【作者】 张彦萍；

【导师】 申书兴；

【作者基本信息】 河北农业大学 ， 蔬菜学， 2011， 博士

【摘要】 为了寻求提高茄子种子活力和幼苗抗冷性的有效方法并探讨其内在机理,本文研究了茄子种子在人工老化过程中的活力和生理变化以及各种种子处理方法对不同老化程度茄子种子的活力和生理指标的影响,并研究了引发处理对低温胁迫下茄子的种子萌发、幼苗生长及抗冷性生理指标的影响。主要结果如下:1.茄子种子在人工老化过程中的活力及生理特性的变化采用人工老化的方法,研究了茄子种子老化过程中的种子活力及生理特性的变化。结果表明:随着种子老化程度的加深,茄子种子的发芽势,发芽率、发芽指数和活力指数均显著下降,种子内的POD、SOD、CAT等氧化酶活性以及淀粉酶、脱氢酶活性呈显著降低趋势,可溶性糖含量和可溶性蛋白含量逐渐减少,而种子的相对电导率和丙二醛(MDA)含量则呈上升趋势;聚丙烯酰胺凝胶电泳显示,在种子老化过程中种子醇溶蛋白及酯酶同工酶谱带有强度减弱和消失现象发生;老化茄子种子的根尖细胞可观察到单桥、双桥、断片,染色体畸变率随老化程度加重而增高。相关分析表明老化种子的活力指数与种子的SOD活性、CAT活性、可溶糖含量、可溶性蛋白含量显著正相关,与MDA含量显著负相关。2.提高茄子种子活力的方法与机理研究采用L9(34)正交试验设计,筛选了吸湿-回干、低温、PEG、CaCl2、KH2PO4、GA、6-BA、AsA、CTS等9种引发方法的浓度、温度、时间的最佳效果组合,并测定了不同活力程度的茄子种子经各种最佳效果组合引发后的种子活力及生理指标的变化。结果显示,9种方法均能不同程度地提高茄子种子活力,其中PEG、CaCl2、KH2PO4、GA、6-BA、AsA、低温等7种引发方法的效果极显著高于对照,以GA的引发效果最好。不同老化程度的种子经引发后,种子内的POD、SOD、CAT及脱氢酶活性增强,种子内的可溶性蛋白和可溶性糖含量显著升高;种子浸提液相对电导率和MDA含显著量降低。相关性分析显示,POD活性、CAT活性、可溶性糖含量、可溶性蛋白含量与种子活力指数显著正相关,MDA含量与种子活力指数显著负相关。3.引发对低温胁迫下茄子种子萌发及幼苗生长的影响应用9种引发处理的最佳组合,研究了引发对低温逆境条件下的茄子种子发芽特性、幼苗生长及抗冷性的影响。结果显示,各种引发方法均能显著提高低温胁迫下茄子种子的发芽势、发芽率、发芽指数和活力指数,芽苗的胚根长、胚芽长、鲜重及根冠比值也相应显著提高;经种子引发的幼苗,在3叶1心和5叶1心时期的壮苗指数极显著高于对照,在4叶1心时经低温胁迫后,叶片内POD、CAT、SOD活性,脯氨酸、可溶性蛋白及可溶性糖含量显著高于对照,而相对电导率和MDA含量显著低于对照,表明9种种子处理方法不仅促进了低温胁迫条件下种子萌发和幼苗生长,而且也增强了幼苗的抗冷性。4.多胺引发处理对茄子种子活力及幼苗抗冷性的影响茄子种子分别用0.25 mmol·L-1的亚精胺(Spd)和精胺(Spm)引发处理24 h后,在10℃、15℃、25℃条件下进行种子发芽试验,并测定幼苗耐冷性等生理生化指标。结果显示,Spd和Spm处理可显著提高种子在低温胁迫条件下的活力,促进幼苗生长,显著降低了低温胁迫条件下幼苗细胞质膜透性和MDA含量,提高了抗氧化酶(SOD、POD、CAT)活性和脯氨酸、可溶性蛋白质的含量,表明多胺引发处理对提高低温胁迫下茄子种子活力及增强幼苗抗冷性具有重要作用。更多还原

【Abstract】 In order to discover the methods and mechanism for improving seed vigor and seedling chilling resistance by seed priming,the changes of seed vigor and physiological indices during accelerated aging, this dissertation studied the effects of various seed treatments on seed vigor and physiological indices,and the primed seed’s germination characters and seedling resistance to chilling under chilling stress were studied in this paper. The main results were as follows:1. Effect of accelerated aging on the vigor and metabolism of eggplant seeds.The changes of seed vigor and biological indices in eggplant seeds during the aging period were investigated using accelerated aging technique. The results showed that with the seed aging,the germination potential,germination rate, germination index and vigor index significantly declined compared with untreated seeds. The activity of antioxidase including POD,SOD and CAT , and the contents of soluble sugar and soluble protein in aged seeds also significantly decreased,while the relative conductivity and MDA content markedly increased. Polyacrylamide gel electrophoresis showed that with the seed aging, some of the bands of gliadin and esteras waned or disappeared. Chromosome bridges, chromo-some breakage and chromosome fragments were detected in aged seeds, chromosome aberration rate increased with the decline of seed vigor. Correlation analysis indicated the eggplant seed vigor indices were correlated with SOD activity, POD activity, soluble sugar content, and soluble protein content, and significantly negatively correlated with MDA content in the seeds.2.Study on the methods and mechanism of improving eggplant seeds vigor.The optimal priming combinations were screened with L9(34) orthogonal experiment design to the priming methods including imbibition-drying , low temperature , polyethylene glycol (PEG), CaCl2, KH2PO4, gibberellin (GA),6-BA,ascorbic acid (AsA) and Chitosan(CTS). The changes of seed vigor and physiological indices were investigated in accelerated-aged eggplant seeds after priming with the optimal priming combinations. The results indicated that all the treatments were effective to improve accelerate-aged seeds vigor,and GA treatment was the best one. With the rise of aged eggplant seed vigor after the seed priming, the activity of POD, SOD,CAT and dehydrogenase increased,and the relative conductivity (REC) and the content of MDA in aged seed significantly increased. Correlation analysis indicated eggplant seeds vigor indices were significantly positively correlated with the activity of POD, CAT,soluble sugar content and soluble protein content, and significantly negatively correlated with the MDA content in the seeds.3. Effects of seed priming on seed vigor and seedling growth under chilling stressOn the basis of optimal combinations obtained from previous seed priming, the seeds germination property and physiological indices of seedling under chilling stress were studied. The results showed that under low temperature, all priming treatment with the optimal combination significantly enhanceded the seed germination indices. At three-to four true leaf stage and five-to-six true leaf stage, the healthy seedling index of the primed seedling was significantly higher than those unprimed. After chilling stress at four-to-five true leaf stage,activities of POD,SOD and CAT,and contents of proline, soluble sugar and soluble protein in the leaves of primed seedling were significantly higher than that unprimed,and the relative electrical conductivity and the MDA content were significantly lower in the priming seedling leaves compared with non-priming seedling leaves. It indicated that seed priming with the nine methods improved not only the seed germination and seedling growth, but also the seedling resistance to the chilling.4. Effect of polyamine priming on eggplant seed vigor and seedling chilling toleranceEffects of Spd and Spm treatments on eggplant seed vigor and seedling chilling tolerance were studied under chilling stress. Seeds of eggplant hybrid‘Fengyan 2’were soaked with 0.25 mmol·L-1of Spd and Spm, respectively for 24 h in dark under 15℃, 20℃and 25℃,while the control was not treated with Spd and Spm. The seed vigor indices and seedling chilling tolerance indices between treatment and untreatment were investigated and compared. Results showed that Spd and Spm treatments significantly improved seed vigor and seeding growth, enhanced the activities of POD,CAT and SOD, increased soluble protein and proline contents, and decreased membrance permeability and MDA contents .The results suggested that Spd and Spm played a vital role in promoting eggplant seed vigor and seedling chilling tolerance.更多还原