Abstract:

Seed coat cracking often occurs in bean seeds harvested under natural conditions. In order to explore the causes of seed coat cracking and improve seed appearance and vigor, we chose the Heilongjiang University ‘Daiguan’and the Heilongjiang University‘Shengguan’as experimental materials, and compared between intact and seed coat cracking (SC) seeds of the same variety. Their length, width, thickness, 100-seed weight and physical properties were measured, and the effect of Phenylpropane metabolic pathway in low temperature was studied at biochemical and molecular level. The results showed that the length, width and thickness of cracked seeds were 11.14% 2.79% 10.15% larger than that of intact seeds respectively, the 100-grain weight increased significantly by 16.79%, the physical properties decreased, and phenylpropane metabolic pathway was enhanced at the transcriptional level. It is speculated that the cotyledon development rate of cracked seeds is higher than that of intact seeds, and the difference of cotyledon and seed coat development rate may be one of the reasons leading to seed coat cracking; low temperature increases the content of Lignin in the seed coat, and the deposition of Lignin lowers the physical properties of the seed coat, which is the direct cause of seed coat cracking.

Key words: common bean, seed coat cracking, low temperature, phenylpropane metabolic pathway, lignin, hundred-grain weight