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J Exp Bot. 2015 Jul;66(13):3931-44. doi: 10.1093/jxb/erv193. Epub 2015 May 7.

Effect of carbohydrates and night temperature on night respiration in rice.

Author information

1
CIRAD, UMR AGAP, F-34398 Montpellier, France.
2
International Rice Research Institute (IRRI), Crop and Environment Science Division (CESD), DAPO Box 7777 Metro Manila, Philippines.
3
Bayer CropScience NV, Innovation Center, Technologie park 38, B-9052 Gent, Belgium.
4
CIRAD, UMR AGAP, F-34398 Montpellier, France International Rice Research Institute (IRRI), Crop and Environment Science Division (CESD), DAPO Box 7777 Metro Manila, Philippines m.dingkuhn@irri.org.

Abstract

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.

KEYWORDS:

Acclimation; Oryza sativa L.; Q10; maintenance and growth respiration; shading; soluble sugars; starch.

PMID:
25954047
DOI:
10.1093/jxb/erv193
[Indexed for MEDLINE]

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