极端端干旱区 3 种优势植物凋落物的分解特征
Alternative TitleLitter Decomposition Characteristics of Three Dominant Plants in Extreme Arid Regions
Thesis Advisor李向义
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline理学硕士
Keyword凋落物分解 极端干旱区 花花柴 骆驼刺 胡杨 Litter decomposition Extreme arid area Karelinia caspia Alhagi sparsifolia Populus euphratica
Abstract凋落物在维持生态系统功能、物质循环和能量流动方面发挥着重要作用。 随着全球碳循环问题受到广泛关注,凋落物的分解对地球生态系统碳预算具有重要的科学意义。然而目前凋落物的分解研究主要集中在森林和草地生态系统,对干旱地区尤其是极端干旱地区凋落物分解的研究相对较少。在极端干旱区凋落物分解规律及分解机制上尚存在较多不明确之处。为探究极端干旱区凋落物的分解特征和规律,本文利用凋落物分解袋法,以塔克拉玛干南缘策勒绿洲边缘荒漠地区优势植物花花柴 (Kareliniacaspia)、骆驼刺(Alhagi sparsifolia)和胡杨(Populus euphratica)的叶片凋落物为对象进行凋落物分解试验,探究极端干旱区凋落物分解特征及主要影响因素。结果表明:(1) 极端干旱区地表凋落物分解集中在凋落物凋落次年的 5-9 月份,有机物的损失是导致质量损失的重要原因。植物叶片掉落后的前 6 个月质量、有机物、水溶性盐和碳的残留率基本保持不变。 在分解时间第 6 个月至地第 9 个月时凋落物质量、有机物、水溶性盐和碳的损失较为迅速,而到分解时间为第 9 个月以后凋落物质量、有机物、水溶性盐和碳的损失又趋于平缓。(2) 水溶性盐含量较高的凋落物,水溶性盐在质量损失中占有较高比例。花花柴水溶性盐损失率高于骆驼刺和胡杨而导致质量损失率也高于骆驼刺和胡杨,而花花柴有机物损失率却低于骆驼刺和胡杨。传统分解模型中利用初始凋落物化学性质来预测凋落物分解特征并不适用于极端干旱区的凋落物分解。(3) 在极端干旱区,降雨同样是影响和限制凋落物分解的重要原因,降雨是导致凋落物质量、有机物和水溶性盐损失的直接因素,光照对凋落物分解的直接影响相对较小。(4) 与悬空处理对比,地表和 2 cm 埋深处理显著提高了凋落物的质量、有机物和水溶性盐的损失。光照下土壤中产生的过氧化氢和羟基自由基对地表和 2 cm 埋深的凋落物分解起到重要作用。(5) 与自然光照条件相比,遮 UV(紫外线) 和黑暗处理显著降低了凋落物的质量、有机物、水溶性盐和碳的损失率,表明极端干旱地区 UV 辐射是促进凋落物的分解的重要因素。
Other AbstractLitter plays an important role in maintaining ecosystem function, materialcycle and energy flow. With the global carbon cycle being widely concerned,litter decomposition is of great scientific significance to the carbon budget ofthe Earth's ecosystem. However, previous studies on litter decompositionmainly focused on forest and grassland ecosystems. There were relatively fewstudies on litter decomposition in arid areas, especially in extreme arid areas.The laws and mechanisms of litter decomposition in extreme arid areas werenot clear. In order to explore the characteristics and laws of litter decompositionin extreme arid areas, litter decomposition bags were used to study the litterdecomposition experiments of leaf litter of dominant plants Karelinia caspia,Alhagi sparsifolia and Populus euphratica in the desert area on the southernedge of Cele oasis in Taklimakan. To explore characteristics and maininfluencing factors of litter decomposition. The results show that:(1) Litter decomposition in extreme arid areas is concentrated in May toSeptember of the following year. The loss of organic matter is an importantcause of quality loss. Leaf quality, organic matter, water soluble salt and carbonremained unchanged in the first six months after leaf fall. The loss of litter mass,organic matter, water soluble salt and carbon was relatively rapid from the 6thmonth to the 9th month of decomposition, while the loss of litter mass, organicmatter, water soluble salt andcarbon tended to be flat after the 9th month ofdecomposition.(2) Litter with high water-soluble salt content, water-soluble salt accountedfor a higher proportion of mass loss. The loss rate of water-soluble saltinKarelinia caspia was higher than that in Alhagi sparsifolia and Populuseuphratic, and the loss rate of organic matter in Karelinia caspia was lowerthan that in Alhagisparsifolia and Populus euphratic. Traditional litter decomposition models using initial litter chemical properties to predict litterdecomposition characteristics are not suitable for litter decomposition inextreme arid areas.(3) In extreme arid areas, rainfall is an important factor affecting andlimiting litter decomposition. Rainfall is a direct factor leading to the loss oflitter mass, organic matter and water-soluble salt, while light has less directimpact on litter decomposition.(4) Compared with the hanging treatment, the surface and 2 cm depthtreatments significantly improved the loss of mass, organic matter andwater-soluble salt. Hydrogen peroxide and hydroxyl radicals produced in soilplayed an important role in litter decomposition at surface and 2 cm depthtreatment.(5) Compared with natural illumination, UV shading and dark treatmentsignificantly reduced the loss rate of litter mass, organic matter, water-solublesalt and carbon, indicating that extreme drought UV radiation promoted litterdecomposition.
Subject Area植物学
Document Type学位论文
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
李成道. 极端端干旱区 3 种优势植物凋落物的分解特征[D]. 北京. 中国科学院大学,2019.
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