The Effects Of Ethyphon Sprayed On Sugarcane Leaves At Tillering-Stage Under Water-Controlled Conditions

In the present experiment, ethyphon (100mg/l) was sprayed on the leaves of two sugarcane varieties, namely, T10 and G17, at tillering-stage under water-controlled conditions with spraying water treament as the control. Leaves of the two sugarcane varieties were sampled periodically to assay the oozing percentages of total solutes and soluble sugar in cells, contents of proline and malondiadehyde, activities of three protective enzymes (SOD, CAT, POD). And leaf water potential and photosynthesis related indexes (Pn,Ci,Tr,Gs) were assayed to show their variations during water-controlling. Qualities of two sugarcane varieties were analysed. According to the results, ethyphon has active effects on the two sugarcane varieties,especially better effects on T10. The results were as follows:1. The ethyphon treament made lower oozing percentages of total solutes and soluble sugar in cells than the control, which decreased the destruction of water deficit to cell memberane.2. The ethyphon treament also obviously promoted the production of malondiadehyde compared with the control, so made bad effects on antioxidation of cell memberane. It indicates the complicate interactions among different physiological processes during the adaptation of ethyphon-treated sugarcane to water deficit.3. The ethyphon treament obviously increased the contents of proline of two sugarcane varieties, which benefited the cell osmoregulation ability to adapt water-controlled conditions.4. The ethyphon treament enhanced the activities of three protective enzymes of the two sugarcane varieties and decreased the bad effects of water deficit, so benefited their growth.5. The ethyphon treament also maintained much higher leaf water potential (LWP) than the control of the two sugarcane varieties, which was very helpful to sugarcane growth and photosynthesis, for higher LWP is the base of all physiological metabolism.6. In the present experiment, the ethyphon treatment increased the net photosynthetic rate (Pn) of the two sugarcane varieties. It is just related to the effects of ethyphon on stomatal conductance (Gs), COi concentration in cells (Ci) ,transpiration rate (Tr) as well as the interaction among these indexes.7. Field investigations showed that the ethyphon treament increased the efficiency of sugarcane tillering significantly, but had repressive effect on sugarcane height. In addition, ethyphon also maintained higher sugar content under water- controlled conditions, which may be the result of interaction of other physiological and bio-chemical metabolism and indicated that ethyphon treament had active effects on sugarcane to adapt to water deficit.