入侵植物野莴苣群落特征及扩散能力研究

Study on community characteristics and dispersal ability of invasive Lactuca serriola

摘要:

【目的】 野莴苣是一种南方常见的有毒入侵田间杂草，野外调查发现已扩散到甘肃省和宁夏回族自治区且分布区仍在扩张，掌握野莴苣群落特征、种子结实性及萌发特性，防止其扩张。【方法】 通过样方调查野莴苣群落特征，统计其花蕾数及结实总数，掌握结实性；通过培养皿滤纸法研究野莴苣种子萌发对温度（5、10、15、20、25、30、35 ℃）和PEG‐6000模拟干旱胁迫（0%、2.5%、5%、10%、15%、 20%、25%、30%、35%）的响应。【结果】 野莴苣能够在撂荒地成为优势种，在路边、林缘等生境均可扩散，野莴苣为小种子，结实率高，适宜风力传播；野莴苣种子在5~35 ℃均可萌发，萌发最适温度为 20 ℃；PEG‐6000浓度为2.5%时，可促进野莴苣萌发，但随着浓度增加，野莴苣种子萌发受到抑制。 【结论】 温度不能限制野莴苣的扩散，重度干旱才能抑制野莴苣的扩散，野莴苣的扩散将成不可忽视的生态问题。

Abstract:

【Objective】 Lactuca serriola，a poisonous invasive weed commonly found in southern China，has al ready spread to Gansu and Ningxia Hui Autonomous Region and continues to expand. In order to prevent its further expansion，it is necessary to understand its community characteristics，seed setting，and germination.【Method】 The study used the quadrat method to investigate its community characteristics and count flower buds and total seeds to gain a better understanding of its seed setting characteristics. Subsequently，the study used the Petri dish filter paper method to investigate the germination of Lactuca serriola seeds in response to temperature （5，10，15，20，25，30， 35 ℃） and PEG-6000 （0%，2.5%，5%，10%，15%，20%，25%，30%，35%）simulated drought conditions. 【Result】 The results showed that Lactuca serriola could become the dominant species in abandoned land and spread in roadsides，forest edges，and other habitats. It was a small seed with a high seed setting rate and was suitable for wind propagation. The germination temperature of Lactuca serriola was wide ranging from 5 ℃ to 35 ℃，with the best germination temperature at 20 ℃. When the concentration of PEG-6000 was 2. 5%，it improves germination，but with increasing concentration，the germination of Lactuca serriola seeds was restrained.【Conclusion】In summary，the study suggests that temperature does not limit the spread of Lactuca serriola，but rather severe drought is the factor that restricts its growth and expansion，making it an ecological problem that cannot be ignored.