秋季叶施尿素及乙烯利对枣树贮藏氮素的影响

EFFECTS OF FOLIAR SPRAY OF UREA AND ETHEPHON IN AUTUMN ON NITROGEN STORAGE AND REUTILIZATION IN JUJUBE TREES

枣树(Zizyphus jujuba Mill.)秋季叶施尿素、乙烯利及尿素十乙烯利均可促进叶片及落性枝的氮素向树体回流,增加树体贮藏氮素水平,尤以尿素+200ppm乙烯利的效果最佳;尿素及乙烯利处理均增加了次年枣吊长度、平均单果重及枣果还原糖含量;尿素处理还显著增加了叶片及新梢含氮量,座果数,但降低了枣果蔗糖含量。枣树秋冬季地上部与根系具有同等重要的贮藏氮素作用;蛋白态氮是主要贮藏形态,为非蛋白态氮的2—3倍。

Non-labelled urea, 15N-labelled urea and ethephon were applied on mature and potted young jujube trees ( Zizyphus jujuba Mill. ) by spray or foliar daub in winter in 1987 and 1988.We studied the effects of leaf nitrogen return to tree after the treatments, the positions and forms of nitrogen reserved, and reutilization of storage nitrogen in the next year.The results were as follows: l.The return of leaf nitrogen was accelerated by autumn foliar urea and ethephon applied, and then the level of storage nitrogen of trees was increased.The results of urea plus 200ppm ethephon were the best. 2 . There were significant in-creases in the length of 'zaodiao' ( a kind of bearing branchlet that falls in late autumn ) , fruit set, average single fruit weight, and the amount of reducing sugar of jujube fruits.Urea also increased the nitro-gen of shoots and leaves, but decreased the amount of sucrose of fruits. 3 . The above-ground organs and roots of jujube trees were of same importance in nitrogen reserved in winter. The main form of sto-rage nitrogen was protein-nitrogen, which amount was more than 2-3 fold than non-protein nitrogen ( soluble nitrogen ) .