Effect of different water supply conditions on soil water content,soil temperature and physiological characteristics of mini-watermelon at the seedling stage

A study was carried out on the effect of different water supply conditions on some indexes of mini-watermelon,including soil water status and soil temperature around crop rootzone,morphological indexes,photosynthetic indexes and physiological indexes.With mini-watermelon Hei Meiren as the material,the irrigation experiment was conducted in the greenhouse,and significance analysis was made of experiment data through the software of DPS.The results showed that,with the reduction of water supply,the soil water content decreased,the stem diameter and LAI(leaf area index) in 1Ep and 1.25Ep treatments were inferior to those in 0.75Ep treatment,and those in 0.5Ep treatment was the lowest.The plant height was 1.25Ep1.0Ep0.75Ep0.5Ep.The content of chlorophyll a,chlorophyll b,chlorophyll a+b in 0.75Ep treatment was the highest,and those in 0.5Ep treatment was the lowest.But the chlorophyll a/b in 0.5Ep treatment was the heighest.The soil temperature around crop rootzone and CSC(cell sap concentration) were 0.5Ep0.75Ep1.0Ep1.25Ep,and between the soil water content and CSC showed quadratic functions.The diurnal change on net photosynthetic rate(Pn) of mini-watermelon was a typical bimodal curve,and showed a trend of 1.25Ep1.0Ep0.75Ep0.5Ep. So it was concluded that the 0.75Ep treatment not only obtained the best morphological indexes and chlorophyll content,but also obtained suitable soil temperature of around crop rootzone,CSC,Pn and stomata conductance under the condition of short water.