不同生境中喜旱莲子草雄蕊雌化的发生及其在花序内的分布模式

Alternanthera philoxeroides in Different Habitats:Occurrence of Stamen Feminization and Its Distribution Pattern Within the Inflorescence

研究入侵植物喜旱莲子草雄蕊雌化现象与生境的关系及其进入入侵地后的繁殖策略,以期补充该入侵植物的入侵理论,为该入侵植物的综合防治提供重要的理论依据。以喜旱莲子草为研究材料,探究不同生境及不同花序位置上雄蕊雌化现象的发生。以雄蕊水平上的雄蕊雌化程度和花水平上的雄蕊雌化频率,作为衡量喜旱莲子草雄蕊雌化现象发生的参数。结果表明:(1)雄蕊雌化现象在喜旱莲子草中普遍发生,雌化程度及雌化频率普遍较高。(2)3种生境中喜旱莲子草雄蕊雌化程度为水生(5.5032)>湿生(5.2403)>旱生(5.2066),雄蕊雌化频率也为水生(86.75%)>湿生(77.28%)>旱生(76.17%)。(3)喜旱莲子草雄蕊雌化现象的发生,从顶部到底部无显著差异。喜旱莲子草的雄蕊雌化现象倾向于在水分充足的条件下发生,该现象在花序内呈相对均匀的分布模式,与其进入入侵地后以无性繁殖为主要繁殖方式的特性相符。

The authors studied the relationship between the stamen feminization phenomenon of the invasive plant Alternanthera philoxeroides and its habitat,and explored its reproductive strategy after entering the invasive site,aiming to supplement the invasion theory of this invasive plant and provide a theoretical basis for its integrated control.In this study,the occurrences of stamen feminization in different habitats and different inflorescence positions were investigated using A.philoxeroides as the study material.The degree of stamen feminization at the stamen level and the frequency of stamen feminization at the flower level were used as parameters to measure the occurrence of stamen feminization in A.philoxeroides.The results show that:(1)stamen feminization occurs commonly in A.philoxeroides,and the degree and frequency of feminization are generally high;(2)the degree of stamen feminization in A.philoxeroides in the three habitats is aquatic(5.5032)>wet(5.2403)>dry(5.2066);the frequency of stamen feminization is also aquatic(86.75%)>wet(77.28%)>dry(76.17%);(3)there is no significant difference in the occurrence of stamen feminization in A.philoxeroides from the top to the bottom.Thus,the phenomenon of stamen feminization in A.philoxeroides tends to occur under conditions of sufficient moistre,and the phenomenon shows a relatively uniform distribution pattern within the inflorescence,which is consistent with its characteristic of asexual reproduction as the main mode of reproduction after entering the invasive site.