木槿与野西瓜苗花特征和繁育系统的比较研究

为比较分析柱头裂片运动的野西瓜苗和不运动的木槿在花特征和繁育系统上的差异,对其花性状、花粉/胚珠比和不同授粉处理的座果率进行了测定。结果表明:(1)木槿与野西瓜苗在花冠大小、花瓣长及底宽、花萼长与宽、雄蕊长、最上轮雄蕊高度、雄蕊柱长及其底径、花柱长度和雌雄异位间均存在十分显著的差异(P<0.01),但二者的最下轮雄蕊高度间无显著性差异(P>0.05)。(2)木槿的花粉/胚珠比为874.90±20.79,繁育系统属兼性异交类型;野西瓜苗的花粉/胚珠比为24.72±0.68,繁育系统属专性自交类型。(3)木槿自然套袋的座果率为0%,人工自交为2.04%,人工杂交为35.85%;野西瓜苗自动自交和人工自交的座果率均为100%,人工杂交为95.30%。木槿与野西瓜苗在花性状、花粉/胚珠比及花部行为等方面形成了与其繁育系统(兼性异交vs.专性自交)相适应的花特征。

Comparative study on floral traits and breeding system of Hibiscus syriacus and H.trionum

To comparatively analyze the floral syndrome between Hibiscus trionum with stigma lobe curvature and H.syriacus without stigma lobe curvature,the floral traits,pollen-ovule ratios and fruit sets of different pollination treatments were measured. The results showed that:(1)There are significant differences in corolla width,petal length and width,petal basal width,sepal length and width,stamen length,height of uppermost stamen,stamen column length and basal diameter,style length and herkogamy between H.syriacus and H.trionum(P<0.01);but there was no significant difference in the height of lowermost stamen between H.syriacus and H.trionum(P>0.05). (2)The pollen-ovule ratio of H.syriacus was 874.90±20.79,it suggested breeding system belongs to the facultative xenogamy;while the pollen-ovule ratio of H.trionum was 24.72±0.68,it suggested breeding system belongs to the obligate autogamy. (3)The fruit set of H.syriacus was 0% under natural conditions of bags,2.04% for hand self-pollination,and 35.8% for hand cross-pollination;for H.trionum,the fruit sets of autonomous selfing and hand self-pollination were both 100%,and 95.30% for the hand cross-pollination. H.syriacus and H.trionum form the floral characteristics adapting to themselves breeding system(facultative xenogamy vs.obligate autogamy),including floral traits,pollen-ovule ratios and floral behaviors.