Abstract:

The structure of endosperm is closely related with the grain quality of rice and is believed to be mediated by environmental conditions. The objectives of this study were to investigate the structure of rice endosperm and the grain quality by a scanning electron microscope. Using four hybrid rice combinations, Liangyoupeijiu, 103S/Zhengjing 2, Fengyouxiangzhan and Shanyou 63, grown in pot and treated with low temperature at 18℃ during 0–10 days(T₁), 11–20 days(T₂), and 21–30 days(T₃) after flowering respectively，and the control temperature 24–27℃. The results showed that the grain was abnormal in exterior shape, the area of chalkiness increased, and the size of the amyloplast, either complex or single, decreased, the difference in the size between complex and single amyloplast increased, their arrangements loosened, and resulted in more complex and fewer single amyloplast by the low temperature treatments. The earlier the low temperature treatment was, the more serious the effect was on the endosperm structure. If plants were subjected to low temperature at early grain filling stage and then grown under a normal temperature at late stages, effects of the low temperature on the grain shape, structure of endosperm and the chalkiness area for inferior grains were serious, whereas those for superior grains were not obvious. The results suggest that the structure of endosperm is deteriorated by low temperature during the grain filling period, leading to poor grain quality of rice.

Key words: Hybrid rice, Low temperature, Amyloplast, Endosperm structure, Scanning electron microscope