飞机草对热带珊瑚岛的生理生态适应性

Ecophysiological adaptability of Chromolaena odorata to tropical coral islands

关键词:  飞机草, 生理生态适应, 解剖结构, 入侵性, 热带珊瑚岛

Key words:   Chromolaena odorata, ecophysiological adaptability, anotomical structure, invasiveness, tropical coral islands

摘要:

入侵植物对环境的适应性是探究其入侵性的基础。西沙群岛为热带珊瑚岛,具有高盐、强碱、高温、强光、干旱等恶劣环境特点。近年来,西沙群岛的一些原生植物群落中出现了飞机草(Chromolaena odorata)入侵现象,可能会对当地脆弱的生态系统造成严重的危害。该文研究了西沙群岛原生植物群落林窗中和文昌市郊飞机草的叶片形态解剖结构、生理学特征、叶片营养元素含量等,拟探讨飞机草对热带珊瑚岛特殊生境的适应性。结果表明:与生长在文昌市的飞机草植株相比,生长在热带珊瑚岛的飞机草叶片较厚、气孔密度较低、叶绿素a及丙二醛含量较低、超氧化物歧化酶活性和过氧化氢酶活性较高,有利于其适应热带珊瑚岛的强光和季节性干旱等环境,并造成较大的潜在入侵性。因此,在热带珊瑚岛植被的保护与恢复过程中,加强对飞机草的监测及防控非常必要。

Abstract:

The research on the adaptabilities of invasive plants to their growing environments is the base to explore their invasiveness. The tropical coral islands of the Paracel Islands have the harsh environmental conditions of high salt and alkali soil, high temperature, strong sunlight and drought. In recent years, the invasion of Chromolaena odorata occurred in some native plant communities on the Paracel Islands, which may cause serious harm to its fragile forest ecosystem. In order to understand the ecophysiological adaptabilities of C. odorata to the tropical coral islands, we investigated the morphological and anatomical structures, physiological characteristics and the nutrient contents in the leaves of C. odorata growing in the suburbs of Wenchang City and forest gaps on the Paracel Islands. The results showed that the plants of C. odorata growing in the Paracel Islands had thicker leaves, lower stomatal density, lower chlorophylla and malondialdehyde(MDA)contents, higher level of superoxide dismutase(SOD)and catalase(CAT)activities than that growing in Wenchang City, which are beneficial to acclimate to the adverse environments of strong light and seasonal drought, and may cause greater invasiveness of the plants. Therefore, it is necessary to strengthen the monitoring and control of C. odorata during the process of protection and restoration on the vegetation of the tropical coral islands.