Studies On The Effects Of Water Supply Treatment At The Elongation Stage In Sugarcane

Irrigation norms of 60mm/ten days,40mm/ten days,20mm/ten days,0mm/ten dayswere planned to imitating raining at the period of elongation. The effects of water supply treatment on agronomic traits, drought-resistant physiology, physiology biochemistry of growth, yield, technical traits, mineral nutrient in sugarcane were studied. The results were as follows.40mm/ten days treatment had the longest plant stalk, the greatest growth speed, steady leaf area index (LAI) and more dry weight of individual plant. 60mm/ten days treatment had longer plant stalk, greater growth speed, steady leaf area index (LAI) and the most dry weight of individual plant. 20mm/ten days treatment had long plant stalk, great growth speed, steady leaf area index(LAI) and much dry weight of individual plant. Omm/ten days treatment had short plant stalk, little growth speed, little leaf area index(LAI) and little dry weight of individual plant.Omm/ten days treatment had the lowest soil moisture content, fresh leaf water content, leaf relative water content, bleaching sap quantity and evaporate speed. And it had the highest water saturation deficit(WSD), malondiadehyde(MDA) and membrane permeability .And its praline(Pro) content and peroxidase activity were higher at earlier stage, but they became lower at the middle and later stage. These meaned that Omm/ten days treatment had suffered drought on the drought stress conditions. 60mm/ten days treatment had the highest fresh leaf water content, leaf relative water content and bleaching sap quantity, and had the lowest water saturation deficit(WSD). 40mm/ten days treatment had the highest soil moisturecontent , proline(Pro) content, evaporate speed and peroxidase activity. And it had the lowest malondiadehyde(MDA) and membrane permeability. 20mm/ten days treatment, its all index of drought-resistant physiology were similar to Omm/ten days treatment. All these meaned that 60mm/ten days and 40mm/ten days treatments were fit to growth, however, 20mm/ten days treatment was harmful to its individuals.Omm/ten days treatment had the lowest photosynthesis rate , gas conductance, Ci and acid invertase activity. And its solube sugar content, chla, b , a+b content , neutral invertase activity and polyphenols oxidase activity were higher at earlier stage, but they became lower at the middle and later stage. And its NRA activity was lower at earlier stage, but they became higher later stage. These all meaned that Omm/ten days treatment was not fit to growth at earlier and middle stage, and was not fit to accumulate sugar at later stage. 40mm/ten days treatment had the highest solube sugar content, chla,b , a+b content , NRA activity, acid invertase activity , gas conductance, Ci. 60mm/ten days treatment had the highest photosynthesis rate. 60mm/ten days treatment had the highest neutral invertase activity and polyphenols oxidase activity. All these meaned that 60mm/ten days and 40mm/ten days treatments were fit to growth.Omm/ten days treatment had the lowest N, P, K content of +1 leaf, and had the highest rudimental N, P, K content of withered leaf and sheath. 60mm/ten days treatment had the highest N, P, K content of +1 leaf, all water supply treatments had low rudimental N, P, K content of withered leaf and sheath. These meaned that Omm/ten days treatment had prevented to absorbing, accumulating, utilizing and transfering in N,P,K fertilizer. 60mm/ten days and 40mm/ten days treatments did better.Omm/ten days treatment had the lowest academic yield, real yield , latest cane sucrose content , sucrose yield per 666. 7m2, and all of 40mm/ten days treatment were highest. There were 5% significant differences of real yield and sucrose yield per 666. 7m2 between water supply treatments andOmm/ten days treatment. The comprehensive effects of 40mm/ten days treatment was best among the four treatments.