Effects Of Night Temperature Increasing On Yield Of Double Cropping Rice And Its Physio-biochemical Mechanisms

In order to investigate the effects of night temperature increasing on yield of double season rice and its physio-biochemical mechanisms, the experiments were carried out in two glass-houses during2010to2011. The main results were as follows:1. The higher-night temperature can obviously accelerate the growth of early and late rice in tillering stage, and increase the number of effective tiller.The growth duration of early and late rice was shortened and the plant height was elevated under rise-night temperature.2. Moderate increase in night temperature was conductive to the total accumulation of dry matter of early and late rice, over-rate increase was against to the formation of dry matter of early rice. Elevated night temperature was conductive to the accumulation of dry matter before the mid-tiller stage of early rice. On the other hand, Higher night temperature influenced the dry matter accumulation in the middle and later periods of late rice.3.The higher-night temperature can obviously decreased net photosynthetic、RuBPCase activity and chlorophyll content of early rice, and the symptoms of oxidative damage were appeared.The activities of protective enzymes SOD and POD decreased, and MDA content increased,the rise-night temperature increased net leaf photosynthetic of late rice, but the effects was not significant.4. The root activity of early rice under higher night temperature was higher than normal night temperature during the early growth stage of spike phase Ⅱ,and the rise-night temperature could also suppress the N,P,K nutrient accumulation.But during maturity stage,the rise-night temperature could decreased the root activity and suppressed material transfering of early rice. And the late rice was different.5. The pollen activity and filled grain percentage of early rice were decreased under night temperature increasing during the middle and late growth stages. However,moderate increase in night temperature was benefit to the spikelets differentiation and promoted plooen activity during the early stage of late rice, and setting percentage of late rice increased, and yield of late rice under higher night temperature became more than control.6. There existed obvious differences in the response to night temperature increasing at different growth stages of double season rice.The spikelets differentiation of early and late rice were all decreased from the stage of panicle differentiation to booting and booting to heading stage.The high-night temperature can obviously promote the panicle degradation,and reduce seed setting rate. But the effects on the panicle abortion of early and late rice under rise-night temperature during the stage of booting to heading were more obvious.