Genotypic variations in carbon isotope discrimination, transpiration efficiency, and biomass production in rice as affected by soil water conditions and N

Abstract

Genotypic and environmental (soil water regime and N level) variation in carbon isotope discrimination (CID) in relation to the gas exchange, transpiration efficiency (A/T), and biomass production were investigated in field experiments using eleven rice (Oryza sativa L.) genotypes. The results showed that genotype was more dominant for variation in CID than in total biomass. Genotypic ranking in CID was consistent across environments because of small genotype × environment interactions. Japonica genotypes tended to have lower CID than indica genotypes. Higher soil water and lower N rate significantly increased CID. Variation in CID was slightly smaller for water regime than for genotype. There was a negative correlation between CID and A/T among genotypes within water regimes. Genotypic variation in CID was associated mainly with variation in stomatal conductance under all soil water regimes and with photosynthetic capacity in late growth stages under aerobic soil conditions. The decrease in CID at higher N was probably due to lower stomatal conductance under aerobic soil conditions and to higher photosynthetic rates under submerged soil conditions. The correlation between biomass and CID was not clear in aerobic soil, whereas it was positive in submerged soil, which indicated that the significance of lower or higher CID for improving biomass productivity may differ under different soil water regimes. Overall, the results implied a possible use of CID as a selection criterion for genotypic improvement in A/T and productivity in rice.Abbreviations: A -net photosynthetic rate; A/T -transpiration efficiency; Ci/Ca -leaf intercellular CO 2 concentration/ambient CO 2 concentration ratio; CID -carbon isotope discrimination; gs -stomatal conductance; HI -harvest index; SLW -specific leaf weight; T -transpiration rate.

The effects of water, nutrient availability and their interaction on the growth, morphology and physiology of two poplar species

“…Cheng et al (2004) have also found that as the N supply increases, the amounts of N in both free amino acids and proteins increase whereas the C/N ratio decreases. Water stress together with fertilization increased WUE (i.e., ␦ 13 C) in poplars, this result is consistent with previous studies (Brück et al, 2000;Welander and Ottosson, 2000;Li et al, 2003;Kondo et al, 2004) stating that WUE is significantly lower in well-watered treatments than in waterstressed treatments, but it increases with an increasing nutrient supply. As for the value of ␦ 13 C, the species effect was not significant.…”

The water adaptability of Jatropha curcas is modulated by soil nitrogen availability

“…30% FC, which were consistent with previous studies [50,51]. Additionally, Pn was negatively correlated with Rs and Rw (Fig.…”

Role of Canopy Coverage in Water Use Efficiency of Lowland Rice in Early Growth Period in Semi-Arid Region

“…Even though plant transpiration could affect the evaporation by altering the VPD inside the canopy, the effects were presumed to be small in this study because the pots were arranged sparsely enough and the experiments were conducted in the early growth period during which the pot was not fully covered by the canopy. Previous studies revealed the effects of stomatal conductance, leaf nitrogen and carbon content, and the ratio of intercellular to ambient CO 2 concentration (C i / C a ) on transpiration efficiency and P/T (Maruyama et al, 1985;Dingkuhn et al, 1989;Adachi et al, 1996) and also reported a negative correlation between P/T and carbon isotope discrimination (CID) (Dingkuhn et al, 1991;Kondo et al, 2004;Impa et al, 2005). However, CID showed a poor relationship with WUE, especially in the tillering period, and Zhao et al (2004) pointed out the possibility of breakdown of relationship between WUE and P/T to explain the poor relationship.…”