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为探讨不同郁闭度板栗林下套种香榧的生长适应性,通过对林地不同郁闭度下香榧幼树的生长量进行分析,采用LI-6400便携式光合测定系统测定不同郁闭度下香榧叶片的光合特性。结果表明,不同郁闭度下香榧幼树生长量,冠幅、苗高和新梢均为郁闭度0.5>全光照>郁闭度0.8,其中郁闭度0.5显著高于郁闭度0.8;地径为全光照>郁闭度0.5>郁闭度0.8。不同郁闭度下叶片Amax在9.61~12.28μmol·m-2·s-1,郁闭度0.5>郁闭度0.8>全光照,遮阴条件下叶片Amax显著高于全光照条件;不同郁闭度下叶片LCP差异也较大,其中全光照下LCP最大,为16.50μmol·m-2·s-1,郁闭度0.5最小,为4.50μmol·m-2·s-1;3种郁闭度下叶片AQE、LSP和Rd差异均不显著。光响应曲线结果显示随着PARi的增强,不同郁闭度下叶片的Pn增大,Tr加大,Tf升高,Gs增大,Ci下降、WUE增加。相比郁闭度0.8和全光照条件,郁闭度0.5更适宜香榧幼林的生长。
In order to investigate the growth adaptability of the fragrant Chinese chestnut under different canopy density, LI-6400 portable photosynthesis system was used to measure the growth of the fragrant chestnut under different canopy density Photosynthetic characteristics. The results showed that under different canopy density, the growth, crown width, seedling height and shoot height of saplings were all in the order of canopy 0.5> full light> canopy 0.8, in which the canopy density 0.5 was significantly higher than that of the canopy density 0.8. Ground diameter is full light> canopy density 0.5> canopy density 0.8. The leaf Amax was 9.61 ~ 12.28μmol · m-2 · s-1, the canopy density 0.5> the canopy closedness 0.8> total light under different canopy degrees. Under shading conditions, the leaf Amax was significantly higher than that under full sunlight. The difference of leaf LCP was also large, among which, the maximum LCP was 16.50μmol · m-2 · s-1 under full light and the minimum was 0.5, which was 4.50μmol · m-2 · s-1. The leaf AQE, LSP and Rd differences were not significant. The results of light response curve showed that Pn increased, Tr increased, Tf increased, Gs increased, Ci decreased and WUE increased with PARi enhancement. Compared to canopy density 0.8 and full sunlight conditions, canopy density 0.5 is more suitable for the growth of Fraxinus mandshurica.