Market Quality Research Division, United States Department of Agriculture, Beltsville, Maryland 20705.
Plant Physiol. 1971 Apr;47(4):537-44. doi: 10.1104/pp.47.4.537.
Promotion of cell wall synthesis (from glucose) in pea (Pisum sativum) stem segments by indoleacetic acid (IAA) develops over a period of 1 to 2 hours and is comprised of a promotion of glucose uptake plus a promotion of the utilization of absorbed glucose. The effect of IAA resembles, in these and other respects, its effect on cell wall synthesis in oat coleoptile segments, but the pea system differs in not being inhibited by galactose or mannose, in involving considerably more isotope dilution by endogenous substrates, and in certain other respects.EFFECTOR INFLUENCES UPON AND TOTAL ACTIVITIES OF THE FOLLOWING ENZYMES OBTAINED FROM ETIOLATED PEA STEM SEGMENTS PRETREATED WITH OR WITHOUT IAA WERE EXAMINED: phosphoglucomutase, uridine diphosphate glucose (UDP-glucose) pyrophosphorylase, nucleoside diphosphokinase, UDP-glucose dehydrogenase, inorganic pyrophosphatase, hexokinase (particulate and soluble), and UDP-glucose-beta-1,4-glucan-glucosyl transferase (beta-glucan synthetase). The first three enzymes mentioned exhibit high activity relative to the flux in vivo, do not appear to show physiologically significant effector responses, and are concluded not to be control points. UDP-glucose dehydrogenase activity is regulated by UDP-xylose. Hexokinase is a potential control point but does not exhibit regulatory effects related to the IAA response. beta-Glucan synthetase is the only one of these enzymes with activity which is increased by treatment of tissue with IAA, and this may be responsible for the effect of IAA on wall synthesis.Assays of metabolite pools support the conclusion that stimulation of polysaccharide synthesis by IAA is due partly to changes in hexokinase reaction rate resulting from an increase in metabolic glucose pool size caused by increased glucose uptake, and partly to increased activity at the polysaccharide synthetase level.
吲哚乙酸（IAA）促进豌豆（Pisum sativum）茎段细胞壁合成（来自葡萄糖）的过程需要 1 到 2 小时，其组成部分是促进葡萄糖摄取和吸收的葡萄糖利用。在这些方面和其他方面，IAA 的作用类似于其对燕麦胚芽鞘段细胞壁合成的作用，但豌豆系统的不同之处在于它不受半乳糖或甘露糖的抑制，涉及到更多的内源性底物的同位素稀释，以及在其他某些方面。
从用 IAA 预处理或未预处理的黄化豌豆茎段中获得的以下酶的效应子影响和总活性进行了检查：磷酸葡糖变位酶、尿苷二磷酸葡萄糖（UDP-葡萄糖）焦磷酸化酶、核苷二磷酸激酶、UDP-葡萄糖脱氢酶、无机焦磷酸酶、己糖激酶（颗粒和可溶性）和 UDP-葡萄糖-β-1,4-葡聚糖-葡萄糖基转移酶（β-葡聚糖合酶）。前三种酶相对于体内通量表现出高活性，似乎没有表现出生理上有意义的效应子反应，因此被认为不是控制位点。UDP-葡萄糖脱氢酶的活性受 UDP-木糖调节。己糖激酶是一个潜在的控制点，但没有表现出与 IAA 反应相关的调节作用。β-葡聚糖合酶是这些酶中唯一一种活性因组织用 IAA 处理而增加的酶，这可能是 IAA 对细胞壁合成的影响的原因。代谢物池的测定支持这样的结论，即 IAA 刺激多糖合成部分是由于葡萄糖摄取增加导致代谢葡萄糖池大小增加，从而导致己糖激酶反应速率的变化，部分是由于多糖合成酶水平的活性增加所致。
