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研究了北方 1 2个落叶树种单位面积叶干重、叶片灰分、有机物质和 7个元素的浓度和含量在落叶前后的变化 ,同一元素不同树种间及同一树种不同元素间有着不同的变化模式 .单位面积叶干重、叶片有机物质浓度和含量在落叶后均表现下降的趋势 ;所有树种叶片灰分浓度和大部分树种的灰分含量 (除刺槐、胡颓子、核桃楸外 )均有增加 ;落叶时 N、P、K的单位叶面积含量均可减少约 1 / 3～ 2 / 3;Mg含量的减少在胡颓子、核桃楸、春榆、蒙古栎、日本落叶松等 5个树种中发生 ,其余树种表现增加 ;落叶中 Fe含量除胡颓子下降外 ,其余均表现升高 ;落叶中 Ca、Si浓度和含量在所有分析树种中均表现增加趋势
The changes of leaf dry weight, leaf ash content, organic matter and seven elements in 12 deciduous tree species in North China before and after deciduous leaf were studied. Different species of the same deciduous tree species and different species of the same tree species had different patterns. Leaf dry weight per unit area, the concentration and content of organic matter in the leaves showed a declining trend after deciduous leaves; the leaf ash concentration of all tree species and the ash content of most tree species (except Robinia pseudoacacia, Elaeagnus bungei, Juglans mandshurica) increased; The leaf area per unit area of N, P and K could be reduced by about 1/3 ~ 2/3. The decrease of Mg content occurred in 5 species of Elaeagnus, Juglans mandshurica, Quercus mongolica and Japanese larch , The rest of the species showed an increase; the content of Fe in the deciduous leaves increased except for the decrease of the Elaeagnus; the concentration and content of Ca, Si in the deciduous leaf increased in all the analyzed species