【作者】 颉建明；

【导师】 黄高宝；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2008， 博士

【摘要】 低温弱光是设施栽培中限制作物产量和品质的重要因素,筛选、培育耐低温弱光品种已成为国内外的育种目标。耐低温弱光性鉴定是研究植物耐性机理和筛选耐低温弱光材料的基础,而所采用鉴定指标的合理性及准确性是对育种材料耐性进行客观评价的关键。辣椒原产中南美洲热带地区,是人们广为喜爱的喜温蔬菜,亦是冬、春设施栽培的主要作物,但冬、春季温室的低温弱光抑制其生长发育,致使其产量和品质降低,制约着设施辣椒冬春季节生产效益的提高和栽培面积的扩大。目前,尚无辣椒耐低温弱光种质鉴定筛选的统一指标和方法。本研究以12个耐低温弱光性不同的辣椒品种为试材,分别研究了在15℃/5℃（昼/夜）、100μmol·m^-2·s^-1PFD低温弱光（模拟节能日光温室冬春季节的实际条件）下和28℃/18℃（昼/夜）、100μmol·m^-2·s^-1PFD常温弱光下处理0d、5d、10d、15d和20d的辣椒幼苗叶片膜脂过氧化（离子渗漏率、MDA）、酶和非酶保护系统（SOD、POD、APX、GR、AsA、GSH）、渗透调节物质（脯氨酸、可溶性糖、可溶性蛋白）、叶绿素和类胡萝卜素（Chla、Chlb、Chla/b、ChlT、Car、Car/ChlT）、叶绿素a荧光参数（Fv/Fm、ΦPSⅡ、Fv′/Fm′、qP、NPQ、Fs、Fm、Fo、Fv、Fm′、Fo′、Fv′）、淀粉、叶面积干重比（SLA）、根冠比共32个单项指标的动态变化规律,为辣椒耐低温弱光性鉴定和耐弱光性鉴定提供理论依据。以冷害指数和低温死亡率为耐低温弱光性的初选依据,以弱光下干物质积累量的变化为耐弱光性的初选依据,应用相关分析和综合隶属函数的方法,分别确立了辣椒耐低温弱光和耐弱光鉴定的指标体系和操作体系,应用该体系对供试12个辣椒品种的耐低温弱光性和耐弱光性进行了鉴定。主要研究结果如下:1.低温弱光和单一弱光处理使辣椒叶片的SLA升高,叶片变薄。在正常条件下,辣椒植株的根冠比逐渐减小,低温弱光和单一弱光处理使根冠比减小缓慢。2.低温弱光和单一弱光处理后,所有辣椒品种的SOD、POD、APX、GR等保护酶活性均被激活。POD活性在20d处理期内均高于处理前,SOD、APX和GR在处理5d或10d形成活性高峰,之后下降,大部分品种在处理末期低于处理前水平;AsA含量显著降低;GSH含量总体上增加;叶片离子渗漏率和MDA含量总体升高。处理初期各种保护酶的活性增强与品种的耐低温弱光性之间没有显著相关性。低温弱光处理15d,辣椒叶片的外观伤害症状开始显现,SOD、APX活性与品种耐低温弱光性之间呈显著正相关,POD和GR活性、AsA和GSH含量均无相关性。单一弱光处理5d的APX活性与品种耐弱光性之间呈显著正相关,其它保护酶活性和非酶保护物质含量与辣椒的耐弱光性之间无相关性。3.低温弱光和单一弱光处理后,辣椒叶片的Pro含量、可溶性糖含量升高,可溶性蛋白含量处理前期升高,后期降低,处理20d全部低于处理前水平。10个品种的Pro含量与品种的耐低温弱光性呈极显著正相关,Pro的累积表现为保护作用;耐低温弱光性较强的4^#品种和较弱的6^#品种中Pro含量与耐性呈负相关,Pro的累积表现为伤害性反应。单一弱光处理5d的Pro含量与辣椒耐弱光性呈显著正相关。低温弱光处理10d的可溶性蛋白和处理20d的可溶性糖与辣椒耐低温弱光性呈显著正相关。4.低温弱光处理使辣椒叶片的Chla、Chlb、ChlT、Car含量降低,Car/ChlT减小,Chla/Chlb增大;单一弱光处理使辣椒叶片的Chla、Chlb和ChIT含量增加,Car含量降低,Car/ChlT减小,Chla/b的变化呈降升降的趋势。低温弱光和单一弱光处理使辣椒叶片的淀粉含量大幅度下降,处理期内均显著低于处理前水平。低温弱光处理5d、15d的Chla/Chlb,处理20d的Car,处理10d、20d的Car/ChlT,处理5d、10d、20d的淀粉含量与辣椒耐低温弱光性显著相关;单一弱光处理任意时期的Car、Car/ChlT,处理5d的Chla、Chlb、ChlT,处理10d的淀粉与辣椒耐弱光性显著相关。5.低温弱光处理使辣椒叶片的ΦPSⅡ、Fv′/Fm′、qP、Fm、Fo、Fv、Fm′、Fo′和Fv′均降低,NPQ和Fs增大。单一弱光处理使辣椒叶片ΦPSⅡ、qP逐渐降低,Fv’/Fm’前期降低,末期升高;Fs、Fo、Fm、Fv、Fm′、Fo′和Fv′均显著升高。低温弱光处理15d辣椒叶片的Fm′、Fv′、Fv′/Fm′、qP、ΦPSⅡ、NPQ均与辣椒耐低温弱光性鉴定综合隶属函数值达极显著相关:单一弱光处理15d辣椒叶片的Fm′、Fo′、Fv′、Fs、qP和处理5d的Fm、Fo与辣椒耐弱光性极显著相关,叶绿素荧光技术可用于辣椒耐低温弱光性和耐弱光性快速、准确、大量的鉴定。6.确立了15项指标组成的辣椒耐低温弱光性鉴定指标体系和操作体系。分别为:15℃/5℃（昼/夜）,100μmol·m^-2·s^-1PFD下处理15d的SOD、APX、Chla/b、Fm′、Fv′、Fv′/Fm′、qP、ΦPSⅡ、NPQ,处理10d可溶性蛋白、淀粉、根冠比,处理20d的可溶性糖、Car、Car/ChlT。8项与耐低温弱光性综合隶属函数值达极显著相关,7项达显著相关。7.确立了21项指标组成的辣椒耐弱光性鉴定指标体系和操作体系。分别为:28℃/18℃（昼/夜）,100μmol·m^-2·s^-1PFD下处理5d的APX、Pro、Fm、Fo、Fv、Chla、Chlb、ChlT、Car、Car/ChlT,处理10d的MDA、淀粉、离子渗漏率,处理15d的Fm′、Fo′、Fv′、qP、ΦPSⅡ、NPQ、Fs、SLA。11项与辣椒耐弱光性综合隶属函数值达极显著相关,10项达显著相关。8.改进的以单叶受低温伤害程度分级统计的冷害指数和植株低温死亡率能较准确反映辣椒品种的耐低温弱光性,可以作为辣椒耐低温弱光性鉴定简单易行的方法。单一弱光处理任意时期的辣椒叶片Car含量和Car/ChlT值均与辣椒耐弱光性鉴定综合隶属函数值达显著正相关,是辣椒耐弱光性鉴定简单、稳定的理想指标。9.由综合隶属函数值鉴定的12个辣椒试验品种耐低温弱光性由强至弱为:湘研1号、海丰12号、陇椒2号、湘辣1号、海丰23号、航椒2号、佳木斯、陇椒1号、陇椒6号、湘研16号、靖远灯笼椒、海丰7号;耐弱光性由强至弱为:湘研16号、陇椒2号、陇椒1号、靖远灯笼椒、佳木斯、陇椒6号、航椒2号、海丰7号、海丰12号、湘研1号、海丰23号、湘辣1号。更多还原

【Abstract】 Low temperature and poor light have become important factors to restrict the yield and quality of the cultivation of vegetables in sunshine greenhouse in deep winter.Therefore,screening,breeding chilling-resistant and poor-light-resistant varieties have become breeding targets for the domestic and foreign breeders.Identification of the chilling- and poor-light-tolerance is the basis on which the mechanisms of tolerance will be understood and the tolerant germplasms will be screened.The rationality and the accuracy of the identification indexes are the keys to evaluate breeding materials for chilling- and poor-light-tolerance objectively.Pepper which originated from the tropical regions in the central and south American is widely popular warm vegetable and is the main crop in winter and spring cultivation facilities.The low temperature and poor light in winter greenhouse often inhibit the growth and development of pepper plant,and result in decrease in yield and quality.At present,there are no agreement methods and indexes to screen and identify the germplasms of chilling -resistant and poor-light -resistant pepper varieties.In this research the changes of morphology,physiology and biochemistry of 12 different chilling- and poor-light-tolerant pepper varieties under low temperature（15℃/5℃,day/night,simulating unfavorable conditions of sunshine greenhouse in deep winter） and poor light(100μmol·m^-2·s^-1,12h photoperiod) stress were studied.Based on these changes,the chilling- and poor-light-tolerances of 12 pepper varieties were identified.The researched morphological,physiological and biochemical indexes of pepper treated under low temperature and poor light stress or under poor light only stress for 20 days contained membrane relative permeability,MDA content,enzyme and non-enzyme-protection system（SOD,POD,APX,GR,AsA,GSH）, osmoprotectant（proline,soluble sugar and soluble protein）,chloroplast pigments（Chla,Chlb,Chla / b,CHlT, Car,Car / CHlT）,chlorophyll a fluorescence parameters（Fv / Fm,ΦPSⅡ,Fv ’/Fm’,qP,NPQ,Fs,Fm,Fo,Fv, Fm ’,Fo ’,Fv’）,starch,SLA,the root/shoot ratio.These 32 indexes were tested on 0d,5d,10d,15d and 20d respectively.The correlations were analyzed between the changes of these 32 indexes and the chilling injury indexes or the mortality rates of pepper seedlings treated at 5℃in the dark for 18 days or 20 days.And the correlations were also analyzed between the changes of these 32 indexes and the dry matter accumulations of pepper seedlings treated for 20 days under 28℃/18℃（day / night）,100μmol·m^-2·s^-1 stress.The indexes whose coefficients of correlation were higher than 0.576（P≤0.05） were selected as preliminarily suitable indexes for evaluating chilling- and poor-light-tolerant pepper varieties.With these indexes,the averaged subordinate function values were calculated.The correlations were analyzed between the averaged subordinate function values and the preliminarily suitable indexes.The indexes whose coefficients of correlation were smaller than 0.576（P≤0.05） were given up.Therefore,the optimal indexes for evaluating chilling- and poor-light-tolerant pepper varieties were secondarily selected.The main results are as follows:1.The SLA of pepper increased,indicatihg the leaves became thinner under low temperature and poor light stress or under poor light only stress.When treated under low temperature and poor light stress or under poor light only stress,the root/shoot ratio of pepper decreased more slowly,compared with control treatment.2.SOD,POD,APX and GR activities in leaves of 12 pepper varieties were activated,after treated under low temperature and poor light stress or under poor light only stress.POD activities in leaves of 12 treated pepper varieties were higher than that in untreated ones during treatment for 20 days.SOD,APX,GR activities in leaves of 12 pepper varieties were highest on 5d or 10d,and then decreased.At the end,most of their activities were smaller in treated leaves than that in untreated ones.When treated under low temperature and poor light stress or under poor light only stress,AsA contents significantly decreased,GSH contents,MDA contents and the membrane relative permeability increased on the whole.There were no correlations between the chilling- and poor-light-tolerances of 12 pepper varieties and the enhanced protective enzymes at the beginning of the treatment.Treated under low temperature and poor light stress for 15 days,damages of pepper leaves could be observed,the significant positive correlations between the chilling- and poor-light-tolerances of 12 pepper varieties and the SOD or APX activities existed.There were no correlations between the chilling-and poor-light-tolerances of 12 pepper varieties and the POD or GR activities,AsA or GSH contents.There were significant positive correlations between the poor-light-tolerances of 12 pepper varieties and the enhanced APX activities in leaves of pepper treated under poor light only stress for 5 days.3.The Pro contents and the soluble sugar contents increased in leaves of 12 pepper varieties treated under low temperature and poor light stress or under poor light only stress for 20 days.The soluble protein contents in leaves of 12 pepper varieties treated under low temperature and poor light stress or under poor light only stress increased and arrived at highest value on 5d,then decreased,and were lower than that in untreated ones on 20d. There were significant positive correlations between the chilling- and poor-light-tolerances of 10 pepper varieties and the Pro contents,suggesting that the accumulations of Pro in leaves of pepper treated under low temperature and poor light stress played an important role in protecting the pepper from chilling and poor light damages.But there were significant negative correlations between the chilling- and poor-light-tolerances of the other two pepper varieties and the Pro contents,indicating that the accumulations of Pro in leaves of pepper treated under low temperature and poor light stress were the results of chilling and poor light damages.There were significant positive correlations between the poor-light-tolerances of 12 pepper varieties and the Pro contents in leaves of pepper treated under poor light only stress for 5 days.There were significant positive correlations between the chilling- and poor-light-tolerances of 12 pepper varieties and the soluble protein contents in leaves of pepper treated under low temperature and poor light stress for 10 days or the soluble sugar contents in that treated for 20 days.4.The Chla,Chlb,ChlT and Car contents decreased,Car / ChlT ratios reduced and Chla / Chlb ratios increased in leaves of 12 pepper varieties treated under low temperature and poor light stress.In leaves of 12 pepper varieties treated under poor light only stress,the Chla,Chlb,ChlT contents increased,Car contents and Car / ChlT ratios reduced,Chla / Chlb ratios decreased at the beginning,and then increased,and decreased at the end of treatment.The starch contents in leaves of 12 pepper varieties treated under low temperature and poor light stress or under poor light only stress for 20 days decreased greatly and were lower than that in untreated ones throughout the treatment.In leaves of pepper treated under low temperature and poor light stress, there were significant correlations between the chilling- and poor-light-tolerances and the Chla / Chlb ratios on 5d or 15d,or the Car contents on 20d,or the Car / ChlT ratios on 10d or 20d,or the starch contents on 5d,10d or 20d.In leaves of pepper treated under poor light only stress,there were significant correlations between the poor-light-tolerances and the any tested Car contents or Car/ChlT ratios,or the Chla,Chlb,ChlT on 5d,or the starch contents on 10d.5.TheΦPSⅡ,Fv’/Fm’,qP,Fm,Fo,Fv,Fm’,Fo’ and Fv’ decreased,the NPQ and Fs increased in leaves of 12 pepper varieties treated under low temperature and poor light stress.In leaves of 12 pepper varieties treated under poor light only stress,theΦPSⅡand qP decreased gradually,Fv’/Fm’ decreased at the beginning, and then increased,the Fs,Fo,Fm,Fv,Fm’,Fo’ and Fv’ increased prominently.It was proposed that the Fm’, Fv’,Fv’/Fm’,qP,ΦPSⅡand NPQ in leaves of pepper treated under 15℃/ 5℃,100μmol·m^-2·s^-1pFD stress for 15 days could be used as simple and convenient tools for identification and screening a large number of chilling and poor-light tolerant pepper varieties,and that the Fm’,Fo’,Fv’,Fs and qP in leaves of pepper treated under 28℃/18℃,100μmol·m^-2·s^-1PFD stress for 15 days,the Fm,Fo,Fv in leaves of pepper treated under 28℃/18℃,100μmol·m^-2·s^-1PFD stress for 5 days could be used as simple and convenient tools for identification and screening a large number of poor-light- tolerant pepper varieties.6.15 optimal indexes for evaluating chilling- and poor-light-tolerant pepper varieties were selected.They were SOD activity,APX activity,Chla/Chlb,Fm’,Fv’,Fv’/Fm’,qP,ΦPSⅡand NPQ in leaves treated under 15℃/5℃,100μmolom·^-2·s^-1PFD stress for 15 days,the soluble protein content,starch content,the root/shoot ratio in leaves treated under 15℃/ 5℃,100μmol·m^-2·s^-1PFD stress for 10days,the soluble sugar contents,Car contents,Car/ChlT ratios in leaves treated under 15℃/ 5℃,100μmol·m^-2·s^-1PFD stress for 20days.7.21 optimal indexes for evaluating poor-light-tolerant pepper varieties were selected.They were the APX activity,Pro contents,Fro,Fo,Fv,Chla,Chlb,CHlT,Car,Car/ChlT in leaves treated under 28℃/18℃, 100μmol·m^-2·s^-1PFD stress（the same as below） for 5days,the MDA contents,starch contents,the membrane relative permeability for 10 days,the Fm’,Fo’,Fv’,qP,ΦPSⅡ,NPQ,Fs and SLA treated for 15 days.8.The chilling- and poor-light-tolerance of pepper varieties can be evaluated by injury indexes based on injury order of every pepper leaf improved by this research and mortality rates treated at 5℃and in the dark preliminarily.The Car contents and the Car/ChlT ratios whose any tested values under poor light only stress had significant correlations with the averaged subordinate function values could be used as convenient and stable indexes for evaluating poor-light-tolerant pepper varieties.9.According to the averaged subordinate function values calculated with 15 selected indexes,the chilling- and poor-light-tolerance orders from strong to weak of the researched 12 pepper varieties are: Xiangyan No.1,Haifeng No.12,Long Jiao No.2,xiangla No.1,Haifeng No.23,Hang Jiao No.2,Jiamusi,Long Jiao No.1,Long Jiao No.6,Xiangyan No.16,Jingyuan Denglong Jiao,Haifeng No.7.On the basis of the averaged subordinate function values calculated with 21 selected indexes,the poor-light-tolerance orders from strong to weak of the studied 12 pepper varieties are:Xiangyan No.16,Long Jiao No.2,Long Jiao No.1, Jingyuan Denglong Jiao,Jiamusi,Long Jiao No.6,Hang Jiao No.2,Haifeng No.7,Haifeng No.12,Xiangyan No.1,Haifeng No.23,xiangla No.1.更多还原