低温胁迫对西瓜抗病砧木幼苗生长和生理特性的影响

发布时间：2018-04-11 06:12

  本文选题：西瓜 + 枯萎病　； 参考：《甘肃农业大学》2017年硕士论文

【摘要】：西瓜枯萎病是一种严重危害西瓜生产的世界性土传病害,随着设施栽培面积的扩大,重茬连作导致枯萎病大面积发生,选育和筛选抗病嫁接砧木是解决西瓜枯萎病有效的途径之一。西瓜属于喜温作物,对低温极为敏感,我国北方大部分地区的设施栽培方式均以春提早和秋延迟栽培为主,北方冬春季节温度较低,低温常会影响设施西瓜的生长发育,制约西瓜产量和品质的提高。通过使用耐冷性较强的嫁接砧木材料,可显著提高接穗品种的耐冷性,为了更好地适应我国北方地区设施栽培的环境,要求筛选出既抗枯萎病,同时耐低温的西瓜嫁接砧木材料,因此,开展西瓜砧木组合材料的枯萎病抗性鉴定、砧木幼苗耐冷性评价及耐冷性生理机制研究具有重要的现实意义。本研究以选配的39份西瓜砧木组合为试材,采用尖镰孢菌(Fusarium oxysporum f.sp.niveum)孢子悬浮液人工接种法,筛选出3份优良抗病砧木组合材料,在此基础上,通过人工气候箱控制温度条件,研究了低温10℃/5℃(昼/夜)(重度低温)、15℃/10℃(昼/夜)(中度低温)和25℃/18℃(昼/夜)(适宜温度)处理对3份西瓜抗病砧木幼苗生长发育、叶片生理生化特性及根系养分吸收特性的影响,以探讨西瓜抗病砧木幼苗对低温环境的适应性及耐冷性生理机制,阐明低温条件下幼苗根系对N、P、K的吸收转运规律,为西瓜抗病砧木材料的抗逆性鉴定评价及设施西瓜栽培中养分科学管理提供理论依据。主要研究结果如下:1.鉴定出本试验所用尖孢镰刀菌为1号生理小种(Race1)。39份西瓜材料中筛选出对Race1表现抗病的材料4份,占总供试材料的10.3%,中抗材料25份,占64.1%,轻抗材料10份,占25.6%,不存在免疫和完全感病材料。2.低温胁迫使3个西瓜抗病砧木幼苗生长受到明显抑制,冷害率和冷害指数显著增加,低温处理10d,3个西瓜砧木组合冷害率均达100%。低温胁迫显著抑制了‘BEH×Ag2-1’、‘BYH×FR328’和‘BEH×FR328’砧木组合的株高、茎粗、叶面积和叶片数的增加,显著降低了砧木组合总干物质的积累分配,结合外部形态观察可知,‘BEH×Ag2-1’叶片边缘轻度萎蔫,无脱水斑,心叶正常,受冷害最轻,‘BEH×FR328’叶片边缘较重萎蔫,出现轻微脱水斑,心叶略失水,受冷害最重,3个西瓜抗病砧木组合耐冷性强弱顺序为‘BEH×Ag2-1’‘BYH×FR328’‘BEH×FR328’。3.低温胁迫显著降低了3个西瓜抗病砧木叶片光合能力。低温胁迫条件下,砧木叶片Chl(a+b)和Car,Chla/Chlb、Pn、Tr、Gs、WUE和Ls显著降低,Ci显著增大,非气孔限制为光合下降主因,叶片Fv/Fm、Fv/Fo、Y(Ⅱ)、ETR和qP显著降低,‘BEH×FR328’叶片NPQ显著降低,而‘BYH×FR328’和‘BEH×Ag2-1’叶片NPQ增加。随低温胁迫度增加,‘BEH×FR328’、‘BYH×FR328’和‘BEH×Ag2-1’叶片Chl(a+b)和Car,Chla/Chlb、Pn、Tr、Gs和Ls,Fv/Fm,Fv/Fo,Y(Ⅱ),ETR和q P降幅均依次减小。重度低温(10℃/5℃)胁迫下,耐低温型组合‘BEH×Ag2-1’叶片Chl(a+b)和Car,Chla/Chlb、Pn、Tr、Gs和Ls,Fv/Fm、Fv/Fo、Y(Ⅱ)、ETR和qP显著高于低温敏感型组合‘BEH×FR328’,而叶片Ci则相反。‘BEH×Ag2-1’叶片吸收利用光能和传递电子效率较高,光合受抑制程度均小于其余2个砧木组合,‘BEH×FR328’光合机构破坏,光合活性受损最重。4.低温胁迫破坏了3个西瓜抗病砧木叶片膜完整性,启动了抗氧化酶系统,增加了渗透调节物质含量。低温胁迫条件下,砧木叶片相对电导率、MDA含量、SOD、POD和CAT活性、可溶性糖、可溶性蛋白和脯氨酸含量显著升高,随低温胁迫程度增加,‘BEH×FR328’、‘BYH×FR328’和‘BEH×Ag2-1’叶片相对电导率、MDA含量升高幅度依次减小,SOD、POD和CAT活性,可溶性糖、可溶性蛋白和脯氨酸含量升高幅度依次增大。重度低温(10℃/5℃)胁迫下,耐低温型组合‘BEH×Ag2-1’叶片相对电导率和MDA含量显著低于中等耐性组合‘BYH×FR328’和低温敏感型组合‘BEH×FR328’,叶片SOD、POD和CAT活性,可溶性糖、可溶性蛋白和脯氨酸含量显著高于低温敏感型组合。抗氧化酶活性和渗透调节物质含量增加增强了植株耐冷性,是西瓜抗病砧木抵抗低温逆境的重要生理机制。5.低温胁迫使3个西瓜抗病砧木幼苗根系生长受到明显抑制。主根长、根体积、根系活力、根系总吸收面积和根系活跃吸收面积均显著降低,耐低温型组合‘BEH×Ag2-1’的上述根系指标值均大于中等耐性和低温敏感型组合。低温胁迫显著降低了3个砧木幼苗茎叶N、P、K含量和根系N、P含量,表明低温降低了植株根系活力,抑制了根系对N、P和K元素的吸收。重度低温(10℃/5℃)胁迫下,耐低温型组合‘BEH×Ag2-1’幼苗根茎叶N、P、K含量显著高于低温敏感型组合‘BEH×FR328’。适温对照(25℃/18℃)幼苗茎叶N、P、K含量高于根系,低温胁迫下茎叶N、P、K含量低于根系,但含量无显著性变化。
[Abstract]:Watermelon wilt is a worldwide soil borne diseases serious harm to watermelon production, with the expansion of cultivation area, cropping even lead to wilt disease occurrence, breeding and screening of resistant rootstocks is one of the effective ways to solve the Fusarium Wilt of watermelon watermelon. Belongs to thermophilic crops, the low temperature is very sensitive, greenhouse cultivation in most parts of North China in early spring and Qiu Yanchi cultivation in the northern winter season, low temperature, low temperature would affect the growth and development of watermelon, restrict the yield and quality of watermelon increased. Through the use of cold tolerance strong grafting materials, can significantly improve the cold tolerance of scion varieties, in order to better to adapt to the cultivation in northern China, which require screening of resistance to Fusarium Wilt of watermelon, grafting material, and low temperature resistance therefore carry out watermelon rootstock composite wilt Disease resistance identification, rootstock seedlings cold tolerance evaluation and research of cold resistance physiological mechanism has important practical significance. In this study, 39 watermelon rootstocks selected as test materials, by Fusarium oxysporum (Fusarium oxysporum f.sp.Niveum) spore suspension inoculation method, selected 3 excellent rootstocks resistant materials on this basis, the temperature control of artificial climate box, on the temperature of 10 DEG /5 DEG (day / night) (severe hypothermia), 15 /10 OC (day / night) (moderate hypothermia) and 25 DEG /18 DEG (day / night) (temperature) treatment on the development of 3 watermelon resistant rootstocks the growth of seedlings, affect the absorption characteristics of physiological and biochemical characteristics of root and leaf nutrient content, to explore the watermelon rootstock seedlings resistance to low temperature adaptability and cold resistance physiological mechanism, clarify the seedling roots under low temperature conditions on N, P, K absorption and transport law, watermelon resistant rootstocks resistant material Inverse nutrient management evaluation and identification of watermelon cultivation in facilities and provide a theoretical basis. The main results are as follows: 1. identified in this experiment with Fusarium oxysporum as race 1 (Race1).39 watermelon accessions were screened for Race1 resistant material 4, accounted for 10.3% of the tested materials. Resistant material 25, accounting for 64.1%, light resistant material 10, accounting for 25.6%, there is no completely immune and susceptible materials.2. chilling stress 3 Watermelon Resistant Rootstock Seedlings Growth was inhibited and the chilling injury rate and chilling injury index increased significantly, 10d low temperature treatment, 3 watermelon rootstocks chilling injury rate reached 100%. at low temperature stress significantly inhibited the 'BEH * Ag2-1', 'BYH * FR328' and 'BEH * FR328' rootstock plant height, stem diameter, leaf area and leaf number increased, significantly reduced the total dry matter accumulation and distribution of rootstocks, combined with morphological observation, "BEH 脳Ag2-1鈥欏彾鐗囪竟缂樿交搴﹁悗钄，

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