大花黄牡丹的开花特性与繁育系统

2019-2020年观察河南省栾川县引种栽培的西藏特有植物大花黄牡丹(Paeonia ludlowii)开花过程和访花昆虫,计算花粉-胚珠比(P/O)和杂交指数(OCI),检测花粉活力与柱头可授性并结合人工控制授粉试验,探究其开花特性和繁育系统类型。结果表明:(1)大花黄牡丹花朵昼开夜合,花朵随花冠展开下垂,伴花冠闭合回升。(2)花淡香,有花内蜜腺,花瓣与雌蕊子房之间是主要泌蜜部位。(3)2019年群体花期为5月17日～6月19日,持续34 d,为集中开花模式;单花花期(8.95±1.28)d。(4)大花黄牡丹从开花第2天至第6天皆具有较高的花粉活力;开花前1天柱头即具有可授性,持续12 d;花粉活力与柱头可授性最强时期高度重合,共2 d。(5)P/O为119 356.31～731 238.07,OCI为4,繁育系统类型为异交、部分自交亲和、需要传粉者。(6)大花黄牡丹可能有无融合生殖,但不稳定,去雄严重影响结实。(7)河南省栾川县大花黄牡丹主要访花昆虫为意大利蜜蜂(Apis mellifera ligustica)、芦蜂(Ceratina sp.)和隧蜂(Halictus sp.)、灰带管蚜蝇(Eristalis cerealis)和黑带食蚜蝇(Episyphus balteatus),其中意大利蜜蜂访花次数最多。(8)大花黄牡丹侧花比顶花结实稳定,杂交育种时建议在侧花开放第3、4天授粉以获得较高结实率。

Flowering Characteristics and Breeding System of Paeonia ludlowii

The flowering process and pollinators of Paeonia ludlowii, an endemic plant in Tibet, which introduced and cultivated in Luanchuan County, Henan province were observed in 2019 and 2020. Pollen ovule ratio(P/O), outcrossing index (OCI), pollen viability and stigma receptivity, artificial pollination were used to study flowering characteristic and breeding system type. The result showed that: (1) P. ludlowii flowers bloomed during the day and closed at night, the flowers tilted down as corolla unfolded and tilt upward as corolla closed. (2) Flowers lightly fragrance with intrafloral nectary, the main secreting site was between petal and ovary. (3) The florescence of group was from May 17 to June 19 in 2019, lasting 35 days, which was a concentrated flowering pattern, well a single flower bloomed (8.95±1.28) d. (4) The pollen activity was high from the 2nd day to the 6th day in florescence, the stigma got receptivity 1 day before flowering and lasted for 12 days. (5) The P/O was 119 356.31-731 238.07, OCI was 4, its breeding system type is outcrossing, partial self inbreeding, and pollinators were required. (6) it may have unstable apomixis, and emasculation will severely affecting seed setting. (7) The main pollinators were Apismellifera ligustica, Ceratina sp., Halictus sp., Eristalis cerealis and Episyphus balteatus. Among them, A. ligustica visited flowers most frequently. (8) The seed setting of side flowers were more stable than that of top flowers, it is recommended to pollinate side flowers on the 3rd and 4th day in florescence to obtain a higher seed setting rate in crossing breeding.