Observation on the germination of pollen and growth of pollen tubes in interspecific distant hybridization of Sect. Paeonia(芍药组（Sect. Paeonia）种间远缘杂交花粉萌发与花粉管生长观察)

In this study, we carried out an interspecific distant hybridization experiment with Chinese Paeonia lactiflora as female parent and P. intermedia, P. obovata, P. veitchii and P. mairei as male parents, aiming to screen the best hybrid combinations. Pollen germination and pollen tube growth of the male parents of both close hybridization and distant hybridization were observed. The results are summarized as follows: 1) three hybrid combinations with high seed-setting rates were identified, namely ‘Miss America’×P. veitchii, ‘Miss America’×P. obovata, and ‘Lian Tai’×P. obovata. Additionally, two hybrid combinations, ‘Miss America’×P. obovata and ‘Karl Rosenfield’×P. obovata, with a higher number of effective seeds and seedling emergence rates, were selected. 2) The status of pollen tube growth within 1-48 h post-pollination was closely observed. It was confirmed that the primary cause of incompatibility in distant hybridization was the callose reaction in the stigma. This study provides a theoretical basis of cytology and germplasm materials for the cultivation of new ornamental peony varieties.(本研究以中国芍药品种为母本，以块根芍药、草芍药、川赤芍、美丽芍药为父本进行芍药组种间远缘杂交试验，筛选优良杂交组合，观察近缘杂交和远缘杂交组合中父本花粉在母本柱头上的萌发及花粉管生长过程。结果表明：1）本试验筛选出3个结实率较高的组合，分别为‘美国小姐’×川赤芍、‘美国小姐’×草芍药以及‘莲台’×草芍药；筛选出2个有效种子数和出苗率较高的组合，为‘美国小姐’×草芍药和‘卡尔红’×草芍药。2）对近缘杂交和远缘杂交授粉后1～48 h内的花粉管生长状态进行观察，明确远缘杂交组合不亲和的主要原因是柱头内部存在胼胝质反应。本研究为培育观赏芍药新品种提供了细胞学理论依据和种质材料。)