STOMATAL AND MESOPHYLL LIMITATIONS OF PHOTOSYNTHESIS IN PHOSPHATE DEFICIENT SUNFLOWER, MAIZE AND WHEAT PLANTS
STOMATAL AND MESOPHYLL LIMITATIONS OF PHOTOSYNTHESIS IN PHOSPHATE DEFICIENT SUNFLOWER, MAIZE AND WHEAT PLANTS
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DOI：
10.1093/jxb/42.8.1003
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发表时间：
1991-08-01
影响因子：
6.9
通讯作者：
LAWLOR, DW
中科院分区：
文献类型：
--
作者：
JACOB, J;LAWLOR, DW
描述了缺磷对向日葵、玉米和小麦植株完全展开叶片的组成和光合CO2同化速率的影响。本文分析了不同磷素水平叶片的气孔和叶肉特性对光合作用的调节，并将其与结构联系起来。缺磷叶片组织水中无机磷（Pi）浓度很低。在任何给定的光强度或CO2分压下测量时，在叶片和气孔导度的光合作用速率较小的植物生长与磷酸盐不足。尽管气孔导度的下降（没有证据的斑片状气孔关闭），光合作用的相对气孔限制是类似的植物生长与缺乏或丰富的磷酸盐。然而，叶肉光合作用的能力大大限制了磷缺乏。缺磷叶片单位叶面积上的小细胞数量比缺磷叶片多。在所有三种植物中，叶片可溶性蛋白质含量均随缺磷而下降;然而，叶片叶绿素含量仅在向日葵和玉米中下降，而在小麦中不下降。这些结果表明，气孔导度并没有限制CO2扩散速率，而叶肉的代谢是限制因素。这表现为羧化效率差和CO2同化的表观量子产率降低，这两者都有助于增加缺磷植物光合作用的相对叶肉限制。
The effects of phosphate deficiency on the composition and photosynthetic CO2 assimilation rates of fully expanded leaves of sunflower, maize and wheat plants are described. The regulation of photosynthesis by stomatal and mesophyll characteristics of leaves of different phosphate status is analysed and related to structure. Phosphate deficient leaves had small concentrations of inorganic phosphate, Pi, in the tissue water. Rate of photosynthesis in leaves and stomatal conductance were smaller in plants grown with inadequate phosphate when measured under any given light intensity or CO2 partial pressure. Despite the decrease in stomatal conductance (and without evidence of patchy stomatal closure), the relative stomatal limitation of photosynthesis was similar in the plants grown with deficient or abundant phosphate. However, the mesophyll capacity for photosynthesis was greatly limited by phosphate deficiency. Leaves deficient in phosphate had larger numbers of small size cells per unit leaf area than leaves with adequate phosphate. The total soluble protein content of leaves decreased with phosphate deficiency in all three species; however, the leaf chlorophyll content was decreased only in sunflower and maize and not in wheat. These results suggest that stomatal conductance did not restrict the CO2 diffusion rate, rather the metabolism of the mesophyll was the limiting factor. This is shown by poor carboxylation efficiency and decreased apparent quantum yield for CO2 assimilation, both of which contributed to the increase in relative mesophyll limitation of photosynthesis in phosphate deficient plants.