外来入侵植物黄花刺茄与其近缘非入侵植物少花龙葵繁育系统的比较

黄花刺茄是一种具有严重危害性的外来入侵植物,本研究以分布于我国的4个黄花刺茄种群为材料,与其同属的外来非入侵植物少花龙葵为近缘种对照,在同质种植园内对其繁育系统进行了比较研究。黄花刺茄和少花龙葵在开放性授粉和补充授粉条件下的平均结籽率没有显著差异;套袋处理下,黄花刺茄的平均结籽率(29.5%)显著低于少花龙葵(47.0%);去雄套袋处理下两者均没有可育种子产出,表明黄花刺茄和少花龙葵均无自发无融合生殖特性。黄花刺茄的平均自交指数为0.38,低于少花龙葵(0.64);平均花粉限制指数(0.29)和平均传粉者的贡献指数(0.49)均大于少花龙葵(0.08和0.31)。目前黄花刺茄分布于中国的12个省份,在全球发生数量为3835次;少花龙葵分布于中国的18个省份,在全球发生数量为10897次。外来入侵植物黄花刺茄的自交亲和性低于外来非入侵植物少花龙葵,说明自交亲和性高低与两种植物的入侵性强弱无显著相关关系,但与其分布范围呈正相关。

Breeding-system comparison between alien invasive Solanum rostratum and its non-invasive congener S. americanum

Solanum rostratum is a severely invasive alien plant species in China. Using four S. rostratum populations and non-invasive congener S. americanum, we conducted a common garden experiment to compare their breeding systems. No significant difference in average seed set between the two species under open pollination and supplementary pollination conditions. However, under the bagged self-pollination condition, S. rostratum had significantly lower average seed set (29.5%) than S. americanum (47.0%). No fertile seeds were detected in the emasculation treatments for both species, suggesting no autonomous apomixis in them. S. rostratum had a lower average autofertility index (0.38) than S. americanum (0.64). S. rostratum had higher average pollen limitation index (0.29) and average pollinator’s contribution index (0.49) than S. americanum (0.08 and 0.31, respectively). S. rostratum was found in 12 provinces of China and in 3835 locations globally, which were lower than S. americanum with 18 Chinese provinces and 10897 locations globally. The invasive alien S. rostratum had lower self-compatibility than the non-invasive alien S. americanum. Thus, the invasiveness of those two species was not significantly correlated with their self-compatibility, but positively correlated with their distribution range.