八角林不同郁闭度对金花茶和山茶生长及光合特性的影响

以金花茶（Camellia nitidissima）和山茶（Camellia japonica）为材料,研究全光照（CK）以及八角（Illicium verum）林冠郁闭度分别为0.9、0.7、0.5时,对2种植物生长和光合特性的影响。结果表明:郁闭度除了对山茶的叶宽影响不显著以外,对金花茶和山茶的各生长指标均有显著影响;与CK相比,金花茶和山茶在郁闭度0.5、0.7、0.9下的株高、地径、生物量都有增加,均显著高于CK,且金花茶的增加幅度大于山茶。2种植物的比叶重都随郁闭度的增加先降后升,都在全光照下最大;2种植物的叶长、叶宽都在全光照下最小,而叶厚在全光照下最大;叶面积、比叶面积随郁闭度的增加先增大后减小,在郁闭度0.7最大,CK最小。金花茶在郁闭度0.7和山茶在郁闭度0.5的P_n均显著高于其他处理,且均随着有效光合辐射强度增加而增大,最后趋于稳定。郁闭度对金花茶和山茶的表观量子效率（AQY）、最大净光合速率（P_max）、光饱和点（LSP）、光补偿点（LCP）和暗呼吸速率（R_d）均有显著影响;随着郁闭度的增大,金花茶和山茶的叶片AQY、P_max、LSP先增大后减小,金花茶均在郁闭度0.7时最大,山茶均在郁闭度0.5时最大;2种植物的LCP在全光照下最大;金花茶R_d在全光照下最大,山茶的R_d在郁闭度0.5下最大。综合分析得知,金花茶和山茶有一定的耐阴能力,且对弱光环境有一定的适应性,适合在郁闭度0.5~0.7下的环境下生长,但强光环境不利于2种植物的生长。

Effects of Different Canopy Density on Growth and Photosynthetic Characteristics of Camellia nitidissima and Camellia Japonica in Illicium verum Forest

The influences on the growth and photosynthetic characteristics of Camellia nitidissima and Camellia japonica were studied under full illumination (CK) and Illicium verum forest canopy density at 0.9, 0.7 and 0.5, respectively. The degree of canopy density had a significant effect on the growth index of C. nitidissima and C. japonica, except that it had no significant effect on the leaf width of C. nitidissima. Compared with total illumination, the plant height, ground diameter and biomass of C. nitidissima and C. japonica increased at a canopy density of 0.5, 0.7, and 0.9, and the increase of C. nitidissima was greater than that of C. japonica. The specific leaf weight of both plants decreased first and then increased with the increase of canopy density, and was the highest under full illumination. The leaf length and leaf width of the two plants were the smallest under full illumination, while the leaf thickness was the largest under full illumination. The leaf area and specific leaf area increased first and then decreased with the increase of canopy density. The canopy density was the largest under 0.7 and the smallest under full illumination. The P_n of C. nitidissima was significantly higher than that of other treatments under the canopy density degree of 0.7 and the canopy density of 0.5, and both increased with the increase of effective photosynthetic radiation intensity, and finally stabilized. The canopy density had a significant effect on the quantum efficiency (AQY), maximum net photosynthetic (P_max), light saturation point (LSP), light compensation point (LCP) and dark respiration rate (R_d) of C. nitidissima and C. japonica. With the increase of canopy density, AQY, P_max and LSP of C. nitidissima and C. japonica increased first and then decreased. C. nitidissima was the largest in canopy density 0.7, and C. japonica was the largest in canopy density 0.5. LCP of the two plants was the largest under full illumination. R_d of C. nitidissima was the largest under full illumination, and R_d of C. japonica was the largest under the canopy density degree of 0.5. According to comprehensive analysis, C. nitidissima and C. japonica had certain tolerance to darkness and had certain adaptability to low light environment. They were suitable for growth under the environment of canopy density of 0.5-0.7, but intense light was not conducive to the two plants.