芍药属组间杂交种皮开裂种子的解剖观察与胚培养

Anatomical observation and embryo culture of intersectional hybrid seeds with ruptured testa in Paeonia L.

【目的】探究芍药属组间杂交种皮开裂种子的内部状态和胚培养成苗表现,为揭示种皮开裂种子的成苗潜力、提高组间远缘杂交育种效率提供参考。【方法】以24个芍药属组间杂交组合种皮开裂的种子为试验材料,解剖后观察并统计胚和胚乳的发育情况,通过离体培养观察胚的萌发和生长规律,分析不同组合种皮开裂种子发育和成苗差异。【结果】芍药属24个组间杂交组合中均出现了种皮开裂的杂交种子,平均种皮开裂率高达61.08%;1767粒种皮开裂种子中,有11.09%的胚乳已腐烂;胚乳未腐烂种子中,约90%以上种子的胚乳存在不同程度的损伤或病变,24.18%的种子内部未观察到可见胚。对解剖得到的1185个组间杂种胚进行离体培养发现,有24.73%的胚不萌发,63.47%的胚生长异常,仅有4.47%的胚能正常生长,得到完整植株。胚培养得到的完整植株具备良好的活力,移栽成活率达到86.79%。24个杂交组合种皮开裂种子通过离体胚培养共得到46株移栽成活的组间杂种苗,平均成苗率为2.60%,接近正常组间杂交种子的播种成苗率(2.75%)。【结论】种皮开裂现象在芍药属组间杂交种子中普遍存在,是组间远缘杂交障碍的重要表现之一,用离体胚培养技术能有效克服这类障碍,提高成苗率。

【Objective】This study investigated the internal state of intersectional hybrid seeds with ruptured testa and the performance of embryo culture for seedling establishment in Paeonia L.to provide references for understanding seedling establishment potential of seeds with ruptured testa and improving the efficiency of intersectional distant hybridization breeding.【Method】Using seeds with ruptured testa of 24 intersectional hybrid combinations in Paeonia L.as experimental materials,the development of embryos and endosperms was observed and counted after anatomy.The germination and growth patterns of embryos were observed via in vitro culture and the differences in seed development and seedling establishment among different hybrid combinations of seeds with ruptured testa were analyzed.【Result】Seeds with ruptured testa appeared in all 24 intersectional hybrid combinations in Paeonia L.,with an average testa rupture rate of 61.08%.Among the 1767 seeds with ruptured testa,11.09%had decayed endosperms.About more than 90%of seeds with undecayed endosperm showed varying degrees of damages or diseases,while no visible embryo was observed in 24.18%seeds.Among the 1185 dissected intersectional hybrid embryos subjected to in vitro culture,24.73%did not germinate,63.47%exhibited abnormal growth,and only 4.47%grew normally into complete plants.The complete plants obtained from embryo culture had good vigor and 86.79%seedlings survived after acclimatization and transplantation.A total of 46 seedlings of intersectional hybrids were obtained through in vitro embryo culture from seeds with ruptured testa in 24 hybrid combinations.The average seedling establishment rate was 2.60%,which was comparable to that of normal intersectional hybrid seeds by sowing(2.75%).【Conclusion】The phenomenon of seed testa rupturing was commonly observed in intersectional hybrid seeds of Paeonia L.,which was one of the important manifestations of intersectional distant hybridization barriers.In vitro embryo culture technology could effectively overcome such barrier and improve seedling establishment rate.