排序方式: 共有1条查询结果,搜索用时 15 毫秒
1
1.
Effects of Nitrate Withdrawal and Resupply on the Assimilation of Nitrate in Leaves of Tomato 总被引:4,自引:0,他引:4
Nitrate reduction in leaves of tomato occurred at the same ratein plants grown in 8.0 mol m3 nitrate as in plants grownin 2.0 mol m3 nitrate, but at a much slower rate in plantsgrown in 0.1 mol m3 nitrate. However, the plants grownin 8.0 mol m3 nitrate had a larger leaf system than theplants grown in 2.0 mol m3 nitrate, and so the totalcapacity to assimilate nitrate was greater in the plants grownin the higher concentration. It was shown that plants grownin 8.0 mol m3 nitrate were better buffered against nitratewithdrawal than plants grown in 2.0 mol m3 nitrate asthe rate of nitrate reduction declined more slowly when plantswere transferred to 0.1 mol m3 nitrate from the higherconcentration than from the lower concentration. Furthermore,leaf expansion continued in the plants transferred from thehigher concentration, whereas it ceased abruptly in the plantstransferred from the lower concentration. It was concluded thatboth continuing expansion and continuing nitrate reduction wereaccompanied, and possibly caused by, a release of nitrate fromstorage pools in the lower part of the stem or the roots. Duringwithdrawal of nitrate the leaves were shown to maintain potentialactivity of the enzyme nitrate reductase although there wasno nitrate to be reduced. When nitrate was resupplied it couldbe reduced very quickly and reduction in the leaves was seento increase within 5 h of resupply. By 3 d after resupply furtherenzyme activity had been induced. Key words: Lycopersicon esculentum Mill, nitrate assimilation, nitrate reductase activity, nitrate withdrawal 相似文献
1