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冷荒漠降水增加对囊果苔草生活史及繁殖对策的影响
李雪峰
学位类型硕士
导师张道远
2017-05-01
学位授予单位中国科学院大学
学位授予地点新疆乌鲁木齐
学位专业工程硕士
关键词囊果苔草 降水增加 繁殖对策 克隆植物 Carex physodes Increasing precipitation Reproductive strategy Clonal plant
摘要Ephemeral plant is a unique existence in cold desert around the world and playsimportant role in maintaining ecological stability in Gurbantunggut desert of Xinjiang,Northwest China. In order to understand the reproductive strategy adjustment ofephemeral plant under continuously precipitation increase in cold desert, we chooseCarex physodes, an endemic ephemeroid rhizomatous clonal plant from Cyperaceaefamily, as study object. The characteristics of seed germination and seedlingestablishment were studied both in indoor control and field survey under snowenhancement in winter and water enhancement in spring-summer seasons. The clonalreproductive strategies and sexual reproduction allocation were also monitored duringthe treatments. The main results and conclusions are as follows:(1) Under different snowfall conditions, the seed vigor and germination rate of C.physodes were different. The seed vigor and germination rate were higher under snowenhancement, indicating that increased snowfall is beneficial to the vigor of seeds,and also subsequent seed germination.(2) Increased rainfall affect the vegetative growth of C. physodes compared withthe natural state. The crown length and width, and the leaf number decreased underwater enhancement, while the plant height increased, with up to 14.41% increaseunder 50% water enhancement. The underground biomass and diameter of rhizomaticroot increased its the waterfall enhancement. This showed that C. physodes maybereduce surface face by reducing leaf number and crown length and width, andincrease the biomass input in underground parts, to adapt to water enhancement inarid desert environment.(3) Compared with the natural waterfall amount, Carex physodes reproductivestrains and vegetative strains numbers increased, and the effect was significant forreproductive strains. Reproductive strains increased by 176% under 30% waterenhancement, and by 281% under 50% water enhancement, and the ratio of reproductive and vegetative stain number was also raised. Thus, the results indicatethat the increase of spring and summer precipitation promotes C. physodesreproductive and vegetative strains growth, which benefit for the populationdevelopment of the species in desert.(4) Compared with the natural state, water enhancement made Carex physodesfruit's length increase, while fruit width decrease. And made seed width increase, andseed length decrease, with 6.52% decrease under 30% water enhancement and 2.55%decrease under 50% water enhancement. The thousand seed weight decreased and thethousand fruit weight increased. These results showed that the increase of spring andsummer precipitation may affect the reproductive organ plasticity of C. physodes, andthe following seed dispersal and inhibition in the desert.
其他摘要类短命植物是新疆准噶尔盆地特殊的植物类群,也是西北干旱区重要植物类群。本研究选择干旱区莎草科(Cyperaceae)苔草属根茎型类短命克隆植物囊果苔草(Carex physodes)为研究对象。采用室内控制和野外观测相结合的技术路线,从种子休眠解除-种子萌发-幼苗建成各环节入手,模拟研究降水增加对其生活史及繁殖对策的影响,探讨囊果苔草的生活史特征变化以及繁殖对策适应特性。研究以期为深入理解全球气候变化背景下(降水增加)温带冷荒漠短命植物适应性机制奠定理论基础。主要研究结果和结论如下:(1)不同增雪条件下,囊果苔草种子活力和萌发率不同。增雪处理下种子活力、萌发率总体高于减雪处理。这表明,冬季降雪增加有利于提高种子的活力,从而提高其潜在的萌发力。(2)水量增加,囊果苔草冠幅减小,叶片数减少,但株高显著增加,增加50%的水量使株高增加 14.41%;水平根茎直径增大,地下生物量增加。说明春夏季降水量增加引起了囊果苔草表型可塑性变化;增加地下克隆构件生物量分配,增强其植株生长力,使之更好地适应沙漠干旱的环境。(3)水量增加,囊果苔草生殖株和营养株数量均增加,且对生殖株的作用达到显著水平,生殖株数量在 30%增水量条件下增加 176%,50%增水量下增加281%,且随着增水量的增加,生殖株与营养株数量的比值有升高的趋势。说明春夏季降水增加均促进囊果苔草生殖株和营养株的生长,但对生殖株的贡献更大。(4)水量增加使囊果苔草果实长有增加的趋势,果实宽有降低的趋势,果实更加倾向于细长;使种子长减小,宽增大,种子更加钝圆。此外,种子千粒重降低,果实千粒重增加。这表明水量增加会影响囊果苔草有性繁殖体形态及生物量分配,进而对该物种的传播与定居产生潜在影响。
学科领域生物工程
语种中文
文献类型学位论文
条目标识符http://ir.xjlas.org/handle/365004/14884
专题研究系统_荒漠环境研究室
作者单位中国科学院新疆生态与地理研究所
第一作者单位中国科学院新疆生态与地理研究所
推荐引用方式
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李雪峰. 冷荒漠降水增加对囊果苔草生活史及繁殖对策的影响[D]. 新疆乌鲁木齐. 中国科学院大学,2017.
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