Relationship between browning and soluble sugar of recalcitrant seeds of chestnut in front of and behind maturation

This study aims to discover the relationship among browning, the contents of soluble sugars and desiccation sensitivity in chestnut seeds. When the seeds matured, the desiccation sensitivity of the seeds was low relatively, the contents of raffinose and stachyose in cotyledons and embryonic axes reached maximum and the relative electric conductivity and ultraviolet absorption value were lowest. The contents of total phenolics and the activity of POD were low in cotyledons and embryonic axes before abscission, then increased remarkably after abscission. After abscission the chestnut seeds were stored in sands. The desiccation sensitivity increased, the contents of raffinose and stachyose in cotyledons and embryonic axes declined, the leakage increased, and the contents of total phenolics and the activity of POD were sharply increased, flowed by browning. The contents of total phenolics were obviously positive correlated to POD activity (r=0.999) and the raffinose contents were obviously negative correlated to POD activity and total phenolics contents respectively (r=-0.998 and r=-0.995) in embryonic axes. The results indicated that the ingredients and the contents of soluble sugars were related to the desiccation sensitivity of chestnut seeds. After maturation, the increasing of the deoxidized sugars (maltose) contents consistent with the browning and the non-deoxidized sugars (raffinose) restrain the browning possibly.