文档介绍：食用型甘薯施用腐植酸和钾肥改善品质的生理基础
these showed that application of humic acid could increase the supply of photosynthetic products, keep clear of photosynthate transport corridors and improve the offloading capabilities of storage root to ensure the supply of sucrose. The activity of sucrose synthase was decreased which gave rise to the diminution of starch synthesis and the increase of sucrose accumulation by use of HA; amylase activity was increased also by use of HA which brought less starch content and higher glucose pared with the control; treatment with HA also got higher fructosan content by means of increasing SST activity than that of the control. HA increased the accumulation of fructose and glucose by means of increasing soluble acid invertase activity as well. To sum up, humic acid could increase the soluble sugar content in storage root by three ways: first, to enhance the supply of soluble sugar to storage root; second, to inhibite the conversion from soluble sugar to starch of storage root; last, to promote the conversion from starch to soluble sugar in storage root.
The result got by determining the content of vitamin C during the key stages of growth showed that the main periods of accumulation of vitamin C in storage root were middle-late stage of growth for Beijing 553, while that for Jishu 22 were intermediate and final growth phases. Vitamin C content was significantly increased by use of HA.
The result got by determining the content of nitrate during the key stages of growth showed that the main periods of accumulation of nitrate in storage root were middle-late stage of growth for Jishu 22, meanwhile treatments with HA got lower nitrate content than that of the control. The result got from Beijing 553 showed the amino acid content in storage root was increased during the key stages of growth, that meant HA could improve quality of storage root by the way of improving the changes from nitrate to ammoniacal nitrogen.
Effect of K on yield and nutrient q