Changes of Matter Accumulation and Relative Enzymatic Activity during Yam Tuber Development

Abstract

Tuber development is a complex physiological process,involving in changes of various components and enzymes activities,so learning about changes of the matter accumulation and enzymes metabolism will help to instruct yam production.In the paper,two different cultivars Guihuai 5 and Guihuai 16 were used to investigate some physiological and biochemical indicators during yam tuber development in 2009—2010.The results showed that tuber length and dry matter content were kept increasing,but AMY enzyme activity decreasing during the tuber development.The main carbohydrates contents,functional substances,and the activities of POD,AI,and SPS presented similar trend:continually increased firstly,and reached various peaks,then decreased.The changes of reducing sugar content and AGPase activity were different between two cultivars.The t-test results indicated that there was a significant difference between two cultivars in dry matter (P=0.011),starch (P=0.031),and saponin (P=0.019).Sucrose content was significantly correlated with soluble sugars content (r5 =0.97**,r16 =1.00**),AGPase activity (r5=-0.85*) and reducing sugars content (r16 =0.87*),and starch content was significantly correlated with polysaccharides (r5 =0.95**),Vc(r5 =0.83*) and saponin (r16 =0.88**) contents as well as tuber length was significantly correlated with dry matter content (r5 =0.97**,r16 =0.87*),AMY activity (r16=-0.95**),AGPase activity (r16=-0.90**),and protein content (r16 =0.83*).To sum up,the sucrose accumulation,SPS and AI activity play a key regulatory effect in yam tuber development,the main functional substances are close correlated between each other.