映山红开花习性与花粉生活力研究

Study on the Flowering Habit and Pollen Viability of R.arborescens Planch

[目的]探讨映山红的开花习性及花粉生活力。[方法]以映山红(Rhododendron arborescens)为试验材料。观察映山红(R.simisiiPlanch)开花的习性;采用离体培养基萌发测定法,以及培养基中蔗糖的浓度、培养温度、硼酸、钙离子等因素对花粉萌发和花粉管伸长的影响。[结果]映山红花期4～6月,单花期3～5 d;花紫色,2～6朵簇生于枝端;花萼5裂,长2～4 mm;花冠宽漏斗状,长4～5 cm,5裂;雄蕊7～10,花药紫色;柱头头状。蔗糖浓度为5%时映山红花粉萌发最好;光照条件下25℃时萌发率最高,达70%以上;培养基为20mg/L硼酸+10 mg/L氯化钙+5%蔗糖+0.5 g琼脂,萌发率最高达87%;在一定浓度(0～20 mg/L)范围内,钙离子对映山红花粉的萌发率影响不大,主要影响花粉管长度;对花粉萌发率的影响比较明显,浓度间差异均达显著水平,在一定硼酸浓度(0～20 mg/L)范围内,随着硼酸浓度的增加花粉的萌发率上升。[结论]该研究可为今后利用映山红开展人工育种奠定基础。

[Objective] To investigate the flowering habit and pollen viability of R.arborescens Planch.[Method] R.arborescens Planch as test material,effects of sucrose concentrations,culture temperature,boric acid and Ca2＋ on the pollen germination and tube growth were studied through in vitro culture method.[Result] The flower season of R.arborescens Planch lasts 4 to 6 months with single flowering phase of 3-5 d;purple,2-6 flowers cluster in the end of branches;calyx 5-lobed,2-4 mm in length;funnel-form corolla,4-5 cm in length,5-lobed;7-10 stamens,purple anther;capitate stigmas.5% sucrose was proved to be the best for the germination of pollen,and the germination rate was the highest at 25 ℃ in daylight（more than 70%）;the optimum combination for the germination of pollen was 20 mg/L boric acid ＋ 10 mg/L CaCl2 ＋5% sucrose ＋0.5% agar,under this condition,the germination rate reached as high as 87%;Ca2＋ had little effect on the germination of pollen in the range of 0-20 mg/L,while which played important role in the growth of pollen tube;the germination rate of pollen increased with boric acid concentration rose（0-20 mg/L）,and the differences among the groups were obvious.[Conclusion] This study would provide reference for the biological engineering of R.arborescens Planch in further research.