Knowledge Resource Center for Ecological Environment in Arid Area
| 荒漠河岸林植物水分利用效率的差异性解析 | |
| 其他题名 | The Analytic differences of desert riparian forest plant water use efficiency |
| 任志国 | |
| 出版年 | 2014 |
| 学位类型 | 硕士 |
| 导师 | 陈亚鹏 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 水分利用效率为反映植物水分利用特征和适应策略的重要参数，是决定植物在干旱区半干旱区生存、生长和物种分布的重要因素之一。植物叶片组织中的稳定碳同位素组成（δ13C值）解析了影响植物碳同化和气孔导度等的生理因子的综合信息，运用稳定同位素法测定植物叶片δ13C值，能直接指示植物的水分利用效率，已成为一种公认的估测植物长期水分利用效率的可靠途径。 \n 本文选择塔里木河下游荒漠河岸林植被作为研究对象，通过测定建群种胡杨﹑柽柳和花花柴等植物的叶片δ13C值，分析不同时间和空间下植物水分利用效率的变化，研究荒漠河岸林水分利用效率的差异性，同时结合地下水埋深和土壤含水量等指标，解译地下水埋深对塔里木河下游建群种植被的水分利用效率的影响，利用双同位素模型，分析植物叶片的气孔导度与叶片内在水分利用效率间的内在联系，探讨叶片水力传导对叶片瞬时水分利用效率的影响。主要得出以下结论： \n 1. 在整个生长季中，荒漠植物胡杨的水分利用效率是先升高，后降低，水分利用效率最高值出现在6月份，最低值出现在8月份；柽柳的水分利用效率最高值出现在5月份，最低值出现在6月份，6月以后水分利用效率逐渐升高，铃铛刺水分利用效率5月份达到最大值，6-9月无明显差异；从5月到9月，草本植物甘草和花花柴的水分利用效率持续降低，这可能与叶片成熟度对稳定碳同位素的调控及植物的生长期有关。距河道不同距离(0 m、50 m、100 m、200 m、500m和800m)，胡杨和柽柳水分利用效率呈现先增加后减少的趋势，塔里木河下游荒漠植物水分利用效率可能与地下水埋深有关。 \n 2. 荒漠河岸林不同物种间水分利用效率存在显著差异，研究发现塔里木河下游荒漠植物中，灌木—铃铛刺、柽柳的水分利用效率最高，其次是乔木—胡杨，最后是草本植物—甘草。叶片δ 13 C值能够指示水分利用效率，取决于植物的遗传特性，也表征了植物的抗旱性，也就是荒漠植物的抗旱性：铃铛刺>柽柳>胡杨>甘草。 \n 3. 随着地下水埋深从2.4 m增加到9.1 m，胡杨叶片δ13C值呈现出先升后降的趋势，且在9.1 m处胡杨很可能是通过减少地上生物量的方式来适应干旱的加剧；而柽柳叶片δ13C值则随着地下水埋深的增加而逐渐增加，其水分利用效率不断增加，且对地下水埋深变化的适应宽度也较大。对比同一地下水埋深下胡杨和柽柳叶片的δ13C值发现，随着地下水埋深不断增加，胡杨的抗旱性比柽柳的弱；对比不同地下水埋深的植物叶片的δ13C值发现，胡杨在不同的地下水埋深采取不同的策略适应干旱环境，而柽柳在不同的地下水埋深则通过增加水分利用效率来抵御干旱的加剧。 \n 4. 由δ18O和δ13C组成双同位素模型探讨气孔导度和水分利用效率的关系，δ13C能够指代内在水分利用效率，叶片组织δ18O能够反映气孔导度的变化，但在荒漠生态系统中，δ18O和δ13C结合起来不能准确地反映胡杨气孔导度和水分利用效率的关系；水力导度变化调节水分和气体交换，影响光合和蒸腾作用，即瞬时水分利用效率。但研究发现：极端干旱环境中，塔里木河下游胡杨水力导度与水分利用效率并无明显相关性。 |
| 英文摘要 | Water use efficiency reflects the important parameters of plant water use characteristic and adapted strategy. It is one important factor that determined to plant survival, growth and species distribution in the arid and semiarid regions. The stable carbon isotope composition (δ13C value) in leaf tissue parsed the comprehensive information on affecting plant carbon assimilation and stomatal conductance even other physiological factors. The application of stable isotope method measured leaf δ13C values has become a recognized and reliable way to estimate the long term water use efficiency of plants. \n This article selected desert riparian forest vegetation at the lower reaches of Tarim River as the research object, by measuring theδ13C value of P. euphratica 、T. chinensis and other plants, analyzed under different temporal and spatial scales of plant water use efficiency changes, studied desert riparian forest WUE differences, combined with groundwater depth and soil moisture content and other indicators, explored the impact groundwater depth on water use efficiency of the constructive species of plants at lower reaches of Tarim River; utilization the dual isotope model to analyze the internal relations between plant stomatal conductance and WUE intrinsic; we research leaf hydraulic conductivity influenced on WUE instantaneous. The main results of this study were summaried as follows. \n 1. Throughout the growing season, WUEs of the desert plants - P.euphratica initially increased, then deceased, the highest water use efficiency appeared in June, the lowest value appeared in August; the highest water use efficiency of T. chinensis and was in May, the lowest in June, WUE gradually increased after June. The highest water use efficiency of Halimodendron halodendron was in May, There were no significant difference between June and September; From May to September, WUE of herbs-Glycyrrhiza﹑Karelinia caspica continuously reduced, It may be related to the maturity of leaves on the regulation of stable carbon isotope the grown of plant. The water use efficiency of P.euphratica and T. chinensis presented a decreasing trend after first increased at different distance from the river (0 m, 50 m, 100 m, 200 m, 500m and 800m), The desert plant water use efficiency may be related to groundwater depth at the lower reaches of Tarim River. \n 2. The water use efficiency had significant differences between different species of the desert riparian forest. The study found WUE of the Shrubs-Halimodendron halodendron, T. chinensis were the highest, followed by Arbor-P.euphratica, WUE of the Herb-Glycyrrhiza was the lowest.Leaf δ13C values can indicate water use efficiency depending on the genetic characteristics of plants, and characterize the drought resistance of plants, In other words, drought resistance of desert plants: Halimodendron halodendron > T. chinensis > P.euphratica> Glycyrrhiza. \n 3. The δ13C value in P. euphratica leaf initially increased, then decreased as the groundwater depth varied from 2.4 to 9.1m. P. euphratica was likely to reduce aboveground biomass to adapt to the intensified drought at 9.1 m. The δ13C values in T. chinensis leaf gradually increased with the increasing groundwater depth, which indicated that water use efficiency and the width of the adapted groundwater depth was increasing when groundwater depth become deeper. Under the same groundwater depth, the δ13C values of leaf in P. euphratica and T. chinensis were compared. It was found that drought resistance of P. euphratica was weaker than that of T. chinensis with the increasing groundwater depth. Under the different groundwater depth, the δ13C values of leaf in P. euphratica and T. chinensis were compared. P. euphratica used different strategies at different groundwater depth to adapt the arid environment, while T. chinensis resisted the intensified drought by increasing water use efficiency. \n 4. We used dual isotope model composed of δ18O andδ13C to explore the relationship between stomatal conductance and water use efficiency. The value of δ13C was able to refer to the intrinsic water use efficiency, the value of tissue δ18O negatively correlated with stomatal conductance, combining the P. euphratica value of δ18O and δ13C did not accurately reflect the relationship between stomatal conductance and water use efficiency in the desert ecosystem; The changes of hydraulic conductance adjust water and exchange gas, affect instantaneous water use efficiency-photosynthesis and transpiration. But the study found: hydraulic conductivity of P. euphratica and water use efficiency of P. euphratica is no significant correlation. |
| 中文关键词 | 水分利用效率(WUE） ; 塔里木河下游 ; 地下水埋深 ; 稳定碳氧同位素 ; 水力导度 |
| 英文关键词 | water use efficiency(WUE) lower reaches of the Tarim River groundwater depth stable carbon and oxygen isotopes hydraulic conductance |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 环境工程 |
| 来源机构 | 中国科学院新疆生态与地理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287432 |
| 推荐引用方式 GB/T 7714 | 任志国. 荒漠河岸林植物水分利用效率的差异性解析[D]. 中国科学院大学,2014. |
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