Characterization and mechanism of seed dormancy in Symplocos paniculata

Abstract

Symplocos paniculata is a highly desirable oil species for biodiesel and premium edible oil feedstock. While germplasm preservation and breeding are crucial, the severity of seed dormancy poses a challenge to successful germination. We employed S. paniculata seeds as experimental materials and conducted an investigation into the types and causes of seed dormancy by analyzing the morphology and developmental characteristics of its embryo, exploring the water permeability property of the endocarp, and examining the presence of endogenous inhibitors, aiming to establish a theoretical foundation for overcoming seed dormancy and maximizing germplasm resource utilization. The findings revealed that the seed embryo had matured into a fully developed embryo, and no dormancy in terms of embryo morphology was observed. Upon reaching maturity, the endocarp of seeds undergoes significant lignification, resulting in notable differences in water absorption between cracked and intact seeds. The impermeability of the endocarp is one of the factors contributing to mechanical restriction. The different phases of endosperm extraction exerted varying effects on the germination of Chinese cabbage seeds, with the methanol phase exhibiting the most potent inhibitory effect. The presence of endogenous inhibitors emerged as the primary factor contributing to physiological dormancy in seeds. GC-MS analysis and validation trials revealed that fatty acids and phenolics, including hexadecanoic acid, oxadecanoic acid, and m-cresol, constituted the main types of endogenous inhibitory compounds found within the endosperm. These findings suggest that the seed dormancy in S. paniculata seeds has endocarp mechanical restriction, and the presence of endogenous inhibitors causes physiological dormancy.

Study on Dormant and Germination Characteristics of Chinese Olive (Canarium album) Seeds

“…Glabra) seeds with a purity level of ≥97.0%, moisture content of ≤7.0%, and a germination rate of ≥85.0% were procured. Chinese cabbage seeds are frequently utilized in experiments to validate seed dormancy inhibitors, given their non-dormant characteristics, high germination rate, straightforward germination process, and short germination cycle [21].…”

Methodological and Physiological Study during Seed Dormancy Release of Symplocos paniculata

“…The seed of S. paniculata , however, exhibits a profound dormancy-induced state, resulting in a significantly sluggish and feeble germination capacity. Under natural conditions, the prolonged dormancy process leads to a significant loss of viability in most S. paniculata seeds, resulting in formidable barriers to seed propagation and severely limiting its potential for cultivation [ 11 , 12 ]. Therefore, it is imperative to systematically investigate dormancy release mechanisms and develop rapid methods to enhance germination of S. paniculata seeds.…”

“…Considerable endeavors [ 13 , 14 ] have been undertaken in recent decades to comprehend the pathways governing seed dormancy release, whether induced by external environmental factors or the inherent characteristics of seeds. The previous studies [ 7 , 11 ] have demonstrated that the seed-coat (endocarp) of S. paniculata seeds exhibits hardness and impermeability, while metabolic inhibitors were also detected in the endosperm. Inherent dormancy in woody species such as Cornus florida [ 15 ], Pinus bungeana [ 16 ], Tilia henryana [ 17 ], Saraca asoca [ 18 ] and Jatropha sinensis [ 19 ] are controlled by maternal structures and embryo physiology.…”

“…Based on our previous findings [ 11 ], it was demonstrated that the dormancy of S. paniculata seeds can be largely attributed to the presence of endogenous inhibitors and a hard endocarp. Therefore, in the present study, we employed pre-treatment through scarification using a NaOH or H 2 SO 4 solution, followed by soaking the seeds in a GA 3 solution and subsequently subjecting them to stratification to investigate its impact on breaking seed dormancy.…”