花粉管顶端FM4-64波动调控机制的细胞学研究

Cytological study on the regulation mechanism of FM4-64 fluctuation at the top of pollen tube

本文通过比较0.3%细胞外钙浓度下生长的和正常培养基下生长的百合花粉管中F4-64荧光波动特性,研究花粉管顶端FM4-64波动机制。结果发现在0.3%外钙浓度下,花粉管中FM4-64波动平均频率减少为对照花粉管的38%,几乎等于花粉管生长速度减少的值;FM4-64波动的平均振幅增大为对照花粉管中的1.84倍,接近于囊泡胞吐速率增大值(1.42)和单位时间内增加的花粉管内腔体积的减小值(0.48)之和。而在同一根花粉管中越靠近顶端部位FM4-64波动振幅和周期越大。这些结果暗示着花粉管生长速度和囊泡向顶端的聚集速度是调节FM4-64波动周期的重要因素;胞吐速率、花粉管内腔体积的变化速率和顶端囊泡密度是调节FM4-64波动振幅的重要因素。

In this study,the characteristics of the fluctuation of FM4-64 fluorescence in lily pollen tubes grown in 0.3%extracellular calcium concentration and in normal culture medium were compared to decipher the underlying mechanism that causes the fluctuation of FM4-64 fluorescence at the top of pollen tube.The results showed that under 0.3%external calcium concentration,the average frequency of FM4-64 fluctuation in pollen tube decreased to 38%of that in control pollen tube,almost equaling to the decrease of pollen tube growth rate;the average amplitude of FM4-64 fluctuation increased by 1.84 times as much as that in control pollen tube,which was close to the sum of the increase of vesicle exocytosis rate(1.42)and the decrease of increasing lumen volume per unit time(0.48).Additionally,the amplitude and period of FM4-64 fluctuation increased with the distance to the top in the same pollen tube.These results suggest that the growth rate of pollen tube and the speed of vesicle aggregation to the top are the important factors regulating the period of FM4-64 fluctuation,while the exocytosis rate,the change rate of the lumen volume of pollen tube and the density of the apical vesicles are the important factors regulating the amplitude of FM4-64 fluctuation.