Knowledge Resource Center for Ecological Environment in Arid Area
| 内蒙古半干旱区榆树疏林和草地凝结水发生规律及其作用 | |
| 其他题名 | Occurrence regularity and ecological effects of dew in elm sparse woods and grassland in semi-arid area of Inner mongolia |
| 王成栋 | |
| 出版年 | 2016 |
| 学位类型 | 硕士 |
| 导师 | 刘美珍 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 凝结水是干旱、半干旱区重要的水资源之一，对该地区内的动植物有着重要的作用。近年来，全球变化越来越受到重视。全球气候变化对全球降水、干旱区及荒漠化区域等的分布格局将产生重要的影响。内蒙古半干旱区土地沙化，年降水量较少，夜间凝结水的量相对于降水量虽然较少，但其作为一种水分来源对于该区植物的生长有着重要的意义。研究该地区凝结水量的时空分布规律、凝结量以及凝结水对该区主要草本植物的生态效应有助于深入理解凝结水的生态作用，并为提高半干旱区水生态效益和生态恢复提供科学依据。2014年7月至10月初，我们在浑善达克沙地南缘的内蒙古多伦县的天然榆树疏林和草地内使用测定凝结水的常规方法——人造凝结面法和称重法——测定大气凝结水和土壤凝结水。并分别在温室及自然条件下测定了凝结水对几种主要草本植物的生理生化指标的影响，主要实验结果如下：(1)、草地凝结水发生的起始时间于夜间19:55至次日凌晨5:06，而疏林地于夜间19:59至次日凌晨6:10之间。草地凝结水平均于凌晨00:29发生，而疏林地平均于凌晨01:59发生，T检验结果表明二者之间有显著性差异(P = 0.0001)。疏林地凝结水发生的起始时间滞后于草地约1.5 h。凝结水结束时间分析结果为草地凝结水结束于4:42至9:12之间；疏林地的凝结水最早结束于5:15，最晚至早晨8:56。草地和疏林地两个样地凝结水结束时间的平均值分别为7:34和7:16，T检验结果表明二者有显著性差异(P = 0.0058)。(2)、草地的凝结水累积持续时间为216.41 h，平均每天5.69 h，而疏林地凝结水累积持续时间为153.42 h，平均每天4.04 h。疏林地凝结水持续时间平均每天比草地短1.65 h，二者差异显著(P = 0.0000)。(3)、草地大气凝结量大于疏林地。整个实验期间草地的人造凝结面上各月的总凝结量数量关系为0.0469 mm(十月) > 0.0324 mm(七月) > 0.0129 mm(九月) > 0.0065 mm(八月)，而疏林地的人造凝结面在整个实验期间没有观察到有凝结水形成。草本植物叶片上的凝结量结果表明，草地各月总凝结量为3.23 mm(九月) > 2.05 mm(八月) > 0.35 mm(七月) > 0.32 mm(十月)，疏林地各月总凝结量为0.98 mm(八月) > 0.36 mm(九月) > 0.11 mm(七月) > 0 mm(十月)。(4)、土壤凝结水中来自深层土壤中的水汽形成的凝结水疏林地大于草地，但无显著性差异。大气水汽在土壤中形成的凝结量和土壤水汽蒸发量综合结果为负值，土壤夜间表现为向大气中失水。疏林地和草地两种样地中土壤深层水汽运移至浅层凝结形成的凝结水量平均值分别为0.0110 mm和0.0092 mm。疏林地中大气水汽在土壤中形成的凝结量和土壤水汽蒸发量综合的净凝结量平均值为-0.1894 mm，草地的为-0.2361 mm，草地夜间土壤蒸发量显著高于疏林地(P = 0.0044)，且两种样地的夜间土壤水分蒸发量均明显高于土壤深层水汽的凝结量，这说明夜间土壤蒸发强烈，虽然有土壤凝结水生成，但不足以补充土壤的蒸发失水量。 (5)、室内控制实验以及原位实验的结果均表明，凝结水对莜麦、羊草、冰草和隐子草等的POD、SOD、CAT酶活性等生理指标无影响。但野外原位进行的实验表明夜间凝结水对榆树幼苗产生正面影响，增强它的抗旱能力，凝结水的存在可缓减由于干旱胁迫导致的榆树幼苗的SOD、CAT酶活性增加，也减少了幼苗叶片中游离脯氨酸的含量。 |
| 英文摘要 | Dew is an important water source in arid and semi-arid area. It has significantly effects on plants and animals living in this area. In recent years, global changes have received an increasing public attentions. Global change will have impact on climate and distribution patterns of global precipitation and desertification in arid area. The soil of semi-arid area in Inner mongolia is becoming desert, and annual precipitation is getting less and less. Dew accumulation at night is though not much relative to the amount of precipitation, but it has important significance as an additional water source for the growth of crops and grass in this area. To study the temporal and spatial distribution regularity of dew at night, we detected the amount of dew and ecological effect on the main herbs. This study can increase basic knowledge of dew research and provide guidance for the desert governance and provide a scientific basis for ecological benefits and ecological restoration in semi-arid zone.From July 2014 to early October, we measured nocturnal dew accumulation of air and soil condensation using the conventional methods, artificial condensation surface method and weighing method in natural elm sparse wood and grassland, in Duolun county of south of Hunshandak Sandland in Inner Mongolia. We measured dew's effect on the physiological and biochemical indexes of several plants in the greenhouse and under natural conditions respectively. The main results as following:(1) The starting time of dew in grassland plot begins from 19:55 to 5:06 next morning, while the time of sparse woods plot begins from 19:59 to 6:10 next morning. Dew occurs on 00:29 in grassland plot and 1:59 in sparse woods averagely. There is significantly difference between two types of vegetation according to t-test result (P = 0.0001). The starting time of dew in sparse woods lags behind about 1.5 h of grassland. The ending time of dew is between 4:42 and 9:12 in grassland, while is between 5:15 and 8:56 in sparse woods. According to the result of t-test, there are significant difference between two types of vegetation(P=0.0058).(2) Total dew duration in grassland is 216.41 h in experiment duration, 5.69 h per day, while the value in sparse woods is 153.42 h, 4.04 h per day. Dew duration in sparse woods is shorter than grassland a day about 1.65 h averagely, with significant difference (P = 0.0000).(3) Air dew accumulation in grassland plot is more than sparse woods. Dew accumulation of each month on artificial condensation plate is 0.0469 mm(Oct) > 0.0324 mm(Jul) > 0.0129 mm(Sep) > 0.0065 mm(Aug). There's no dew be observed on plates in sparse woods plot. The results of total dew accumulation on herbaceous leaves in grassland and sparse woods are 3.23 mm(Sep) > 2.05 mm(Aug) > 0.35 mm(Jul) > 0.32 mm(Oct) and 0.98 mm(Aug) > 0.36 mm(Sep) > 0.11 mm(Jul) > 0 mm(Oct) respectively.(4) The soil dew in sparse woods condensed from vapor in deep soil is more than grassland's, but there's no significant difference between two types of vegetation. The result which the dew condensing into soil from air vapor added with amount of evaporation of soil water is less than zero, so soil is lost water to air at night in two types of vegetation. Amount of dew condensing in superficial soil from deep soil are 0.0110 mm and 0.0092 mm in sparse woods and grassland separately. Average of net dew accumulation including soil dew condensed from air and evaporation of soil water is -0.1894 mm in sparse woods, and -0.2361 mm in grassland. Nocturnal soil evaporation in grassland is signally higher than value in sparse woods (P = 0.0044), nocturnal soil evaporation in both types of vegetation are markedly higher than condensation from deep soil.(5) Results of controlling experiments and experiments in situ indicate that dew has no effects on plants'(Avena sativa, Agropyron criststum, Leymus chinensis, Cleistogenes squarrosa et al.) physiological and biochemical indexes such as POD, SOD and CAT enzymatic activity. But dew on leaves at night has positive effects on elm seedlings, it can enhance drought resistance of elm seedlings. Dew can relieve the level of SOD and CAT enzymatic activity which because of drought. |
| 中文关键词 | 半干旱区 ; 榆树疏林 ; 凝结水 ; 发生规律 ; 生态作用 |
| 英文关键词 | semi-arid area elm sparse woods dew occurrence regularity ecological effect |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院植物研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287819 |
| 推荐引用方式 GB/T 7714 | 王成栋. 内蒙古半干旱区榆树疏林和草地凝结水发生规律及其作用[D]. 中国科学院大学,2016. |
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