Studies On Some Factors Affecting Ratoon Germination Of Sugarcane

Shoot sprouting of first ratoon was investigated with five sugarcane varieties under field conditions. Some of inner factors affecting the ratoon, which including the contents of amylum, total soluble sugar, sucrose, reducing sugar, nitrogen, phosphorus, potassium and soluble protein, and the activities of acid invertase and peroxidase in the leaves of ratoon crop, were determined. The meteorological data were also collected and analyzed. The results were as follows.1) Temperature was a dominant environmental fatcor affecting the shoot sprouting of the ratoon cane. The suitable air temperature accompanied with sound relative moisture in soil was very important for the ratoon budding, which resulted in increased activities of acid invertase and decreased peroxidase(POD), and stronger decomposition of amylum and sucrose and more accumulation of photosynthate, and higher contents of nitrogen, phosphorus, potassium in the ratoon crop. The varieties with higher N, P and K in the leaves during shoot sprouting and early growth stage of the ratoon crop grew faster and recorded higher cane yield as compared with the others.2) Acid invertase played a key role in shoot sprouting of the ratoon crop, which inverted the sucrose into reducing sugar for further utilization by the newly growing shoots. The variety YT91/976, which grew fast and recorded the highest cane yield, showed the increscent acid invertase activity in the leaves at the early growth stage.3) The peroxidase activity in the leaves was high at the early growth stage of the ratoon crop but was decreasing with speeding up of the plant growth. The varieties CP80/1827 and XTT16, which had stronger shoot-sprouting ability and produced more millable stalks, showed obviously higher peroxidase activity than the others.4) The fast-growing and high-yield variety YT91/976 showed the highest amylum, tolal soluble sugar, sucrose and reducing suger in the leaves in most of the measurements at the early growth stage. The varieties CP80/1827 and XTT16 showed rather high amylum and sucrose but not total soluble sugar and reducing sugar in the leaves at the shoot sprouting stage, which might suggest that amylum and sucrose were more important than total soluble sugar and reducing sugar for the bud germination in the ratoon cane clumps.