Division of Plant Physiology, Indian Agricultural Research Institute, 110 012, New Delhi, India.
Photosynth Res. 1988 Sep;17(3):267-75. doi: 10.1007/BF00035453.
The carbondioxide compensation point (Γ), dry matter production, and the activities of nitrate reductase (NR), glycolate oxidase (GO), ribulose 1,5-bisphosphate carboxylase (RuBPC) and phosphoenolpyruvate carboxylase (PEPC) were measured in wheat, grown on media, containing nitrate or ammonium. Significantly higher Γ and lower dry matter was observed in plants supplied with ammonium-nitrogen (NH4-N), as compared to those supplied with nitrate-nitrogen (NO3-N). The activities of NR and PEPC were higher in plants grown on NO3-N than to those grown on NH4-N. There were no significant differences in the activities of GO and RuBPC irrespective of whether NO3-N or NH4-N was supplied. None of the enzymes was found to be associated directly with the Γ.PEPC activity accounted the measured differences in the Γ and biomass production between NH4-N and NO3-N supplied plants. The relationship between PEPC and the Γ is discussed.
二氧化碳补偿点（Γ）、干物质产量以及硝酸还原酶（NR）、乙醛酸氧化酶（GO）、核酮糖-1,5-二磷酸羧化酶（RuBPC）和磷酸烯醇式丙酮酸羧化酶（PEPC）的活性，在以硝酸盐或铵盐为养分的培养基中生长的小麦中进行了测量。与供应硝酸盐氮（NO3-N）的植株相比，供应铵态氮（NH4-N）的植株的 Γ 和干物质明显更高。在以 NO3-N 为氮源生长的植株中，NR 和 PEPC 的活性高于以 NH4-N 为氮源生长的植株。GO 和 RuBPC 的活性无论供应的是 NO3-N 还是 NH4-N，均无显著差异。未发现任何一种酶与 Γ 有直接关系。PEPC 活性解释了 NH4-N 和 NO3-N 供应植株之间 Γ 和生物量产量的差异。讨论了 PEPC 与 Γ 的关系。
