IMHE OpenIR  > 山地表生过程与生态调控重点实验室
高寒草原优势物种根系构型特征与生长适应机制
Alternative TitleRoot systems architecture characteristics and growth adaptation mechanism of dominant species in alpine steppe
Language中文
马星星
Thesis Advisor王小丹
2016
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name博士
Degree Discipline自然地理学
Keyword粗根 细根 根长 增温 施肥 功能型
Other Abstract

本文以藏北高寒草原紫花针茅群落优势物种为研究对象,通过生长季野外采样,获得主要物种(紫花针茅、青藏苔草、火绒草、昆仑蒿、冰川棘豆和丛生黄耆)的根系基本参数(根长、根表面积、根平均直径、根体积、根尖数和根分叉数)并确定该物种的根系构型类型及主要参数;通过2年的增温实验(年均增温幅度 2.68℃),测定植物地上生物量、不同土壤深度地下生物量、植物养分含量、土壤养分含量,揭示根系生物量在温度因子下的动态变化及响应,阐明根系参数在增温条件下的适应性;通过施肥(每年施氮量 5.25gN m-2)实验,测定剔除不同功能群植物(莎草、杂草和莎草+杂草)中紫花针茅根系的参数,回答生长预防性理论或验证土壤养分浓度梯度的迁移机制,明确高寒草原根系形态学上的适应机制。为未来气候变化条件下,高寒草地的群落稳定性提供理论支撑。主要研究结果和结论如下: 1)不同类型根系构型物种具有不同的优势根系参数,且不同物种有不同的根系构型主要参数。密丛型植物紫花针茅在总根长、根尖数和分叉数上显著高于其它根系构型植物。轴根型植物冰川棘豆、丛生黄耆和昆仑蒿在根系平均直径总根表面积和总根体积上具有优势。紫花针茅根系构型的主要参数是总根长和根尖数。青藏苔草的主要参数是总根长和分叉数。昆仑蒿根系构型的主要参数是根总表面积和总根长。火绒草根系构型的主要参数是根总体积和根总表面积。根分叉数是影响冰川棘豆根系构型的主要参数。丛生黄耆根系构型的主要参数是总根长和分叉数。 2)短期增温对植物生物量无显著影响。增温处理下,群落地上部分生物量和总根系生物量有增加的趋势,但不显著;而 R/S 有下降的趋势,这也意味着增温后植物将更多生物量分配于地上部分。增温处理下,活根生物量和死根生物量均呈增加趋势,但并不显著,且死根增加幅度高于活根,导致 L/D(活根/死根生物量)减少。增温对不同深度的根系生物量、粗根生物量、细根生物量和 C/F(粗根/细根生物量)都没有显著影响。增温后,生长季的延长和土壤中养分的可获得性提高是生物量增加的可能因素,但由于增温时间比较短,未形成显著性差异。 3)增温对紫花针茅群落中紫花针茅、青藏苔草和昆仑蒿的根系基本参数和构型主要参数有不同的影响。增温对紫花针茅根系基本参数和根系构型主要参数都没有显著影响。平均直径和总根体积是紫花针茅根系构型的两个主要参数。增温显著增加了青藏苔草的根长及根尖数,对根表面积、平均直径、根体积和分叉数没有显著影响。 增温处理将青藏苔草根系构型主要参数由总根表面积和总根体积转换为总根表面积。增温减少了昆仑蒿的分叉数,对其根长、根表面积、平均直径、根体积和根尖数没有显著影响。增温处理将昆仑蒿根系构型主要参数由根尖数和总根长变为总根表面积和总根体积。 4)施肥和剔除不同的功能群植物对紫花针茅根系基本参数和构型主要参数影响不同。施肥显著增加了紫花针茅 6个根系基本参数。剔除莎草和杂草,施肥使紫花针茅根系构型主要参数由根平均直径和总根体积转化为总根表面积。剔除杂草,紫花针茅根系构型主要参数在对照和施肥样地均为根平均直径和总根体积。剔除莎草,施肥使紫花针茅根系构型主要参数由总根表面积转化为为根平均直径和总根体积

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Three experiments were conducted in Stipa purpurea community in Xainza Alpine Steppe and Wetland Ecosystem Observation Station (30°57′ N, 88°42′ E, 4675 m a.s.l.) on the north Tibetan Plateau. We harvested six main species (S. purpurea, Carex moocroftii, Leontopodium nanum, Oxytropis glacialis, Astragalus confertus and Artemisia nanschanica) in the S. purpurea community to gain the basic root parameters, such as root length, root surfarea, root mean diameter, root volume, root tips and forks, and make clear the main parameters, which play an important role in root architecture. A 2-year warming (2.68℃) experiment by using open top chambers (OTCs) was also conducted. Via shoot biomass, root biomass at different soil depth, plant nutrient concentration and soil nutrient concentration to investigate the effect of experimental warming on root biomass dynamics and adaptation of root architecture. A 5.25gN m-2y-1 fertilizing experiment, with different functional groups (grass, grass and sedges, grass and forb), was also conducted. By root parameters for S.purpurea to answer growth pre-emption theory or verify the migration mechanism of soil nutrient concentration by fertilization experiment. The main research results and conclusions are as follows: 1) Species with different type of root architecture had an advantage in different root parameters and species had different main parameters of root architecture. Total root length, root tips and root forks of S. purpurea, dense cluster type plant, were much greater than species with other root types. Mean diameter, root surf area and root volume of O. glacialis, A.confertus and A. nanschanica, shaft type root plants, were much higher than other species. Total root length and tips were the main parameters for S. purpurea root architecture. Total root length and root forks were the main parameters for C. moocroftii root architecture, respectively. Total root surf area and total root length were the main parameters for A.nanschanica. Total root volume and total root surf area were the main parameters for L.nanum. Root forks were the main parameters for O. glacialis. Total root length and root forks were the main parameters for A. confertus root architecture. 2) Short-term warming had no significant effect on shoot and root biomass. Warming increased shoot and root biomass, which was not significant. However, R/S (root/shoot biomass) was declined by warming, which was not marked and indicated that warming allocated more biomass to shoot rather than root. Live and dead root biomass were enhanced in warming plot, which was not significant. Warming increased higher root death rate, which led a decrease in L/D (live/death root biomass). Warming had no significant effect on coarse root biomass, fine root biomass, C/F (coarse root /fine root) and biomass at different soil depths. Warming extended the growing season and increased the availability of soil nutrients, which may be the reason why biomass increased. 3) Warming had different effects on root basic parameters and the main parameters of root architecture for S. purpurea, C. moocroftii and A. nanschanica in the S. purpurea community. Warming had no marked influence on root basic parameters and the main parameters of root architecture for S. purpurea, with total root length and tips as the main parameters of root architecture. Root length and tips for C. moocroftii were enhanced by warming and the main parameters of root architecture were transferred from total root surfarea and volume to total root surf area. Warming decreased root forks for A. nanschanica and changed the main parameters of root architecture from total root tips and length into total root surf area and volume. 4) Fertilization and different combination of functional group had significant influence on root basic parameters and the main parameters of root architecture for S. purpurea. Fertilization significantly increased all root basic parameters of S. purpurea across the three functional groups. Fertilization transferred the main parameters of root architecture from mean root diameter and volume to total root surf area in grass functional group. There were no differences between the fertilization and control plot in the main parameters of root architecture for S. purpurea in grass and sedges functional group. Fertilization transferred the main parameters of root architecture from total root surf area to mean root diameter and volume in grass and forb functional group.Key Words: Coarse root, Fine root, Root length, Warming, Fertilization, Functional group 

Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/18987
Collection山地表生过程与生态调控重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
马星星. 高寒草原优势物种根系构型特征与生长适应机制[D]. 北京. 中国科学院大学,2016.
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