【摘要】 为探讨植物根系吸收过程中氮素亏缺与补给及其影响，１９９４～１９９５年，通过沙培盆栽试验，研究了２ａ生杨树、刺槐及两者混植在全营养、缺氮、缺钾和缺磷条件下根、茎、叶中氮素营养的变化特性。结果表明：刺槐根含氮量２％～３％，刺槐茎、叶以及杨树根、茎、叶含氮量均为０．１％～１％，刺槐和杨树的含氮量均按根＞茎＞叶根面土分布。正常营养条件下，混交杨根面土含氮量约等于混交槐根面土含氮量＞纯槐根面土含氮量＞纯杨根面土含氮量。在极度缺乏Ｎ素时，植物生长受到抑制，但与正常植株相比植物的氮素百分含量并不低，杨树中氮素积累量由０．５１ｇ下降到０．０７９ｇ，刺槐中Ｎ素积累量由１．９４ｇ下降到１．２７ｇ。在极度缺乏Ｐ或极度缺乏Ｋ时，植物中氮素积累量受其影响都有不同程度的下降。杨树与刺槐混交，能够改良土壤中氮素的分布状况，提高杨树根、茎、叶中氮素含量，但２ａ生的混交杨在干重方面并不优于纯林杨，在全营养或缺磷条件下混交杨中氮素积累量高于纯林杨。更多还原

【Abstract】 The experiments were carried out in 1994 and 1995. Two yearold Shanhaiguan poplar, Robinia pseudoacacia and mixed seedlings of both species were sand cultured with Hoagland′s solutions which had either complete nutrients or deficiency of either elements of N, P or K. Nitrogen element of root, stem, leaf were determined. The results showed that root N contents of Robinia pseudoacacia were　2%～3%, stem and leaf N conents of Robinia pseudoacacia and root, stem, leaf N contents of Shanhaiguan polar were about 0.1%～1%. N contents of both species descended according to the sequence:root>stem>leafrhizospheric soil. Under complete nutrition treatment, rhizospheric soil N contents descended as follows:mixed poplar stand>mixed Robinia pseudoacacia stand> pure Robinia pseudoacacia stand>pure poplar stand. Under extreme nitrogen deficiency treatment, growth was depressed although plant N contents were not reduced comparing to the control treatment. Therefor N accumulation per tree was reduced:the accummulation of N in poplar decreased from 0.51g/tree to 0.079g/tree, and that in Robinia pseudoacacia decreased from 1.94g/tree to 1.27g/tree. Under extreme deficiency of P or K treatment, the N accumulation was also affected by some extend. Mixing polar with Robinia pseudoacacia can improve the distribution state of N nutrition in soil and increase N contents in root, stem leaf of Populus sp. However, biomass of two yearold mixed poolar stand was not higher than that of pure poplar stand. Under complete nutrition or P deficient treatment, N accumulation of mixed polar stand was higher than that of pure stand.更多还原