两个杨树无性系中大量元素含量的年变化

研究了两个杨树无性系(I-69杨和I-72杨)各生物组分中大量元素年变化规律。结果表明:两个无性系的大量元素在其各生物组分中的含量相近,变化规律相似;两个杨树无性系营养元素氮、磷、钾、钙、镁均以叶中元素含量的年变化幅度最为明显,分别为82.6%、82.2%、84.7%、85.7%和88.7%;当年生小枝与2年生小枝积累大量元素的规律相似;各生物组分生长最旺盛的时期存在养分的“稀释效应”;氮、磷、钾的平均含量以叶中最大,钙、镁以当年生木质部最大。研究结果可为杨树人工林的营养管理和地力维护提供依据。

Annual Dynamics of Macro-element Contents in Various Biological Components of Poplar Clones

Poplar is one of the dominant trees which developed very quickly in China in recent years.It is important to study annual dynamics of macro-element contents in order to improve the ability of poplar plantation nutrient management.Annual dynamics of macro-element contents of clone I-69 and clone I-72 were studied.Results indicated that the value and the annual dynamics of N,P,K,Ca and Mg in different biological components of two poplar clones were similar.Among these components,annual variations of nutrient contents in leaves were the most obvious,and its variation value was 82.6% for N,82.2% for P,(84.7%) for K,85.7% for Ca,and 88.7% for Mg respectively.The rule of macro-element accumulated in one-year-old and two-year-old branch was similar,dilute effects of nutrient content existed during the eugenic period of various biological components;among various biological components,mean contents of N,P,K of leaves were maximal and mean contents of Ca,Mg of one-year-old xylems were maximal.The results would provide primary data for nutrient management and productivity maintenance of poplar plantation.