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积雪覆盖变化对荒漠植物种子萌发的影响
别必武
学位类型硕士
导师张元明
2016
学位授予单位中国科学院大学
学位授予地点北京
学位专业植物学
关键词积雪覆盖 荒漠植物 种子萌发 萌发类型 生活型 古尔班通古特沙漠
摘要为适应荒漠生态系统不利的气候与自然环境条件,荒漠植物形成了多样化的生存策略。植物种子的成功萌发是植物群落建成的重要基础,其发生时间与强度决定了植物定居的成功率与地理分布,对荒漠生态系统的稳定与功能维持具有重要意义。 本文选择古尔班通古特沙漠35种不同生活型植物为研究对象,包括一年生草本14种,短命植物6种,多年生草本6种,灌木3种,半灌木5种,小乔木1种,研究三种不同积雪覆盖变化(自然降雪、加倍降雪和去除降雪)对荒漠植物种子萌发的影响。结果表明: 1、根据室内萌发率和萌发持续时间,35种供试植物种子可分为四种萌发类型,包括高萌速萌型(高萌发率、快速萌发)、高萌缓萌型(高萌发率,缓慢萌发)、低萌速萌型(低萌发率、快速萌发)和低萌缓萌型(低萌发率、缓慢萌发)。 2、野外不同积雪处理下,共有16种植物发生萌发现象,其它19种植物种子未见萌发,说明积雪处理能抑制某些植物种子萌发或引起种子休眠。在萌发的16种植物中,有12种植物种子野外萌发率与积雪量成正相关(P<0.05),4种无显著关系。不同生活型的种子对积雪的响应不同。一年生草本和半灌木均表现为种子萌发率与积雪厚度正相关(P<0.05),而多年生草本均表现为种子萌发率与积雪厚度无显著相关关系,短命植物对积雪响应不一致。不同萌发类型的种子中,低萌缓萌型种子萌发率均与积雪厚正相关(P<0.05),其他萌发型的种子对积雪响应并不一致。 3、将野外积雪处理后19种未萌发种子继续进行室内培养,发现有10种萌发,9种未见萌发,表明积雪处理抑制了某些种子萌发。在后续萌发的植物中,有3种植物种子总萌发率显著高于其室内本底萌发率(P<0.05),表明尽管积雪处理抑制了这类种子野外萌发,却能提高其潜在萌发率(处理后室内萌发率高于处理前),具有正效应;5种植物种子总萌发率与室内本底萌发率无显著差异,表明积雪处理对这类种子萌发潜力无影响;2种植物种子总萌发率显著低于室内本底萌发率(P<0.05),表明积雪处理对这类种子萌发潜力具有负效应。将野外19种未萌发种子进行室内培养,发现9种种子未萌发,可能属于积雪诱导种子休眠或积雪诱导种子失活。 荒漠生态系统中,植物种子萌发对积雪覆盖等环境变化表现出不同的响应策略,这种多样化的种子萌发响应模式,有利于荒漠植物群落在环境剧烈变化或逆境中保持结构和功能的稳定。
其他摘要To adapt to harsh environmental conditions in desert ecosystems, the plant community evolves various survival strategies under continuous succession. The seed germination of desert plants is the basis for community establishment and survival. The seed germination time and intensity determine the succession rate and geographic distribution of the plant community, which are of great importance to stability maintenance and succession of desert ecosystem. 35 desert species including different lifeforms (14 species of annual herbs, 6 species of ephemeral plants, 6 species of perennial herbs, 3 species of shrubs, 5 species of subshrubs, 1 specie of small tree) from Gurbantunggut desert were selected to study the effects of different snow covers on seed germination. Three kinds of snow cover treatments were settled in this study, i.e. double snow cover, natural snow cover and snow removal. The results showed: 1. Based on the results from indoor experiments, the seed germination types could be divided into four types, including high germination percentage with rapid germination rate, high germination percentage with slow germination rate, low germination percentage with rapid germination rate and low germination percentage with slow germination rate. 2. Sixteen species were observed the occurrence of seed germination under field snow treatments, out of which 12 species presented positive effect (P<0.05) and 4 species with no significant effect. Seeds of different life-forms have different responses to changed snow cover. The seed germination rates of annual herb and sub-shrub had positive response (P<0.05) to double snow cover, and perennial herbs with medium effects, and ephemeral plants with different effects. The seeds of low germination percentage with slow germination rate had positive response (P<0.05) to the amount of snow cover, and others were not consistent. 3. After re-germination of 19 species which did not germinate in field treatment sites, we found that 10 species germinated. After snow cover treatments, the potential germination percentages of 3 species surpassed its germination rate indoor, indicating that snow cover show positive effects on potential germination percentages. Snow cover can show medium or negative effects on potential germination percentages respectively. We also found that 9 species did germinate, which maybe due to snow-induced dormancy or inactivation of seeds. The seed germination of different plants in desert system showed different responding strategies to the changes of snow cover. Our study implicated that the diversified response modes are beneficial to maintaining stability of desert vegetation structure and function under the global climate change.
学科领域植物学
语种中文
文献类型学位论文
条目标识符http://ir.xjlas.org/handle/365004/14709
专题研究系统_荒漠环境研究室
作者单位中科院新疆生态与地理研究所
推荐引用方式
GB/T 7714
别必武. 积雪覆盖变化对荒漠植物种子萌发的影响[D]. 北京. 中国科学院大学,2016.
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