黄牡丹远缘杂交后代花粉粒特征

为揭示牡丹远缘杂交后代花粉粒的特征,测定了以肉质花盘亚组黄牡丹为母本,革质花盘亚组栽培品种‘日月锦’、‘层中笑’、‘百园红霞’等为父本的10个远缘杂交组合,共计11个亲本、25个后代的花粉畸形率和萌发率,用扫描电镜观察了花粉粒形态,同时也观察了花和叶的形态特征。结果表明:与双亲相比,杂交后代的花粉量极少,花粉粒萌发率极低,畸形率极高,畸形花粉粒扭曲、破碎或粘成团块状。25个杂交后代的花粉粒均为超长球形,具三拟孔沟,与母本黄牡丹和绝大多数父本一致;但杂交后代的花粉粒小于双亲,外壁纹饰类型受父本影响较大,为小穴状、穴状、网状和粗网状。结合前人的观察结果,25个杂交后代中15个与父本的纹饰类型一致,与母本纹饰类型一致的杂交后代仅有6个,与父母本纹饰类型均不同的杂交后代有4个。形态观察发现杂交后代具有父本的花盘革质、心皮被毛的特征,而小叶分裂程度较母本减轻但小叶裂片较母本加宽;花径则介于父母本之间。其中,心皮被毛、小叶裂片加宽可以结合花粉粒特征作为以黄牡丹为母本的远缘杂交后代的形态识别标记。

Pollen grain features of distant hybridized progenies of Paeonia lutea

To reveal the pollen grain features of tree peony distant hybridized progenies, the pollen grain forms of 10 dis-tant hybridization combinations, which were crossed from female parent subsect. Delavayanae Paeonia lutea and male parents Subsect Vagiatae cultivars‘Jitsugetsu Nishiki’ ,‘Cengzhongxiao’ and ‘Baiyuan Hongxia’ , totaling 11 parents and 25 progenies, were tested and the pollen grain forms were examined by scanning electron microscopy ( SEM) ,also floral and leaf morphologies were observed. The results indicated that comparing with both parents, the progenies yielded very few pollen grains with extremely low germination rate but high deformity rate and the deformed grains being twisted, broken or clustered. The progenies pollen grains were shaped like ultra-subprolate with 3-colporoidate, consistent with that of P. lutea and most male parents;while the size was smaller than that of both their parents. The extine patterns in-cluded foveolae, foveolate, reticulate and thick-reticulate, greatly affected by their male parents. Combining with the previous results,15 out of the total 25 progenies sharing the patterns of their male parents, only 6 being the same as their female parents, and 4 differing from either parent. Morphologic observation showed that the progenies had leathery flora discs and hairy carpels as their male parents,while the division of leaflet lobes was more shallow but wider than those of their female parent. The flower diameters ran between both parents. Therefore, hairy carpels and widened leaflet lobes plus pollen grain features can be used as morphological identification marks of distant hybridized progenies of which P. lutea is the famle parent.