【作者】 熊俊兰；

【导师】 熊友才；

【作者基本信息】 兰州大学 ， 生态学， 2012， 硕士

【摘要】 本研究以家山黧豆(Lathyrus sativus L.)为试验材料,采用盆栽土培的方法,在生长环境控制的条件下,通过不同外源施加0.1mg/L24-表油菜素内酯(24-epibrassinolide, EBL)的方法(浸种、叶面喷施、浸种+叶面喷施),连续跟踪土壤逐渐干旱下山黧豆幼苗叶片毒素p-N-草酰-L-a,β-二氨基丙氨酸(β-N-oxalyl-L-a, β-diaminopropionic acid, β-ODAP)含量的动态变化,并测定生长、水分状况、气体交换参数、脯氨酸含量、抗氧化酶活性等指标。干旱胁迫梯度为80%田间持水量(field water capacity, FWC)、50%FWC、40%FWC和30%FWC。在另一单独试验中,跟踪不同水分条件下EBL对山黧豆生物量分配、产量和籽粒β-ODAP含量的影响,其控水梯度为80%FWC、50%FWC和35%FWC。运用数理统计分析方法,揭示24-表油菜素内酯对山黧豆β-ODAP生物合成及干旱适应性的生理生态影响及机理,得出如下主要结果：(1)EBL对山黧豆的耐旱能力具有显著增强效应。干旱胁迫下,外源施加EBL显著提高了山黧豆幼苗株高和叶面积,减缓干旱对山黧豆幼苗生长的抑制作用。水分条件为50%FWC时,与对照组相比,浸种处理、叶面喷施、浸种+叶面喷施处理山黧豆株高分别提高了12.9%、11.9%和17.4%,叶面积分别提高了52.3%、47.7%和56.8%；水分条件为40%FWC时,株高提高了14.3%、13.7%和14.7%,叶面积提高了59.2%、28.5%和47.7%；水分条件为30%FWC时,株高提高了16.7%、11.9%和19.50%,叶面积提高了29.2%、9.7%和24.3%。在土壤逐渐干旱下直至永久萎蔫过程中,EBL处理可以减缓山黧豆幼苗叶片气孔导度和相对含水量的下降速度,增加干旱下存活天数和降低致死土壤含水量。(2)同步跟踪发现,外源施加EBL提高了山黧豆渗透调节和抗氧化调节能力。外源施加EBL显著提高了叶片脯氨酸含量和抗氧化酶(SOD、APX和CAT)活性,其中浸种十叶面喷施法效果最显著,水分条件为30%FWC时效果最好。与对照组相比,水分条件为30%FWC时,浸种+叶面喷施处理组山黧豆幼苗叶片脯氨酸含量增加了60.4%,SOD活性增加了68.3%,APX活性增加了26.4%,CAT活性提高了238.7%。(3)EBL对山黧豆生物量积累和产量形成总体上具有促进作用,但因施加方式和干旱梯度不同出现差异性表现。不同水分条件下,外源施加EBL均能提高山黧豆总生物量,水分条件为50%FWC时达到显著水平。水分条件为80%FWC时,浸种、浸种+叶面喷施处理可以通过促进山黧豆营养和繁殖器官生长(根重、茎重、叶重和荚重)共同提高山黧豆总生物量,叶面喷施处理则主要通过促进营养器官生长(根重、茎重和叶重)提高山黧豆总生物量。水分条件为50%FWC时,EBL各处理均能促进山黧豆营养和繁殖生长(荚重、叶重、茎重和根重)提高山黧豆总生物量,其中荚重和叶重达到显著水平。水分条件为35%FWC时,浸种、浸种+叶面喷施处理可通过促进营养器官生长(茎重、叶重和根重)提高总生物量,叶面喷施则可通过促进营养和繁殖器官生长(茎重、叶重、根重和荚重)共同提高。(4)EBL调控下山黧豆营养生长和繁殖生长的能量分配出现策略性改变,不同施加方法的效果不同。浸种处理可以促进水分胁迫程度较低时(80%FWC和50%FWC)山黧豆的营养和繁殖生长,随着水分程度的增加,该处理则偏重于促进山黧豆的营养生长。叶面喷施处理主要促进水分为80%FWC时的营养生长,水分条件为35%FWC时主要促进繁殖生长。浸种+叶面喷施可以促进水分条件为80%FWC时山黧豆繁殖生长,水分条件为50%FWC和35%FWC时,更多促进营养生长。(5)EBL对山黧豆毒素β-ODAP的生物合成的调控效应因干旱胁迫梯度不同呈现不同趋势。水分条件为80%FWC、50%FWC和40%FWC时,EBL对山黧豆幼苗叶片β-ODAP含量影响不显著。在30%FWC条件下,外源施加EBL降低山黧豆幼苗叶片β-ODAP含量,对照组β-ODAP含量为4.52mg/g,浸种、叶面喷施、浸种+叶面喷施处理组分别为4.43mg/g、3.80mg/g、3.2mg/g,表明EBL可以提高山黧豆幼苗干旱适应性同时降低β-ODAP含量,以浸种+叶面喷施效果最好,可以达到显著水平。EBL对80%FWC时山黧豆籽粒β-ODAP影响不大,但可以提高50%FWC时β-ODAP的含量,但均未达到显著水平。水分条件为50%FWC时,对照组含量为4.59mg/g,浸种、叶面喷施、浸种+叶面喷施含量分别为5.53mg/、5.23mg/g、4.61mg/g。水分条件为35%FWC时,EBL叶面喷施处理则显著降低了β-ODAP含量,对照组为5.96mg/g,叶面喷施处理为5.14mg/g。综上所述,外源施加EBL对干旱适应能力具有显著的调控效应,但对β-ODAP生物合成的调控因施加方式和干旱胁迫程度的不同而出现差异性表现。推测EBL是通过增强山黧豆干旱适应能力而相应地降低毒素β-ODAP含量,但机理仍很复杂,与营养生长和繁殖生长的不同能量分配对策密切相关。更多还原

【Abstract】 In this study, pot-culture experiments with soil medium were conducted using grass pea (Lathyrus sativus L.) as test material under environment-controlled conditions. Dynamics of toxin β-N-oxalyl-L-α, β-diaminopropionic acid (β-ODAP) concentrations were continuously tracked and determined in leaves of grass pea seedlings using exogenous application methods with0.1mg/L24-epibrassinolide (EBL) including seed priming (sp), foliar application (fa) and seed priming and foliar application (sf). Other parameters including growth, water status, gas exchange index, proline contents and activities of antioxidant enzymes were also synchronously measured. Drought stress gradients were designed as field water capacity (FWC) of80%,50%,40%and30%respectively. In a separate experiment, the effects of EBL exogenous application on biomass distribution, grain yield and β-ODAP concentrations in seeds were tracked and measured in grass pea in three gradients of water supply including80%FWC,50%FWC and30%FWC respectively. Mathematical statistics methods were employed to elucidate eco-physiological effects of EBL application on β-ODAP biosynthesis and drought adaptability and its mechanism in grass pea. The major results were achieved as follows:(1) EBL was observed to significantly enhance drought tolerance of grass pea. It alleviated the adverse effect and promoted the growth of plant height and leaf area in grass pea seedlings under drought stress. Sp, fa and sf treatment increased plant height by12.9%,11.9%and17.4%, leaf area by52.3%,47.7%and56.8%under50%FWC; plant height by14.3%,13.7%and14.7%, leaf area by59.2%,28.5%and47.7%under40%FWC; plant height by16.7%,11.9%and19.5%, leaf area by29.2%,9.7%and24.3%under30%FWC. EBL also slowed down the rate of decrease in leaf relative water content, stomatal conductance, increased the survival days and decreased the withering soil water content for grass pea seedlings from sufficient water supply to permanent withering point.(2) The results of synchronous tracking indicated that exogenous application of EBL improved the abilities of osmotic adjustment and antioxidant adjustment in grass pea seedlings. There was an increase in the leaf proline content and activity of antioxidant enzymes(SOD, APX, CAT) of treated seedlings. Compared to untreated ones, the sf treatment under30%FWC increased the proline content by60.4%, activity of SOD by68.3%, activity of APX by26.4%, activity of CAT by238.7%.(3) In general, EBL played a role to promote biomass accumulation and yield information in grass pea, but it varied from application treatments of EBL and drought stress gradient. EBL could increase the total biomass of grass pea under different water conditions, especially under50%FWC. Under80%FWC, sp and sf treatment increased the total biomass through improving the growth of vegetative and productive organs of grass pea, such as root, stem, leaf and pod dry weight; while fa treatment increased the biomass by increasing the vegetative organs including root, stem and leaf dry weight. Under50%FWC, EBL could improve pod, leaf, stem and root dry weight, and the increase in pod and leaf dry weight reached a significant level. Under35%FWC, sp and sf treatment could increase the total biomass by increasing the stem, leaf and root dry weight; while fa treatment increase the biomass by improving the stem, leaf, root and pod dry weight.(4) Strategic variation in energy distribution for vegetative growth and productive growth was observed under the regulation of EBL, however the effects of different application treatments were different. Sp treatment could promote the vegetative and productive growth of grass pea under80%FWC and50%FWC, and more increase vegetative growth under35%FWC. Fa treatment could promote the vegetative growth under80%FWC, and more increase productive growth under50%FWC and35%FWC. Sf could promote the productive growth under80%FWC, and more increase vegetative growth under50%FWC and35%FWC.(5) Regulatory effects of on the P-ODAP biosynthesis relied on drought stress gradients. There was no obvious effect on P-ODAP in the leaves of grass pea seedling under80%FWC,50%FWC and40%FWC. EBL could decrease the β-ODAP content under30%FWC, the P-ODAP content of the control under30%FWC was4.52mg/g, but sp, fa and sf treatment was4.43mg/g,3.80mg/g and3.2mg/g. We saw that EBL could improve drought tolerance but decrease the P-ODAP content under30%FWC, and sf is the best effective treatment. EBL had little effect on P-ODAP content in grass pea seeds under80%FWC, but increased β-ODAP content under50%FWC. The β-ODAP content of the control under50%FWC was4.59mg/g, but sp, fa and sf treatment was5.53mg/g,5.23mg/g and4.61mg/g. Fa treatment could significantly reduce the content of β-ODAP under35%FWC, the p-ODAP content of the control was5.96mg/g, but fa treatment was5.14mg/g.In summary, exogenous EBL application could significantly regulate the adaptability of grass pea to drought, but different treatment and drought stress gradient had different effect on β-ODAP biosynthesis. We speculated that EBL could reduce the β-ODAP content by improving the drought adaptability of grass pea, but the mechanism was very complex and closely related with energy allocation of vegetable growth and reproductive growth of grass pea.更多还原