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  本文選題：大豆 + 硅�。� 參考：《中國農(nóng)業(yè)大學》2016年博士論文

【摘要】：由臭氧層損耗引起的UV-B輻射增強會對植物產(chǎn)生一系列不利影響,硅營養(yǎng)能夠提高植物對UV-B輻射脅迫的抗性,但其作用機理尚不清楚。本研究以雙子葉作物大豆(Glycine max (L.)Mell)為試驗材料,在人工氣候室條件下,采用營養(yǎng)液培養(yǎng)方式,研究了硅(K2Si03· nH2O,1.70 mM)營養(yǎng)對UV-B輻射增強脅迫(5.4Kj m-2 d-1)下大豆幼苗形態(tài)變化、初生代謝物質(zhì)和次生代謝物含量、植物內(nèi)源激素水平、葉片蛋白質(zhì)表達量以及DNA損傷情況的影響。旨在闡明硅在提高植物對UV-B輻射的防護、修復功能中的生物學效應(yīng)及其機理。主要結(jié)果如下：1.W-B輻射增強對大豆幼苗形態(tài)的影響包括：引起葉片細胞死亡加劇,葉片卷縮,葉面積減��；使總根長變短,根系平均直徑、根體積和表面積均變��；改變干物質(zhì)在地上部與地下部之間的分配,減少干物質(zhì)積累量。硅預(yù)處理能有效緩解UV-B輻射脅迫對幼苗的影響,表現(xiàn)為：減輕葉片的細胞死亡和卷曲程度,抑制根系總根長、表面積和體積的減小,減輕對植株生長的抑制,降低生物量的減少幅度。2.UV-B輻射脅迫下,大豆幼苗葉片的內(nèi)源激素IAA含量降低,ABA和ETH含量升高,IAA/ABA比值降低；硅預(yù)處理能抑制UV-B輻射引起的IAA含量下降,并降低ABA和ETH含量,使IAA/ABA比值上升。UV-B輻射脅迫降低可溶性糖和可溶性蛋白的含量,增加游離氨基酸的含量；硅預(yù)處理則能緩解可溶性糖和可溶性蛋白含量的降低,并降低游離氨基酸的含量。UV-B輻射脅迫誘導苯丙氨酸解氨酶PAL的活性增強,促進次生代謝物質(zhì)蠟質(zhì)、UV-B吸收物質(zhì)、酚類物質(zhì)和類黃酮合成的增加,提高大豆幼苗對輻射脅迫的被動適應(yīng)能力；硅預(yù)處理能進一步促進PAL酶活性的增加,提高葉片內(nèi)蠟質(zhì)、酚類物質(zhì)和類黃酮的含量,增強植株對輻射脅迫的抗性。3.UV-B輻射脅迫下,硅預(yù)處理能夠通過調(diào)節(jié)相關(guān)蛋白表達使大豆幼苗更好地適應(yīng)環(huán)境,這些調(diào)控涉及到代謝/能量、次級代謝、防御系統(tǒng)、抗氧化系統(tǒng)、激素合成等方面。UV-B輻射脅迫通過調(diào)控分子信號物質(zhì)乙烯和ROS誘導病原相關(guān)蛋白(PR)的積累,使得植物獲得系統(tǒng)抗性。硅預(yù)處理能夠顯著提高幼苗的廣譜抗病性,并改善植物的光合作用和次生代謝。4.UV-B輻射脅迫誘導大豆幼苗葉片中CPDs的形成和積累,而直接的氧化脅迫并不能誘導CPDs的形成,即DNA的光化產(chǎn)物CPDs只能通過UV-B脅迫的直接輻射誘導形成。大豆葉片中CPDs的修復以光修復為主。硅預(yù)處理能夠減少CPDs的形成、通過促進光修復作用,提高DNA損傷的修復能力、減少CPDs的積累。硅預(yù)處理可通過以下機制減輕UV-B輻射對DNA的傷害：1)修復機制,光裂合酶主導的修復作用；2)避免機制,紫外吸收物質(zhì)介導的表皮屏蔽作用；3)抗氧化機制,誘導抗氧化物質(zhì)合成的增加,如抗壞血酸等。
[Abstract]:The increase of UV-B radiation caused by ozone layer loss will have a series of adverse effects on plants. Silicon nutrition can increase the resistance of plants to UV-B radiation stress, but its mechanism is not clear. Using Glycine max L.Mell. a dicotyledonous crop as experimental material, the morphological changes of soybean seedlings under UV-B radiation enhanced stress (5.4Kj m-2 路d-1) were studied under the condition of artificial climate room and nutrient solution culture. Effects of primary and secondary metabolites, endogenous hormones, protein expression in leaves and DNA damage. The aim of this paper is to elucidate the biological effects and mechanism of silicon in the protection and repair of UV-B radiation in plants. The main results were as follows: 1. The effects of W B radiation on the morphology of soybean seedlings were as follows: the death of leaf cells was aggravated, the leaf was curled and the leaf area was decreased, the total root length was shortened, the mean diameter of root system, root volume and surface area were decreased; To change the distribution of dry matter between the aboveground and underground parts and reduce the dry matter accumulation. Silicon pretreatment could effectively alleviate the effects of UV-B radiation stress on seedlings, such as reducing the cell death and curl degree of leaves, inhibiting the decrease of root total root length, surface area and volume, and reducing plant growth. Under UV-B radiation stress, the contents of endogenous hormones IAA and ETH in soybean seedling leaves increased and the ratio of IAA / ABA decreased, silicon pretreatment inhibited the decrease of IAA content induced by UV-B radiation, and decreased the contents of ABA and ETH. The ratio of IAA/ABA increased. UV-B radiation stress decreased the content of soluble sugar and soluble protein, increased the content of free amino acid, and reduced the content of soluble sugar and soluble protein after silicon pretreatment. The activity of phenylalanine ammonia-lyase PAL was enhanced under UV-B radiation stress, and the synthesis of secondary metabolite, waxy substance, phenolic substance and flavonoid was increased, and the activity of phenylalanine ammonia-lyase (PAL) was increased under UV-B radiation stress. Silicon pretreatment could further increase the activity of PAL, increase the contents of wax, phenols and flavonoids in leaves, and enhance the resistance of soybean seedlings to radiation stress. 3. UV-B radiation stress, silicon pretreatment could increase the activity of PAL, increase the contents of wax, phenols and flavonoids in leaves, and enhance the resistance of soybean seedlings to radiation stress. 3. Silicon pretreatment can improve the adaptation of soybean seedlings to the environment by regulating the expression of related proteins, which involves metabolism / energy, secondary metabolism, defense system, antioxidant system, In hormone synthesis, UV-B radiation stress induced phylogenetic resistance by regulating the accumulation of molecular signaling substances ethylene and ROS. Silicon pretreatment could significantly improve broad-spectrum disease resistance, photosynthesis and secondary metabolism. 4. UV-B radiation stress induced the formation and accumulation of CPDs in soybean seedling leaves, but direct oxidative stress could not induce the formation of CPDs. That is, CPDs, the photochemical product of DNA, can only be induced by direct radiation under UV-B stress. The repair of CPDs in soybean leaves was mainly light repair. Silicon pretreatment can reduce the formation of CPDs, improve the repair ability of DNA damage and reduce the accumulation of CPDs by promoting photorepair. Silicon pretreatment can alleviate the damage of UV-B radiation to DNA by the following mechanisms: 1) repair mechanism, 2) avoidance mechanism of photolysis synthase, and 3) antioxidation mechanism of ultraviolet absorbent substance mediated epidermal shielding. Induces an increase in the synthesis of antioxidants, such as ascorbic acid.
【學位授予單位】：中國農(nóng)業(yè)大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：S565.1

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本文編號：1936121