粒重差异显著的两种水稻颖果发育比较

为了探讨控制水稻(Oryza sativa L.)颖果发育的因素,选择了颖果干重有显著差异的Ootikara(大粒,36mg/粒)和Habataki(小粒,18 mg/粒)两个水稻品种,比较颖果重量、胚乳细胞数、果皮和胚乳的结构以及某些生理活性等变化.结果指出:与Habataki相比,Ootikara子房壁细胞和颖果的持续生长期长,最终颖果的胚乳细胞数目和每个细胞的平均干重大;Ootikara颖果的脱氢酶和H2O2酶活性、穗的呼吸速率、剑叶的绿色程度和光合速率等维持高水平的时间长;Ootikara子房背部维管束失去功能的时间也较迟.结果表明,大粒品种的库容大和生理活性期长是其颖果能显著增大的生理原因.

Comparison of Caryopsis Development Between Two Rice Varieties with Remarkable Difference in Grain Weights

Two rice (Oryza sativa L.) varieties, Ootikara with big grain (36 mg/grain) and Habataki with small grain (18 mg/grain), were used to study the factors that control caryopsis development. We compared the differences of caryopsis weight, the number of endosperm cell, the structures of pericarp and endosperms, changes of physiological activities, and so forth during the caryopsis development. The main results showed that the growth period of the cell of ovary wall and the caryopsis of Ootikawa was longer compared with that of Habataki, resulting in the formation of more endosperm cells and heavier cell weight. In Ootikawa, it has a longer period of maintaining a high level of dehydrogenase and catalase activities, and higher level of respiratory rate of the ears, the degree of greening and photosynthetic rate of the flag leaf, and a longer functional maintenance period of the dorsal carpellary bundles in the ovary. And all these features indicated that the larger capacity and the longer active period of the caryopsis in Ootikara would lead to the notable expansion of the caryopsis.