Ar^+诱变拟南芥雄性不育材料花器官表型分析及小孢子发生细胞形态学观察

Cytological Studies on Microsporogenesis and Morphological Analysis on Floral Organs of the Male-sterile Lines of Arabidopsis thaliana

利用低能氩离子作为诱变源诱变拟南芥种子,选用诱变剂量为1.5×1017ions/cm2,30 keV的能量。在其M2群体中根据有无果荚及其果荚是否异常,筛选出tc243不育突变体。用石蜡切片技术,在光学显微镜下观察拟南芥部分雄性不育材料小孢子发育过程和各时期的花形态特征,分析雄性不育的原因。从花表型上分析导致雄性不育的原因有三个方面:(1)柱头伸长过快;(2)花药生长过慢;(3)花药开裂晚。从小孢子发生的细胞形态学观察表明花粉败育主要发生在小孢子四分体时期,此时绒毡层正常,小部分四分体正常,大部分四分体外面的的胼胝体过早降解释放游离小孢子,此时的绒毡层还没解体不能提供小孢子发育所需要的营养物质,使过早释放的小孢子不能正常发育,导致最后形成大量没有活力的花粉粒。

A screen for Arabidopsis thaliana fertility mutant, mutagenized by low-energy argon ion beam with 5 × 10 ^17 ions/cm^2 and 30 keV, yields male-sterile mutant tc243. Microsporogenesis of male-sterile Arabidopsis thaliana line was investigated cytologically by using paraffin section with light microscopy and the floral organs morphology was analyzed at different developmental stage. It is concluded that there are three reasons resulted in male-sterility by floral organs abormality as follows： （ 1 ） The stomium enlongates faster; （2） Anther filaments do not elongate sufficiently to position the locules above the stigma at anthesis ; （ 3 ） The anther locules do not dehisce at the time of flower opening （ although limited dehiscence occurs later）. Moreover, the observation on microsporogenesis showned that the male-sterility was occurred because of the early released tetrad which can not develop normally for not getting the needed nuritration supplied by tapetum, then many invalid pollens were formed.