【作者】 姚慧；

【导师】 夏凯；

【作者基本信息】 南京农业大学 ， 植物学， 2014， 硕士

【摘要】 低温胁迫是农业生产中的一种常见自然灾害,低温会严重影响玉米幼苗的生长发育和产量,所以研究改善玉米幼苗对低温胁迫的耐受力及分析其可能的生理过程,在玉米的生产上具有重要意义。肌醇是人、动物和微生物生长所必需的一种水溶性维生素,对植物的生长发育非常重要,它能够参与磷脂酰肌醇的信号转导通路、生长素储存和运输、植酸的生物合成、细胞壁生物合成以及植物对胁迫的响应。植酸和植酸钙镁是肌醇的衍生物,但它们在植物上的应用非常少。本研究以“苏玉24”玉米为供试材料,通过叶面喷施不同质量浓度的肌醇,随后进行4℃低温处理,探索出肌醇缓解玉米冷害的最佳浓度,然后进一步对比分析常温和低温下肌醇对玉米幼苗生理过程的影响,结果表明：0.8g/L肌醇对玉米幼苗低温胁迫的保护效果最好。4℃低温下,玉米幼苗叶片内丙二醛含量、SOD、CAT、POD活性、H2O2含量、O2·-产生速率和游离脯氨酸含量均显著升高,叶绿素含量均显著降低；与水对照组相比,外源肌醇处理组的丙二醛、H2O2含量和O2·-产生速率均显著降低,而SOD、CAT、POD活性、叶绿素和游离脯氨酸含量均显著增加。结论：外源施加0.8g/L肌醇能减轻活性氧积累,增强抗氧化系统酶活性,保护膜结构和功能,降低膜脂过氧化伤害程度,从而缓解低温胁迫对玉米幼苗的伤害。以肌醇衍生物进行了类似的实验。通过叶面喷施不同质量浓度的植酸和植酸钙镁,随后进行4℃低温处理,探索它们对玉米冷害的作用效应,并进一步探究它们对玉米幼苗生理过程的影响。结果表明：外源植酸能缓解低温胁迫对玉米幼苗的冷害,且以1.6g/L植酸的缓解效果最好。4℃低温下处理组与对照组的SOD、CAT、POD活性均显著升高,且处理组的丙二醛含量显著小于对照组,而SOD、CAT、POD活性、叶绿素和游离脯氨酸含量均显著大于对照组。结论：植酸能够减轻低温胁迫对膜脂过氧化的伤害程度,减少活性氧积累,增强抗氧化系统酶活性,保护膜结构和功能。更多还原

【Abstract】 Low temperature stress is a common natural disaster in agricultural production, which would severely reduce the growth, development, and production of maize. Therefore, it’s urgent to find ways to improve the chilling tolerance of maize and figure out the possible mechanism. Inositol is a water-soluble vitamin which is required for the growth of human being, animals, and microorganisms. Among them, inositol is extremely important for plant growth, and is involved in phosphatidylinositol signaling pathway, auxin storage and transport, phytic acid biosynthesis, cell wall formation and plant response to stresses. Phytic acid and phytin are two derivates of inositol, but they are not commonly used in plant production.A maize cultivar "Suyu 24" was used in this study. The maize seedlings were foliar-sprayed with inositol solutions at certain concentrations, and then subjected to chilling treatment at 4℃. After that, the effect of inositol on the chilling responses and its physiological processes in maize seedlings was examined and analyzed. The results showed that 0.8 g/L inositol exhibited the strongest mitigating effect the low temperature-induced injuries in maize seedlings. Under chilling stress, the seedlings had the increased SOD, CAT, and POD activities, MDA, H2O2, superoxide anion and free proline contents, but the decreased chlorophyll content. Inositol application caused the significant decrease of MDA, H2O2 and superoxide anion contents, but the increase of SOD, CAT and POD activities, chlorophyll and free proline content. In conclusion, exogenous 0.8 g/L inositol were capable of reducing the accumulation of reactive oxygen species, enhancing the activities of antioxidant enzyme system, protecting the structure and function of membrane, reducing the membrane lipid peroxidation, thus mitigating the chilling injuries in maize seedlings.The actions of the two derivates of inositol were also examined. The maize seedlings were incubated at 4℃ after foliage spraying of different concentrations of phytic acid and phytin, and their effects on mitigating the chilling-induced injuries in maize seedlings was explored. Moreover, the actions of phytic acid and phytin on physiological processes involved in chilling responses were analyzed. The results showed that exogenous phytic acid can mitigate the low temperature-induced injuries in maize seedlings, and the best concentration is 1.6 g/L. SOD, CAT, and POD activities increased for both control and treatment at 4℃; MDA content of treatment were significantly lower than control, while SOD, CAT, and POD activities, chlorophyll and free proline content were significantly higher. Above results suggest that exogenous phytic acid is able to reduce the membrane lipid peroxidation, decrease the accumulation of reactive oxygen species, enhance the activities of antioxidant enzyme system, and protect the structure and function of membrane in maize seedlings under chilling stress.更多还原