Hormonal regulation of assimilate utilization in barley leaves in relation to the development of their source function
Hormonal regulation of assimilate utilization in barley leaves in relation to the development of their source function
复制标题
DOI：
10.1023/a:1016324312244
复制
发表时间：
2002-07-01
影响因子：
1.4
通讯作者：
Kaminskaya, OA
中科院分区：
文献类型：
--
作者：
Kiseleva, IS;Kaminskaya, OA
研究了植物激素浓度和比例的变化与叶片生长、光合作用、同化物的利用和源功能的发展的关系。用碳同位素C-14示踪光合作用产物从叶片中的利用和流出。采用固相免疫酶法测定内源激素浓度。结果表明，在未达到较高光合作用速率的幼叶(其最终面积的五分之一)中，高达80%的同化物在取食(CO2)-C-14一天后被并入结构性多糖(纤维素和半纤维素)中。在叶片生长和来源功能发育过程中，结构多糖的合成量下降到10%，而醇溶化合物(AWSC)的合成量增加到80%。单糖和低聚糖可作为碳水化合物的运输形式，分别占AWSC的30%和40%。同化物用于蛋白质合成的百分比随着叶片的生长而降低。所揭示的变化与叶片发育不同阶段游离激素的浓度和比例有关。ABA和IAA浓度的降低和ABA/IAA比值的增加与源功能的发展、纤维素和半纤维素合成的下降以及AWSC的增加有关。ABA水平可以通过将碳流分配给用于叶片细胞生长的高分子化合物(纤维素、半纤维素和蛋白质)的合成或碳水化合物的运输形式的合成来调节叶片光合作用的利用途径。较高的ABA水平有利于第一条途径，而较低的水平则将叶片代谢切换到第二条途径。
Growth, photosynthesis, utilization of assimilates, and the development of a source function in leaves were studied in relation to changes in concentrations and ratios of phytohormones. Carbon isotope C-14 was used to trace utilization and outflow of photosynthetic products from the leaf. Concentrations of endogenous phytohormones were determined by solid-phase immunoenzyme assay. It was shown that, in juvenile leaves (one-fifth of their finial area), which did not attain a high rate of photosynthesis, up to 80% of assimilates were incorporated into structural polysaccharides (cellulose and hemicellulose) one day after feeding with (CO2)-C-14. During leaf growth and the development of its source function, the synthesis of structural polysaccharides declined to 10%, but the formation of alcohol- and water-soluble compounds (AWSC) grew to 80%. Monosaccharides and oligosaccharides, which could act as transport forms of carbohydrates, constituted 30% and 40% of AWSC, respectively. The percentage of assimilates utilized for protein synthesis decreased with leaf growth. The revealed changes correlate with the concentration and the ratio of free forms of phytohormones at various stages of leaf development. Development of a source function, a decline in cellulose and hemicellulose syntheses, and an increase in AWSC were related to the decrease in ABA and IAA concentrations and the increase in the ABA/IAA ratio. The ABA level can regulate the pathways of photoassimilate utilization in leaves by partitioning carbon flows either to the synthesis of high-molecular-weight compounds (cellulose, hemicellulose, and proteins), used for cell growth in leaves, or to the synthesis of transport forms of carbohydrates. A high ABA level favors the first pathway while low level switches leaf metabolism to the second one.