不同土壤水分条件下2种灌木蒸腾耗水特性研究

Research on Transpiration and Water Consumption Characteristics of Two Kinds of Shrubs under Different Soil Water Conditions

以麻叶绣线菊(Spiraea cantoniensis)和小紫珠(Callicarpa dichotoma)为试验材料,采用盆栽控水法设置4个水分梯度,分别为田间最大持水量的95%(水分充足)、75%(轻度缺水)、55%(中度缺水)和35%(严重缺水),研究不同水分条件下2种灌木蒸腾耗水规律。结果表明:随着土壤含水量的下降,2种灌木的株高和单株叶面积显著减少。土壤含水量是决定植物耗水量大小的主要因素,2种灌木耗水量由大到小依次为水分充足>轻度缺水>中度缺水>严重缺水。在相同水分条件下,小紫珠的单株总耗水量和昼夜耗水量大于麻叶绣线菊,2种灌木白天平均耗水量占昼夜总耗水量的74.89%以上,说明主要耗水来自白天。从环境因子来看,2种灌木耗水量与温度和光照强度呈显著正相关,与相对湿度呈显著负相关,随着水分减少,环境因子对耗水量的影响逐渐减弱。从叶片尺度来看,2种灌木蒸腾速率与气孔导度呈显著正相关,与水气压亏缺呈极显著负相关。综合分析可知,小紫珠更适宜于水分充足地区,在水分不足或干旱频繁的地区更适合发展耗水量小的麻叶绣线菊。

Using Spiraea cantoniensis and Callicarpa dichotoma seedlings as test materials,the research used potting water control method to set four water moisture gradient,respectively 95%of water holding capacity of the largest in the field(enough moisture),75%(mild shortage of water),55%(moderate shortage of water)and 35%(an acute shortage of water),researched different transpiration and water consumption of two kinds of shrubs under the different water conditions.The results showed that:with the decrease of soil water content,the area of plant height and single leaf of both shrubs decreased significantly.Soil water content was the main factor to determine the water consumption of plants,and the water consumption of the two shrubs was in the order of water sufficient>mild water shortage>medium water shortage and>severe water shortage.Under the condition of same water,the total water consumption per plant and round-the-clock water consumption of Callicarpa dichotoma were higher than that of Spiraea japonica.The average diurnal water consumption of two kinds of shrubs accounts for over 74.89% of the total water consumption of day and night.That means the main water consumption comes during the day.From the perspective of environmental factors,the water consumption of the two shrubs was positively correlated with temperature and light intensity,and negatively correlated with relative humidity.With the decrease of water,the influence of environmental factors on water consumption was gradually weakened.In terms of leaf scale,transpiration rate of the two shrubs was positively correlated with stomatal conductance and negatively correlated with water pressure deficit.Comprehensive analysis shows that Callicarpa dichotoma is more suitable for adequate water areas,while Spiraea cantoniensis is more suitable for the water shortage or frequent drought area.