摘要
用细胞学和统计学方法研究了Ｃａ２＋ 通道专一性阻滞剂ｎｉｆｅｄｉｐｉｎｅ（Ｎｉｆ）对烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍＬ．）离体花粉萌发、花粉管生长及生殖核分裂的影响。１０－ ４ ｍ ｏｌ／ＬＮｉｆ可抑制花粉萌发。Ｎｉｆ对花粉管生长的影响与其浓度和处理持续时间有关，１０－ ４ ｍ ｏｌ／Ｌ Ｎｉｆ始终抑制花粉管生长；而１０－ ７～１０－ ５ ｍ ｏｌ／ＬＮｉｆ在较短时间内起不同程度的促进作用，之后逐渐过渡为抑制花粉管生长。较高浓度处理可使花粉管形态趋向异常，细胞质流动趋于停滞。Ｎｉｆ抑制生殖核的有丝分裂，相对推迟分裂高峰。Ｎｉｆ使花粉管中的金霉素（ＣＴＣ）荧光趋于减弱，表明Ｎｉｆ通过抑制Ｃａ２＋ 通道活性产生生理效应。
The deals with the effects of nifedipine (Nif), a Ca 2+ channel blocker of rather high specificity,on pollen germination,pollen tube growth and division of generative nucleus (GN) in experimentlly germinated pollen tubes of Nicotiana tabacum L. Pollen germination was inhibited by the addition of 10 -4 mol/L Nif whereas no significant inhibition by 10 -7 ～10 -5 mol/L Nif was observed.The effects of Nif on pollen tube growth were related to its concentration and duration of treatment.At the earlier stage, tube growth was promoted at the lower concentrations (10 -7 ～10 -5 mol/L),but was significantly inhibited at a concentration of 10 -4 mol/L Nif.With increasing time of culture,even the lower concentrations also became harmful;the stronger the concentration,the earlier the transition from promotion to inhibition.Generally, inhibition of tube growth occurred within 24 hours of culture with different extent in various concentrations. Moreover, higher concentrations also tended to disturb tube morphology and cytoplasmic streaming.Nif was observed to perturb GN division at various concentrations,either blocked it completely at 10 -4 mol/L,or only delayed it at 10 -7 ～10 -5 mol/L.The dynamics of membrane associated calcium in pollen tubes was tested with chlorotetracycline (CTC).With increasing time of culture and escalating Nif concentration,CTC fluorescence weakened gradually,indicating that the physiological effects of Nif is mediated by its in hibition on Ca 2+ channel activities.
基金
国家自然科学基金
