Root and Shoot Respiration of Perennial Ryegrass Are Supplied by the Same Substrate Pools: Assessment by Dynamic 13C Labeling and Compartmental Analysis of Tracer Kinetics1[OA]
Root and Shoot Respiration of Perennial Ryegrass Are Supplied by the Same Substrate Pools: Assessment by Dynamic 13C Labeling and Compartmental Analysis of Tracer Kinetics1[OA]
复制标题
多年生黑麦草的根和芽呼吸由相同的底物池提供：通过动态 13C 标记和示踪动力学区室分析进行评估1[OA]
作者：
C. Lehmeier;Fernando Alfredo Lattanzi;R. Schäufele;M. Wild;H. Schnyder
多年生黑麦草（Lolium perenne）芽和根呼吸的底物供应系统根据成分库和池的功能特性进行了表征：大小、半衰期以及对根和芽呼吸的贡献。这些研究是在持续光照的恒定条件下生长的多年生黑麦草进行的。植物用13CO2/12CO2标记1至600小时，然后测量芽和根在黑暗中呼吸CO2的速率和13C/12C比率。相对于芽，根中的标签出现延迟约 1 小时；除此之外，两个器官中的示踪剂时间进程非常相似。呼吸示踪动力学的区室分析表明，在两个器官中，三个池提供了所有呼吸碳的 95%（一个非常慢的池，其动力学无法表征，仅提供剩余的 5%）。芽和根中池的半衰期和相对大小也几乎相同（半衰期< 15 分钟、大约 3 小时和 33 小时）。短期储存在提供呼吸作用方面的重要作用在两个器官中都很明显：只有 43% 的呼吸作用是由当前的光合产物提供的（固定碳通过两个最快的池直接转移到呼吸中心）。碳在芽和根的呼吸供应系统中的停留时间实际上是相同的。根据这一证据和其他证据，我们认为这两个器官是由同一池提供的，并且停留时间是由芽通过当前光合产物和储存沉积/动员通量控制的。
The substrate supply system for respiration of the shoot and root of perennial ryegrass (Lolium perenne) was characterized in terms of component pools and the pools' functional properties: size, half-life, and contribution to respiration of the root and shoot. These investigations were performed with perennial ryegrass growing in constant conditions with continuous light. Plants were labeled with 13CO2/12CO2 for periods ranging from 1 to 600 h, followed by measurements of the rates and 13C/12C ratios of CO2 respired by shoots and roots in the dark. Label appearance in roots was delayed by approximately 1 h relative to shoots; otherwise, the tracer time course was very similar in both organs. Compartmental analysis of respiratory tracer kinetics indicated that, in both organs, three pools supplied 95% of all respired carbon (a very slow pool whose kinetics could not be characterized provided the remaining 5%). The pools' half-lives and relative sizes were also nearly identical in shoot and root (half-life < 15 min, approximately 3 h, and 33 h). An important role of short-term storage in supplying respiration was apparent in both organs: only 43% of respiration was supplied by current photosynthate (fixed carbon transferred directly to centers of respiration via the two fastest pools). The residence time of carbon in the respiratory supply system was practically the same in shoot and root. From this and other evidence, we argue that both organs were supplied by the same pools and that the residence time was controlled by the shoot via current photosynthate and storage deposition/mobilization fluxes.