Sugar repression of photosynthesis: The role of carbohydrates in signalling nitrogen deficiency through source:sink imbalance
Sugar repression of photosynthesis: The role of carbohydrates in signalling nitrogen deficiency through source:sink imbalance
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DOI：
10.1046/j.1365-3040.1997.d01-17.x
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发表时间：
1997-01-01
影响因子：
7.3
通讯作者：
Driscoll, SP
中科院分区：
文献类型：
--
作者：
Paul, MJ;Driscoll, SP
这项工作的目的是研究碳水化合物是否参与信号氮缺乏通过源：库不平衡。在从先前氮充足的植物中提取氮的过程中，研究了烟草的光合代谢8天以上，其中来源：在此时间尺度内，氮充足植物的光合速率、Rubisco蛋白质和氨基酸含量略有下降，碳水化合物含量下降幅度较大。从生长介质中去除氮导致光合速率大幅下降（在生长条件下8天后减少35%，在高和低测量CO2下也明显减少），这是由于Rubisco蛋白质的量大量减少造成的（8d后62%）和Rubisco活性，较高量的己糖先于光合活性和蔗糖和淀粉积累的损失，减少来源：遮荫的库比防止了光合活性的损失和己糖和其他碳水化合物的增加，这些数据表明，在完整植物中伴随着缺氮的光合作用的减少具有在模型系统中观察到的光合作用的糖抑制的特征，但是在光合作用下降之前己糖的积累很小，糖阻遏光合作用在生理条件下更关键地取决于C：N状态的叶子比单独的碳水化合物状态的可能性进行了讨论。
The aim of this work was to examine whether carbohydrates are involved in signalling N deficiency through source:sink imbalance. Photosynthetic metabolism in tobacco was studied over 8 d during the withdrawal of N from previously N-sufficient plants in which the source:sink ratio was manipulated by shading leaves on some of the plants, In N-sufficient plants over this timescale, there was a small decline in photosynthetic rate, Rubisco protein and amino acid content, with a larger decrease in carbohydrate content, Withdrawal of N from the growing medium induced a large decrease in the rate of photosynthesis (35% reduction after 8 d under the growing conditions, with a reduction also apparent at high and low measuring CO2), which was caused by a large decrease in the amount of Rubisco protein (62% after 8 d) and Rubisco activity, Higher amounts of hexoses preceded the loss of photosynthetic activity and sucrose and starch accumulation, Reduction of the source:sink ratio by shading prevented the loss of photosynthetic activity and the increase in hexoses and other carbohydrates, These data indicate that the reduction of photosynthesis that accompanies N deficiency in intact plants has the characteristics of sugar repression of photosynthesis observed in model systems, but that the accumulation of hexose prior to the decline in photosynthesis is small, The possibility that sugar repression of photosynthesis under physiological conditions depends more crucially on the C:N status of leaves than the carbohydrate status alone is discussed.