玉米花粉管伸长的时空进程

以玉米花丝为材料,采用苯胺蓝染色法检测授粉后玉米花粉管的伸长进程。授粉0.5 h后开始每隔1 h对花丝取样,直至48 h;所取花丝经固定、软化和苯胺蓝染色后压片,在倒置荧光显微镜紫外光滤片下观测花粉管伸长情况。结果表明,花粉在授粉后0.5 h就开始萌发,随后花粉管开始伸长并逐渐加速,3 h后以较高速度0.8~0.9 cm/h伸长,维持17 h后速度开始下降,22 h后大部分进入子房,整个过程中花粉管的平均伸长速度为0.68 cm/h。玉米花粉离体自然条件下的生命时间为5 h,此后开始分解。在玉米花粉介导转基因时需对离体的花粉与外源基因进行处理,这个过程消耗花粉部分内容物和能量,且影响花粉的活力,是玉米花粉介导法转化率偏低的一个重要原因。

Space-time Processes of Maize Pollen Tube Elongation

Used maize filaments as the research materials, the process of pollen tube elongation through aniline blue staining was observed. Filaments of half an hour after pollination was started to be sampled, and sampling continued every 1 hour till the 48th h. The filament samples were fixed, softened, stained, and squashed onto a slide; then pollen tubes were observed under an inverted fluorescence microscope with UV filter. The results showed that this method could help to clearly observe the elongating pollen and its stop point. Pollen started to germinate in 0.5 h after pollination, and pollen tube extension sped up to a speed of 0.8-0.9 cm/h, and continued for 17 h, then finally slowed down and went into ovary in 22^nd hour. The average speed of pollen tube elongation was 0.68 cm/h. The life span of pollen in vivo was about 5 h under natural condition, then the pollen was began decomposed. Thus, in the procedure of maize pollen-mediated gene transformation, the mixing process of in vitro pollen and foreign gene would expend partial pollen internal content, vigor and energy, which lead to relatively low transformation rate.