慈姑雌花在自然居群中的受粉过程——花粉粒落置、萌芽及花粉管生长的荧光显微观察

The process of pollen accepting in natural population of Sagittaria trifolia Linn. —observation of pollen loading, germinating and pollen tube growth by fluorescence microscopy

用荧光显微术观察了慈姑（Ｓａｇｉｔｔａｒｉａ ｔｒｉｆｏｌｉａ Ｌｉｎｎ）不同时期的雌花柱头上花粉粒的落置、萌发及花粉管的生长过程与途径。结果表明：该种雌花开花２ｈ 柱头受粉率为０，开花４ｈ 和８ｈ受粉率分别为５３８％ 和９８３％ ，柱头上花粉萌发率达１００％ ；花粉管沿雌蕊之向心一侧的组织中穿行，至子房基部后部分花粉管转向胚珠，由珠孔进入珠心。本研究发现该种花粉管常穿过子房基部至花托组织，并可进入其他雌蕊中。

The pollen loading ,germinating and pollen tube growth during the process of flowering of Sagittaria trifola Linn.was observed by fluorescence microscopy.The results are as follows :The rate of pollen accepting on stigmas 2 hours after flowers opening is 0.This value of 4 hours or 8 hours after flowers opening is 53.8%or 98.3% respectively.The frequency of pollen germination on stigmas is 100%.Pollen tubes penetrated the centripetal tissues to the bases of pistils.Some pollen tubes circumambulated to the ovules,the others penetrated the bases of pistils to the tissues of receptacles and came into other pistils .The authors deduced that this behavior of S.trifolia inconduced to the assurance of fruit-sets.