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干热河谷区车桑子(Dodonaea viscosa)对典型胁迫因子的响应
Alternative TitleResponses of Dodonaea viscosa to Typical Stressful Factors in Dry-Hot Valley
王雪梅
Subtype博士
Thesis Advisor刘刚才
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline土壤学
Keyword干热河谷 水分胁迫 养分胁迫 土壤微生物 丛枝菌根真菌
Abstract植物受到环境胁迫的现象是普遍存在的。在全球变化的背景下,水分胁迫和养分胁迫问题严重影响了植物和土壤系统。然而,在胁迫条件下,植物与土壤微生物间的相互作用关系仍不清楚。干热河谷生态环境具有水分与养分双重胁迫的特点,植被恢复一直是该区生态和经济建设的重难点工作。在该区植被受到水分与养分因子严重的胁迫条件下,土壤微生物在植物生长中的作用尚不可知。车桑子(Dodonaea viscosa)是干热河谷区的优势物种,具有耐干旱、贫瘠的特性,被作为一种植被恢复树种推广应用。因此,本论文以车桑子苗为研究对象,通过研究车桑子生理生长和土壤微生物特性对水分胁迫、氮磷养分胁迫的相互响应特性,揭示环境胁迫下植物生理生长与土壤微生物的内在联系;同时,通过研究车桑子生理生长对土壤微生物变化的响应,阐明该区土壤微生物对植物生理生长的影响。主要取得了以下4个方面的研究结果:(1) 水分胁迫对车桑子生理生长的影响 水分胁迫显著影响了车桑子间的相互作用关系、形态特征和生理特征。低水分条件下,车桑子间的竞争作用增强,其株高、叶面积和生物量生长显著受到抑制,叶片相对含水量、叶水势、气孔导度、蒸腾速率和净光合速率显著降低,但其叶片氮磷浓度、氮磷重吸收效率和水分利用效率显著提高。其中,土壤水分含量对叶片相对含水量和气孔导度影响最大。在较低的叶水势下车桑子依然能够维持70%左右的相对含水量,主要表现为御旱策略。 水分胁迫显著抑制了土壤微生物活性。过氧化氢酶、β-葡萄糖苷酶、脲酶、酸性磷酸酶活性、土壤微生物量氮和土壤呼吸速率在低水分条件下均显著降低。同时,相比高水分条件,低水分条件对脲酶活性的降低程度达到57.76% ± 4.83,较其他酶活性的降低程度更大。 土壤微生物活性的变化通过影响土壤养分进而作用于车桑子养分吸收和利用。水分胁迫对微生物活性的抑制作用减少了土壤养分供给,但在低水分条件下,车桑子通过提高对叶片氮磷的重吸收效率和增加叶生物量的分配比例来提高对养分的吸收和利用,其氮重吸收效率达到50%,磷重吸收效率接近70%,叶-茎生物量的异速生长斜率达到1.0。同时,土壤水分对脲酶活性的影响主要为间接效应,光合速率对脲酶活性的直接影响更大;并且低水分下脲酶活性受到的抑制作用较光合速率小。(2) 氮磷养分胁迫对车桑子生理生长的影响 不同土壤上车桑子受到的氮磷养分胁迫类型不同。低海拔区燥红土上的车桑子主要受到氮限制,加氮促进了车桑子生长、生物量积累、叶片氮的吸收和叶绿素总量的提高;高海拔区黄棕壤上的车桑子主要受到磷限制和氮饱和胁迫,加磷促进了车桑子生长、生物量积累和叶片磷的吸收,而加氮抑制了车桑子生长和生物量积累;中海拔紫色土上氮磷胁迫类型不明显,趋于氮磷的共同限制。 在不同养分限制的土壤上,土壤微生物通过提高相关土壤酶的分泌效率增加植物可利用性养分。在氮限制的燥红土上,土壤脲酶效率最高;在磷限制的黄棕壤上,土壤磷酸酶效率最高。同时,微生物对土壤有效养分的变化能做出直接的响应;燥红土上脲酶效率的响应和土壤有效氮响应显著负相关,黄棕壤上磷酸酶效率的响应和土壤有效磷响应显著负相关,并且这种响应强度较车桑子对土壤养分变化的响应强度更大。 土壤有效养分含量并不是决定车桑子生长的最主要因素。车桑子生物量和土壤有效氮、磷含量显著负相关。三种土壤类型上,燥红土和紫色土上的车桑子生长均显著优于土壤养分含量更高的黄棕壤。(3) 根际土壤微生物对车桑子生理生长的影响 根际土壤微生物对车桑子生理生长具有显著的正效应。接种低海拔区燥红土根际微生物和高海拔区紫色土根际微生物均显著促进了车桑子生长、生物量积累和叶片氮磷养分的吸收。但根际微生物对车桑子的这种促进作用依赖于温度;两个海拔区的根际微生物均在较高温条件下才对车桑子表现出正效应,而在较低温条件下土壤微生物对车桑子生长的促进作用并不明显。 根际土壤微生物驱动了车桑子对温度变化的响应。在接种根际微生物的处理,较高温条件促进了车桑子生长、生物量积累和叶片氮磷养分的吸收;而在没有接种根际微生物的处理,温度对车桑子生理生长特性没有显著影响。 接种根际微生物促进了车桑子对土壤有效氮磷的吸收尤其是磷营养的吸收。高温条件下,接种低海拔微生物和高海拔微生物的叶片氮总量分别比灭菌处理增加了178.22% ± 34.03 和250.44% ± 9.62;叶片磷总量分别比灭菌处理增加了841.52% ± 92.31 和 806.39% ± 91.55。因此,接种微生物处理使车桑子从土壤中吸收了更多的氮磷养分,从而使接种处理的土壤有效氮、磷含量和土壤微生物生物量显著更低。(4) AMF对车桑子生理生长的影响 AMF对车桑子生理生长具有显著的正效应。接种AMF显著促进了车桑子生长、生物量积累和净光合速率,增加了车桑子茎的木质素含量,并提高了其木质化比例。燥红土上,接种AMF处理的茎木质化比例接近80%;黄棕壤上,接种AMF处理的茎木质化比例接近60%。茎的木质化显著降低了茎的饱和含水量。 接种AMF处理的车桑子对干旱和贫瘠的胁迫环境采取保守的适应策略。接种AMF处理的车桑子叶片氮磷浓度显著降低,同时其比叶面积显著降低、而叶干物质含量显著增加。 燥红土上接种乡土AMF对车桑子生理生长具有更加明显的促进作用。干旱增加了燥红土上车桑子对AMF的菌根依赖性,同时车桑子对乡土AMF的依赖性较非乡土AMF(Glomus mosseae和Glomus etunicatum)更大。并且燥红土上接种乡土AMF对车桑子净光合速率的促进作用也较非乡土AMF更大。 论文研究结果表明,虽然干热河谷区植物生长受到水分与养分胁迫,但该区土壤微生物在维系当地的植被生长中扮演着重要角色。经过长期的适应和选择,干热河谷植物与自身的土壤微生物在当地土壤环境中已形成了十分紧密的共生关系。因此,在干热河谷植被恢复过程中,应考虑对地下微生物系统尤其是与植物密切相关的共生真菌进行恢复。
Other AbstractIt is common that plants are subjected to environmental stresses. Under the background of global change, water stress and nutrient stress have seriously affected plant and soil systems. However, the interaction between plants and soil microorganisms in the stressful conditions is not clear. The ecosystem of dry-hot valley is characterized by water stress and nutrient stress, and the re-vegetation has always been a major and difficult task in ecological and economic construction in the area. However, under the condition that soil moisture and nutrients extremely restrict the vegetation growth in this area, the role of soil microbes in plant growth is still unknown. Dodonaea viscosa, the dominant species with resistances to drought and barren in dry-hot valley, is widely used for vegetation restoration in this area. Therefore, focusing on D. viscosa, the responses of D. viscosa and soil microorganisms to water stress and nutrient stress were studied, thus revealing the plant-soil microbe interaction in the context of environmental stresses; besides, the effects of soil microorganisms on D. viscosa growth were researched, thus clarifying the effects of soil microbes on plant growth. The main results were showed as following 4 aspects:(1) The Effect of Water Stress on Growth and Physiological Characteristics of D. viscosaWater stress affected the intraspecific interactions, morphological and physiological characteristics of D. viscosa. Under low water condition, the intraspecific competition of D. viscosa increased; height, leaf area and biomass reduced, and the leaf relative water content, leaf water potential, stomatal conductance, transpiration rate and net photosynthetic rate decreased significantly, but the N and P concentrations, re-absorption efficiency of N and P and water use efficiency of the leaves significantly improved. Among these responses, the relative water content and stomatal conductance were most affected by soil water content. But the relative water content of D. viscosa still maintained around 70% even in the lower leaf water potential. The drought resistance of D. viscosa was characterized by drought / dehydration avoidance.Soil microbial activities were significantly inhibited by water stress. The catalase, β-glucosidase, urease, acid phosphatase activity, soil microbial biomass N and soil microbial respiration decreased significantly under low water condition. The decrease of urease activity by low water condition reached 57.76% ± 4.83, which was greater than other soil enzymes.Changes of soil microbial activity affected the nutrient absorption and utilization of D. viscosa by affecting soil nutrients. Inhibition of soil microbial activity by water stress reduced the soil available nutrient supply. D. viscosa improved the resorption efficiency of N and P and increased leaf biomass partition to absorb and utilize more nutrients under the low water condition. The leaf N resorption efficiency was 50%, leaf P resorption efficiency was close to 70%, and the slope of the log (leaf biomass) – log (stem biomass) reached 1.0 under the low water condition. Besides, the effect of soil water content on urease activity was mainly indirect, and the net photosynthetic rate had a greater direct effect on urease activity. The inhibition of urease activity by low water condition was smaller than that of photosynthetic rate.(2) The Effect of N or P Stresses on Growth and Physiological Characteristics of D. viscosaD. viscosa was suffered from different nutrient stress in different soils. D. viscosa grown in dry red soil was stressed by N limitation; N addition promoted D. viscosa growth, biomass accumulation, leaf N concentration and chlorophyll content. D. viscosa grown in yellow brown soil was stressed by P limitation and N saturation; P addition promoted D. viscosa growth, biomass accumulation and leaf P concentration, and N addition suppressed the growth of D. viscosa. However, limitation type on purple soil was not obvious, and D. viscosa growth tended to be co-limited by N and P.In soil with different nutrient limitation, soil microbes increased plant available nutrients by increasing the efficiency of related soil microbial enzymes. Soil urease efficiency was the highest in dry red soil with N limitation, and phosphatase efficiency was the highest in yellow brown with P limitation. Besides, soil enzyme efficiency was directly altered by soil available nutrients. The urease efficiency was negatively correlated with soil available N in dry red soil, and phosphatase efficiency was negatively correlated with soil available P in yellow brown soil, and the response intensity was greater than that of D. viscosa. Soil available N and P nutrients were not the determining factor for D. viscosa growth. Biomass of D. viscosa was negatively correlated with soil available N and P. Among the three soil types, despite the soil nutrients were the highest in yellow brown soil, D. viscosa grew better in dry red soil and purple soil than in yellow brown soil significantly. (3) The Effect of Rhizosphere Soil Microorganisms on Growth and Physiological Characteristics of D. viscosaRhizosphere soil microorganisms had positive effects on D. viscosa growth. D. viscosa planted in inoculated rhizosphere microbes from both dry red soil and purple soil showed a better performance, produced more biomass and accumulated significantly more N and P nutrients than those in an autoclaved control. However, these positive effects of the microbes on D. viscosa growth strongly depended on temperature; the positive effects of soil microbes on D. viscosa were stimulated under warmer condition, while these effects were insignificant under colder condition. Rhizosphere soil microorganisms drove the responses of D. viscosa to temperature change. In inoculated rhizosphere microbe treatments, warming had positive effects on D. viscosa growth, biomass accumulation and nutrient absorption, while these positive effects disappeared in the autoclaved control treatment.Inoculating rhizosphere microorganisms enhanced the nutrient absorption of D. viscosa, especially P absorption. Compared with the autoclaved treatment, the increase in total leaf N content under warmer condition was 178.22% ± 34.03 and 250.44 % ± 9.62 for inoculated rhizosphere microbes from dry red soil and purple soil, respectively; and the increase in total leaf P content was 841.52% ± 92.31 and 806.39% ± 91.55, respectively. Therefore, because D. viscosa in the inoculated rhizosphere microbes absorbed more N and P from the soil than those in autoclaved microbes, the soil available N, available P and soil microbial biomass in inoculated rhizosphere microbes were lower than those in autoclaved control. (4) The Effect of Arbuscular Mycorrhizal Fungi (AMF) on Growth and Physiological Characteristics of D. viscosaAMF had significant positive effects on D. viscosa growth. Inoculating AMF significantly improved D. viscosa growth, biomass accumulation and net photosynthetic rate. Inoculating AMF also significantly increased the lignin content of the D. viscosa stem, and improved the degree of lignification, which significantly reduced the saturated water content of the stem. The degree of lignification of the D. viscosa stem inoculated with AMF was close to 80% in dry red soil, and it was close to 60% in yellow brown soil. D. viscosa inoculated with AMF adopted conservative adaptation strategy for drought and barren stressful environment. Inoculating AMF significantly reduced leaf N and P concentrations of D. viscosa when harvest, and D. viscosa inoculated with AMF had lower specific leaf area and higher leaf dry mass content than those of uninoculated AMF treatment.Compared with the non-native AMF, the native AMF had obvious advantages on the growth of D. viscosa in dry red soil. Drought increased the dependence of D. viscosa on AMF in dry red soil, and the dependence of D. viscosa on native AMF was significantly greater than on non-native AMF (Glomus mosseae and Glomus etunicatum). Besides, the promotion effect of native AMF on net photosynthetic rate of D. viscosa was also greater than that of non-native AMF in dry red soil. The findings in this paper indicate that although plant growth in dry hot valley is limited by water and soil nutrient, soil microbes play a critical role in maintaining the growth of local vegetation. Over time, suites of plants and their soil microorganisms in dry hot valley have been selected that are best able to coexist with local communities under home soil conditions. In the process of vegetation restoration in dry hot valley, consideration should be taken into the restoration of the soil microbial system, especially the symbiotic mycorrhizal fungi, which are closely related to plants. 
Pages164
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24766
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
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
王雪梅. 干热河谷区车桑子(Dodonaea viscosa)对典型胁迫因子的响应[D]. 北京. 中国科学院大学,2018.
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