively higher, W leaf , P N and g s under water stress and could also maintain high values of photochemical efficiency (Fv/Fm, U e , U PSI and ETR) than Sugandha Samba and Swarna and the genotypic differences in the response of PSII activity could be exploited as traits for the selection of drought tolerant rice genotypes.

Effect of varying NaCl doses on flavonoid production in suspension cells of Ginkgo biloba: relationship to chlorophyll fluorescence, ion homeostasis, antioxidant system and ultrastructure

“…Carotenoids can facilitate the non-radiative dissipation of excitation energy and increase antioxidant protection (Stahl and Sies 2003), in the present work, carotenoids content was reduced at C50 mM NaCl, but the Chl t/Car ratio did not decrease in the presence of different NaCl levels except at 100 and 175 mM NaCl in contrast to another report, where Chl t/Car ratio decreased in Ginkgo tree leaves under open-field condition compared with shade enclosure condition (Wang et al 2014). Furthermore, the Chl t/Car ratio in different rice genotypes had different responses to water stress (Gauthami et al 2014). This indicated that chlorophyll content was more affected than that of carotenoids under abiotic stress, and it seems that the level of Chl t/Car ratio was different between cell level and the whole plant level, and a species or genus.…”

Genotypic variation of photosynthetic gas exchange and stomatal traits in some traditional rice (Oryza sativa L.) landraces from Koraput, India for crop improvement

“…Results of the present study indicated that traditional landraces showed better photosynthetic efficiency but unable to increase grain yield, because increase in leaf photosynthesis may not necessarily leads to increase in grain yield (Gu et al 2013). In rice, higher leaf P N was reported to be correlated with gs and carboxylation capacity (Gauthami et al 2014). The WUE can be influenced by both variation in P N or E and both, which have been reported earlier in rice (Gauthami et al 2014).…”

“…In rice, higher leaf P N was reported to be correlated with gs and carboxylation capacity (Gauthami et al 2014). The WUE can be influenced by both variation in P N or E and both, which have been reported earlier in rice (Gauthami et al 2014). There have been several reports that the incorporation of desired natural genetic variation in photosynthesis through breeding programmes, leads to increase in crop photosynthesis (Haritha et al 2017).…”

Physiological characterization and allelic diversity of selected drought tolerant traditional rice (Oryza sativa L.) landraces of Koraput, India

“…Photosynthesis forms an important aspect of plant metabolism and balance sheet of growth and development, which is known to be sensitive to drought and water deficit (Gauthami et al 2014). In this study, we evaluated the photosynthetic performance of the studied landraces of Koraput under different durations of drought.…”