Growth and Photosynthesis in the First Leaf of Barley The Effect of Time of Application of Nitrogen
Growth and Photosynthesis in the First Leaf of Barley The Effect of Time of Application of Nitrogen
复制标题
大麦第一片叶的生长和光合作用施氮时间的影响
DOI：
10.1093/oxfordjournals.aob.a084658
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发表时间：
1972
期刊：
影响因子：
--
通讯作者：
J. E. Dale
中科院分区：
文献类型：
--
作者：
J. E. Dale
使用Proctorbarley生长在砂控制环境条件下，它表明，当氮的应用，如硝酸盐，延迟超过第4天，此时第一叶开始展开，绝对和相对生长速度的幼苗降低，使年轻的植物显着较小。延迟施用硝酸盐导致第一叶的长度、宽度、面积和干重减少，并且通过红外气体分析测量的第8天的光合活性也降低。第一叶对14 CO2的吸收的测量表明，在第2天或第4天施用硝酸盐导致在第8-12天期间的高固碳率。而在第6天或第8天施用导致显著较低的最大固定速率，其维持的时间较短。当第8天施用硝酸盐时，第7-14天的总固碳量仅为第2天施用硝酸盐的植物叶片的60%。当以叶片干重为基础比较固碳量时，发现所有处理的最大值相似，这表明，叶片固定量的差异主要是由于处理对叶面积的影响。对于所有处理，证实到第14天发生光合活性下降。这是不相关的光合活性在第二片叶子，也没有出现的第三leaf.Analysis的第一片叶片的不同部分表明，所有的供应时间，无论是在生长和光合活性的影响。叶干重没有增加后，第8天的任何治疗，但当硝酸盐施加在第8天植物表现出四倍的光合速率增加。这在有关羧化和光合作用中的其他阻力的意义进行了讨论。
UsingProctorbarley grown in sand under controlled-environment conditions it was shown that when application of nitrogen, as nitrate, was delayed beyond day 4, at which time the first leaf was beginning to unfold, absolute and relative growth-rates of seedlings were reduced so that the young plants were significantly smaller. Delay in nitrate application led to reduction in length, breadth, area, and dry weight of the first leaf, and also to a lower photosynthetic activity on day 8, as measured by infra-red gas analysis.Measurement of the uptake of14CO2by first leaves showed that application of nitrate on days 2 or 4 led to high rates of fixation of carbon over the period days 8–12, whereas application on days 6 or 8 led to a substantially lower maximum rate of fixation which was maintained for a shorter period. When nitrate was applied on day 8 total fixation of carbon over the period days 7–14 was only 60 per cent of that for leaves on plants for which nitrate was supplied on day 2.When amounts of carbon fixed were compared on a leaf dry-weight basis, maximum values were found to be similar for all treatments, suggesting that the differences in fixation per leaf result mainly from the effect of treatment on leaf area. For all treatments it was confirmed that a decline in photosynthetic activity occurred by day 14. This was not correlated with photosynthetic activity in the second leaf, nor with emergence of the third leaf.Analysis of different parts of the lamina of the first leaf showed all to be affected by the timing of the supply, both in growth and in photosynthetic activity. Leaf dry weight did not increase after day 8 for any treatment, yet when nitrate was applied on day 8 plants showed a fourfold increase in photosynthetic rate. The significance of this in relation to carboxylation and other resistances in photosynthesis is discussed.