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作 者 ：肖瑜

期 刊 ：植物生态学报 1993年 17卷 4期 页码：358-363

关键词：叶生物量；叶净生产量；平均叶龄；周转时间；

Keywords:Leaf biomass, Leaf net production, Life expectancy, Turnover time,

摘 要 ：根据森林和林木各器官生物量随时间的变化，林冠叶片(叶群体)生长和死亡规律及数学生态学的原理，得出了叶的生物量、年净生产量和平均叶龄之间的关系。一般表达式为P=│lnlx│·B/x(式中Pn为叶年净生产量，lx为特定叶龄的存留率，B为叶生物量，x为平均叶龄)。当林冠叶片达到平衡时，Pn=0.693·B／x；存留率为36.8%时，成为目前用平均叶龄计算叶年净初级生产量的形式。本文证明了后一种特殊形式之所以被人们广泛采用是因为混淆了平均叶龄与叶量周转时间这两个概念；这种方法估算的结果比正常值约高30%。 还用实例讨论了用0—1龄级平均叶龄估算叶净生产量所不可避免的偏大原因，用本文提出的公式对某些叶净生产量的计算数值进行了修正；结果表明，与实际情况比较吻合。

Abstract:The general relationship among biomass, net production and life expectancy of leaves, according to the changing of the forest and components of trees in biomass, growth and mortality of leaf populations and mathematical principles of population ecology, is developed: Pn =lnlxB/X, where Pn is net production, lx age-specific survivorship, B biomass and X life expectancy of leaves. When a population is at this equilibrium, Pn =0.693·B/X the relation becomes the common expression by which almost all the ecologists are now using to calculate leaf net primary production from the data of life expectancy when a population has a survivorship of 36.8%. Also it is proved that the common expression, only being used in a particular situation, now accepted and used widely to be user′s confusion of leaf life expectancy with leaf turnover time, the use of the method appears to increase the results by as high as 30% or more. Two case studies are discussed here to show that, an overestimation of net primary production is unavoidable by using life expectancy of 0—1 age-class to compute it. The formula proposed in this paper is used to correct some of the calculated values of net production. The results show that Corrected values are well in accordance with those observed in practical situation.

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