YS型小麦温敏不育系A731雄性败育的细胞学研究

Cytological Studies on Male Fertility Abortion of YS Type Thermo-sensitive Male Sterile Wheat Line A731

为了明确YS型小麦温敏不育系雄性败育发生的具体时期和败育的细胞学机理,以温敏不育系A731和其同型保持系731B为供试材料,采用花粉粒制片和石蜡切片法,对其花药形态特征及小孢子形成和发育过程进行细胞学观察。结果表明,不育系和保持系均能进行正常的减数分裂形成小孢子;保持系731B的花药和小孢子发育正常,只有极少数后期发育不正常;不育系A731花粉不育类型为典败和圆败;单核期小孢子可正常形成核,二核期正常形成营养核和精核,但有些营养核不清晰,三核期花粉粒染色后精核呈圆形,不能形成梭形精子;二核期花药中绒毡层提前解离侵入药室,造成小孢子败育。表明该温敏不育系的败育主要发生在二核期到三核期,推测二核期是其雄性败育发生的关键时期,败育的原因可能与绒毡层结构的异常有关。

YS type thermo-sensitive male sterile wheat line is a valuable material for heterosis study and utilization.In this study,the pollen grain production and paraffin section of male-sterile line A731 and its maintainer line 731B were observed to clarify its key period of abortion and cytological mechanism of male sterility.The results showed that both male sterile line and maintainer line can proceed normal meiosis to the formation of the anther,and the development of small spores of 731B were normal,only a very small part were abnormal at the later stage.The pollen sterility type of male sterile line A731 were stained as spherical abortive;small spores had a normal formation of the nucleus at mononuclear phase,the vegetative nucleus and sperm nucleus were formed at binucleate,but some vegetative nucleus was not clear.Pollen stained with fluorescent dye showed that the sperm nucleus were round instead of the particle shape at trinucleate;At binucleate phase,the tapetum of anther dissociated in advance and intruded into chamber resulting in microspore abortion.These indicated that the sterility of this thermo-photoperiod sensitive male sterile occurred between binucleate and trinucleate phases,so binucleate phase is the critical period,the reasons for abortion might associate with the abnormal of tapetum structure.