【作者】 张志新；

【导师】 邹志荣；

【作者基本信息】 西北农林科技大学 ， 蔬菜学， 2009， 硕士

【摘要】 本试验以抗旱性不同的番茄（Solanum Lycopersicum L.）品种毛粉802和皇冠666幼苗为材料,采用营养液水培法,用不同浓度（0（CK）,50,75,100 g·L^-（1））的聚乙二醇（PEG6000）模拟水分胁迫,研究不同胁迫条件下番茄幼苗多胺的代谢变化。然后在中度胁迫水平（75 g·L^-（1） PEG6000）下,喷施外源精胺（Spm）,浓度设0、0.05、0.1、0.5 mmol·L^-（1）四个梯度,研究外源Spm对水分胁迫下番茄幼苗生理特性的影响。研究结果如下:1.水分胁迫影响番茄幼苗叶片和根系中的多胺代谢,随胁迫时间的延长,毛粉802和皇冠666叶片和根系中游离Put、Spd、Spm含量及ADC、ODC、PAO活性均呈先上升后下降的趋势,且除PAO外上升幅度随胁迫程度加重而增大。2.水分胁迫下番茄幼苗叶片和根中ADC、ODC活性与Put含量极显著正相关,表明ADC、ODC共同调控胁迫条件下番茄幼苗Put的合成代谢。3.水分胁迫下番茄幼苗多胺代谢活跃,且不同胁迫水平下多胺代谢间差异显著,胁迫处理下毛粉802叶片中3种多胺（Put、Spd、Spm）含量以及ADC、ODC活性的上升幅度都较皇冠666要高,多胺代谢与番茄抗旱间关系密切。4.水分胁迫下番茄幼苗体内各种代谢受到干扰,叶片内抗氧化的保护酶活性先增强后下降,可溶性蛋白质和游离脯氨酸含量增加,膜脂过氧化产物MDA的含量也增加,PAO活性得到提高。外源Spm处理后缓解了水分胁迫对番茄的伤害,相比胁迫对照,其保护酶活性增强,可溶性蛋白质含量增加,而游离Pro和MDA含量有所下降,PAO活性也受到抑制,有利于消除体内的活性氧自由基,减轻膜损伤,增强番茄抗旱能力。5.外源Spm可以提高番茄幼苗对水分胁迫的适应能力,且对抗旱性弱的皇冠666作用效果更好,但对正常水培条件下的番茄幼苗影响不大,其作用机理有待进一步研究。0.1 mmol·L^-1的外源Spm对番茄幼苗水分胁迫的缓解效果最好,为最适喷施浓度。更多还原

【Abstract】 In a hydroponic culture with nutrient-solution, different concentrations of PEG6000(0(CK),50,75,100 g·L~-(1)) were added to stimulate different degrees of drought stress, aimed to study the changes of polyamines metabolism in two species of tomato seedlings, named as Maofen 802 and Huangguan 666, with different drought-resistance. In moderate stress(75 g·L~-(1) PEG6000), spraying exogenous spermine(Spm)with four gradients of 0、0.05、0.1、0.5 mmol·L~-(1), the effect of physiological characteristics on tomato seedlings was studied under water stress. The results showed as follows:1. The water stress affected polyamines metabolism in leaf and root of tomato seedlings. As stress time continued, the contents of free-Put, free-Spd, and free-Spm increased firstly and then decreased, the activity of ADC, ODC and PAO showed the same trend, moreover, rising amplitude increased as water stress aggravated except for PAO activity.2. There were a significantly positive correlation between ADC, ODC activity and Put content in the leaf and root of tomato seedlings under water stress. It showed that both ADC and ODC regulated anabolism of Put in tomato seedlings under water stress.3. Polyamines metabolism became active for tomato seedlings under water stress, and there existed significant differences among different water stress. The contents of three kinds of polyamines(Put、Spd、Spm)and ADC, ODC activity in the leaf of Maofen 802 seedlings showed higher rising amplitude than those of Huangguan 666. It demonstrated that there were close relation between polyamines metabolism and drought resistance for tomato.4. Normal metabolism was interfered in tomato seedlings under water stress. Antioxidant enzymes activity in leaf rose first and then decreased, soluble protein and free proline content increased, membrane lipid peroxidation produce MDA content increased, and PAO activity increased. Compared to the control, damage from water stress was relieved after spraying exogenous Spm to the tomato seedlings, which showed that protective enzyme activity reinforced, soluble protein content increased, while free proline and MDA content decreased, PAO activity was inhibited. All those were beneficial to remove reactive oxygen species, relieve membrane damage and enhance drought-resistance ability of tomato seedlings. 5. Spraying exogenous Spm could enhance adaptive ability to defend water stress for tomato seedlings, and it had better effect on Huangguan 666. However, it had little influence on the tomato seedlings under normal hydroponic culture. The interactive mechanism deserved to make further research. It showed that the optimum concentration of exogenous Spm sprayed to tomato seedlings was 0.1 mmol·L~-(1), which could relieve the effect of water stress effectively.更多还原