本文選題：羊草 + 鹽脅迫�。� 參考：《西南大學》2017年碩士論文

【摘要】：羊草(Lemymus chinensis(Trin.))是一種禾本科多年生的重要牧草,不僅具有草質可口、蛋白含量高、草量多等特點,還對防止水土流失,改善草原生態(tài)環(huán)境等有重要的作用。而各種脅迫因素的加劇、生態(tài)環(huán)境的破壞使羊草的生長受到嚴重的威脅。油菜素內酯(Brassinolide,BR)是一種新型的植物生長調節(jié)劑,可有效促進植物的生長發(fā)育,緩解脅迫對植株造成的傷害。本文通過外源噴BR,研究其對羊草生長的影響,以及緩解羊草在鹽脅迫和高溫脅迫下的傷害,并探討其作用機理,為調控羊草的抗逆性提供理論依據和技術參考。主要研究結果如下:1.不同濃度油菜素內酯對鹽脅迫下羊草生長發(fā)育的作用通過外源噴施不同濃度(0.01mg/L、0.1mg/L、1mg/L)的BR處理鹽脅迫(NaCl濃度為150 nmol/L)的羊草幼苗,探尋其對羊草生長發(fā)育的影響。試驗表明:適當濃度的BR有助于緩解鹽脅迫對羊草生長造成的傷害,其中0.1mg/L的BR處理增加羊草株高、葉面積、根冠比、葉綠素b、類胡蘿卜素、可溶性蛋白、干鮮重效果最好以及MDA的含量最低,葉面積與干鮮重與對照相比,差異顯著;而0.01mg/L的BR濃度增加葉綠素總量、葉綠素a、根系活力和脯氨酸的含量最多,效果最好。就五種抗氧化酶的活性來講,超氧化物歧化酶(SOD)和谷胱甘肽還原酶(GR)活性最高的處理是BR濃度為0.01mg/L,抗壞血酸過氧化物酶(APX)和過氧化物酶(POD)活性最高的處理是BR濃度為1mg/L,而過氧化氫酶(CAT)活性最高的處理在BR濃度為0.1mg/L。綜合分析可知,在本試驗中的鹽脅迫下噴施BR的適宜濃度為0.01-0.1mg/L。2.不同濃度油菜素內酯對高溫脅迫下羊草生長發(fā)育的作用通過在常溫下用不同濃度(0.01mg/L、0.1mg/L、1mg/L)的BR處理高溫(光照10h/38℃,黑暗14h/25℃)脅迫的羊草幼苗,探討其對羊草生長發(fā)育的影響。試驗表明,在常溫下:適宜濃度的BR有助于增加羊草的株高、葉面積、葉長、葉寬、干鮮重、光合色素、脯氨酸、可溶性物質和抗氧化酶的活性,減少MDA的含量;其中從羊草的株高、干鮮重來看,1mg/L的BR濃度處理顯著地增加了羊草干物質的積累;從根系活力來看,BR濃度為0.1mg/L時,根系活力最大,有助于羊草的生長。在高溫下,適宜濃度的BR處理,可緩解高溫脅迫對羊草的傷害:1mg/L的BR處理時,葉綠素a、類胡蘿卜素、葉綠素總量、葉綠素a/b值,脯氨酸含量以及GR的活性最大;0.1mg/L的BR濃度處理時,羊草的葉寬、干鮮重、葉綠素b、可溶性糖和蛋白、根系活力和SOD、CAT、APX的活性最大,MDA的含量最小;BR濃度為0.01mg/L時,株高、葉面積、葉長以及POD的活性最大。綜合來說,在本試驗的條件下,在常溫時:BR濃度為0.1mg/L和1mg/L時,促進羊草生長和提高生物量的效果顯著;在高溫時:BR濃度為0.1mg/L處理緩解高溫脅迫對羊草帶來的傷害較為適宜。
[Abstract]:Lemymus chinensis Trina (Lemymus chinensis) It is a kind of gramineous perennial forage, which not only has the characteristics of delicious grass quality, high protein content and much grass quantity, but also plays an important role in preventing soil erosion and improving grassland ecological environment. However, the growth of Leymus chinensis was seriously threatened by the aggravation of various stress factors and the destruction of ecological environment. Brassinolide Brassinolide (Brassinolide) is a new plant growth regulator which can effectively promote plant growth and development and alleviate the damage caused by stress. In this paper, the effects of exogenous BRR on the growth of Leymus chinensis were studied, and the injury of Leymus chinensis under salt and high temperature stress was alleviated, and its mechanism was discussed, which provided theoretical basis and technical reference for regulating the resistance of Leymus chinensis to stress. The main results are as follows: 1. Effects of different concentrations of Brassinolide on the growth and Development of Leymus chinensis under Salt stress the effects of Br on the growth and Development of Leymus chinensis with NaCl concentration of 150 nmol / L) were investigated by spraying different concentrations of 0.01 mg / L (0.1 mg / L) Br. The results showed that the appropriate concentration of Br could alleviate the harm caused by salt stress on the growth of Leymus chinensis, and the Br treatment of 0.1mg/L increased the plant height, leaf area, root / shoot ratio, chlorophyll b, carotenoid, soluble protein. The effect of dry fresh weight was the best and the content of MDA was the lowest, the difference between leaf area and dry fresh weight was significant, while Br concentration of 0.01mg/L increased the content of total chlorophyll, chlorophyll a, root activity and proline, and the effect was the best. As far as the activity of five kinds of antioxidase is concerned, The highest activity of superoxide dismutase (SOD) and glutathione reductase (Glutathione reductase) was 0.01 mg / L, the highest activity of ascorbic acid peroxidase (APX) and peroxidase (POD) was 1 mg / L, while the activity of catalase was the highest. The higher concentration of Br was 0.1 mg / L ~ (-1) 路L ~ (-1) 路L ~ (-1). The optimum concentration of Br sprayed under salt stress was 0.01-0.1 mg / L ~ (-2). Effects of different concentrations of Brassinolide on the growth and Development of Leymus chinensis under High temperature stress the effects of Br on the growth and Development of Leymus chinensis under High temperature (10h/38 鈩，

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