title: Heat Stress Is More Damaging to Superior Spikelets than Inferiors of Rice (Oryza sativaL.) due to Their Different Organ Temperatures.
abstract: In general, the fertility and kernel weight of inferior spikelets of rice (Oryza SativaL.) are obviously lower than those of superior spikelets, especially under abiotic stress. However, different responses to heat stress are seemed to show between the superior and inferior spikelet, and this response is scarcely documented that the intrinsic factors remain elusive. In order to reveal the mechanism underlying, two rice plants with different heat tolerance were subjected to heat stress of 40°C at anthesis. The results indicated that a greater decrease in fertility and kernel weight was observed in superior spikelets compared to inferior spikelets. This decrease was primarily ascribed to their different organ temperatures, in which the temperature of the superior spikelets was significantly higher than that of inferior spikelets. We inferred the differences in canopy temperature, light intensity and panicle types, were the primary reasons for the temperature difference between superior and inferior spikelets. Under heat stress, the fertility and kernel weight of superior and inferior spikelets decreased as the panicle numbers per plant were reduced, which was accompanied by significantly increasing the canopy temperatures. Thus, it was suggested that the rice plant with characteristic features of an upright growth habit and loose panicles might be more susceptible to heat stress resulting from their higher canopy and spikelets temperatures.
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Guanfu
authors.initials: G
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Baohua
authors.initials: B
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Caixia
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Xiufu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Qianyu
authors.initials: Q
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute Hangzhou, China.
authors.forename: Longxing
authors.initials: L
authors.lastname: Tao
keywords: heat injury; inferior spikelets; organ temperatures; rice (Oryza Sativa L.); superior spikelets