In vitro germination and rapid detection of pollen viability for Choerospondias axillaris
[Objective]This study aims to screening the suitable cultivation conditions and time of in vitro pollen germination as well as studying the rapid detection method of pollen viability for Choerospondias axillaris,thus providing reference for artificial pollination and hybrid breeding of Choerospondias axillaris in the future.[Method]The flower spikes of Choerospondias axillaris which will be bloomed were collected.Mature pollen of Choerospondias axillaris through hydroponic method was collected.Different concentrations of sucrose,boric acid and calcium chloride were set up.The L16(43)orthogonal test design and liquid culture method were used to select the best pollen culture conditions and culture time of Choerospondias axillaris in vitro.I2-KI staining method,TTC staining method and red ink staining method were used to dyeing the pollen respectively.Combined with the germination rate obtained after the culture of the best pollen germination conditions in vitro,different staining methods were compared to find a suitable method for rapid detection of pollen viability of Choerospondias axillaris.[Result]Sucrose,boric acid and calcium chloride had significant effects on pollen germination rate and pollen tube length of Choerospondias axillaris(P<0.05).The effects of three factors on pollen germination of Choerospondias axillaris were as follows:sucrose(A)>calcium chloride(C)>sucrose(B).The results of the orthogonal experiment showed that the combination of 20%sucrose,0.3%boric acid and 0.03%calcium chloride had the best pollen germination effect.with the pollen germination rate of 91.41%and the pollen tube length of 250.91 μm.According to the results of range and variance analysis,the combination of 20%sucrose,0.3%boric acid,and 0.02%calcium chloride,had the best pollen germination effect.After verification,the pollen germination rate is 93.27%,and the pollen tube length is 296.34 μm.The results were superior to the combination of 20%sucrose,0.3%boric acid,and 0.03%calcium chloride.When the pollen was cultured in vitro for 6h,the pollen germination rate tended to stabilize,and the pollen tube length was moderate and not stacked,which was conducive to observation and statistical data.The red ink dyeing method had a similar germination rate to pollen in vitro germination culture,and there was no significant difference between the two methods(P>0.05),which can be used as a rapid detection method of the pollen vitality of Choerospondias axillaris.[Conclusion]The best culture combination for pollen germination in vitro of Choerospondias axillaris is 20%sucrose,0.3%boric acid and 0.02%calcium chloride.The optimal cultivation time is 6 h.The red ink dyeing method is suitable for rapid detection of pollen viability of Choerospondias axillaris.