The microscopic structures of the endosperm of indica rice varieties with different quality before and after gelatinization were observed using scanning electron microscope. The results showed that the degree of gelat...The microscopic structures of the endosperm of indica rice varieties with different quality before and after gelatinization were observed using scanning electron microscope. The results showed that the degree of gelatinization varied in different parts of the grain and in different varieties under the same experimental conditions. The gelatinization of dorsal side was the most complete. Its cells were decomposed totally into puff-like or flocculent materials. The ventral side gelatinized less thoroughly, appearing agglomerate and some cell frames were still visible. The middle part gelatinized most incompletely and the cells were still integrated. Evident differences in gelatinization were observed among different varieties, the dorsal, ventral and middle parts of high quality varieties gelatinized more thoroughly than those of the corresponding parts of low quality varieties respectively. An obvious concavity often appeared in the middle of the cross-section of the low quality grains while the cross-section of high quality grains was normally flat. The same phenomenon was noted when comparing the early maturing indica rice and the late maturing indica rice. Varietal difference of gelatinization in dorsal sides was not as distinct as in middle parts and ventral sides. The difference among dorsal side, middle part and ventral side in gelatinization was greater in low quality grains than that of high quality grains. In addition, a lot of ruptured cells were observed in the cross-section of high quality rice, while few of them could be found in the low quality rice. Apparently, the number of ruptured cells is positively correlated with rice quality. Quality of rice grain also has positive correlation with the rate of water absorption and extension. High rates of water absorption and extension lead to better gelatinization of rice grain, and hence indicate good quality.展开更多
A 花的颜色不同主要是因为花瓣内所含化合物的成分(色素)不同。这些化合物大致可以分为两种,即花青素和胡萝卜素。花青素极不稳定,遇酸呈红色,遇碱呈蓝色,中性呈紫色,酸碱性的强弱还直接影响着色彩的深浅。胡萝卜素能使花呈现出黄、橙...A 花的颜色不同主要是因为花瓣内所含化合物的成分(色素)不同。这些化合物大致可以分为两种,即花青素和胡萝卜素。花青素极不稳定,遇酸呈红色,遇碱呈蓝色,中性呈紫色,酸碱性的强弱还直接影响着色彩的深浅。胡萝卜素能使花呈现出黄、橙、红等色彩,而胡萝卜素种类较多,目前已知的有八十多种。自然界的植物种类繁多,它们生存的环境也各不相同,在两种色素的作用下,植物才能开出五彩缤纷的花朵。展开更多
文摘The microscopic structures of the endosperm of indica rice varieties with different quality before and after gelatinization were observed using scanning electron microscope. The results showed that the degree of gelatinization varied in different parts of the grain and in different varieties under the same experimental conditions. The gelatinization of dorsal side was the most complete. Its cells were decomposed totally into puff-like or flocculent materials. The ventral side gelatinized less thoroughly, appearing agglomerate and some cell frames were still visible. The middle part gelatinized most incompletely and the cells were still integrated. Evident differences in gelatinization were observed among different varieties, the dorsal, ventral and middle parts of high quality varieties gelatinized more thoroughly than those of the corresponding parts of low quality varieties respectively. An obvious concavity often appeared in the middle of the cross-section of the low quality grains while the cross-section of high quality grains was normally flat. The same phenomenon was noted when comparing the early maturing indica rice and the late maturing indica rice. Varietal difference of gelatinization in dorsal sides was not as distinct as in middle parts and ventral sides. The difference among dorsal side, middle part and ventral side in gelatinization was greater in low quality grains than that of high quality grains. In addition, a lot of ruptured cells were observed in the cross-section of high quality rice, while few of them could be found in the low quality rice. Apparently, the number of ruptured cells is positively correlated with rice quality. Quality of rice grain also has positive correlation with the rate of water absorption and extension. High rates of water absorption and extension lead to better gelatinization of rice grain, and hence indicate good quality.
