西藏高原草地生态系统丛枝菌根真菌的地理分布

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 西藏高原草地生态系统丛枝菌根真菌的地理分布 DOI: 10.5846/stxb201411192291 作者: 作者单位: 西藏大学农牧学院,西藏大学农牧学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目(41161043,41461054) Geographical distribution of arbuscular mycorrhizal fungi in the grassland ecosystems of the Tibetan Plateau Author: Affiliation: Agricultural and Animal Husbandry College,Tibet University,Agricultural and Animal Husbandry College,Tibet University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:西藏高原是地球上极具特色的地理单元,对生物物种的形成与演化具有重要影响。基于孢子形态学鉴定,对从藏东南到藏西北(海拔高差 > 3500 m,年均温、年均降水量差异分别 > 20 ℃、 > 800 mm)高原热带、亚热带、温带、亚寒带和寒带环境下发育而成的热性草丛、暖性草丛、温性草原、温性荒漠、高寒草甸草原、高寒草原、高寒荒漠和高寒荒漠草原中的AM真菌群落进行研究,结果表明,不同类型草地间AM真菌的群落相似度普遍较低,环境对AM真菌群落具有重要影响。从藏东南到藏西北,不同类型草地间AM真菌的群落相似度呈下降趋势(Jaccard相似性系数从0.52降至0.20),AM真菌群落组成及结构变化渐趋加大,不同草地中的同种植物(包括广谱种、青藏高原特有种)AM真菌群落相似度亦不同。沿藏东南到藏西北环境梯度,随草地寒旱程度的逐步加剧,AM真菌种的丰度,特别是种数、Shannon-Weiner指数在总体上趋于显著(P < 0.05)下降,孢子密度则在总体上趋于显著提高,优势种比例、Shannon-Weiner指数亦表现出增加的趋势,表明AM真菌物种多样性虽趋于下降,但生存及对环境的适应能力趋于提高。海拔、土壤pH、有效磷和有机碳含量对AM真菌群落组成均具显著影响,但海拔对水热环境的影响决定着土壤环境的变化。因此,海拔和寒旱程度不断上升所导致的pH显著提高、土壤有机碳和有效磷含量显著下降的综合作用影响并决定着AM真菌的群落组成。研究结果对进一步理解西藏高原生物多样性的产生和维持机制等具有重要的参考价值。 Abstract:The Tibetan plateau is a unique geographical unit that plays important roles in the formation and evolution of biological species. On the basis of spore morphology, we preliminarily investigated arbuscular mycorrhizal (AM) fungal communities in tropical tussock (TT), warm tussock (WT), temperate desert steppe (TDS), temperate desert (TD), alpine meadow steppe (AMS), alpine steppe (AS), alpine desert (AD), and alpine desert steppe (ADS) environments in southeastern to northwestern Tibet (altitude > 3500 m; mean annual temperature difference > 20 ℃; mean annual amount of precipitation difference > 800 mm), including plateau tropic, subtropic, temperate, subfrigid, and frigid zones. The results showed that the community similarity of AM fungi in different types of grasslands was generally low, and the type of environment had an important effect on the AM fungal community. Community similarity of AM fungi in different types of grassland demonstrated a decreasing trend from southeastern to northwestern Tibet (Jaccard similarity coefficient decreased from 0.52 to 0.20). Changes in the composition and structure of the AM fungal community increased gradually. AM fungal community similarity for the same plant species (including a broad spectrum of species and species endemic to the Qinghai-Tibetan Plateau) in different grasslands was also different. With a gradually aggravated degree of cold and drought in the grasslands along the environmental gradient from southeastern to northwestern Tibet, the abundance of AM fungi species, especially the number of species, showed significantly decreasing trends, according to the Shannon-Weiner index (P < 0.05). At the same time, spore density demonstrated dramatically increasing trends, and the proportion of dominant species in relation to the Shannon-Weiner index also showed a tendency to increase. This indicated that although the diversity of AM fungi showed decreasing trends, their survival and adaptability to the environment tended to improve. The effects of altitude, soil pH, effective phosphorus, and organic carbon content on AM fungal communities were significant, whereas the effects of altitude on the hydrothermal environment determined the changes in the soil environment. Therefore, AM fungal community composition was determined by the comprehensive effects of a dramatic increase in pH and soil organic carbon and a dramatic decrease in effective phosphorus content due to the gradually increasing altitude and degree of cold and drought. Our results have an important reference value for the further understanding of the production and maintenance of organism diversity in the Tibetan Plateau. 参考文献 相似文献 引证文献