结实与不结实紫薇花粉的萌发特性

Germination characteristics of fruiting and nonfruiting Lagerstroemia indica pollen

【目的】明确紫薇花粉形态特征,探究蔗糖、硼酸以及植物生长调节剂对紫薇花粉萌发的影响,以期为紫薇属花粉活力研究和杂交育种提供理论基础。【方法】本试验以新鲜紫薇花粉为试验材料,通过电子扫描显微镜观察紫薇花药和花粉形态特征,通过荧光显微镜判断花粉是否具有活力,通过离体萌发法和完全随机二因素试验讨论蔗糖和硼酸对紫薇花粉萌发的影响,采用单因素试验法探究萘乙酸(NAA)、吲哚乙酸(IAA)以及赤霉素(GA3)对紫薇花粉萌发的影响。【结果】结实紫薇花药较干燥,表面粗糙厚实,花粉数量多,长雄蕊花粉饱满,极轴长与赤道轴长比值(P/E)1.70,短雄蕊P/E值为1.50。不结实紫薇花药较湿润,表面较光滑,开裂少,长雄蕊花粉平均极轴长(P)30.13μm,赤道轴长(E)21.21μm;短雄蕊平均极轴长(P)22.42μm,赤道轴长(E)20.12μm,P/E比值为1.11,花粉均为长球形。结实紫薇花粉在柱头上有明显的花粉管萌发,而不结实紫薇花粉在柱头上未发现花粉管。蔗糖与硼酸组合试验对花粉萌发有显著影响,蔗糖浓度在100~200 g/L间时,花粉萌发率随硼酸浓度的增加而增加,蔗糖浓度为250 g/L时,随着硼酸浓度的增加紫薇花粉萌发率下降。NAA浓度在0.5~10 mg/L时,花粉萌发率随NAA浓度的增加而增加。IAA浓度在1~10 mg/L之间时,花粉萌发率随IAA浓度的增加而增加。GA3浓度在20~80 mg/L之间时,花粉萌发率均有所提高。【结论】结实紫薇和不结实紫薇花药和花粉外观形态差异不大,不结实紫薇花粉没有活力。结实紫薇花粉离体培养中,蔗糖浓度为200 g/L与硼酸浓度为150 mg/L的配置组合对紫薇花粉萌发的处理效果最好。NAA、IAA以及GA3浓度分别为10 mg/L、10 mg/L、60 mg/L时对紫薇花粉萌发的促进作用最佳。

【Objective】This study was designed to clarify the morphological characteristics of Lagerstroemia indica pollen and explore the effects of sucrose,boric acid and plant growth regulators on the pollen germination of Lagerstroemia indica,in order to provide a theoretical basis for the study of pollen viability and cross-breeding of Lagerstroemia.【Method】In this study,fresh Lagerstroemia indica pollen was used as experimental materials,and the morphological characteristics of Lagerstroemia indica anther and pollen were observed by a scanning electron microscope,and the fluorescence microscopy was used to determine whether the pollen was alive.The effect of sucrose and boric acid on pollen germination was discussed by in vitro germination method and completely randomized twofactor tests.The effect of naphthalene acetic acid(NAA),indoleacetic acid(IAA)and gibberellin(GA3)on pollen germination was investigated by single-factor tests.【Result】The fruiting Lagerstroemia indica anthers were dry,which surface was rough and thick,and the pollen quantity was high.The pollen of long stamens was full,and the ratio of the polar axis to the equatorial axis(P/E)of long stamens was 1.70,while the P/E value of short stamens was 1.50.The anther of nonfruiting Lagerstroemia indica was wet,the surface was smooth with less cracking,The average pole axial length(P)of stamen pollen of nonfruiting Lagerstroemia indica was 30.13μm,and the equatorial axial length(E)was 21.21μm.The average pole axial length(P)of short stamens was 22.42μm,which equatorial axial length(E)was 20.12μm,and the P/E ratio was 1.11.Pollen tube germination was found on the stigmas of fruiting Lagerstroemia indica pollen,while pollen tube germination was not found on stigmas of nonfruiting Lagerstroemia indica pollen.The combination test of sucrose and boric acid had a significant effect on pollen germination.When the sucrose concentration was between 100 and 200 g/L,the pollen germination rate increased with the increase in boric acid concentration.When the sucrose concentration was 250 g/L,the pollen germination rate decreased with the increase in boric acid concentration.When the concentration of NAA was 0.5-10 mg/L,the germination rate of pollen increased with the increase in NAA concentration.When IAA concentration was between 1 and 10 mg/L,the pollen germination rate increased with the increase in IAA concentration.When the concentration of GA3 was between 20 and 80 mg/L,the germination rate of pollen was increased.【Conclusion】There was no significant difference in the appearance and morphology of anthers and pollen between fruiting Lagerstroemia indica and nonfruiting Lagerstroemia indica,and the pollen of nonfruiting Lagerstroemia indica has no vitality.In vitro culture of Lagerstroemia indica pollen,the combination of sucrose concentration of 200 g/L and boric acid concentration of 150 mg/L have the greatest effect on pollen germination.When the concentrations of NAA,IAA and GA3 were 10 mg/L,10 mg/L and 60 mg/L,the promotion effect of pollen germination is the best.