ISWC OpenIR  > 水保所知识产出(1956---)
不同氮素水平下 白 羊 草生长和生理对 短期 干旱 及复水的响应
李 帅
Subtype硕士
Thesis Advisor徐炳成
2015-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword白羊草 持续干旱胁迫 复水 氮素水平
Abstract

黄土高原半干旱丘陵区降雨量少且年季分布不均,水分是该地区植被恢复和生态
建设的主要限制因子,同时该地区还存在土壤氮素缺乏问题。本地植物种在长期的自
然选择中,形成了独特的适应机制,系统研究其在不同水氮条件下的生长与生理生态
特征,可为合理利用其进行植被建设提供依据。选取黄土丘陵区天然草地群落优势种
白羊草(Bothriochloa ischaemum)为研究对象,采用盆栽控制试验,设置 3 种氮素处理
(N0:不施氮,N1:0.1 g N Kg -1 和 N2:0.2 g N Kg -1 ),在其拔节期分别进行持续干旱
胁迫处理以及土壤含水量降至60% FC(田间持水量)、40% FC和20% FC时复水至80%
FC,比较不同水氮条件下白羊草的叶片气体交换参数、叶绿素荧光参数、生物量和水
分利用,主要结果如下:
(1)持续干旱胁迫显著降低了白羊草叶片的净光合速率(Pn)(P<0.05),但对叶片 PS
Ⅱ最大光化学量子效率(Fv/Fm)影响不显著;在土壤含水量不低于 40% FC 时白羊草
叶片 Fv/Fm 与充分供水差异不显著。在土壤含水量降至 20% FC 时叶片全部枯萎卷曲
变黄,但在复水后能够全部迅速复绿,叶片 Pn 和 Fv/Fm 能恢复至充分供水处理水平。
(2)N1 处理的白羊草叶片 Fv/Fm 在 30% FC 土壤含水量下仍与充分供水差异不显
著,复水后其叶片 Pn 和 Fv/Fm 显著高于 N0 和 N2 处理(P<0.05)。复水后 N2 处理的
Pn 和 Fv/Fm 显著低于 N0 处理(P<0.05)。
(3)施氮处理显著降低了白羊草的根冠比(P<0.05),N1 施氮处理下生育末期总生
物量显著高于其他 2 种氮素处理(P<0.05),N1 在 20% FC 复水后的水分利用效率显著
高于其他水分处理(P<0.05)。
综上,白羊草具有忍耐脱水的能力,在 20% FC 土壤含水量下仍能够存活并在复
水后恢复至正常的生理状态,在生物量上产生补偿效应。施氮水平为 0.1 g N Kg -1 时
有利于白羊草的光合作用、生物量积累和水分利用。
关键词:白羊草;持续干旱胁迫;复水;氮素水平

Other Abstract

There is little rainfall and the distribution of annual and seasonal rain is uneven in semi-
arid Loess Plateau hilly region. Water is a major limiting factor of vegetation restoration and
ecological construction in the region where is lack of nitrogen. After long-term natural
selection, native species have formed a series of adaptation mechanisms under the local
natural environment. Therefore, the study of physiological adaptability of native dominant
species under different water and nitrogen conditions can provide a theoretical basis for the
rational use of this species in vegetation construction. The natural grassland dominant
species B. ischaemum in loess hilly region was used under potted contidion. There were three
nitrogen treatments (N0- no nitrogen, N1-0.1 g N Kg -1 and N2-0.2 g N Kg -1 ) and four water
treatments (continuous drought stress and re-watering B. ischaemum to 80% field capacity
(80% FC) when the soil water content fall to 60% FC, 40% FC and 20% FC, respectively).
The study aimed to compare gas exchange parameters, chlorophyll fluorescence parameters,
biomass allocation and water use efficiency of B. ischaemum in different water and nitrogen
conditions in the jointing stage. The main results were as follows:
(1) Continuous drought stress significantly reduced the net photosynthetic rate (Pn) of
B. ischaemum, but maximum photochemical efficiency (Fv/Fm) had no significance. When
soil water content was not less than 40% FC, Fv/Fm under sufficient water supply condition
had no significant difference with that under continuous drought stress. B. ischaemum could
rehydrated green quickly even soil water fall to 20% FC, Fv/Fm and Pn could recover to the
level of sufficient water supply.
(2) There were no significant differences of Fv/Fm between sufficient water supply and
N1 treatment under 30% FC soil water content. Fv/Fm and Pn were significantly higher of
N1 treatment after re-watering than N0 and N2 treatment. Fv/Fm and Pn were significantly
lower of N2 treatment than N0 treatment after re-watering.  (3) Nitrogen treatment significantly reduced root-shoot ratio of B. ischaemum (P<0.05).
The total biomass was significantly higher with N1 treatment than other treatments (P<0.05),
and the water use efficiency was significantly higher with N1 treatment than other treatments
when rehydrated at 20% FC soil water content (P<0.05).
In summary, B. ischaemum has desiccation tolerance. It can survive when the soil water
content fall to 20% FC and recover to higher physiological activity after re-watering. It is
advantageous to photosynthesis, biomass accumulation and water use of B. ischaemum when
applying nitrogen fertilizer at 0.1 g N Kg -1 .
KEY WORDS: Bothriochloa ischaemum; continuous drought stress; re-watering; nitrogen
supply conditions

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/9027
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
李 帅. 不同氮素水平下 白 羊 草生长和生理对 短期 干旱 及复水的响应[D]. 北京. 中国科学院研究生院,2015.
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