哀牢山12种木质藤本植物在不同生境下叶片解剖结构的比较

摘要

Choosing respectively six heliophile lianas (Rosa longicuspis,Actinidia callosa,Celastrus angulatus,Holboellia latifolia, Sabia yunnanensis,Rubus paniculatus) and six skiophyte lianas (Kadsura coccinea,Euonymus vagans,Jasminum urophyllum, Hydrangea anomala,Heterosmilax japonica,Embelia procumbens) in subtropical evergreen broad-leaved forest of Ailao Mountains of Yunnan province, China as the study targets, through light microscopy and paraffin sectioning, the leaf anatomical structure of each species were studied. For each species, study was conducted on the samples collected from three habitat gradients namely forest gap, forest edge and inside the forest. The results were as follows: (1) From gap, edge to the forest inside, the average thickness of leaf blade, the upper epidermis and palisade tissue, the cell height of palisade tissue and the ratio of the thickness of palisade tissue to that of sponge tissue showed the tendency of decrease, besides the trend of decline of the six sun-adapted taxa is greater than that of other six shade-adapted taxa. (2) The numbers of cell layer and the length of palisade cell significantly reduced and shortened with the environmental light intensity decline, which resulting in the average thickness of the palisade tissue was significantly smaller accompanying with the diminish of light intensity. The thickness of palisade tissue might therefore used to be an important index responding to the change of inhabitats. (3) The average of phenotypic plasticity index (PPI) of all twelve lianas was 0.47. Among them, PPI of six sun-adapted taxa (0.58) was higher than that of six shade-adapted taxa (0.36). These results suggested that the leaf anatomical structure of lianas exhibit strong adaptability to the light intensity. Comparing with the shade-adapted taxon, sun-adapted liana species showed stronger adaptability to the habitats with heterogeneity light, which could possibly explain the sun-adapted liana species had higher distribution frequency in all the three habitats in this studied subtropical evergreen broad-leaved forest of Ailao Mountains, whereas the shaded-adapted liana species tended to distribute at edge of forest or inside the forest.%为了探讨藤本植物对不同生境的适应性，以哀牢山亚热带常绿阔叶林中12种常见的木质藤本植物为研究对象，包括6种林窗更新的、喜光或适应高光强生境的常绿蔷薇（Rosa longicuspis）、山羊桃（Actinidia callosa）、南蛇藤（Celastrus angulatus）、五风藤（Holboellia latifolia）、云南清风藤（Sabia yunnanensis）、圆锥悬钩子（Rubus paniculatus）和6种林缘或林内更新的、喜荫或适应低光强生境的冷饭团（Kadsura coccinea）、石宝茶藤（Euonymus vagans）、川西尾叶素馨（Jasminum urophyllum）、冠盖绣球（Hydrangea anomala）、肖菝葜（Heterosmilax japonica）和葡萄酸藤子（Embelia procumbens），使用石蜡切片法对其在林窗（全光照）、林缘（遮荫）和林内（荫生）3种生境下的植物叶片进行了解剖观察和比较分析，研究不同生境对这12种木质藤本植物叶片结构的影响。结果表明，（1）从林窗到林缘再到林内，12种木质藤本植物的叶片平均厚度、上表皮平均厚度、栅栏组织平均厚度、栅栏组织细胞平均长度和栅海比均呈现逐渐降低的趋势，且林窗更新的木质藤本植物的下降趋势大于林缘、林内更新的。（2）栅栏组织细胞层数及其长度随生境光强减弱显著减少和变短，导致栅栏组织平均厚度显著变小，可作为藤本植物响应生境变化的重要指标。（3）12种木质藤本植物的总体表型可塑性指数平均值为0.47，其中，6种林窗更新的藤本植物的总体表型可塑性指数平均值（0.58）大于6种林缘、林内更新的藤本植物的（0.36）。结果说明，木质藤本植物叶片解剖结构表现出对生境光强具有很强的适应性；同时，喜光或适应高光强的藤本植物对异质光生境的适应能力强于喜荫或适应低光强的藤本植物，这可能是前者能够在常绿阔叶林3种生境中具有更高分布频率，而后者多分布于林缘和林内生境的原因之一。