Characteristics of flowering and pollination of Leucospermum cordifolium

Abstract

[ Objective ] This study aims to understand the flowering and fruiting characteristics of Leuco- spermum 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 . cordi- folium as materials to study flowering phenology , floral characteristics , pollen vitality , stigma acceptabili- ty , 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 dimin- ished setting rate of L . cordifolium . The presence of callose on the pistil and ovary , as well as the enlarge- ment of the pollen tube tip , are also important reasons for the low setting rate.

Keywords

• leucospermum cordifolium
• floral characteristics
• pollen viability
• pollination characteristics