入侵植物飞机草和南美蟛蜞菊种子萌发特征对热带珊瑚岛生境的响应

Responses of Seed Germination Characteristics of Invasive Plants Eupatorium odoratum and Sphagneticola trilobata to Tropical Coral Island Habitat

摘要:

入侵植物对热带珊瑚岛植被及生态系统产生严重威胁，研究热带珊瑚岛生境下入侵植物的种子萌发特征，可为预判入侵植物在热带珊瑚岛的扩张潜力提供科学依据。该研究以入侵植物飞机草(Eupatorium odoratum)、南美蟛蜞菊(Sphagneticola trilobata)和原生植物林泽兰(E. lindleyanum)种子为对象，通过“人为增温3 ℃+海砂基质+水”模拟热带珊瑚岛生境，测定种子萌发性状。结果表明：飞机草种子萌发性状主要受海砂基质和增温的影响；南美蟛蜞菊和林泽兰种子萌发性状则主要受海砂基质的影响。在热带珊瑚岛生境下，3种植物的繁殖潜力均显著低于大陆生境，飞机草和南美蟛蜞菊繁殖潜力降幅尤为显著。飞机草种子扩张潜力与林泽兰相当，但南美蟛蜞菊种子扩张潜力显著高于林泽兰。虽然飞机草和南美蟛蜞菊被人为带入热带珊瑚岛后的繁殖潜力有所下降，但其种子萌发特征对珊瑚岛生境的适应性和高于原生物种的扩张潜力均表明这2种入侵植物将对珊瑚岛植被生态系统造成威胁，在今后的研究中应当着重关注热带珊瑚岛生境入侵植物的防控工作。

关键词:热带珊瑚岛;入侵植物;入侵潜力;种子萌发

Abstract:

Invasive plants pose a serious threat to the vegetation ecosystem on tropical coral islands. Studying the seed germination characteristics of invasive plants in tropical coral island habitats can provide scientific basis for predicting the expansion potential of invasive plants on tropical coral islands. The seed germination characteristics of invasive species Eupatorium odoratum, Sphagneticola trilobata, and coral island native species E. lindleyanum were compared under the simulated tropical coral island habitat via "3 ℃ warming + marine sand matrix + water". The results showed that the seed germination traits of E. odoratum were mainly affected by marine sand matrix and elevated temperature, while those of S. trilobata and E. lindleyanum were mainly affected by marine sand matrix. In tropical coral island habitats, the reproductive potential of the three plants was significantly lower than that in mainland habitats, in particular for E. odoratum and S. trilobata. The seed expansion potential of E. odoratum was similar to that of E. lindleyanum, but S. trilobata had higher seed expansion potential than E. lindleyanum. Although the reproductive potential of E. odoratum and S. trilobata decreased after being introduced into tropical coral island, the adaptability of their seed germination characteristics to the habitat and the expansion potential of invasive plants were higher than that of native species, indicating that the two invasive plants would pose a threat to the vegetation ecosystem of the tropical coral islands. In the future, it should be focused on the prevention and control of invasive plants in tropical coral islands.

Key words:Tropical coral island;Invasive plant;Invasion potential;Seed germination