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美味猕猴桃原生质体再生植株细胞遗传学研究 Ⅱ.性别性状变异和小孢子发生及其发育命运

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

  • 摘要: 对美味猕猴桃同一雌株叶原生质体再生植株进行了形态学、细胞学以及育性特性的比较研究,确认该体细胞无性系性别性状发生变异。其中60%雄性再生植株退化的雌蕊仍保留不同程度的雌性化特征,但雌性全不育;小孢子则能发育成有功能的雄配子体,但有一定的功能缺陷。再生雌株中P1组群性状特征与母株相似;P2组群花发育畸形,导致雌性不育或育性极差。细胞学研究表明,小孢子母细胞减数分裂时染色体异常行为对小孢子发生的影响不能决定其性别类型;雌株类型小孢子败育过程有受基因调控的细胞学特征。认为雌株和雄株小孢子的发育受控于不同的基因体系,具性别的特异性。再生植株性别性状发生变异可能是性别控制基因或染色体发生结构性变异所致。母株染色体上累积的结构性变异与该遗传基础具易变性密切有关。

     

    Abstract: 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.

     

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