PHOTOSYNTHESIS, LEAF RESISTANCES, AND RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE DEGRADATION IN SENESCING BARLEY LEAVES
PHOTOSYNTHESIS, LEAF RESISTANCES, AND RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE DEGRADATION IN SENESCING BARLEY LEAVES
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DOI：
10.1104/pp.65.6.1103
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发表时间：
1980-01-01
期刊：
影响因子：
7.4
通讯作者：
HUFFAKER, RC
中科院分区：
文献类型：
--
作者：
FRIEDRICH, JW;HUFFAKER, RC
研究了大麦初生叶衰老过程中核酮糖-1,5-二磷酸羧化酶（RuBPCase）的丧失与光合作用下降的关系。RuBPCase的缺失约占可溶性蛋白减少的85%。RuBPCase与vitroRuBPCase活性（r = 0.95）和总光合作用（r = 0.96）高度相关。然而，在叶片衰老的早期阶段，每毫克RuBPCase的光合速率增加。非还原糖浓度与光合作用呈负相关（1%水平）。与非还原性糖相比，游离α-氨基氮在衰老过程中明显下降。叶绿素下降，蛋白蛋白酶活性增加，但这些变化似乎与光合作用和RuBPCase的下降没有密切关系。叶肉抗性增加的速率与光合作用和RuBPCase下降的速率相同。气孔抗性比叶肉抗性增长更快，约占co2扩散抗性总增长的24%。在衰老的最后阶段，细胞间空气中的co2浓度下降。虽然RuBPCase的丢失可能是叶片衰老过程中光合作用下降的主要原因，但也必须考虑其他因素，如体内调节和气孔孔径等。
The relationship between loss of ribulose-1,5-bisphosphate carboxylase (RuBPCase) and the decline in photosynthesis during the senescence of barley primary leaves was assessed. Loss of RuBPCase accounted for about 85% of the decrease in soluble protein. RuBPCase was highly correlated within vitroRuBPCase activity (r = 0.95) and gross photosynthesis (r = 0.96). However, the rate of photosynthesis per milligram RuBPCase increased during the early stages of leaf senescence. The concentration of nonreducing sugars was negatively correlated (1% level) with photosynthesis. Free α-amino N, in contrast to nonreducing sugars, declined markedly during senescence. A decrease in chlorophyll and an increase inin vitroprotease activity was observed, but these changes did not appear to be closely related to the decline in photosynthesis and RuBPCase. Mesophyll resistance increased at the same rate that photosynthesis and RuBPCase declined. Stomatal resistance increased more rapidly than mesophyll resistance and accounted for about 24% of the total increase in resistance to CO2diffusion. The concentration of CO2in the intercellular air spaces decreased during the last stage of senescence. Although loss of RuBPCase probably is the primary event responsible for the decline in photosynthesis during leaf senescence, other factors such asin vivoregulation and stomatal aperture must also be considered.