Studies on pollen germination and storage of Cycas species.

Pollen suspension culture was conducted under combinational conditions of different grades of pH and concentrations of sucrose and boric acid to estimate pollen viability of Cycas debaoensis,C.bifida,C.parvulus,C.eloneata. Pollen viability of C.parvulus and C.elongata was also estimated after being stored in different temperature and humidity conditions.The results showed that:(1)the optimal medium for the germination of those cycad's pollen was compose of 1%—2.5%sucrose+100-500 mg/L boric acid and pH was in the range of 6.5—7.0;(2)the pollen stored in a sealed container with desiccant in room temperature was viable up to one month;(3) the pollen being stored under 0℃in a container without desiccant could kept its viability over 4 months;(4)through artificial pollination, the seed setting rate of C.elongata could be up to 90.3%by using liquid nitrogen stored pollen,which is no remarkable difference to those of using fresh pollen;(5)the pollen of C.elongata,after stored in liquid nitrogen for period of time,did not show significant loss of viability after dried to 13.2%—15.5%of water content and the results indicated that stored in liquid nitrogen can be used as a long term storage measure for cycad pollen.