本文關(guān)鍵詞：γ-氨基丁酸（GABA）調(diào)控鹽脅迫下玉米種子萌發(fā)和幼苗生長(zhǎng)的機(jī)制　出處：《東北農(nóng)業(yè)大學(xué)》2016年博士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 玉米 GABA 鹽脅迫 轉(zhuǎn)錄組測(cè)序 生理特性

【摘要】：玉米是我國(guó)重要的糧食和飼料作物,在國(guó)民經(jīng)濟(jì)中占有重要的地位。鹽漬化土壤是一種廣泛分布的低產(chǎn)土壤,是造成世界范圍內(nèi)作物減產(chǎn)的主要環(huán)境因子之一。鹽脅迫會(huì)影響作物正常的生長(zhǎng)發(fā)育,而玉米又是中度鹽敏感型作物,鹽脅迫會(huì)嚴(yán)重影響玉米的生理代謝,從而直接影響玉米的生長(zhǎng)發(fā)育和產(chǎn)量品質(zhì)形成。為了探究γ-氨基丁酸(GABA)提高玉米耐鹽性的機(jī)制,本論文選擇兩種耐鹽性不同的玉米為試驗(yàn)材料,研究鹽脅迫下GABA對(duì)種子萌發(fā)、幼苗生長(zhǎng)、抗氧化酶系統(tǒng)、氮代謝、內(nèi)源激素含量、光合系統(tǒng)和基因差異化表達(dá)的影響,旨在明確GABA提高玉米耐鹽能力的生理途徑和由其誘導(dǎo)的差異表達(dá)基因的相關(guān)功能及與耐鹽性的關(guān)系。試驗(yàn)于2014年和2015年在東北農(nóng)業(yè)大學(xué)農(nóng)學(xué)院溫室進(jìn)行,選用耐鹽型玉米品種鄭單958和鹽敏感型玉米品種東農(nóng)253為供試品種,轉(zhuǎn)錄組測(cè)序采用鄭單958父本昌7-2。通過(guò)前期試驗(yàn)篩選,種子萌發(fā)的Na Cl脅迫濃度定為100 mmol/L,幼苗生長(zhǎng)的Na Cl脅迫濃度為150mmol/L。試驗(yàn)GABA的施用濃度分別為0、0.25、0.5、1和2 mmol/L。種子萌發(fā)試驗(yàn)采用與試驗(yàn)設(shè)置對(duì)應(yīng)濃度的溶液為萌發(fā)基質(zhì)進(jìn)行發(fā)芽試驗(yàn),水培介質(zhì)選用1/2霍格蘭營(yíng)養(yǎng)液,當(dāng)玉米幼苗生長(zhǎng)到三葉一心時(shí),對(duì)幼苗進(jìn)行處理。主要研究結(jié)果如下:(1)施用一定濃度的GABA能有效的緩解Na Cl造成的萌發(fā)抑制現(xiàn)象。Na Cl脅迫下,0.5mmol/L GABA處理的鄭單958和東農(nóng)253種子的發(fā)芽率、發(fā)芽勢(shì)、活力指數(shù)和貯藏物質(zhì)轉(zhuǎn)運(yùn)率分別比單獨(dú)Na Cl脅迫處理的種子高。0.5 mmol/L GABA處理種子對(duì)于緩解Na Cl脅迫對(duì)胚根長(zhǎng)和胚芽鞘長(zhǎng)抑制作用效果最好,與單獨(dú)Na Cl脅迫相比鄭單958胚根和胚芽鞘長(zhǎng)分別升高了46.76%和49.69%;東農(nóng)253為58.52%和45.14%。GABA處理能顯著的提高α-淀粉酶的活性,從而促進(jìn)種子的萌發(fā),其中0.5 mmol/L GABA效果最好。(2)一定濃度的GABA都能緩解Na Cl脅迫對(duì)幼苗生長(zhǎng)的抑制,有利于幼苗形態(tài)建成。GABA處理植株的株高和莖葉干鮮重都高于單獨(dú)Na Cl處理的植株,其中GABA濃度為0.5mmol/L的處理效果好于其他GABA處理。GABA緩解Na Cl脅迫對(duì)東農(nóng)253的生長(zhǎng)抑制的效果好于鄭單958。GABA能提高Na Cl脅迫下根系干鮮重的積累,增加根系總長(zhǎng)度、根表面、根體積和根尖數(shù),降低根系平均直徑。通過(guò)根系掃描圖片可知,0.5 mmol/L GABA有利于根毛的生成,這促進(jìn)了Na Cl脅迫下根系水分和養(yǎng)分的吸收,是玉米幼苗生長(zhǎng)良好的重要保證。(3)一定濃度的GABA能有效的降低鹽脅迫下葉片內(nèi)的MDA和O2·-含量,其中0.5mmol/L的GABA效果最佳。Na Cl脅迫會(huì)顯著的提高超氧化物歧化酶(SOD)、過(guò)氧化物酶(POD)和過(guò)氧化氫酶(CAT)活性以便清除體內(nèi)的MDA和O2·-,GABA能進(jìn)一步提高抗氧化酶活性,其中0.5 mmol/L的GABA效果最佳。(4)外源施加GABA也能提高幼苗葉片和根系的內(nèi)源GABA含量。在正常生長(zhǎng)和Na Cl脅迫條件下,GABA均能提高葉片和根系內(nèi)的可溶性蛋白含量,降低丙酮酸含量。外源GABA加入后會(huì)產(chǎn)生GABA的反饋調(diào)節(jié),使得GAD活性降低。GAD活性降低會(huì)導(dǎo)致谷氨酸含量升高,從而又會(huì)反饋調(diào)節(jié)GS、GOGAT和GDH活性,使其活性降低。通過(guò)反饋調(diào)控作用會(huì)使得氮代謝的進(jìn)程中各種物質(zhì)間的轉(zhuǎn)化趨于穩(wěn)定,因此會(huì)使得可溶性蛋白水解減少,而丙酮酸可更好的參與其他代謝物質(zhì)的生成,因此含量下降。(5)NaCl脅迫下,葉片和根系內(nèi)的ABA含量會(huì)明顯升高,這有利于植株提高抗性。由于ABA是抑制生長(zhǎng)型激素,并且它與促生長(zhǎng)型激素有拮抗作用,所以葉片和根系內(nèi)的IAA、GA和ZR含量下降,從表型上看則表現(xiàn)為生長(zhǎng)量下降。外源GABA的加入能改善植株多種代謝,如提高抗氧化酶系統(tǒng),從而減少了脅迫帶來(lái)的損傷,因此GABA處理的植株的ABA含量下降,IAA、GA和ZR含量上升,從表型上看表現(xiàn)為植株恢復(fù)生長(zhǎng)。(6)外源GABA的加入能降低Na Cl脅迫對(duì)葉片造成的損傷,減少葉綠素的分解,從而提高SPAD值、光合速率、蒸騰速率和氣孔導(dǎo)度。改善植株光合作用會(huì)提高CO2的利用率,使胞間CO2濃度出現(xiàn)下降或者平穩(wěn)的趨勢(shì)。(7)通過(guò)轉(zhuǎn)錄組測(cè)序的分析,得到了鹽脅迫下GABA誘導(dǎo)的差異表達(dá)的基因,通過(guò)基因功能對(duì)比,選取了與試驗(yàn)生理指標(biāo)相關(guān)的差異表達(dá)基因。在上調(diào)表達(dá)的基因中,有調(diào)控過(guò)氧化物酶體生物合成蛋白質(zhì)的基因,有調(diào)控生長(zhǎng)素響應(yīng)因子的基因,有調(diào)控LHCII型葉綠素a、b結(jié)合蛋白的基因。在下調(diào)表達(dá)的轉(zhuǎn)錄子中,有調(diào)控谷氨酸合成酶的基因,有調(diào)控吲哚-3-乙醛氧化酶,有調(diào)控脫落酸應(yīng)答的基因。這些基因的上調(diào)或下調(diào)表達(dá)會(huì)引起與其對(duì)應(yīng)的生理指標(biāo)發(fā)生變化,從而在分子層面揭示在Na Cl脅迫下GABA的功能和作用。
[Abstract]:Maize is an important food and feed crops, occupies an important position in the national economy. The soil salinization is a widely distributed soil and low yield, which is one of the main environmental factors in the world crop production. Salt stress will influence the normal growth and development of crops, maize is also moderately salt sensitive crops. Salt stress seriously affects the physiological metabolism of maize, which directly affect the formation of maize growth and yield and quality. In order to explore the gamma aminobutyric acid (GABA) mechanism to improve the salt tolerance of maize, this paper selects two kinds of different salt tolerant maize as test material, study on Seed Germination under Salt Stress GABA. Seedling growth, antioxidant system, nitrogen metabolism, endogenous hormone content, photosynthetic system and gene differential expression, physiological pathways to clear GABA to improve maize salt tolerance and difference induced by its surface The related gene and its relationship with the function of salt tolerance. The experiment was conducted in Northeast Agricultural University College of Agriculture Greenhouse in 2014 and 2015, selection of salt tolerant maize varieties Zhengdan 958 and salt sensitive maize varieties Dongnong 253 as tested varieties, transcriptome sequencing using Zhengdan 958 male Chang 7-2. through pre screening test, Na seed germination of Cl concentration was 100 mmol/L, seedling growth Na Cl stress concentration 150mmol/L. concentration test of GABA were 0,0.25,0.5,1 and 2 mmol/L. seed germination by solution and test set the corresponding concentration for germination medium germination test, hydroponic culture medium using 1/2 Hoagland nutrient solution, when the growth of maize seedlings to clover only when processing the seedlings. The main results are as follows: (1) the application of a certain concentration of GABA can effectively alleviate the Na Cl caused by the phenomenon of.Na germination under Cl stress, 0.5mmol/ L GABA of Zhengdan 958 and Dongnong 253 seed germination rate, germination index, vigor of storage material and transport rate than Na Cl stress treatment.0.5 mmol/L GABA high seed seed treatment is best for the mitigation of Na Cl stress on radicle length and coleoptile length inhibition effect, and Na compared to Cl stress Zhengdan 958 radicle and coleoptile length were increased by 46.76% and 49.69%; Dongnong 253 was 58.52% and 45.14%.GABA treatment could significantly improve the activity of alpha amylase, thereby promoting seed germination, one of the best 0.5 mmol/L GABA. (2) a certain concentration of GABA can relieve Na Cl stress on seedling growth inhibition that is conducive to seedling morphogenesis of.GABA plant height and leaf dry weight were higher than those in the Na Cl of the plant, the concentration of GABA was better than the other treatment effect of 0.5mmol/L GABA.GABA Na Cl to ease the stress on the treatment of Dongnong 2 53 the growth inhibition effect on Zhengdan 958.GABA can improve the Na Cl stress on root fresh and dry weight accumulation, increase the total root length, root surface, root volume and root number, average root diameter decreased. The root scan pictures shows that 0.5 mmol/L GABA facilitates the formation of root hairs, which promoted the Na Cl stress water and nutrient uptake, growth is an important guarantee of good maize seedlings. (3) to a certain concentration of GABA under salt stress in the leaves of MDA and O2 content decrease, of which 0.5mmol/L GABA is the best.Na Cl stress high superoxide dismutase (SOD), provided significant peroxide the enzyme (POD) and catalase (CAT) activity to scavenge MDA and O2 - GABA, which can further improve the activity of antioxidant enzymes, including 0.5 mmol/L GABA (4). The best effect of exogenous GABA could increase endogenous GABA content in seedling leaves and roots. In the normal growth and Na Cl stress condition, GABA could increase the content of soluble protein in leaves and roots, decreased pyruvate content will produce GABA. The feedback regulation of exogenous GABA added, making GAD activity decreased.GAD activity decreases glutamate content increased, which in turn will feedback regulation of GS, GOGAT and GDH activity, the the activity is reduced. Through making the conversion of nitrogen metabolism in the process of various substances between the stable feedback regulation, thus makes the hydrolysis of soluble protein decreased in other metabolites generated while pyruvate can be better, therefore decreased. (5) under NaCl stress, ABA content in root and leaf will be increased significantly this is conducive to improve the resistance of plants,. Because ABA is inhibition of growth hormone, and it promote the antagonism of growth hormone, so in root and leaf of IAA, decreased GA and ZR content in phenotype Look at the performance of growth decreased. The addition of exogenous GABA can improve the metabolism of plant variety, such as improving the anti oxidase system, thereby reducing the damage caused by stress, so the ABA content of GABA treated plants decreased IAA, increased GA and ZR content from phenotypically characterized by plant growth and recovery. (6) exogenous the addition of GABA can reduce the Na Cl stress on leaf damage, reduced chlorophyll decomposition, thus increasing the SPAD value, photosynthetic rate, transpiration rate and stomatal conductance. Improve plant photosynthesis will improve the utilization rate of the CO2, the intercellular CO2 concentration decreased or stable trend. (7) through the analysis of the transcriptome sequencing, expression was obtained under different salt stress induced by GABA gene, gene function by comparison, selects the differences associated with the physiological index test of gene expression. The up-regulated genes, regulation over peroxisomal biosynthesis Protein genes, regulation of auxin response factor gene regulation of LHCII chlorophyll a, B binding protein gene transcription. In down regulated expression, regulation of glutamate synthase gene regulation -3- indole aldehyde oxidase, regulation of abscisic acid responsive genes. These genes up-regulated or down regulated expression of physiology the index will cause the corresponding changes, so as to reveal the stress function and the role of GABA in the Na Cl at the molecular level.

【學(xué)位授予單位】：東北農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：S513

【參考文獻(xiàn)】

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本文編號(hào)：1370338