4种木本植物对热带珊瑚岛极端环境的适应策略解析

Analysis of Adaptation Strategies of Four Woody Plants to the Extreme Environment of Tropical Coral Island Based on Functional Traits

摘要:

为探索适生木本植物对热带珊瑚岛极端环境的适应策略，从海南文昌移栽夹竹桃（Nerium indicum）、黄金香柳（Melaleuca bracteata）、桑树（Morus alba）和银叶树（Heritiera littoralis）到热带珊瑚岛，对两地植物的叶片形态解剖学特性和抗性生理特征进行比较研究。结果表明，与文昌相比，热带珊瑚岛桑树的比叶面积显著增高；夹竹桃的栅栏海绵组织比无显著差异，而其他3种植物则显著降低；夹竹桃和桑树的叶绿素含量显著增高，黄金香柳和银叶树则显著降低；桑树的总抗氧化能力显著降低，其他3种植物则显著升高；夹竹桃的脯氨酸含量显著降低，其他3种植物则显著升高。因此，4种木本植物为适应热带珊瑚岛生境，夹竹桃和桑树呈现出“提高碳同化潜力-承受更高伤害”策略；而黄金香柳和银叶树呈现为“提高抵抗力-降低碳同化潜力”策略。

Abstract:

In order to explore the adaptation strategies of suitable woody plants to the extreme environment of tropical coral islands, Nerium indicum, Melaleuca bracteata, Morus alba, and Heritiera littoralis were transplanted to tropical coral island from the nursery of Wenchang City, Hainan Province, the morphological and anatomical characteristics of leaves and physiological characteristics of resistance of plants in two places were compared. The result showed that compared with Wenchang, the specific leaf area (SLA) of Morus alba in tropical coral island increased significantly. There was no significant difference in ratio of palisade tissue to sponge tissue (P/S) of N. indicum, while P/S of other three plants decreased significantly. The chlorophyll content of N. indicum and Morus alba increased significantly, while that of Melaleuca bracteata and H. littoralis decreased significantly. The total antioxidant capacity (T-AOC) of N. indicum, Melaleuca bracteata and H. littoralis increased significantly, while that of M. alba decreased significantly. The free proline (Pro) content in N. indicum leaves decreased significantly, while that of Melaleuca bracteata, Morus alba and H. littoralis increased significantly. Therefore, in order to adapt to the tropical coral island habitat, Morus alba and N. indicum showed a strategy of "enhancing carbon assimilation potential and sustaining higher damage", while Melaleuca bracteata and H. littoralis showed a strategy of "improving resistance and reducing carbon assimilation potential".