针垫花开花授粉生物学特性

Characteristics of flowering and pollination of Leucospermum cordifolium

【目的】深入了解针垫花的开花结实特性,探求结实率低的原因,推动其种子生产、杂交育种、花期调控以及新品种培育工作。【方法】以针垫花为主要材料,对其开花物候、花部特征、花粉活力、柱头可授性、杂交指数、授粉结实特性进行研究。【结果】(1)针垫花的花期一般在冬末、早春至夏季;(2)最适合测定其花粉活力的离体萌发培养基为30 g/L蔗糖+150 mg/L硼酸+50 mg/L氯化钙;(3)在开花第1—7天柱头可授性逐渐加强,第5-7天时最为强烈;杂交指数估算结果表明针垫花部分自交亲和,异交,需要传粉者;(4)田间观测发现,在自然状态下结实率较低,但可以自发完成授粉,不存在无融合生殖现象;(5)人工授粉试验发现针垫花异株异花授粉的结实率最高,为17.14%,而自花授粉的结实率最低,为4.94%。【结论】针垫花的雌雄蕊异熟是导致自然结实率低的原因;雌蕊花柱与子房部位的胼胝质以及花粉管顶端膨大畸形也是造成结实率低的重要原因。

[Objective]This study aims to understand the flowering and fruiting characteristics of Leucospermum cordifolium and the reasons of low fruiting rate in order to promote seed production,hybrid breeding,flowering period regulation,and new variety cultivation.[Methods]This report used L.cordifolium as materials to study flowering phenology,floral characteristics,pollen vitality,stigma acceptability,hybridization index,and pollination and fruiting characteristics.[Results](1)The flowering period of L.cordifolium was in late winter,or early spring to summer.(2)The most suitable in vitro germination medium for measuring pollen vitality contained 30 g/L sucrose+150 mg/L boric acid+50 mg/L calcium chloride.(3)The receptivity of the stigma was gradually increased from 1 day to 7 day of flowering,and was strongest from 5 day to 7 day.The results of hybridization index indicated that L.cordifolium was partially self-compatible or cross compatible,requiring pollinators.(4)Field observation showed that fruiting rate was low in its natural state,but it could spontaneously complete pollination and there was no phenomenon of apomixis.(5)The artificial pollination experiment found that L.cordifolium had the highest setting rate of 17.14%,while self-pollination had the lowest setting rate of 4.94%.[Conclusion]The disparity in maturation times of the pistil and stamen is the primary factor contributing to the diminished setting rate of L.cordifolium.The presence of callose on the pistil and ovary,as well as the enlargement of the pollen tube tip,are also important reasons for the low setting rate.