KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 古尔班通古特沙漠梭梭(Haloxylon ammodendron)与白梭梭（Haloxylon persicum） 冠层降雨氮素输入及微生物固氮 | |
| Alternative Title | Nitrogen input and microbial nitrogen fixation in canopy of Haloxylon ammodendron and Haloxylon persicum in Gurbantungut Desert |
| 岳跃蒙 | |
| Subtype | 硕士 |
| Thesis Advisor | 唐立松 |
| 2020-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学硕士 |
| Keyword | 梭梭 白梭梭 氮素 固氮微生物 根系活性 H.ammodendron H.persicum nitrogen nitrogen-fixing microorganisms root activity |
| Abstract | 干旱区的水分和养分相对匮乏，雨水是干旱区植物水分和养分的重要来源，氮素作为植物生长发育最重要的元素之一， 雨水微量氮素输入在干旱区植物的生长发育中发挥着重要作用， 了解植物获取氮素的来源对干旱区植物的保护与恢复意义重大。本研究通过文献分析研究区氮沉降的变化， 定期采集植物和雨水样本， 结合乙炔还原法（ARA） 、 TTC（2， 3， 5－三苯基氯化四氮唑） 法等方法， 测定古尔班通古特沙漠南缘梭梭与白梭梭枝条中的 N/P、 雨水经植物冠层后水分分配量和养分含量的变化特征、 梭梭冠层和土壤的固氮作用以及植物根系的活性，为干旱区植物获取氮素方式的多样性、维护植物自身稳定的生长发育以及干旱区植物氮素平衡提供理论依据和数据支持。研究结论如下：（1）随着人类活动的加剧，受人类活动影响较大的区域氮沉降基本高于受人活动影响较小的区域， 荒漠-绿洲农田生态系统的沉降量也有所增加。 虽然研究区氮沉降量有所增加，但是梭梭与白梭梭 N/P 均小于 14，依旧表现为 N 受限；就整体规律而言， 4-9 月份梭梭与白梭梭 N/P 呈现先增加后减少、再增加再减少的趋势，差异并不显著，说明植物处在一种较为稳定的 N 受限生长状态。（2）雨水在经过植物冠层后会实现水分和养分的分配。自然状态下， 梭梭与白梭梭形成树干茎流的最低降雨量理论值分别为 2.04 mm、 2.13 mm；树干茎流量、穿透雨量、截留雨量与降雨量都存在显著的正相关关系。 截留雨所占比例会随着降雨量的增加而减少，树干茎流和穿透雨比例则随着降雨量的增加而增加；并且随着降雨量的不断增加，最终， 梭梭与白梭梭树干茎流、穿透雨、截留雨会分别达到 13.1%、 57.24%、 30.59%和 4.46%、 86%、 4.27%的理论比例。雨水在经过冠层后， TN、 TP、 NH4+-N、 NO3--N、 NO2--N 浓度增加，但 TP、NO3--N 出现了穿透雨浓度小于雨水的现象。除 NH4+-N 外，各离子的月输入量与雨水中的离子相比均有所增加；雨水在经过梭梭与白梭梭冠层后 TN 输入量均增加 2 倍左右，且单位面积净增加量分别为 10.000 kg N· hm-2、 7.761 kgN· hm-2，即通过冠层流向土壤中氮的来源有超过一半以上是未知的。（3） 在干燥处理、自然状态、加湿处理三种处理下，野外和实验站内的梭梭枝条的乙烯产量差异均不显著；野外多年生梭梭乙烯产量表现为加湿处理>自然状态>干燥处理， 与站内两年生梭梭三种处理下的乙烯产量规律并不一致，但都能证明固氮微生物确实在发挥作用。通过室内八种处理探究土壤固氮微生物活性的影响因素，发现施加无氮营养液、湿润条件下乙烯产量显著增加；在干燥环境下，土壤固氮微生物活性都较低，野外土壤固氮菌随着土壤湿度的增加而增加也很好证明了固氮微生物活性受水分影响较大。（4）雨水经过植物冠层后输入的氮素和水分会对植物根系产生或多或少的影响。其中， 梭梭与白梭梭根凸数量均未表现出一定的规律性，这种不规律性也很好的证明了植物根系对环境变化的适应性； 梭梭与白梭梭根系活性均表现为先增加后减小的变化趋势，相比较而言，白梭梭变幅更小，差异性更加不显著。 7、 8 月份根系活性增强， 说明植物从浅层土壤中吸收的养分会有所增加。 |
| Other Abstract | Rainwater plays as an essential source of water and nutrients for plants in aridareas since both resources are relatively scarce there. In the meantime, given thatnitrogen is considered one of the foremost elements for the growth and developmentof plants, the input of rainwater trace nitrogen wields a significant part in the growthand development of plants in arid areas. Therefore, it is of great significance for plantconservation and restoration in those areas to learn about the accessible sources ofnitrogen. This study investigated the changes of nitrogen deposition in regarding areathrough literature analysis. With periodically collected plant and rainwater samples,the study also adopted acetylene reduction assay (ARA) and TTC (2,3,5-triphenyltetrazolium chloride) method to determine the N/P and the changecharacteristics of water allocation and nutrient contents of rainwater after passingthrough the canopy in the twigs of Haloxylon ammodendron and Haloxylon persicumin Gurbantunggut Desert, as well as the nitrogen fixation of Haloxylon ammodendroncanopy and soil and the activity of their root system. Thereupon, it provides atheoretical basis and data support for the diversity of accesses of plants in the aridareas to nitrogen, the maintenance of those plants for their stable growth anddevelopment, and their nitrogen balance. The conclusions obtained are showing asfollows:(1) With the intensification of human activities, the nitrogen deposition in theregions that are more impacted by them is found to be generally higher than that in theregions that are less impacted by them. Meanwhile, regarding deposition is alsodiscovered to increase to a certain extent in desert-oasis farmland ecosystem. Thougha certain growth of nitrogen deposition in the studied area, both N/P values ofHaloxylon ammodendron and Haloxylon persicum are lower than 14, still with an Nrestricted manifestation. In terms of the overall regularity, the N/P of both botanicspecies intends to change in an order of rising, decreasing, rising and then decreasingfrom April to September. However, the difference in changes is not significant, whichindicates that those plants are in a state of relatively stable N-restricted growth.(2) Water and nutrient allocation takes place after rainwater passes through thecanopies of studied plants. In the natural state, the minimal theoretical rainfall generated when H.ammodendron and H.persicum perform stemflow are 2.04 mm and2.13 mm, respectively. The stemflow, throughfall and interception rainfall of trunksall share a positive correlation with rainfall. As the rainfall raises, the proportion ofinterception rainfall shrinks whereas that of stemflow and throughfall grows.Moreover, with the continuous increase of rainfall, the stemflow, throughfall andinterception rainfall of H.ammodendron and H.persicum will reach up to theoreticalvalues of 13.1%, 57.24% and 30.59%, and 4.46%, 86% and 4.27%, respectively.After rainwater passes through the canopy, the concentrations of TN, TP, NH4+-N,NO3--N and NO2--N in rainwater increase, but with an occurrence where theconcentrations of TP and NO3--N in throughfall is lower than that in rainwater. Inaddition to NH4+-N, the monthly input of each of other ions improves to some extentif compared with the ions in rainwater. After rainwater passes through the canopy ofH.ammodendron and H.persicum, the TN input of both species of plants doubles or so,and their net increase per unit is area 10.000 kg N·hm2 and 7.761 kg N·hm2,respectively. This implies that more than half of the nitrogen sources flowing throughthe canopy to the soil are unknow.(3) There is no significant difference between H.ammodenron in wild andexperiment station in the ethylene production of their twigs after being dried, naturalstate and humidified. In wildly perennial H.ammodenron, the ethylene production isfound to be the largest under humidification, followed by under natural state anddrying (i.e. humification>natural state>drying). This is not consistent with theethylene production of biennial H.ammodendron in the experimental station afterthose three treatments. But both can prove that nitrogen-fixing microorganisms dofunction. Besides, the exploration of the influencing factors of soil nitrogen-fixingmicroorganisms through eight indoor treatments suggests a significant increase inethylene production when nitrogen-free nutrient solution and moisture is applied.Comparatively, those microorganisms present lower activity in a dried environment.Meanwhile, the nitrogen-fixing microorganisms in field soil proliferate as themoisture of soil heightens. This is sound evidence for the activity of nitrogen-fixing microorganisms to be considerably subject to the influence of water.(4) The nitrogen and water that rainwater inputs after passing through canopyare found to have more or less influence on the root systems of plants. Therein, theamount of root convex of H.ammodendron and H.persicum shows no certainregularity, which however proves the adaptability of root systems to environmentalchanges. The root activity of both species of plants tends to improve first and thenweakens. In comparison, the variation in root activity of H.persicum is milder thanthat of H.ammodendron, and the difference is even more insignificant. In addition,root activity is found to enhance in July and August, which suggests a certain increasein the nutrients that plants absorb from the shallow soil. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15468 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 岳跃蒙. 古尔班通古特沙漠梭梭(Haloxylon ammodendron)与白梭梭（Haloxylon persicum） 冠层降雨氮素输入及微生物固氮[D]. 北京. 中国科学院大学,2020. |
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