Subjects: Biology >> Botany submitted time 2023-08-24 Cooperative journals: 《广西植物》
Abstract： To study the seed dormancy and germination mechanism of Xanthoceras sorbifolium, the seeds of four cultivars (‘Putong’(PT),‘Qihong’(QH), ‘Wofeng’(WF) and‘Woshi’(WS)) were stored at -20 ℃ for different periods (30, 60, 90, 120, 150 d). The seed germination indexes were determined in each treatment, and the changes of reserve substance and hormone content were also analyzed in three stages including before storage, after storage, and 7 days germination. The results were as follows: (1) Cold storage could significantly promote the germination rate (Gr) and germination potential of small seeds (PT, QH). The best treatment was cold storage for 60 days, and the Gr was to 48.3 % and 58.3%, respectively. The effect of cold storage on large seeds (WF and WS ) was lower than that of small seeds. (2) The kernel oil content, seed shell thickness (SST) in four cultivar seeds all decreased significantly during periods of cold storage and germination, especially in the 3-7 days of germination, the oil content and SST (except WS cultivar) decreased notably. However, water content in kernels increased rapidly within 1-3 days of germination and then slowly increased to the peak value at the 7th day. The contents of starch and soluble sugar in kernels increased significantly at the 3th or 4th day of germination. (3) Cold storage increased GA/ABA and tHor/ABA ratios in small seeds (PT, QH), promoted oil degradation, made seed shell thinning and break seed dormancy. In conclusion, the main factors leading to dormancy in Xanthoceras sorbifolium seeds are large in size, higher shell thickness and hardness, physiological post-ripening, and belongs to comprehensive dormancy type. Cold storage at -20 ℃ for 60 d could improve the germination rate of PT, QH and WF seeds, reduces dormancy degree, while the cold storage time of WS seeds needs prolonging to 150 days. The method using -20 ℃ storage with wet sand germination is a rapid and simple method to promote Xanthoceras sorbifolium seeds germination. This study provides a reference for the promotion of superior varieties and the research on the seed breaking dormancy mechanism in Xanthoceras sorbifolium.
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