甘露醇和蔗糖对菊花低温离体保存的影响

离体保存技术在植物种质资源保存方面具有独特优势和重要意义。为改善菊花离体保存技术,本研究以4个不同生长势的菊花品种为试验材料,在7±2℃条件下研究渗透调节物质甘露醇和蔗糖对不同菊花品种离体保存的影响,观察统计不同浓度蔗糖和甘露醇处理下菊花离体保存试管苗不同阶段的存活率和绿叶数,并对保存后试管苗的叶和茎段的组织结构、恢复生长能力和遗传稳定性进行了观察和鉴定。结果表明,保存12个月后,在MS培养基中添加15 g·L^-1甘露醇处理对南农橙乒乓和小洋菊试管苗的离体保存效果最佳,存活率分别达86.67%和93.33%;20 g·L^-1甘露醇处理对蒙娜丽莎黄和橙安娜保存效果最优,存活率分别达到80.00%和93.33%。60 g·L^-1蔗糖处理,南农橙乒乓和小洋菊保存12个月存活率均达到70%以上,但相比甘露醇处理,其绿叶数少、生长状况差;高浓度蔗糖(45～90 g·L^-1)对蒙娜丽莎黄和橙安娜保存效果不佳。保存12个月后,20 g·L^-1甘露醇处理的蒙娜丽莎黄和橙安娜、15 g·L^-1甘露醇处理的小洋菊和南农橙兵兵的叶片和茎段细胞间隙减小,细胞密度增加,试管苗恢复正常培养45 d后不同品种菊花生长良好,株高、叶片数、茎粗、节间长等形态指标及SSR分子标记图谱与对照相比无显著差异,保持了良好的遗传稳定性。本研究为菊花种质资源的低温离体保存提供了理论依据与技术支撑。

Effects of Sucrose and Mannitol on in vitro Conservation of Chrysanthemum at Low Temperature

In vitro techniques for conservation plant germplasm resources have unique advantages and important significance. To improve the conservation technology in chrysanthemum in vitro, four chrysanthemum cultivars with different growth potentials were as materials. The effects of osmotic substance mannitol and sucrose on chrysanthemum in vitro conversation were investigated at 7±2℃ in the present study. The survival rate and number of green leaves of plantlets treated with different concentrations of sucrose and mannitol were observed and counted at different stages. The histological structure, restoring growth ability and genetic stability of the leaf and stem segments were observed and identified. The results showed that MS medium with 15 g·L^-1 mannitol had the best effects on Nannong Chengpingpang and Xiao yangju in vitro conservation with the survival rates of 86.67% and 93.33% after 12 months, respectively. The MS medium with 20 g·L^-1 mannitol was the best for Monalisa Yellow and Anastasia Orange in vitro conservation, and the survival rate was 80.00% and 93.33%, respectively. The survival rate of Nannong Chengpingpang and Xiaoyangju were higher than 70% in MS medium with 60 g·L^-1 sucrose, but the plantlets had less green leaves and were poor growth status compared with mannitol treatments. Supplement with high concentrations sucrose (45~90 g·L^-1) in MS medium didn't work well for Monalisa Yellow and Anastasia Orange. The cell gap of leaves and stem segments of the 4 varieties, which Monalisa Yellow and Anastasia Orange treated by 20 g·L^-1 mannitol and Xiao yangju and Nannong Chengpingpang treated by 15 g·L^-1 mannitol, decreased and the cell density increased after 12 months in vitro conservation. The plantlets grew normally on normal condition after 45 days in vitro conservation. The regenerated plantlets height, number of leaf, stem diameter, internode length and SSR molecular marker profiles of vegenerated plantlets showed no significant difference from the control, indicated in vitro conservation kept the genetic stability. The results of this study provided a theoretical foundation and technical support for in vitro conservation of chrysanthemum.