【作者】 刘健伟；

【导师】 罗庆熙；

【作者基本信息】 西南大学 ， 蔬菜学， 2010， 硕士

【摘要】 茄子属喜温性蔬菜作物,常常遭遇病害和冷害。冬春设施栽培中常会遇到低温危害,其结果可使茄子生长发育受阻,产量和品质下降。茄子的最适生育温度为22～30℃,在17℃以下生长发育变得缓慢,10℃以下便出现新陈代谢失调的现象,发生冷害的临界温度是7.2℃。茄子在进行保护地栽培过程中,温度的伤害主要来自于冷害。蔬菜作物生理活动常因冷害而受到障碍,冷害发生的平均温度一般为0-10℃。冷害对植物造成伤害时,其程度除取决于温度高低外,还取决于低温持续时间的长短。由于茄子栽培的区域性强,在我国研究茄果类蔬菜抗冷方面,关于番茄和辣椒的研究报道较多,但在茄子方面报道较少。茄子抗冷性受多种特异的数量抗冷基因调控,因此,影响茄子抗冷性因素是多方面的。许多学者指出,指标单一化不能正确反映植物的抗冷性实质。因此只有综合评价各种因素,才能得出正确的结论,这将是今后研究工作的重点。从茄子的生长特点来看,其对环境是比较敏感的。目前茄子抗冷性生理学研究的热点主要集中在寻找茄子合适的砧木上,还有就是寻找合适的外源物质来提高其抗冷性,如水杨酸(SA)、脱落酸(ABA)等,随着新型外源物质的发展,相信其对茄子抗冷性的研究将带来新的机遇。5-氨基乙酰丙酸(ALA)是卟啉化合物生物合成的关键前体物质,在自然界动植物中广泛存在。ALA是生物合成叶绿素、血红素、维生素B、光敏素等物质的必须因子,在生物体内光合作用与呼吸作用中联系十分广泛。国外的研究进展表明一定浓度下,5-氨基乙酰丙酸在提高植物逆性方面有一定的作用。Hotta等将三叶龄水稻幼苗根系浸泡在1mg/LALA溶液中,1d后转放于5℃低温中5d,实验结果表明,经过ALA处理的幼苗干物质提高72%,存活率提高30%,老叶寿命延长。Watanabe等在通过比较12种植物生长调节物质后,对棉花耐盐性影响的实验中发现,以1.5%NaCI处理的植株全部死亡,而由100mg/L～300mg/L ALA处理的植株的受害率仅为20%～30%,且植株干重和鲜重在与未经NaCI处理的植株相比差异不显著。亚精胺(Spd)是多胺其中的一种物质。在原核生物和真核生物中多胺是一种广泛存在的生物活性物质,是一类在植物体内普遍存在的低分子量脂肪族含氮碱。刘爱荣等研究实验结果表明通过用不同浓度梯度的精胺和亚精胺对油菜种子浸种和蕾薹期的喷施,亚精胺和精胺在提高植物抗逆性方面其最适宜浓度在0.01-lmmol/L范围内。王学等研究发现在0.1-0.5 mmol/L浓度时,Spd可减轻Hg2+处理产生的毒害,当喷施Spd达到浓度1 mmol/L时,SOD、POD、CAT、APX活性已逐渐开始降低。目前国内最新的进展中,研究发现Spd浸种处理可提高番茄幼苗抗氧化酶活性,从而减轻盐胁迫对番茄幼苗生长的抑制作用,特别是对盐敏感品种的效果更为显著。也有实验表明在盐胁迫下,较低浓度的外源Spd浸种处理能够促进番茄种子的萌发,增加幼苗叶片保护酶活性,且以0.25 mmol/L Spd处理效果最好。水杨酸是一种在植物中的次生代谢产物,它是一种广泛存在的物质,其应用已经十分广泛。植株能够经光合和抗氧化来保护和抑制干旱胁迫下造成的损伤。干旱胁迫下叶片中SA的含量增多,结果显示SA可提高植株的抗干旱能力。还有些表明SA能够增强植物耐热性。西红柿和大豆经过0.1～0.5mmo1/L SA浸种植株能够表现出对高温、低温以及干旱胁迫的抵抗能力,经过水杨酸灌根的幼苗可得到与浸种相似的结果。孙艳等研究发现250mg/LSA能够十分有效地增多黄瓜壮苗指数,提高黄瓜的抗性。本实验通过对茄子抗冷性有提高作用的三种外源物质进行比较研究,对茄子不同的抗冷指标进行综合分析,筛选出对提高茄子幼苗抗冷性效果较好的外源物质,并研究其作用机理,为这种新型外源物质的进一步应用推广和更深入的研究在低温胁迫下茄子育种和栽培提供理论基础和技术依据。本实验结果如下：1.用三种不同浓度的外源物质(SA、ALA、spd)以及CK处理四叶一心的茄子幼苗叶片,低温5℃胁迫4天后,测定电导率,比较分析三种外源物质对茄子抗冷性的影响。实验表明5-氨基乙酰丙酸(ALA)和亚精胺(Spd)与对照和水杨酸(SA)相比,能够显著降低茄子的电导率,提高茄子的抗冷性,减轻低温对茄子幼苗的伤害,其中3mmol/LSA喷施茄子时,电导率最小。2.用四种不同浓度的5-氨基乙酰丙酸(ALA)(0.05mg/L、0.5mg/L、lmg/L和5mg/L)以及CK处理四叶一心的茄子幼苗,再将幼苗进行低温5℃胁迫4天,每天测定茄子叶片SOD、POD、CAT的活性,4天后测定脯氨酸(Pro)、丙二醛(MDA)、叶绿素(ch1)含量,实验表明1mg/L 5-氨基乙酰丙酸(ALA)与其它浓度相比能够显著减轻低温对茄子幼苗的损伤,提高茄子的抗冷性。3.用四种不同浓度的亚精胺(Spd)(O.Olmmol/L、0.1mmol/L、0.5mmol/L、lmmol/L)以及CK处理四叶一心茄子幼苗,再将幼苗进行低温5℃胁迫4天,每天测定SOD、POD、CAT的活性,4天后测定脯氨酸(Pro)、丙二醛(MDA)、叶绿素(chl)含量,实验表明0.5mmol/LSpd与其它浓度相比能够显著减轻低温对茄子幼苗的损伤,提高茄子的抗冷性。4.分别用1mg/L 5-氨基乙酰丙酸(ALA)和0.5mmol/L亚精胺(Spd)以及CK处理四叶一心茄子幼苗,低温胁迫4天后,分别测定茄子幼苗的电导率、丙二醛、脯氨酸、抗坏血酸含量。实验表明最适浓度的ALA比最适浓度的Spd更能有效提高茄子的抗冷性。更多还原

【Abstract】 Eggplant is a kind of thermophile vegetable crop, often suffer cold and disease. It is also encountered chilling hurt in winter and spring controlled cultivation, and it can results in the delay the growth, decline of yield and quality. The optimum growth temperature for eggplant is 22～30℃, under 17℃the growth will be slowed down; and under 10℃the plant will follow metabolic disturbance. The critical temperature of chilling injury is 7.2℃. In protected cultivation of eggplant, the temperature injuries come mainly from chilling injury. Regular physical activity vegetables impeded due to chilling injury, and chilling injury happens in the average temperature of 0～10℃. The level of chilling damage to plants is depends not only on the temperature level, also on the duration of low temperature. As the eggplant production has strong regional habit, in the cold- resistance study of fruit vegetables, there are lots of research report on tomato and pepper, but few on eggplant.Eggplant’s cold-resistance can be controlled by many specific cold-resistance genes, so cold-resistance of eggplant is influenced by many factors. A large number of scholars pointed out that single index can not reflect the real cold-resistance of plants right. Evaluating all kinds of factors comprehensively can obtain the correct conclusions and it will be the focus of future researches.Growth of eggplant is sensitive to its environment. Currently, the research of eggplant’s cold-resistance physiology focus mainly on looking for the right rootstock and the suitable outside sources of chemicals, such as salicylic acid （SA）, abscisic acid （ABA） and so on, to increase the eggplant’s cold-resistance capability. With the development of new exogenous substances, the research of cold resistance of eggplant will bring new opportunities.5-aminolevulinic acid （ALA） is a key precursor of the porphyrin’s biosynthesis and it exist in nature plants and animals widespread. ALA is needed for the biosynthesis of chlorophyll, protoheme, vitamin B, phytochrome and other substances. It connects Photosynthesis and Respiration widely. Researches abroad showed that on certain concentration of 5-aminolevulinic acid, it can improve the stress resistance capability of plants. Hotta, etc. left the rice plant in the 1mg/L ALA for 1 day, then shifted to 5℃for 5 days, the experimental results showed that after ALA treatment, the dry matter of the plant increased 72%, the survival improved 30% because of the old leaves’ life extended. Watanabe, etc. had compared 12 plant growth regulators and after the experiment of the salt tolerance of cotton, found that with 1.5% NaCl treatment, all plants were dead, but with the 100mg/L～300mg/L ALA treatment, the death was only 20% to 30% and compared with the untreated with NaCl, the plant dry weight and fresh weight were not significant.Spermidine （Spd） is a kind of substance of polyamines. It is a biologically active substance existing in prokaryotes and eukaryotes widely. Also, it is a class of low molecular weight aliphatic nitrogen-containing base which generally exist in plants. Ai-Rong Liu, etc. showed that by using different concentrations of Spermine and Spermidine to treat the seed and the bud of rape. they all have the most suitable concentration in the range of 0.01～1mmol/L which can increase plants stress resistance capability.Xue Wang, etc. found that if used 0.1～0.5 mmol/L Spd, it can reduce the toxicity which produced by Hg²⁺, when the spray concentration of Spd reach to 1mmol/L, SOD, POD, CAT, APX activity have gradually started to decrease. Currently, the latest study found that soaking Spd could increase the antioxidant enzyme’s activities of tomato seedlings, thereby reduced salt stress on tomato seedlings’ growth inhibition, particularly for the salt-sensitive species is more significant. There were experiments showed that under salt stress, low concentrations of exogenous Spd soaking can promote the germination of tomato seeds and increase the activity of protective enzymes in leaves, and 0.25 mmol/L Spd did have the best effect.Salicylic acid is a secondary metabolites in plants. It is a widespread material and have been used widely. All plants can protect and restrain the damage that caused by drought stress through photosynthesis and antioxidant. Under the drought stress, the content of leaves’ SA increased. The result showed that SA can enhance plant drought resistance. Others showed that SA can enhance the heat resistance of plants. After using 0.1-0.5mmol/L SA to soak tomato and soybean seed, the plants showed the capability of resisting high temperature, low temperature and drought stress, and irrigating roots through the salicylic acid had the similar result. Yan Sun, etc. found that 250mg/L SA can increase cucumber seedling index effectively and enhance the resistance of cucumber.In this study, through compared with the three exogenous substances that can improve the chilling resistance of eggplants, and comprehensive analysis the different cold-resistance indexes in eggplant, so that we can select a better exogenous substance and study its mechanism to provide the theoretical and technical basis for the new exogenous substance’s further application, promotion and research in the breeding and cultivation of eggplant under the low temperature stress.The results as follows:1.By using the three exogenous substances of different concentrations （SA, ALA, Spd） and CK to deal with the eggplant seedling leaves in four-leaf-stage and keep them under 5℃for 4 days, then measured electrical conductivity and compared the influence on the cold-resistance capability of three kinds of exogenous substances. Experiments show that compare the 5-aminolevulinic acid （ALA） and spermidine （Spd） with the CK and salicylic acid （SA）, ALA and Spd can reduce the conductivity significantly, improve the cold resistance of eggplant and reduce the injury to eggplant seedlings when face the low temperature stress. When apply 3mmol/L SA, the conductivity is minimum.2.By using four different concentrations of 5-aminolevulinic acid （ALA） （0.05mg/L,0.5mg/L, 1mg/L and 5mg/L） and CK and measured SOD, POD, CAT levels everyday, after 4 days to measure the content of proline （Pro）, malondialdehyde （MDA） and chlorophyll （chl）, experiments show that compared with other concentrations, the 5-aminolevulinic acid （ALA） of lmg/L can reduce the damage of low temperature on eggplant seedlings significantly and improve the cold resistance of eggplant.3.By using four different concentrations of spermidine （Spd） （0.01mmol/L, 0.1mmol/L,0.5mmol/L, 1mmol/L） and CK in four-leaf-stage eggplant seedling and keep under 5℃for 4 days and measured SOD, POD, CAT levels everyday, after 4 days to measure the content of proline （Pro）, malondialdehyde （MDA） and chlorophyll （chl）, experiments showed that compared with other concentrations, the spermidine （Spd） of 0.5mg/L can reduce the damage of low temperature on eggplant seedlings significantly and improve the cold resistance of eggplant.4.By using lmg/L 5-aminolevulinic acid （ALA）,0.5mmol/L spermidine （Spd） and CK in four-leaf-stage eggplant seedling and keep under 5℃for 4 days, then measured the content of electrical conductivity, malondialdehyde （MDA）, proline （Pro）and ascorbic acid. Experiments showed that the optimal concentration ALA is more effective than the optimal concentration of Spd in improving cold resistance of eggplant.更多还原