膏桐花粉活力与柱头可授性及其生殖特性研究

Pollen Viability,Stigma Receptivity and Reproductive Features of Jatropha curcas L.(Euphorbiaceae)

采用TTC法测定了膏桐花粉的活力和寿命，用联苯胺-过氧化氢法测定其柱头可授期，以套袋结果检测花粉活力与柱头可授性的变化，以研究柱头颜色变化与柱头可授性的关系以及开花式样对生殖成功的影响。结果表明：（1）膏桐雄花单花花期一般为2d，花后0～9h内花粉活力相对较高，24～33h后花粉活力较低，48h后花粉基本无活力。（2）膏桐雌花单花期为5～12d，柱头可授性在花后1～4d最强，5～8d可授性开始逐渐降低，第9天基本失去可授性。（3）膏桐柱头表面无明显的渗出物，柱头的可授性与柱头颜色的变化相关，柱头绿色越多，柱头可授性越强；遇降雨时，少量雌花的花瓣展开而柱头仍呈球状，或者花瓣不展开而柱头先悼出，此时柱头可授性较差。（4）膏桐常表现为雄性先熟，尽管雌花数目较少，但开放速率较快，且集中在第3～5天开放，雌花开放完毕也仍有雄花未开放，为展开后的柱头留有较长时间等候昆虫传送花粉，为保障生殖成功提供了机会，但少数花序先开雌花，后开雄花，有支持异交而降低自交的倾向。

Jatropha curcas is a pantropical deciduous shrub. It is monoecious,and male and female flowers are produced in the same inflorescence. Its pollen viability was evaluated by TTC（2,3,5-triphenyl tetrazolium chloride）test,its stigmatic receptivity was estimated by benzidine-H2O2 method,the stigma color in relation to its receptivity was observed,and the pollen viability and stigmatic receptivity were tested through emasculation,bagging and artificial pollinating. The results are as follows： （1）The life span of the male flower is about 2 days. Its pollen viability is relatively high in 9 hours after blooming and gets low 33 hours later. The pollen hardly has any viability after 48 hours. （2）The life span of the female flower is about 5- 12 days. The receptivity is strong during 1st-4th day and begins to decline on 5th day and on 9th day,stigma completely lose its receptivity. （3）There is not obvious secretion on the stigma. The stigma receptivity has relations with the change of its color. The higher the proportion of green stigma to the whole stigma is, the stronger its receptivity is. If rain,a few styles do not open after perianth＇s opening,or unopened stigma reached out of unopened petal. In this case, the stigma receptivity is quietly low. （4）Normally, J. curcas shows protandry,while the female flowers open very quickly with 60% of which open from the 3rd to the 5th day. There are still many unopen male flowers after all female flowers opened. This provide a long time for receptive stigma to get pollens from male flowers, and enhance the opportunity of reproductive successs. In a few racemes, the female flowers opened firstly shows a tendency to promote xenogamy and minimize geitonogamy.