KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 模拟降水和氮沉降变化对短命植物生活史的影响 | |
| Alternative Title | Effects of simulated precipitation and nitrogen deposition on the life history of ephemeral plants |
| 陈艳锋 | |
| Subtype | 博士 |
| Thesis Advisor | 张道远 |
| 2019-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学博士 |
| Keyword | 古尔班通古特沙漠 降水变化 氮沉降 短命植物 生活史 Ephemeral plants Gurbantunggut desert Life history Nitrogen deposition Precipitation |
| Abstract | 古尔班通古特沙漠是亚欧内陆干旱区的重要组成部分，也是我国面积最大的固定半固定沙漠，该区域独特的山地-荒漠-绿洲地理格局在全球范围内都独具特色。同时，该区域也是中亚植物区系与喜马拉雅、蒙古和地中海植物区系的交汇区，特别是研究区广泛发育的早春短命植物，长期以来，被认为是研究植物响应环境变化的理想材料。近年来，由于气候变化和人类活动加剧引起的降水和氮沉降变化，导致该区域生态系统对环境变化的响应表现出极大的不确定性。然而，前人关于降水和氮沉降变化对短命植物影响的研究多集中在某一生活型植物或植物生活史的某些方面， 而对不同生活型短命植物生活史的系统研究一直没有得到足够的重视。本研究自 2016 年 9 月至 2018 年 10 月，以中国科学院干旱区生物地理与生物资源实验室为试验平台， 以四种一年生短命植物尖喙牻牛儿苗（Erodiumoxyrhynchum M. Bieb.） , 小花荆芥（Nepeta micrantha Bunge.） , 毛穗旱麦草（Eremopyrum distans (C.Koch) Nevski.）, 抱茎独行菜（Lepidium perfoliatum Linn.）和四种多年生短命植物囊果苔草（Carex physodes M. -Bieb.）， 粗柄独尾草（Eremurus inderiensis (M. Bieb.) Regel.）， 棱果芥（Syrenia siliculosa (M. Bieb.)Anders.）， 小山蒜（Ixiolirion tataricum (Pall.) Herb.） 为研究对象， 在古尔班通古特沙漠典型荒漠区开展了降水、 氮沉降及其互作的多因子控制试验，系统研究了冬季积雪变化对不同生活型短命植物种子休眠释放和萌发的影响， 春夏季增水、增氮及其互作对不同生活型短命植物生长过程、生物量积累与分配和子代适合度的影响，研究结果将为系统揭示环境变化背景下不同生活型短命植物种群的发展趋势积累理论资料。本研究的主要结果如下：（1） 新收获的不同生活型短命植物种子室内萌发实验和野外埋藏种子的萌发动态监测试验均表明，不同生活型短命植物种子的萌发率并没有表现出生活型之间的差异性，而是具有物种特异性。积雪变化对不同生活型短命植物种子休眠释放的影响总体表现为增雪促进或无明显影响，减雪抑制或无明显影响。因此，短命植物种子在休眠释放和萌发上的差异是植物长期适应恶劣荒漠环境的结果，体现了短命植物在种子萌发阶段的适应对策。（2） 一年生短命植物的多数形态、数量和生物量性状均呈现前期快速增加，后期趋于平缓或下降的趋势，并在炎热的夏季来临之前完成繁殖生长。因此，一年生短命植物属于杂草对策（Ruderals）。多年生短命植物的大部分形态、数量和生物量形状呈现缓慢上升趋势， 并且在试验的前两年并未进行繁殖生长， 主要通过地下块茎或鳞茎的休眠度过环境恶劣时期。因此，多年生短命植物的生长属于典型的胁迫耐受对策（Stresstolerators）。增水、增氮及其互作促进了大部分一年生短命植物的生长， 并且干旱年份增水的促进效果更为显著，但是干旱年份增氮对部分物种却有一定的抑制作用，如 2017 年增氮显著抑制了春秋萌尖喙牻牛儿苗生长；同时，增水、增氮及其互作显著促进了多年生短命植物的生长，水氮互作的促进作用最为显著。因此， 增水、增氮及其互作促进了大部分一年生和多年生短命植物的生长，但受年际间降水的影响，部分物种存在差异性响应。（3） 对短命植物生物量积累与分配的研究发现，一年生短命植物的变化主要源自于年际间降水量的变化，而多年生短命植物的变化既受年际间降水变化的影响，也体现出生物量在年际间不断积累的过程。同为一年生短命植物的不同物种对增水、增氮及其互作的响应也存在差异，然而对于多年生短命植物而言，增水、增氮及其互作对其生物量积累总体表现为促进作用。 特别是对根冠比的研究发现，一年生短命植物的根冠比在 0-0.2 之间，多年生短命植物的根冠比却在 10-30 之间，上述差异的出现，一方面可能与不同生活型短命植物的生活史对策有关，另一方面与不同生活型短命植物的物候差异有关。 同时， 增水、增氮及其互作对一年生短命植物的繁殖分配具有负效应或无效应。 因此，环境条件的改善趋向于促进一年生短命植物营养器官的生长。（4） 增水、增氮及其互作对子代适合度的研究发现，除 2017 年的增水对小花荆芥种子产量有抑制作用以外， 2017 年和 2018 年的增水、增氮及其互作对一年生短命植物的种子产量均为促进或无明显影响作用。增水、增氮及其互作促进一年生短命植物种子生产，大部分物种的种子百粒重反而呈现降低趋势，这又印证了种子数量与大小之间的权衡关系。 除了 2017 秋萌尖喙牻牛儿苗以外， 大部分一年生短命植物符合子代萌发率与子代大小之间的正相关关系，这很可能与群落中春萌与秋萌尖喙牻牛儿苗存在竞争有关。综上表明， 不同生活型短命植物种子休眠释放和萌发过程对积雪变化的响应并没有表现出生活型之间的差异性，而具有物种特异性；在生长阶段， 一年生短命植物对环境变化的响应要比多年生短命植物更加敏感，并且多年生短命植物在试验的前两年未进行繁殖生长。 同时，在生长阶段增水、增氮又可以通过影响子代数量、大小和休眠间接的影响子代种子萌发与幼苗建成。 因此，未来降水和氮沉降变化将首先会对一年生短命植物产生影响，而对多年生短命植物的影响可能需要更长时间的试验研究。 |
| Other Abstract | The Gurbantunggut Desert is an important part of the arid zone of Asia and Europe,and it is also the largest fixed and semi-fixed desert in China. The geographicalpattern of mountain-desert-oasis in this desert is considered to be the unique in theworld. Moreover, this desert is also the intersection of Central Asian flora with theQinghai-Tibet and Mongolian flora, and ephemeral plants are a unique part of desertflora, which are considered a plant group for studying the responses of plants toenvironmental changes. Recently, changes in precipitation pattern and nitrogendeposition caused by climate change and human activities have led to significantuncertainties in the response of ecosystems to the Gurbantunggut Desert. However,the effects of precipitation and nitrogen deposition on ephemeral plants mainlyfocused on some aspects of life history in current. Systematic research on theresponses of different life-forms ephemeral plants to environmental changes wasextremely lacking.Multi-factor control experiments of increased water, nitrogen and their interactionswere conducted to ephemeral plants, including Erodium oxyrhynchum M. Bieb.,Nepeta micrantha Bunge., Eremopyrum distans (C. Koch) Nevski., Lepidiumperfoliatum Linn., Carex physodes M. -Bieb., Eremurus inderiensis (M. Bieb.) Regel.,Syrenia siliculosa (M. Bieb.) Anders., Ixiolirion tataricum (Pall.) Herb. fromSeptember 2016 to October 2018 in the typical desert area of Gurbantunggut Desert.The seed germination experiments were conducted in the Key Lab of Biogeographyand Bioresource in Arid Land, Chinese Academy of Sciences. The effects of snowcover on seed dormancy release and germination in different life-forms ephemeralplants in winter, and the effects of increased water, nitrogen and their interactions onthe growth, biomass accumulation and allocation and offspring fitness of differentlife-forms ephemeral plants were systematically studied in spring and summer. Theresults of the study will reveal the development trend of different life-formsephemeral plant populations under global environmental change, and it will predict the influence of ephemeral plant changes on the pattern of desert ecosystems. Themain results of this study were as follows:(1) Fresh harvested seeds with ephemeral plant of germination experiment in thelaboratory and in the field indicated that the seed germination percentage of differentlife-forms ephemeral plants did not differ in plant life-forms, but it showed significantspecificity depending on species. The effect of seed dormancy release in differentlife-forms ephemeral plants by snow cover showed that increased snow promoted orwas no significantly effect on the dormancy release of seeds, and decreased snowinhibited or was no significantly effect on the dormancy release of seeds. Therefore,the dormancy variation of ephemeral plants in different life-forms is the result thatplants adapted to changeable desert environment in long-term, and it also revealed thedifferences in variation strategies of life-forms ephemeral plants during the seedgermination stage.(2) The morphology, quantitative and biomass traits of annual ephemeral plantsshowed a rapid increasing trend in the early stage of life history, and then it tends tobe flat or decreasing tendency in the later period of life history, and finished the lifehistory before the summer. Therefore, the annual ephemeral plants belong to thetypical ruderal strategy (R). The morphological, quantitative and biomass traits ofperennial ephemeral plants showed a slow increasing trend, and their growth rate wasslow and no reproductive growth, and they went through the stage of harshenvironment in summer and winter by the dormancy of underground tubers or bulbs.Therefore, the perennial ephemeral plants belong to typical stress tolerance strategy(S). Increased water, nitrogen and their interactions promoted the most ofmorphological and quantitative traits of annual ephemeral plants, but it also showeddifferences between species and years. For example, the effect of increased water inthe dry year is more significant than that of the wet year, and increased nitrogen in dryyear has an inhibitory effect on some annual species; similarly, increased water,nitrogen and their interactions significantly promoted the growth of perennialephemeral plants, and the promotion of water and nitrogen interactions is moresignificant than other treatments. Therefore, increased water, nitrogen and their interactions promoted the growth of annual and perennial ephemeral plants, but due tochanges in the interannual precipitation, some annual ephemeral plants showed adifferent responses to increased nitrogen.(3) Studied on the biomass accumulation and allocation of ephemeral plant haverevealed that the those of annual ephemeral plants changing were mainly caused byprecipitation, while those of perennial ephemeral plants changing were affected byprecipitation and biomass accumulation in interannual. Different species of the annualephemeral plants also have different responses to increased water, nitrogen and theirinteractions, however, increased water, nitrogen and their interactions promotedbiomass accumulation of perennial ephemeral plants. Root/shoot ratio of annualephemeral plants was between 0 and 0.2, but root/shoot ratio of perennial ephemeralplants was between 10 and 30. The differences of root/shoot ratio of differentlife-forms in ephemeral plants were likely related to the life history strategies ofdifferent life-forms ephemeral plants, it was also likely related to the difference ofphonological stages. Increased water, nitrogen and their interactions have negativelyor no effect on the reproductive allocation of annual ephemeral plants. Therefore, theimprovement of environmental conditions tends to promote the growth of vegetativeorgans of annual ephemeral plants, but perennial ephemeral plants did not reproducein the first two years of the experiment.(4) Studied on the offspring fitness found that increased water, nitrogen and theirinteractions promoted or had no significant effect on the seed yield of annualephemeral plants in 2017 and 2018, except that increased water has an inhibitoryeffect on the seed yield of N. micrantha in 2017. Increased water, nitrogen and theirinteractions promoted seed production of annual ephemeral plants, while the100-grain weight of most species showed a decreasing trend, which was basicallyconsistent with the trade-off theory between seed quantity and mass. The positivecorrelation between the seed germination percentage and seed size was alsoconfirmed in the most annual ephemeral species, but the relationship between the seedsize and germination percentage of the autumn germinated E. oxyrhynchum were notaccording with above rules in 2017. It may be related to the competition between spring and autumn-germinated E. oxyrhynchum occurred in the community.In conclusion, the seed dormancy release of annual and perennial ephemeral plantsdid not differ in life-forms in response to changes of snow cover, depending onspecies. The responses of annual ephemeral plants are more sensitive to changingenvironment than perennial ephemeral plants. Therefore, future increasedprecipitation and nitrogen deposition will have a more significant impact on annualephemeral plants than perennial ephemeral plants, which may require longerexperimental studies on perennial ephemeral plant. |
| Subject Area | 植物学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15313 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 陈艳锋. 模拟降水和氮沉降变化对短命植物生活史的影响[D]. 北京. 中国科学院大学,2019. |
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