【作者】 王磊；

【导师】 曹福亮；

【作者基本信息】 南京林业大学 ， 森林培育， 2013， 博士

【摘要】 分根区交替灌溉（APRI）不但是一种生物节水技术，也是一种重要的植物生理生化调控手段。为了探讨分根区交替灌溉对银杏水分管理策略的适应性和活性次生代谢物的影响，本研究以3年生分根盆栽银杏为试材，试验采取双因素三水平设计，因素1为供水方式（分别为分根区交替渗灌、固定根区渗灌和全根区渗灌），因素2为供水量（3个梯度为正常水分供应、轻度干旱和重度干旱），研究了银杏生长分化、生理生态、抗旱响应、次生代谢物等方面指标，并结合SPAC系统、等水/异水的抗旱机制以及次生代谢物产生机理进行了分析讨论，主要结论如下：（1）相对于常规灌溉方式，分根区交替灌溉在没有降低银杏生长量的同时，显著提高了银杏根冠比、吸收根、根系活力，增强了银杏对资源的获得能力，在轻度干旱胁迫下能保护银杏的细胞膜少受伤害。分根区交替灌溉最大限度的激发了补偿效应，在不影响植物光合速率和水分状况的情况下大大提高了植物的水分利用效率，充分发挥了植物本身的生物学节水潜力。分根区交替供水处理的银杏维持较高的叶绿素含量、Fv/Fm、Yield、qP，有效缓解光抑制，保护了光合结构，同时还缓解了光合色素的分解，利于银杏的二次生长。（2）银杏水分利用效率与活性氧和质膜伤害相关指标的相关性显著，说明银杏水分利用效率相对于其干旱胁迫的响应和适应而言，具有滞后性，所以一味的追求提高水分利用效率会使银杏受到严重的活性氧胁迫。分根区交替灌溉提高银杏WUE的原因一是在不明显降低光合速率的情况下显著降低了蒸腾速率和气孔导度，进而提高了水分利用效率；二是提高了根系的导水率，即根系的吸收能力得到了增强。（3）在不同的供水条件下，ABA与银杏的水分状况调控、渗透调节和活性氧代谢等过程关系密切。ABA的积累不但在银杏与环境因子之间的联系中发挥了重要作用，而且在银杏叶片水分状况和相关抗旱代谢调节机制之间也具有重要的地位。（4）银杏气孔导度与叶片水分状况和渗透物质相关性高；叶水势与水分状况指标、逆境信号、渗透调节和资源获得指标关系密切。研究发现银杏是等水植物，水势的变化配合了气孔调节，叶水势影响了气孔导度对ABA的敏感性，银杏气孔调节是化学和水力信号共同作用的结果，水分亏缺条件下通过气孔和水势调节在SPAC系统中尽量维持了银杏体内的水分平衡。（5）银杏主要在两方面提高了干旱适应能力：一方面通过降低气孔导度来减少水分散失，提高水分利用效率，避免过度蒸腾而引发导管的气塞发生和水势的过度降低，同时，通过提高根冠比、增加吸收根和根系活力，以尽可能多的吸收水分。另一方面，增加渗透物质的积累、提高活性氧清除能力、合成生物活性物质保护核酸、蛋白和膜脂的结构和功能；银杏的这一系列反应，其目的是维持体内水分状况在正常范围内，以保证正常生理活动的进行。（6）分根区交替灌溉和轻度干旱胁迫可以促进脯氨酸和多胺的积累，说明分根区供水和土壤含水量为最大持水量的55%时，银杏的抗性最强。脯氨酸和多胺在银杏叶片的积累具有反馈机制，使得其含量水平根据胁迫情况的不同而维持相应的动态平衡。银杏叶片脯氨酸在植物逆境胁迫过程中与内源激素、渗透调节和活性氧清除等密切相关，说明脯氨酸广泛地参与了植物在水分亏缺响应和适应性的相关过程。不同种类和形式的多胺，在植物逆境胁迫适应相关的过程中作用不同，以多胺储存、离子平衡、渗透调节、生物大分子保护等功能为主。银杏叶片脯氨酸含量和P5CS活性呈极显著的线性关系，在多胺的生物合成过程中精氨酸途径起到了关键作用，发现在干旱胁迫条件下，多胺和脯氨酸的生物合成途径可能存在对鸟氨酸的竞争现象。（7）分根区交替灌溉和轻度干旱胁迫利于银杏叶片黄酮和萜内酯的累积，以及苯丙氨酸解氨酶和查尔酮异构酶等关键酶活性的提高。发现银杏叶片黄酮的合成和积累与活性氧胁迫及内源激素关系密切，银杏黄酮可能在细胞生长与分化调节以及延缓衰老和保护生物大分子等方面发挥了直接或间接的作用。而银杏萜内酯在银杏体内广泛的参与了植物的生长、分化以及逆境信号转导和胁迫适应等过程，但与银杏的生长和分化调节方面关系更为密切。银杏黄酮、萜内酯次生代谢物合成机制是氧化应激效应假说、生长与分化假说、资源获得假说的综合体现。分根区交替灌溉不但可以提高银杏的适应能力和水分利用效率，而且还是一种不降低生物量而能提高银杏黄酮、萜内酯含量的简便、安全、可靠的方法。更多还原

【Abstract】 Alternative partial root-zone irrigation (APRI) is not only a biological water-savingtechnology, but also an important means of regulation of plant physiology and biochemistry. Inorder to explore the adaptability and the impact on secondary metabolites of APRI on the watermanagement strategy of Ginkgo, this research takes the3-year split root potted ginkgo as testmaterials, and the test takes two-factor three-level design: factor1is the water supply(Alternative partial root-zone subsurface irrigation, the fixed root zone subsurface irrigation andfull root zone subsurface irrigation); factor2is the amount of water supply (the three gradientsare normal water supply, mild drought and severe drought), doing research on the parameters ofthe growth and differentiation,physiology and Ecology, drought response, secondarymetabolites of ginkgo, combing with the analysis and discussion of SPAC system, such asIsohydric/Anisohydric behavior drought-resistant mechanism of water and the mechanism ofsecondary metabolites, the main conclusions are as follows:(1) Compared with conventional irrigation methods, APRI did not reduce the amount ofginkgo growth, but significantly improved the ginkgo root to shoot ratio, absorbing roots, rootactivity, and at the same time enhanced the ability of Ginkgo access to resources, and made theginkgo membrane less harm in mild drought stress. APRI stimulated the maximumcompensation effect, greatly improved plant water use efficiency and root to shoot ratio notaffecting the photosynthetic rate of plant water status, gave full play to the biologicalwater-saving potential of the plant itself. The ginkgo of partial root alternate water treatmentmaintained high chlorophyll content, Fv/FM, Yield, qP, effectively alleviated photo inhibitionprotect photosynthetic structure, but also eased the decomposition of photosynthetic pigments,and promoted to second growth of ginkgo.(2) The water use efficiency of Ginkgo and reactive oxygen species with the plasmamembrane injury index was significantly correlated. This showed that Ginkgo water useefficiency relative to its drought stress response and adaptation, with a lag, so blind pursuit toimprove the efficiency of water use would make the ginkgo by a serious reactive oxygen stress.One reason of APRI to improve ginkgo WUE was that APRI significantly reduced thetranspiration rate and stomata conductance, thus improved the efficiency of water use with a notsignificantly reduction in the photosynthetic rate; the second was that APRI increased the roothydraulic conductivity, and enhanced root absorption capacity. (3) Under different water conditions, ABA and ginkgo water status regulation, osmoticregulation and reactive oxygen metabolism were closely related. The accumulation of ABAplayed an important role not only in the link between ginkgo and environmental factors, butalso in the Ginkgo leaf water status and related drought metabolic regulation mechanism.(4) Ginkgo stomatal conductance and leaf water status and osmotic substances related tohigh; the indicators of leaf water potential and water status, stress signal, osmotic adjustmentand resource indicators closely related. This study found that ginkgo was isohydric plants, andwater potential in line with the stomatal regulation, leaf water potential impacted on thesensitivity of stomatal conductance to ABA, Ginkgo stomatal regulation was the result of therole of chemical and hydraulic signals. Under water deficit the ginkgo through the stomata andwater potential adjustment in the SPAC system would try to keep the body water balance.(5) Ginkgo improved the drought adaptability mainly in two ways:the one hand, byreducing the stomatal conductance to reduce water loss, improving the efficiency of water use,to avoid excessive transpiration caused by the catheter air lock and excessive reduction of thewater potential, at the same time, to increase the absorption of roots and root activity to absorbwater as much as possible; on the other hand, the increase in the accumulation of osmolytes,improving the ability of active oxygen scavenging, the synthesis of biologically activesubstances to protect the structure and function of nucleic acids, proteins and membrane lipids.The series of reactions of the Ginkgo aimed to maintain body water status within the normalrange to ensure normal physiological activity.(6) The APRI and mild drought stress could contribute to the accumulation of proline andpolyamines, which showed that under the condition that APRI and soil water content of55%ofthe maximum water holding capacity, the ginkgo most resistant. The accumulation of prolineand polyamines in Ginkgo biloba had a feedback mechanism which could maintain the dynamicequilibrium at a level, depending on the stress situation. Ginkgo biloba proline, endogenoushormones and active oxygen scavenging in plant stress in osmotic adjustment was closelyrelated showed that proline extensively involved in the process of the plants in the water deficitresponse and adaptability. Different types and forms of polyamines in plant stress adaptationrelated to the polyamine storage, ion balance, osmotic adjustment, protection of biologicalmacromolecules based. Ginkgo leaf proline content and P5CS activity was a significant linearrelationship. arginine pathway played a key role in polyamine biosynthesis, and this studyfound that there may be a competition to ornithine in polyamine, and proline biosyntheticpathway under drought stress.(7) APRI and mild drought stress conducive to the accumulation of Ginkgo bilobaflavonoids and terpene lactones, and the improving of phenylalanine ammonia-lyase andchalcone isomerase activities of key enzymes. This study found that the synthesis andaccumulation of ginkgo flavonoid, reactive oxygen stress and endogenous hormones closelyrelated,and ginkgo flavonoids may play directly or indirectly in cell growth and differentiationregulation and anti-aging, and the conservation of biological macromolecules. Ginkgolides in ginkgo body widely involved in plant growth, differentiation and stress signal transduction andstress adaptation process, but ginkgolides and ginkgo growth,differentiation regulation relatedmore closely. Ginkgo flavonoids, the terpene lactones secondary metabolite synthesismechanism were the comprehensive reflection of the hypothesis of oxidation stress effects,growth/differentiation balance and resource availability.APRI not only could improve the ability to adaptability and water use efficiency of theginkgo, but also was a simple, safe and reliable method improving the content of flavonoids,terpene lactone in ginkgo, without reducing the biomass.更多还原