不同供水条件对温室小型西瓜苗期根区土壤水分、温度及生理指标的影响

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

以小型西瓜"黑美人"为试验材料,在日光温室内进行了灌溉试验研究,试验设置1.25Ep(Ep为两次灌水时间间隔内的蒸发皿蒸发量)、1.0Ep、0.75Ep和0.5Ep四个供水处理,以探求不同供水条件对温室小型西瓜根区土壤水分变化、土壤温度、西瓜的形态指标、水分生理指标和光合生理指标的影响,并采用DPS分析软件对数据进行了显著性分析。土壤含水量随供水量的降低依次减少;株高呈现1.25Ep>1.0Ep>0.75Ep>0.5Ep处理趋势,茎粗和LAI变化规律为0.75Ep>1.0Ep>1.25Ep>0.5Ep处理;叶绿素a、叶绿素b和叶绿素a+b均以0.75Ep处理最高,0.5Ep处理最低,而叶绿素a/b值为0.5Ep处理最高;根层土壤温度变化呈0.5Ep>0.75Ep>1.0Ep>1.25Ep处理趋势;各处理叶片细胞液浓度呈"单峰"曲线,不同处理之间表现为0.5Ep>0.75Ep>1.0Ep>1.25Ep处理,土壤含水量与细胞液浓度间呈较好的二次曲线关系;光合速率和气孔导度的日变化规律呈"双峰"曲线,各处理之间呈1.25Ep>1.0Ep>0.75Ep>0.5Ep处理趋势。西瓜苗期采用0.75Ep处理能够获得最好的形态指标和叶片光合色素含量,在用水量少的前提下获得了较适宜的根区土壤温度、叶片细胞液浓度、较高的光合速率和气孔导度值。

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.