Knowledge Resource Center for Ecological Environment in Arid Area
| 河西荒漠区凝结水及其生态作用初步研究 | |
| 其他题名 | The preliminary study on condensation water and its ecological role in desert area of Hexi |
| 庄艳丽 | |
| 出版年 | 2008 |
| 学位类型 | 硕士 |
| 导师 | 赵文智 |
| 学位授予单位 | 中国科学院寒区旱区环境与工程研究所 |
| 中文摘要 | 凝结水是当物体表面温度低于周围大气露点温度时，大气中汽态水在物体表面凝结形成的水源。在水资源匮乏的沙漠生境，凝结水是除零星降雨以外主要的水资源之一。与降水相比，荒漠区凝结水量尽管非常小，但它已被认为是干旱区水资源的重要补充形式。因此，深入系统了解干旱生境中凝结水的发生以及对干旱胁迫条件下荒漠一年生植物的生态作用具有重要意义。\n通过野外观测，结合生态学、气象学和数理统计学等多学科方法，探讨不同天气条件及不同生境凝结水量的分布与持续时间；以一年生草本植物雾冰藜（Bassia dasyphylla）为研究对象，通过控制实验探讨植物对凝结水发生的响应以及植物叶片是否能够吸收凝结水以及凝结水是否影响供试植物的水分生理和生长。主要结论有：\n1 不同天气状况及不同生境对凝结水量及持续时间的影响\n对天气条件而言，晴天凝结水积累量最大且日出后持续时间最长，有风天气凝结水积累量相对最小且日出后持续时间最短。多云天气这两个指标居中。对于凝结水量积累的最大值而言，晴朗天气时丘间低地处值最大即0.09mm，其次是阴坡0.066mm，最后是阳坡0.065mm；有风天气条件下黎明时平均凝结水量最小，且阳坡最大凝结水量积累值仅为0.04mm；而多云天气时3种生境最大凝结水量值保持在0.043-0.05mm之间。凝结水最大值出现的时间随生境而变化，并不是出现在黎明或日出。无论哪种天气状况，3种生境阴坡的凝结水持续时间最长，并且晴天时3种生境凝结水的持续时间都最长。\n2 荒漠一年生植物对凝结水发生的响应\n凝结水的发生提高了雾冰藜的日平均净光合速率，仅提高了胁迫条件下植株清晨的气孔导度、植株的水势和相对含水量。而水分充足状况下凝结水的发生对植株的水分状况影响不大。\n凝结水的发生改变了植株的形态学特征。从形态结构的响应来看，无论哪种水分状况，凝结水的发生都增加了整株雾冰藜的生物量积累、减小了根冠比以及茎/地上部分；凝结水的隔绝增加了茎和根的分配量。而胁迫条件下，凝结水的发生可以明显减少植株的黄叶量和黄叶/总叶，但对正常水分条件的植株来说影响不大。 \n模拟凝结水显著提高了水分充足和水分胁迫状况下雾冰藜的气孔导度，仅提高了胁迫状况下植株的净光合速率。对于植株的水分状况而言，模拟凝结水仅提高了水分胁迫状况下植株的水势和相对含水量，而对正常水分状况的植株影响较小。对植株的形态学特征而言，模拟凝结水提高了植株的地上生物量，仅提高了胁迫水分状况植株的地下生物量。两种水分状况下，凝结水的模拟对植株基径的效应不明显。 |
| 英文摘要 | Condensation water is the condensation of atmospheric moisture on objects that have radiated sufficient heat to lower their temperature below the dew point temperature of the surrounding air. Condensation water is an important source of moisture in addition to sporadic rain, especially in desert environments, where water resources are limited. Although condensation water is limited in desert environments comparing with the precipitation, it is recognized as the important supplement of water resources. We must learn more about the ecological roles of condensation water for annual plant in the drought stress environment to take advantage of the only source of water in arid season.\nBassia dasyphylla, is one of the major sand binding annual plant with the features of drought tolerance, salinity, wind-resistant, which mainly distributes in the desert environments, so Bassia dasyphylla may have an ecological function for an obstruction to movement of sand and stabilization of the oasis. To study the ecological role of condensation water to Bassia dasyphylla can provide valuable information and contribute to ecological restoration of the desert area.\nCombining with controlled experiments and field observation, using multi-disciplinary approaches of ecology, meteorology and mathematical statistics, to explore the distribution and duration of condensation water under different weather conditions and different habitats, reveal the responses of desert annual plants on condensation water occurrence, ravel whether leaves of desert major herb Bassia dasyphylla can absorb condensation water and whether condensation water will impact the water physiology of tested plants, reduce the water stress situation of them and promote their growth. The results show as follows:\n1. The impact of different weather condition and habitat to amounts and duration of condensation water.\nClear mornings yielded the highest condensation amounts and the longer condensation duration, whereas windy mornings yielded the lower condensation amounts and the shorter duration. Cloud mornings exhibited intermediate values. Clear days resulted in the highest average maximal amounts with the lowland stations obtaining the highest mean 0.09mm followed by the sun-shaded stations(0.066mm) and sun-exposed stations(0.065mm).Windy mornings exhibited the lowest average amounts of condensation at dawn and the highest average maximal amounts of the sun-exposed stations is 0.04mm. Windy mornings exhibited maximal amount of condensation 0.043-0.05mm. Maximal condensation values may not necessarily be obtained at sunrise. Whatever the weather conditions, the duration of sun-shaded stations are the longest and the condensation water duration of the clear days is also the longest in three habitats.\n2. Responses of desert annual plant to condensation water\nCondensation water increased average photosynthesis rate of Bassia dasyphylla. Meanwhile, Condensation water increased stomatal conductance, water potential and relative water content with deficient watering regime. However, condensation water has little impact on water relations in well-watered regime.\nThe occurrence of condensation water changes the morphological features of the plants. From the response of the morphological structure, whichever pattern of moisture conditions, the occurrence of condensation water always increases the whole biomass accumulation of Bassia dasyphylla, reduce the root-shoot ratio and the ratio of stem / aboveground; the isolation of condensation water increase the distribution amount of stem and the root. And under stress conditions, the occurrence of condensation water can significantly reduce the amount of yellow leaves and the ratio of yellow leaves/ total leaves, while there’s little effect on the plant under normal water conditions.\nCondensation water application significantly increased stomatal conductance and aboveground dry mass of water-stressed and well-watered seedlings. And it affected photosynthesis rate, water potential, relative water content and root dry mass of water-stressed seedlings only. There was a small effect of artificial condensation water on diameter in water-stressed and well-watered regime. |
| 中文关键词 | 凝结水 ; 雾冰藜 ; 光合强度 ; 水分状况 ; 形态特征 ; 生态作用 |
| 英文关键词 | Condensation water Bassia dasyphylla Photosynthesis rate Water relations Morphological features Ecol |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286649 |
| 推荐引用方式 GB/T 7714 | 庄艳丽. 河西荒漠区凝结水及其生态作用初步研究[D]. 中国科学院寒区旱区环境与工程研究所,2008. |
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