CYTOGENETIC STUDIES ON REGENERATED PLANTS DERIVED FROM PROTOPLASTS OF ACTINIDIA DELICIOSA Ⅱ.VARIATION OF SEX CHARACTER,MICROSPOROGENESIS AND IT'S DEVELOPMENTAL FATE

Compartive studies of morphology,cytology and sex character on regeneratedplants derived from leaf protoplasts of one pistillate plants of Actinldia deliciosa werecarried out.The variatioh of sex character occurred in these regenerated plants can be divided into three groups that were staminte plants (S) and two kinds of pistillate plants(P₁ and P₂).Sixty percent of regenerated plants were staminate plants,the degeneratedpistil of which still retained femaleness to some extent,but was female sterile completely.Functional male gametophytes with certain defect can develop from microspores.Thecharacter of group P₁ was similar to parent plant,but the flowers of group P₂ developoedaberrantly that led to female sterile or very low fertility.It was revealed by cytologicalexamination that the abnormal behaviour of chromosome occurred in meiosis of microspore mother cell (PMC) is not sufficient to determine the sexual type.It was suggested that the abortion of microspores in pistillate plants is regulated by gene,and thedevelopment of microspores in pistillate and staminate plants is regulated by differentgenes and with sex specificity.It inferred that the variation of sex character in regenerated plants is the results of the expression of sex-regulated gene or the structional variation of chromosomes.It was considered also that structural variation accumulated on thechromosomes of parent plant makes the genetic composition unstable.