Effect of carbohydrates and night temperature on night respiration in rice

Peraudeau Sebastien, Lafarge Tanguy, Roques Sandrine, Quiñones Cherryl O., Clément-Vidal Anne, Ouwerkerk Pieter B.F., Van Rie Jeroen, Fabre Denis, Jagadish Krishna S.V., Dingkuhn Michaël. 2015. Effect of carbohydrates and night temperature on night respiration in rice. Journal of Experimental Botany, 66 (13) : 3931-3944.

https://doi.org/10.1093/jxb/erv193

Article de revue ; Article de revue à facteur d'impact

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Quartile : Outlier, Sujet : PLANT SCIENCES

Résumé : Global warming causes night temperature (NT) to increase faster than day temperature in the tropics. According to crop growth models, respiration incurs a loss of 40–60% of photosynthate. The thermal sensitivity of night respiration (R n) will thus reduce biomass. Instantaneous and acclimated effects of NT on R n of leaves and seedlings of two rice cultivars having a variable level of carbohydrates, induced by exposure to different light intensity on the previous day, were investigated. Experiments were conducted in a greenhouse and growth chambers, with R n measured on the youngest fully expanded leaves or whole seedlings. Dry weight-based R n was 2.6-fold greater for seedlings than for leaves. Leaf R n was linearly related to starch (positive intercept) and soluble sugar concentration (zero intercept). Increased NT caused higher R n at a given carbohydrate concentration. The change of R n at NT increasing from 21 °C to 31 °C was 2.4-fold for the instantaneous response but 1.2- to 1.7-fold after acclimation. The maintenance component of R n (R m'), estimated by assimilate starvation, averaged 28% in seedlings and 34% in leaves, with no significant thermal effect on this ratio. The acclimated effect of increased NT on R m' across experiments was 1.5-fold for a 10 °C increase in NT. No cultivar differences were observed in R n or R m' responses. The results suggest that the commonly used Q10=2 rule overestimates thermal response of respiration, and R n largely depends on assimilate resources.

Mots-clés Agrovoc : Oryza sativa, métabolisme des glucides, respiration cellulaire, facteur climatique, facteur du milieu, température, changement climatique, adaptation aux changements climatiques, perte, biomasse, teneur en glucides, feuille, croissance, ombrage, rythme circadien, analyse de régression