豚草在广东的分布及其生长发育特性

Distribution and growth characteristics of common ragweed(Ambrosia artemisiifolia L.) in Guangdong Province,China

【背景】豚草是一种世界性恶性害草,目前已入侵我国广东部分地区。【方法】通过定点调查与线路踏查相结合的方法,调查豚草在广东的发生分布与危害状况;通过种子在系列温度下的萌发试验和发生地定点定期的观察,掌握豚草在广东的生长发育特性。【结果】目前,豚草在广东广泛分布于北部的韶关、清远和东北部的梅州一带,东部的汕头、汕尾和西部的肇庆、湛江有局部分布,珠江三角洲一带尚未见分布。在广东发生的豚草,种子没有休眠性,成熟种子落地后遇到适宜的环境即可萌发。一年中豚草有2个出苗高峰期,分别是春季3～4月、秋冬季11～12月,幼苗可越冬生长;在湿润的生长环境下,不同生育期豚草可共存,且部分豚草开花结实后地上茎叶干枯,茎基和地下根部存活,形成丛生状的亚灌木。刈割试验表明,留茬高度和茎节数对豚草再萌生新枝的能力有显著影响。【结论与意义】豚草在广东省正逐渐向中南部扩散,对珠江三角洲的农业生态环境和人体健康将构成严重威胁,应引起各部门的关注,以控制其进一步扩散。

[ Background] Common ragweed （Ambrosia artemisiifolia L. ） is a worldwide noxious weed and has successfully invaded several regions of Guangdong Province, China. [ Method ] A. artemisiifolia＇s distribution in Guangdong Province was surveyed with fixed-point and line assessment methods. Seeds from Fugang County populations were collected for further studies on the growth and morphological development of the species. In greenhouse conditions, seeds were planted in a gradient of temperatures and germina- tion rate were checked. Phenological events （e. g. first shoot, flowering, etc. ） were recorded in natural occurrence habitats. [ Re- suit] The surveys showed that A. artemisiifolia＇s distribution encompassed the northern and northeastern parts of Guangdong Prov- ince, including Shaoguan, Qingyuan, and Meizhou City, as well as the eastern regions, such as Shantou and Shanwei City, and western regions of Zhaoqing and Zhanjiang. Up to now, it has not been found in Pearl River Delta. No dormancy was noted for the collected seeds of A. artemisiifolia. There were two peaks of germination occurrences in natural habitats ： one in March to April, and another in November to December. It was therefore possible to observe plants at various growth stages anytime during the year. Mor- phologically, some plants formed stocky tuft plants while others, small shrubs. [ Conclusion and significance ]A. artemisiifolia may be spreading towards the central and southern regions of Guangdong Province, and inevitably becoming a threat to agriculture and human health in Pearl River Delta.