Cen Y P, Turpin D H, Layzell D B
Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Plant Physiol. 2001 Aug;126(4):1555-65. doi: 10.1104/pp.126.4.1555.
Simultaneous measurements of CO(2) (CER) and O(2) (OER) exchange in roots and shoots of vegetative white lupin (Lupinus albus) were used to calculate the flow of reducing power to the synthesis of biomass that was more reduced per unit of carbon than carbohydrate. On a whole-plant basis, the diverted reductant utilization rate (DRUR which is: 4 x [CER + OER]) of shoot tissue was consistently higher than that of roots, and values obtained in the light were greater than those in the dark. An analysis of the biomass being synthesized over a 24-h period provided an estimate of whole-plant DRUR (3.5 mmol e(-) plant(-1) d(-1)), which was similar to that measured by gas exchange (3.2 mmol e(-) plant(-1) d(-1)). Given that nitrate reduction to ammonia makes up about 74% of whole-plant DRUR, root nitrate reduction in white lupin was estimated to account for less than 43% of whole-plant nitrate reduction. The approach developed here should offer a powerful tool for the noninvasive study of metabolic regulation in intact plants or plant organs.
通过同时测量营养期白羽扇豆（Lupinus albus）根和地上部的二氧化碳（CER）和氧气（OER）交换，来计算用于合成单位碳比碳水化合物还原程度更高的生物量的还原力流量。在整株植物水平上，地上部组织的转移还原力利用率（DRUR，即：4×[CER + OER]）始终高于根部，且光照下获得的值大于黑暗中的值。对24小时内合成的生物量进行分析，得出了整株植物DRUR的估计值（3.5 mmol e(-) 植物(-1) d(-1)），这与通过气体交换测量的值（3.2 mmol e(-) 植物(-1) d(-1)）相似。鉴于硝酸盐还原为氨约占整株植物DRUR的74%，据估计白羽扇豆根部的硝酸盐还原占整株植物硝酸盐还原的比例不到43%。本文开发的方法应为完整植物或植物器官代谢调控的非侵入性研究提供一个强大的工具。
