ISWC OpenIR  > 水保所知识产出(1956---)
黄 土丘 陵区根际 微生物对 退耕地 植被恢复
张 超
Subtype博士
Thesis Advisor刘国彬 ; 薛萐
2013-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword根际 植被类型 撂荒演替 微生物群落结构 黄土丘陵区
Abstract

根际是指根系周围、受根系生长影响的土体,由于其环境的特殊性,根际土壤的
研究已经成为植物营养学、生态学及土壤学等学科的热点,鉴于我国在黄土高原植被
恢复方面对根际环境尚未全面系统地开展研究工作,本研究选取黄土丘陵区坡耕地退
耕后的不同植被恢复类型和撂荒演替初级阶段的主要植被群落为研究对象,采用磷脂
脂肪酸图谱技术(PLFA)和碳素利用技术(BIOLOG)系统研究了根际微生物对植
被恢复的响应过程,重点分析了不同植被类型对根际微生物量、酶活性、微生物群落
结构和代谢功能特征的影响以及撂荒演替过程中根际微生物群落结构的演变特征,以
期为深入认识该区植被恢复中土壤微生物的作用机理提供科学依据。主要结果如下:
1.  不同植被恢复类型根际 微生物特征
黄土丘陵区退耕地六种植被恢复类型中(年限均为8年),相对于人工灌木(柠条、
沙棘)和人工草地(沙打旺、柳枝稷),自然形成的天然草地(阿尔泰狗娃花、茵陈
蒿)具有较高的根际有机碳、全氮、微生物量碳、微生物量氮、酶活性、微生物群落
结构多样性以及碳源代谢功能多样性。
微生物指标中,代谢熵、脲酶、基础呼吸、水溶性碳及纤维素酶可作为评价黄土
丘陵区根际土壤生物质量的关键指标。结合标准化模型,建立了根际土壤生物质量指
标体系及评价方法,提出了根际微生物指数,结果表明,天然草地对根际土壤生物质
量的改善效果最佳,其次是人工草地,最后是人工灌木。
不同植被类型中,天然草地的根际效应(根际>非根际)较为广泛,主要体现在
有机碳、全氮、微生物量碳、微生物量氮、基础呼吸、过氧化物酶、革兰氏阴性菌、
细菌、真菌以及微生物总量。
2.  撂荒 演替 过程 中根际 微生物 的演变 特征
黄土丘陵区退耕地撂荒演替过程中,有机碳、全氮、微生物量碳、微生物量氮、
基础呼吸和酶活性具有较强的根际效应。
群落优势种根际微生物指标并非都高于伴生种,其优势主要体现在有机碳、全氮、
微生物量碳、微生物量氮以及糖类碳源利用效率,而在微生物群落结构、酶活性以及羧酸类碳源利用效率上并未表现出优势。
演替前期的植物茵陈蒿群落根际微生物性质波动较为强烈,而中后期铁杆蒿变化
规律性较强,总体随退耕年限呈增加趋势。
3. 人工模拟 撂荒 演替 根际 微生物群落结构特征
黄土丘陵区撂荒演替中不同阶段的优势种植物茵陈蒿、铁杆蒿和长芒草革兰氏阴
性菌、细菌含量和微生物总量根际效应显著,表现为距离根系越近,微生物含量越高。
在相同条件下,演替中后期植物铁杆蒿和长芒草的细菌和微生物总量的根际效应
大于前期植物茵陈蒿,而革兰氏阳性菌和真菌根际效应低于茵陈蒿。
在植被竞争中,前期植物茵陈蒿和中后期植物铁杆蒿、长芒草的根际微生物群落
对竞争的反应不同,表现为三者相互竞争时,茵陈蒿的根际微生物种类未发生变化,
铁杆蒿和长芒草则显著降低;茵陈蒿的根际微生物含量显著高于铁杆蒿和长芒草。
4.  撂荒演替 中不同 群落优势种 植物 之 间化感作用
种子萌发试验表明,不同演替阶段的群落优势种茵陈蒿、铁杆蒿和长芒草相互之
间其高浓度浸提液不仅对对方的种子萌发具有抑制作用,而且对自身种子萌发也具有
一定自毒作用。黄土丘陵区退耕地撂荒演替过程中植物之间存在化感作用,这种群落
间的化感作用可能是推动植被演替的原因之一。
关键词:根际;植被类型;撂荒演替;微生物群落结构;黄土丘陵区

Other Abstract

Rhizosphere is commonly defined as the soils where the root activity significantly
affects the biological properties of soil. Due to the special environment, the rhizosphere
micro-zone has become one of hot topic for the plant nutrition, plant physiology, ecology
and soil science. Because the lack of the available and comprehensive work on the
rhizosphere soils in the hilly loess region, the present study chose the different revegetation
types and the vegetation community in the natural succession on the abandoned cropland
to analyze the response of rhizosphere soil microorganism to the revegetation using
phospholipid fatty acids and BIOLOG carbon utilization technology. The study mainly
investigated the effect of revegetation types on rhizosphere soil microbial biomass,
enzymes activities, microbial community structure diversity and metabolic functional
diversity as well as the dynamic of microbial community structure diversity during the
abandoned cropland for natural succession. The results could provide scientific basis for
the understanding of microbial function during the vegetation restoration. The main results
are as follows:
1. The characteristic of rhizosphere microbial properties under different
revegetation types
Six vegetation types with 8-year-old were evaluated: two artificial (i.e. planted by
humans) shrublands (Caragana korshinskii and Hippophae rhamnoides) species, two
artificial grasslands (Astragalus adsurgens and Panicum virgatum) and two species from
croplands that were abandoned for natural recovery (Artemisia capillaries and
Heteropappus altaicus). The results showed the higher value of organic C, total N,
available Mn, available Cu, available Zn, microbial biomass C, microbial biomass N,
enzymes activities, microbial community structure diversity and carbon resource metabolic
functional diversity was record for the natural grassland compared to the artificial  shrublands and artificial grassland.
Among the microbial properties, metabolic quotient (BR/MBC), BR, urease,
water-soluble C and cellulase were found to be most important for assessing rhizosphere
soil biological quality. Results of rhizosphere soil microbial index indicated that natural
grasslands are most effective for the improvement of rhizosphere soil biological quality in
the hilly loess region, followed by the artificial grassland and artificial shrubland.
A significant difference was found on the rhizosphere effect under the different
vegetation types. Natural grassland species have the significant rhizosphere effect than the
artificial shrubland and artificial grassland.
2. The dynamic of rhizosphere microbial properties during the abandoned
cropland for natural succession.
During the natural succession, the significant rhizosphere effect was only found in
organic C, total N, microbial biomass C, microbial biomass N, basal respiration, enzymes
activities and microbial community structure.
Not all the microbial properties in the rhizosphere soil of dominant species were
higher than those of companion species. The higher value in the rhziosphere of dominant
species was found in organic C, total N, microbial biomass C, microbial biomass N as well
as the metabolic on carbohydrate resources than that of companion species, while in the
enzymes activities and the metabolic on carboxylic acids, the dominant species did not
showed the higher value.
The successional stage of the ecosystem can significantly affect the microbial
properties in the plant rhizosphere. In the current study, the pioneer species, A. capillaries,
exhibited significant fluctuations in the microbial properties, whereas the middle-late
species, A. sacrorum, presented an increasing trend.
3. The characteristics of rhizosphere microbial community structure in the
natural succession simulation
Three community dominant species of the succession, A. capillaries, A. sacrorum and
S. bungeana showed the significant microbial rhizosphere effect in G-negative bacterial,
bacterial and total microbial biomass, their contents decreased with the increase of distance
from root surface.
At the same soil conditions, the middle-late successional species, A. sacrorum and S.  bungeana had a higher rhizosphere effect of bacterial and total microbial biomass while
had the lower G-positive bacterial and fungi rhizosphere effect than that of the pionner
species, A. capillaries,
In the successional vegetation competition, the microbial community structure
rhizosphere soil of A. capillaries and A. sacrorum and S. bungeana responded differently
to the competition. In the competition between A. capillaries and A. sacrorum, as well as
between A. capillaries and S. bungeana, the number of microbial PLFA of A. capillaries
did not change, while that of A. capillaries and S. bungeana decreased significantly.
Furthmore, the microbial contents in the rhizopshere soil of A. capillaries was greatly
higher than that of A. capillaries and S. bungeana.
4. Allelopathic effect of dominant plants of vegetation commnutiy during the
abandoned cropland for natural succession
In the seed germination experiment, an inhibition was found on the seed germination
of A. capillaries, A. sacrorum and S. bungeana with each other in their high concentration
of aqueous extracts. Furthermore, a self-allelopathic effect was observed for the seed
germination of A. capillaries. In conclusion, there is a significant alleopathic effect
between vegetation communities during the abandoned cropland for natural succession,
this effect maybe the one of the reseaons for promoting the vegetation succession in the
loess hilly region.
Keywords: Rhizosphere; Vegetation types; Abandoned cropland for natural succession;
Microbial community structure; Loess hilly region

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8974
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
张 超. 黄 土丘 陵区根际 微生物对 退耕地 植被恢复[D]. 北京. 中国科学院研究生院,2013.
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