Factors Controlling Endosperm Cell Number and Grain Dry Weight in Wheat: Effects of Shading on Intact Plants and of Variation in Nutritional Supply to Detached, Cultured Ears
Factors Controlling Endosperm Cell Number and Grain Dry Weight in Wheat: Effects of Shading on Intact Plants and of Variation in Nutritional Supply to Detached, Cultured Ears
复制标题
控制小麦胚乳细胞数量和籽粒干重的因素：遮荫对完整植株的影响以及对分离培养穗营养供应变化的影响
DOI：
--
复制
发表时间：
1984
期刊：
影响因子：
--
通讯作者：
C. Jenner
中科院分区：
文献类型：
--
作者：
Bk Singh;C. Jenner
已经在小麦中研究了胚乳细胞数量与籽粒干重之间的关联，以及胚乳细胞分裂对有机营养素可用性的依赖性。使用两种不同的程序来改变细胞分裂阶段谷物的营养供应。分离的穗在蔗糖（0-60 g 1-1）和谷氨酰胺（0.125-0.75 g N 1-1）溶液中培养，或将完整植物暴露于高（560 µmol m-2 s-1）或低（55 µmol m-2 s-1）光子辐照度。每个胚乳的细胞数和谷物干重都对外部介质中的营养物质浓度和光子暴露水平有反应。在细胞分裂停止之前，每个细胞的平均干重相对独立于营养水平或光子暴露水平，但在灌浆后期，培养穗中每个细胞的干重显示出对外部介质中营养物质浓度的依赖性。从谷物中提取了一定量的蔗糖、其他可溶性碳水化合物和可溶性氨基氮，并且在每粒谷物的基础上，所有部分的量随着供应到耳朵的营养物水平的变化以及光子暴露而变化。然而，发育中的谷物中这些营养物质的浓度（以干重或水为基础计算）与谷物中的细胞分裂速率无关。虽然收集到的证据支持这样的观点，即发育中的胚乳的生长（细胞数量和干重）尤其是通过提供有机营养物来控制，但控制机制的性质尚不清楚。细胞分裂似乎并没有直接受到营养供应的影响，其机制涉及发育中的谷物中能量和蛋白质合成底物的浓度。
The association between endosperm cell number and grain dry weight, and the dependence of endosperm cell division on the availability of organic nutrients, have been investigated in wheat. Two different procedures were used to vary the supply of nutrients to the grains during the phase of cell division. Detached ears were cultured in solutions of sucrose (0-60 g 1-1) and glutamine (0.125-0.75 g N 1-1), or intact plants were exposed to high (560 µmol m-2 s-1) or low (55 µmol m-2 s-1) photon irradiance. Cell number per endosperm, and grain dry weight, were both responsive to the concentration of nutrients in the external medium, and to the level of photon exposure. Average dry weight per cell was relatively independent of the level of nutrition or of photon exposure until cell division had ceased but, in the later stages of grain-filling, dry weight per cell in the cultured ears displayed a dependence upon the concentration of nutrients in the external medium. Amounts of sucrose, other soluble carbohydrates and soluble amino nitrogen were extracted from the grains and, on a per grain basis, the amounts of all fractions varied in response to variation in the level of nutrients supplied to the ears, and to photon exposure. However, concentrations of these nutrients in the developing grains, calculated on a dry weight or water basis, were not associated with the rate of cell division in the grains. While the evidence gathered supports the notion that growth (in cell number, and dry weight) of the developing endosperm is controlled inter alia by the provision of organic nutrients, the nature of the controlling mechanism is obscure. It seems that cellular division is not affected directly by nutritional supply through a mechanism involving the concentration of substrates for energy and protein synthesis within the developing grain.