不同郁闭度板栗林下套种香榧的光合生理特性研究

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。

The photosynthetic and physiological characteristics of Torreya grandis interplanted with chestnut forests under different canopy densities

The growth adaptability of Torreya grandis interplanted with Chinese chestnut under different canopy densities were analyzed.The photosynthetic characteristics of Torreya grandis leaf under different canopy densities were determined using the LI-6400 portable photosynthesis system.The results showed as follows.The crown,seedling height and new shoots were the best under the canopy density of 0.5 followed by full exposure and the canopy density of 0.8.The growth of Torreya grandis under the canopy density of 0.5 was significantly higher than other conditions;however,the ground diameter was the largest under full exposure,then the canopy density of 0.5,and the canopy density of 0.8.The Amax of Torreya grandis leaf under different canopy densities was between 9.61 and 12.28 μmol·m-2·s-1 with a tendency of the canopy density of 0.5 ＞ canopy density of 0.8＞full exposure.The Amax of Torreya grandis grown in the overshadow condition was significantly higher than that in full exposure.The LCP of Torreya grandis under different canopy densities was significant different.The Lcp was the largest (16.50 μmol·m-2·s-1) under the full exposure condition and the minimum (4.50 μmol·m-2·s-1) under the canopy density of 0.5.The AQE,LSP and Rd of Torreya grandis leaf under different canopy densities had no significant difference.The light response curves showed that the values of Pn,Tr,Tf,Gs and WUE increased by increasing PARi,but the value of Ci decreased.Torreya grandis grew well under the canopy density of 0.5 compared to other densities.