NITROGEN AND PHOTOSYNTHESIS IN THE FLAG LEAF OF WHEAT (TRITICUM-AESTIVUM L)
NITROGEN AND PHOTOSYNTHESIS IN THE FLAG LEAF OF WHEAT (TRITICUM-AESTIVUM L)
复制标题
DOI：
10.1104/pp.72.2.297
复制
发表时间：
1983-01-01
期刊：
影响因子：
7.4
通讯作者：
EVANS, JR
中科院分区：
文献类型：
--
作者：
EVANS, JR
小麦（T. aestivum L. cv Yecora 70）植物与各种浓度的可用于根的硝酸盐N一起生长。剑叶取样开始后，他们已经达到完全扩展，并继续在整个衰老。气体交换率，核酮糖-1，5-二磷酸（RuP 2）羧化酶活性，叶绿素，可溶性蛋白质，N和P的量进行了测定每个旗叶。CO2同化率是唯一相关的叶片总氮，无论营养处理，季节和叶龄。同化速率随叶片氮的增加而增加，但当叶片氮超过125 mmol N/m2时，二者关系的斜率明显下降。叶绿素含量和RuP 2羧化酶活性与叶片氮含量近似成正比。随着叶片老化，RuP 2羧化酶活性和计算的HIll活性平行下降。在正常环境CO2分压下，细胞间CO2分压总是这样，同化速率受到RuP 2羧化和RuP 2再生能力的限制。初始斜率的CO2同化速率对细胞间CO2分压的变化与羧化酶活性呈非线性关系。这可能是由于有限的电导CO2在壁和液相中的扩散，导致细胞间隙和羧化位点之间的CO2分压下降。使用双倒数图来获得转移电导的估计值。
Wheat (T. aestivum L. cv Yecora 70) plants were grown with various concentrations of nitrate N available to the roots. Sampling of flag leaves began after they had reached full expansion and continued throughout senescence. Rates of gas exchange, ribulose-1,5-bisphosphate (RuP2) carboxylase activity, and the amounts of chlorophyll, soluble protein, N and P were determined for each flag leaf. Rate of CO2 assimilation was uniquely related to total leaf N irrespective of nutrient treatment, season and leaf age. Assimilation rate increased with leaf N, but the slope of the relationship declined markedly when leaf N exceeded 125 mmol N/m2. Chlorophyll content and RuP2 carboxylase activity were approximately proportional to leaf N content. As leaves aged, RuP2 carboxylase activity and calculated HIll activity declined in parallel. With normal ambient partial pressure of CO2, the intercellular partial pressure of CO2 was always such the rate of assimilation appeared colimited by RuP2 carboxylation and RuP2 regeneration capacity. The initial slope of rate of CO2 assimilation against intercellular partial pressure of CO2 varied nonlinearly with carboxylase activity. This was probably due to a finite conductance to CO2 diffusion in the wall and liquid phase which causes a drop in CO2 partial pressure between the intercellular spaces and the site of carboxylation. A double reciprocal plot was used to obtain an estimate of the transfer conductance.