Comparative Study On Pollen Fertility Difference Of Three Kinds Of Zingiberaceae Herbs

Zingiber zerumbet,Z.zerumbet f.variegated and Z.nudicarpum was perennial herb in Zingiberaceae,distributed in the global tropical and subtropical regions.Z.zerumbet was one of new ornamental plant with the red inflorescence,as well as Z.zerumbet f.variegated with the color-spot leaves.However,compared with the fertile Z.nudicarpum,Neither self-sterility nor hybrid sterility of Z.zerumbet and Z.zerumbet f.variegated was fertile,and its genetic improvement difficult.This study was based on infertile(Z.zerumbet,Z.zerumbet f.variegated)and fertile(Z.nudicarpum)materials,which were used for the experiment,such as artificial cross-pollination and pollen germination in vitro,in addition,exploring the difference about the gene expression of pollen during stigma germination between the infertile and the fertile materials.The abortion mechanism of this three materials was discussed,which laid the theoretical foundation for the future hybrid breeding of the Z.zerumbet.The main findings are as follows:(1)The fertility analysis of Z.nudicarpum showed that under the condition of artificial cultivation in Guangzhou,the seed setting rate of Z.nudicarpum was 75%,which was fertile,while the variation of Z.zerumbet and Z.zerumbet f.variegated could not bear fruit under the same conditions.(2)Comparison of Pollen of three kinds of Ginger Flower by experiment such as Pollen germination in vitro,Observation of pollen morphology by scanning electron microscope(SEM)and Determination of pollen activity.The results showed that there were significant differences in the germination rate of three different species of Ginger,the germination rate of Z.nudicarpum was the highest(70.71%),the rate of Z.zerumbet f.variegated was 17.5%,and the lowest was Z.zerumbet.There was no significant difference in the appearance of pollen morphology between the fertile Z.nudicarpum andthe infertile Z.zerumbet f.variegated and Z.zerumbet.After the pollen was treated with I2-KI method,the normal pollen rate of Z.nudicarpum,Z.zerumbet f.variegated and Z.zerumbet was 60.12%.29.14% and 10% respectively.The pollen abortion rate of Z.zerumbet and Z.zerumbet f.variegated was 78.58% and 53.01%,respectively.The results showed that the pollen types of Z.nudicarpum were mainly normal pollen,and the pollen types of Z.zerumbet f.variegated and Z.zerumbet were mainly round abortive pollen,and the starch content in pollen was not high.(3)The temporal and spatial expression patterns of MALE GAMETOPHYTE DEFECTIVE 2(MGP2),MALE GAMETOPHYTE DEFECTIVE 4(MGP4)and BURSTING POLLEN(BUP)were studied by fluorescence quantitative PCR.The results showed that MGP2,MGP4 and BUP of three different species of Ginger,were found in pollen which higher than leaves,bracts,roots,petals.At the early stage of pollen germination,there was no significant difference among the three groups,but the relative expression of Z.nudicarpum increased significantly in the latter stage of pollen germination,while Z.zerumbet f.variegated and Z.zerumbet decreased significantly in the latter stage of pollen germination.At 1 h of pollen germination,the expression of Z.nudicarpum was significantly higher than Z.zerumbet f.variegated and Z.zerumbet.(4)RNA in situ hybridization analysis showed that MGP2,MGP4 and BUP had hybridization signals on the pollen tube at 1 h of germination,but weak or no signals were found on the Z.zerumbet and the Z.zerumbet f.variegated on the pollen tube at 1 h of germination.