Servaites J C, Tucci M A, Geiger D R
Department of Biology, University of Dayton, Dayton, Ohio 45469.
Plant Physiol. 1987 Oct;85(2):370-4. doi: 10.1104/pp.85.2.370.
Application of a 17-millimolar solution of glyphosate (GLP) to sugarbeet (Beta vulgaris L.) leaves resulted in an immediate and rapid decline in the level of ribulose bisphosphate (RuBP). Phosphoglyceric acid level began to decrease about 2 hours following the decline in RuBP level. Photosynthesis rate declined linearly with RuBP level, but only when the RuBP level had decreased to about twice the RuBP carboxylase active site concentration. This occurred about 4 hours following GLP-application. At this time starch synthesis also declined abruptly. The activation state of RuBP carboxylase did not change for 8 hours following GLP application and then decreased slightly from 70 to 50% when the RuBP level fell below the RuBP carboxylase active-site concentration. Triose-phosphate, hexose-phosphate, and adenylate energy charge did not change for 8 hours following GLP-application. These data indicate that GLP induced a depletion of carbon or phosphate or both from the photosynthetic carbon reduction cycle, reducing the rate of regeneration of RuBP, photosynthesis, and starch synthesis, while having little effect upon the rate of sucrose synthesis and transport.
将浓度为17毫摩尔的草甘膦（GLP）溶液施用于甜菜（Beta vulgaris L.）叶片后，核酮糖二磷酸（RuBP）水平立即迅速下降。在RuBP水平下降约2小时后，磷酸甘油酸水平开始降低。光合速率随RuBP水平呈线性下降，但仅当RuBP水平降至约为RuBP羧化酶活性位点浓度的两倍时才会如此。这一情况在施用GLP后约4小时发生。此时淀粉合成也突然下降。施用GLP后8小时内，RuBP羧化酶的活化状态没有变化，然后当RuBP水平降至RuBP羧化酶活性位点浓度以下时，活化状态从70%略微降至50%。施用GLP后8小时内，磷酸丙糖、磷酸己糖和腺苷酸能荷没有变化。这些数据表明，GLP导致光合碳还原循环中的碳或磷或两者耗尽，降低了RuBP的再生速率、光合作用和淀粉合成，而对蔗糖合成和运输速率影响很小。
