摘要
硝酸还原酶(NADH:NR E.C.1.6.6.1,以下简称NR)是植物体内硝酸盐同化过程中的关键酶。在植物氮素代谢中起着重要作用,它对植物的生长发育有重要的影响。NR的酶量及活力控制着硝态氮转化的速率,不同生长速率类型的树木,NR活力表现不同,速生类型的NR活力要大于生长慢的类型。NR可望成为早期鉴定的指标。林木一般多栽培于山地,立地条件难以做到均一,必然使得各个个体植株的NR活力产生差异。为了正确评价NR活力在不同生长速率类型间的差异(即:在大田条件下,不同生长速率类型无性系植株所表现出的NR活力差异,是本身的特性还是由外界环境,特别是土壤肥力条件所造成。),除了在测定技术上增加诱导处理措施可以克服环境差异外,本文主要研究氮素水平对不同生长速率类型的杉木NR活力的影响,为大田鉴定指标化提供依据。
Nitrate reductase activity (NRA), chlorophyll, protein, free amino acid and nitrate contents of different clones of Cunniughamia lanceclata were determined in relation to nitrogen fertilizer. Nitrogen was supplied as NH4NO3.There were differences of (NRA) between the fast growing and slow growing clone seedlings. The former exhibited higher NRA. They were 8-10 μmol NO2-30 min/g fresh weight but the latter was 6.2 μmol NO2/30 min/g fresh weight. NRA in seedling leaves increased with the increase of nitrogen fertilizer. While the concentration of nitrogen fertilizer was higher than 350 mgN/L, NRA decreased. But NRA in fast growing clone seedlings were higher than those in slow growing clone seedlings. They had NRA values of 10-12 and about 7.1 μmol NO2-/30 min/g fresh weight, respectively.In certein concent rantion range of nitrogen fertilizer, chlorophyll, protein and free amino acid contents increased with the increase of nitrogen fertilizer concentration, but while nitrogen concentration was higher than 350 mg N/L, chlorophyll content decreased, protein content did not increase in the fast growing clone but decreased in the slow growing clone, and free amino acid contents increased.Nitrate content in branch phloem was relative to NR activity in its leaves. When NR activity was higher, nitrate content was not high, but while NR activity decreased under high nitrogen level, i.e 700 mg N/L, nitrate content obviously increased. These results showed that nitrogen fertilizer could induce NR activity but it could not change the difference in NR activity in leaves between fast growing clone and slow growing clone. The difference in NR activity is stable. NR activity may be a useful index of growth potential when nitrogen fertilizer is not a limiting factor of NR activity.
出处
《林业科学研究》
CSCD
北大核心
1989年第1期88-92,共5页
Forest Research
基金
国家自然科学基金
关键词
杉木无性系
氮肥
硝酸还原酶
Cunninghamia lanceolata clone
Nitrogen fertilizer
Nitrate reductase
