Synthetic and Maintenance Respiratory Losses of 14CO2 in Uniculm Barley and Maize
Synthetic and Maintenance Respiratory Losses of 14CO2 in Uniculm Barley and Maize
复制标题
Uniculm 大麦和玉米中 14CO2 的合成和维持呼吸损失
DOI：
10.1093/oxfordjournals.aob.a085168
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发表时间：
1976
期刊：
影响因子：
4.2
通讯作者：
C. E. Powell
中科院分区：
文献类型：
--
作者：
G. Ryle;J. Cobby;C. E. Powell
在正常光合作用过程中，测定了大麦和玉米全株或单叶暴露在含有均匀比活度14CO_2的空气中30-60分钟后的呼吸损失。14CO_2的总呼吸外流可以用两个主要成分来描述：一种是强烈的外流，半衰期为4-8h，与分生组织中新组织的生物合成有关；另一种是强度较小的外流，半衰期为26-120h，主要与代谢活动的维持有关。14CO2的(生物)合成外排总量为标记同化物(14C：14C)的25%至35%，通常对温度和光照强度不敏感。维持流出量占标记同化物或其衍生物的12%至27%：总流出量一般随着高温和低光照强度的增加而增加。维持性外排速率表现为正常温度反应(Q10≏2)。结论是，从长期来看，将同化产物转化为新增长的效率不太可能超过65%，而且通常会更低。
The respiratory losses of14CO2from whole plants of uniculm barley and maize were measured following exposure of the whole plant or a single leaf to air containing a uniform specific activity of14CO2for 30–60 min during normal photosynthesis. The total respiratory efflux of14CO2could be described in terms of two main components: an intense efflux characterized by a half-life of 4–8 h, which was identified with the biosynthesis of new tissue in meristems; and a much less intense efflux characterized by a half-life of 26–120 h, which was primarily identified with the maintenance of metabolic activity. The (bio)synthetic efflux of14CO2totalled between 25 and 35 per cent of the labelled assimilate (14C:14C), and was generally insensitive to temperature and light intensity. The maintenance efflux totalled between 12 and 27 per cent of the labelled assimilate or its derivatives: the total generally increased with high temperature and low light intensity. The rate of the maintenance efflux showed a normal temperature response (Q10≏2). It is concluded that the efficiency of conversion of assimilate into new growth is unlikely to exceed 65 per cent in the long term, and will generally be less.