滇牡丹的开花特征及繁育系统

Flowering Characteristics and Breeding System of Paeonia delavayi

以滇牡丹(Paeonia delavayi)种群数量最大、分布最集中的香格里拉群体为研究对象,通过3 a的连续观察,运用花粉活力检测、柱头可授期检测、花粉—胚珠比(P/O)、套袋试验等分析其开花特征及繁育系统。结果表明:滇牡丹种群整体花期为5月中旬至6月中下旬,单花花期6～9 d,花朵虫食率高并促进雄蕊提前散粉;正常发育的滇牡丹花瓣打开1～2 d后自内向外开始散粉,可持续5～6 d,常温下花粉活力持续时间较长,柱头在花瓣打开前1 d至打开后3 d授粉成功率均较高,散粉滞后可认为是雄蕊后熟;P/O值为(6 124～9 713)∶1,花粉量大,为较高授粉成功率提供了可能性;繁育系统中不同套袋试验表明,滇牡丹不存在自花授粉和无融合生殖现象,具有较弱的风媒传粉能力,同株异花能产生少量种子,但种子量少且饱满度较低,人工异株异花授粉和自然杂交结实率最高。繁育系统研究认为滇牡丹应为以昆虫为主要媒介的异花传粉植物,自然条件下种子的形成主要依赖于昆虫传粉活动。

Paeonia delavayi （Peaoniaceae） , the largest and the most concentrated population in Shangri-La, Yunnan Province, China, was investigated to analyze the characteristics of flower and breeding system by the detections of pollen viability, stigma receptivity period, pollen-ovule ratio （P/O） and bagging test for successive three-year observation and experiment. The results are as follows ： The florescence of P. delavayi is from mid-May to late June with anthesis period of 6-9 days, and maintained a high percentage of damaged seeds to promote early loose powder of stamen ; The flowers begin dissemina- ting pollen from inside after 1-2 days of petals opening, can maintain 5-6 days, and the activity of pollen can keep longer at normal temperature; The stigma keep a high seeds rate between one day before the petals open to three days after the petals open, and the characteristics of disseminating hysteresis is defined as stamens post-maturation; P/O value is from 6 124 ： 1 to 9 713 ： 1, suggesting that the larger quantity of pollen can increase the higher seeding rate; By bagging test, P. delavayi has no self-pollination and apomixes phenomenon with a weak capacity of the anemophily; Artificial geitonoga- my with strains of different flowers can produce a small amount of mature seeds with low plumpness; The seed setting rate of artificial xenogamy and natural pollination were higher than the others. P. delavayi is cross-pollination plant, and the seeds depend on insect activities for pollination in natural conditions.