风铃木花粉萌发最适培养基及贮藏条件的筛选

Optimization of culture media and storage for germination of Handroanthus spp.pollen

【目的】筛选适宜风铃木花粉离体萌发的培养基成分及其质量浓度,并探究花粉的最佳贮藏条件。【方法】以紫花风铃木(Handroanthus impetiginosus)和黄花风铃木(H.chrysantha)的花粉为研究对象,先使用单因素试验初筛花粉离体萌发培养基中蔗糖、H_(3)BO_(3)、CaCl_(2)的适宜质量浓度和培养温度范围,再利用正交试验检验各成分之间的交互作用对花粉萌发的影响,筛选出花粉离体萌发的最适培养基;使用离体萌发法探究干燥处理对贮藏花粉活力的影响,以及干燥与新鲜花粉在不同温度(25(室温),4,-20℃)下贮藏0~30 d花粉活力的变化趋势。【结果】单因素试验结果表明,适宜紫花风铃木花粉萌发的培养基中蔗糖质量浓度为50~150 g/L,H_(3)BO_(3)质量浓度为50~200 mg/L,最适萌发温度为25℃;适宜黄花风铃木花粉萌发的培养基中蔗糖质量浓度为50~200 g/L,H_(3)BO_(3)质量浓度为100~200 mg/L,最适萌发温度为27℃;2种风铃木花粉在不添加CaCl_(2)的培养基中萌发率均显著高于其他处理,表明Ca^(2+)或Cl^(-)对花粉萌发起抑制作用。正交试验中紫花风铃木在蔗糖100 g/L+H_(3)BO_(3)100 mg/L+CaCl_(2)200 mg/L的培养基中萌发率为48.31%,显著高于其他处理,但显著低于单因素试验中同质量浓度蔗糖和H_(3)BO_(3)下CaCl_(2)为0 mg/L的萌发率(75.23%);黄花风铃木在蔗糖150 g/L+H_(3)BO_(3)200 mg/L+CaCl_(2)0 mg/L的培养基中萌发率为62.69%,显著高于其他处理。相同贮藏温度下,干燥处理能减缓花粉活力的下降速度;随着贮藏时间的延长,不同处理下的花粉活力均逐渐降低;新鲜或干燥花粉活力在-20℃贮藏条件下的下降速度均明显低于25和4℃贮藏条件,表明贮藏时间相同时,一定温度范围内贮藏温度越低,越有利于花粉活力的保持。【结论】紫花风铃木花粉离体萌发最适培养基为蔗糖100 g/L+H_(3)BO_(3)100 mg/L,培养温度25℃;而黄花风铃木花粉离体萌发最适培养基为蔗糖150 g/L+H_(3)BO_(3)200 mg/L,培养温度27℃;干燥处理后再进行低温贮藏能更好地保持风铃木花粉活力。

【Objective】This study screened the suitable medium components and concentrations for in vitro germination of Handroanthus spp.pollen and explored the best storage conditions.【Method】Suitable temperature and concentrations of sucrose,H_(3)BO_(3)and CaCl_(2)in medium for Handroanthus impetiginosus and H.chrysantha pollen were preliminarily screened.Then,the orthogonal experiment was used to test the interaction between components to select the optimal medium for in vitro germination of pollen.The influence of drying treatment on storage pollen viability was investigated and the changes of pollen viability of dried and fresh pollen at different storage temperatures(25(room temperature),4 and-20℃)and storage times(0-30 d)were analyzed.【Result】The single factor tests showed that the optimal sucrose concentration,H_(3)BO_(3)concentration and temperature for in vitro germination of H.impetiginosus pollen were 50-150 g/L,50-200 mg/L and 25℃,while those for in vitro germination of H.chrysantha pollen were 50-200 g/L,100-200 mg/L and 27℃,respectively.Pollen germination rates of both Handroanthus spp.species in the medium without CaCl_(2)were significantly higher than other groups,indicating that Ca^(2+)or Cl^(-)inhibited pollen germination.In the orthogonal tests,the germination rate of H.impetigi-nosus in the medium of sucrose 100 g/L+H_(3)BO_(3)100 mg/L+CaCl_(2)200 mg/L was 48.31%,which was significantly higher than other groups,but it was significantly lower than that of the single factor experiment with sucrose 100 g/L+H_(3)BO_(3)100 mg/L+CaCl_(2)0 mg/L(75.23%).The germination rate of H.chrysantha in the medium of sucrose 150 g/L+H_(3)BO_(3)200 mg/L+CaCl_(2)0 mg/L was 62.69%,which was significantly higher than that in other groups.At same storage temperatures,drying treatment slowed down the descent rate of pollen viability.With the extension of storage time,pollen viability under different treatments decreased gradually.The descent rates of fresh or dry pollen viability at-20℃were significantly lower than 25℃and 4℃,indicating that lower storage temperature within certain range was more beneficial to maintain pollen vitality at same storage times.【Conclusion】The optimal conditions for in vitro germination of H.impetiginosus pollen were sucrose 100 g/L+H_(3)BO_(3)100 mg/L at the temperature of 25℃,while the optimal conditions of H.chrysantha pollen were sucrose 150 g/L+H_(3)BO_(3)200 mg/L at 27℃.Drying treatment followed by low-temperature storage could better maintain the vitality of Handroanthus spp.pollen.