华南地区4种林分改造树种的叶片养分季节动态

Leaf Nutrient Dynamics in Four Tree Species of Rehabilitated Forest in South China

为了了解叶片养分含量的季节变化,为幼林养分管理提供参考,研究了红锥Castanopsis hystrix、黎蒴Castanop-sis fissa、山杜英Elaeocarpus sylvestris和樟树Cinnamomum camphora幼林的叶片氮、磷、钾的季节动态.鲜叶叶面积用微电子面积测量仪测定.叶片N含量用凯氏定氮法测定,叶片P含量用酸溶-钼锑抗比色法测定,叶片K含量用原子吸收分光光度法测定.研究结果表明:红锥1月和4月的叶N、P含量高,4月的K含量高;黎蒴1月的叶N含量高,4月的叶P含量高,1月和4月的叶K含量高;山杜英1月的叶N和P含量高,1月和4月的叶K含量高;1月为樟树的叶N含量高峰,1月和4月的叶P含量高,4月的叶K含量高.叶片的养分含量高峰和落叶前的养分转移有关.红锥和樟树7月的叶N、P含量较低,黎蒴、山杜英和樟树7月份的叶K含量低.

In order to understand seasonal changes of leaf nutrients for nutrient management of young stands,nutrient dynamics were studied in leaves of young Castanopsis hystrix,Castanopsis fissa,Elaeocarpus sylvestris and Cinnamomum camphora stands.Fresh leaf area was measured by microelectronic area gauge,N was determined by micro-Kjeldahl technique,P was analyzed colorimetrically by chloro molybdophosphonic blue colour,and K was analyzed using atomic absorption spectrophotometry.The results showed that leaf N and P contents were high in January and April,and K content was high in April for C.hystrix;Leaf N content was high in January,leaf P content was high in April and leaf K content was high in January and April for C.fissa.Leaf N and P contents were high in January and K content was high in January and April for E.sylvestris;Leaf N content was high in January,leaf P content was high in January and April,leaf K content was high in April for C.camphora.Nutrient peaks were related to nutrient translocation from old leaves before senescence and falling.Leaf N and P contents were low in July for C.hystrix,and C.camphora,and leaf K content was low in July for C.fissa,E.sylvestris and C.camphora.