枣树蒸腾耗水变化规律

摘要

对壶瓶枣单木蒸腾速率、单株耗水量的变化规律以及蒸腾速率与土壤含水量的关系进行了研究.结果表明:枣树蒸腾速率的日变化呈单峰曲线,夜间枣树树干也有微弱的茎流.枣树不同物候期蒸腾速率变化规律不同,萌芽期和落叶期蒸腾速率较小,而果实膨大期最大.枣树平均蒸腾速率在4月最高.枣树日累计蒸腾量曲线呈"S"型,蒸腾日累计量为10.47L.生长季枣树单株蒸腾耗水总量为1 257.6 L,4-10月份各月耗水量分别占生长季总耗水量的2.5%、11.9%、20.3%、21.5%、23.3%、14.9%和3.3%.枣树萌芽期、展叶期、开花坐果期、果实膨大期、果实成熟期和落叶期的蒸腾量分别占生长季总耗水量的2.5%、8.1%、17.2%、52.5%、17.5%和2.3%.枣树蒸腾量与土壤含水量关系密切,在土壤含水量较低时(低于12.4%),蒸腾量随着土壤含水量的增加而升高;当土壤含水量在12.5%～16.0%时,随着土壤含水量的增加,蒸腾量随土壤含水量增加的幅度减缓,当土壤含水量超过16.0%时,蒸腾量随土壤含水量的增加而升高的趋势不明显.对枣树进行灌溉处理,其蒸腾速率有了明显的提高.%A systematic investigation of the changes in transpiration rate and plant water consumption of Zizyphus jujuba cv. ‘ Huping’ was performed by thermal dissipation sap velocity probe. Results show that the daily variation in transpiration rate of Jujube trees can be described with a unimodal curve. Jujube trees have weak night-time sap flow. The change in transpiration rates is various in different phenological phases. The transpiration rates in germination stage and defoliation period are lower and that in the fruit enlargement period is the highest. The highest average transpiration rate is in April.Daily cumulative value of transpiration by jujube trees shows an S-shaped curve. The total transpiration per jujube tree was 10. 47 L. The total water consumption for transpiration by per jujube tree was 1 257.6 L in growing season. The monthly water consumption during April and October accounted for 2.5％, 11.9％, 20. 3％, 21.5％, 23. 3％, 14.9％ and 3.3％ of the total water consumption, respectively. The transpiration in germination stage, leaf-expansion period, flowering and fruit beating period, fruit enlargement period, fruit mature period, and defoliation period accounted for 2.5％, 8.1％, 17.2％, 52.5％, 17.5％ and 2.3％ of the total water consumption, respectively. The transpiration rate of jujube trees is closely related with soil water content. Transpiration of jujube trees increases with increasing soil water content when it is lower than 12.4％; the increasing range of transpiration declines with increasing soil water content when it is between 12.5％ and 16.0％; the change in transpiration is not obvious when soil water content is higher than 16.0％. The transpiration rate can be significantly increased by irrigation.