【作者】 张驰；

【导师】 吴永尧； 彭振坤；

【作者基本信息】 湖南农业大学 ， 生化与分子生物学， 2004， 硕士

【摘要】 硒是重要的生命微量营养元素之一，己知与硒营养缺乏有关的人、畜疾病多达60余种，而硒在地球上分布广泛但又极不均匀，全世界有2/3的地区缺硒，我国缺硒地区亦占2/3以上，其中1/3为世界公认的严重缺硒区，缺硒严重威胁人类健康和畜牧业的发展。人畜硒营养水平取决于摄入食物的含硒量，植物是自然界硒循环生态链和无机硒转化为有机硒的关键载体，又是人畜摄入硒元素最重要的直接硒源。 本文以油菜为对象，运用多种生理生化手段，从多侧面、全方位地进行了硒应用于油菜栽培及品质改良作用的系统研究。试验以中油杂二号品种为主要研究对象，采用土培、土培与水培相结合栽培，用原子吸收分光光度法作为硒含量的检测手段，系统研究了油菜苗期对硒的吸收、积累、分布的动态；对环境硒的耐受能力；不同供硒水平对油菜生长发育、干物质及硒累积量及动态、生物产量、含硒量的影响；不同供硒水平的油菜的根系氧化还原能力、叶片叶绿素含量、蛋白质含量、氨基酸含量分析；硝酸还原酶、过氧化物酶、超氧化物歧化酶的活性测定；脂质过氧化产物丙二醛及植物抗性指标脯氨酸含量的测定；用分级盐析沉淀法进行了从油菜中提取分离含硒蛋白的探索；对油菜中硒的赋存形态进行了探讨。 结果表明：油菜对环境中的硒有一定生物富集作用，使富集硒的浓度超过环境硒浓度（即便在高硒环境也是如此），其富集作用随植株生长发育而增强；根系吸收的硒经同化被运送到各个器官积累，各器官的含硒量亦随该器官的生长而提高，苗期各器官的含硒量依次为：根系＞叶片＞茎，植株从环境中吸收的无机硒被同化转化为有机态硒；油菜中硒有不同的赋存形态及分布，硒在水溶性生物大分子中的分布为：籽粒中：蛋白质＞多糖＞核酸，不同类型的蛋白质结合硒量为：盐溶蛋白＞水溶蛋白＞醇溶蛋白＞碱溶蛋白；叶片中：蛋白质结合硒较少，在一定补硒浓度范围内，随着生长发育和土壤持硒能力升高而增强。硒对油菜的生物效应符合微量元素生物效应剂量规律，硒浓度范围在(土培＜21.0mgSe.kg^-1 soil，水培＜15.0mgSe.L^-1)时随着硒浓度的增加，根系氧化还原能力、叶绿素含量、蛋白质含量提高；过氧化产物丙二醛的含量降低；能显著促进油菜生长发育，维持旺盛的生长活力，延缓衰老，增强抗逆性，提高植物硒含量，有明显的增产和改善营养品质的效果；随硒浓度的进一步提高上述诸项指标逆转，对油菜生长产生毒害作用。经过对多种提取分离措施的筛选，建立起分级盐析沉淀从油菜蛋白质中分离含硒蛋白组分的分离分组方法，为进一步纯化含硒蛋白提供了依据和基础。 根据本研究结果，结合他人在油菜硒研究方面的工作，笔者认为：（1）补硒栽培是提高油菜产量、改进品质的重要措施，建议把硒作微肥在广大的缺硒和低硒地区推广，以此来改良农牧业生产的硒生态环境，提高植物硒营养水平:（2）硒在油菜体内发挥重要的生理生化作用，可能是油菜必需的微量营养元素;（3）充分利用高硒地区丰富的生物硒资源，开发硒含量准确的硒治疗助剂和各类补硒保健产品，为治疗和预防缺硒相关疾病，提供高利用度无毒副作用的硒生物制品，使高硒地区的宝贵富硒植物资源得以开发增值，可促进地方经济发展，保障人类健康。更多还原

【Abstract】 Selenium is one of important elements to life, above 60 kinds of diseases and cancers are related to the lack of selenium. Selenium is distributed widely but extremely unevenly on the earth, 2/3 of area in the world lacks selenium and so does China, of which 1/3 is considered to be in terrible lack of selenium. This situation seriously threatens the health of human beings and the development of animal husbandry. The nutritive level of selenium in human and pultry is determinated by the selenium content in the food taken. Plant is the key link in the ecological selenium and the inorganic selenium cycle and it is also the most important direct selenium resource for the human and the poultry.Using multi- physiological and biochemical methods, the author studied systematically the selenium application on Brassica Napus from all aspects. Combining soil culture and liquid culture and using atom absorption spectrometry to detect selenium, the author studied systematically the following items on Brassica Napus: the trends of the absorption, accumulation, distribution of selenium in seedling stage, the endurance ability with the selenium in the environment,the effect of different provided selenium level in the growth and development, dry matter, accumulation of selenium,the producing and the content of selenium in Brassica Napus. According to the analysis on the protein, the amino acid content and the measurement of the activity of NR, peroxidese, SOD, Amylase etc and MDA which is the product of Lipid per oxidation and using unprovided selenium and different provided selenium, the author studied the physiological function and interior mechanism of selenium in organic body and its resistance. In addition, the author managed to extract and separate the protein containing selenium by the fractional precipitation, and probed the occurrence form of selenium in Brassica Napus.The Brassica Napus could accumulate and absorb selenium in the environment positively even with high selenium concentration and thus made the selenium concentration higher than that of the environment. The accumulation become stronger and stronger with the development. The selenium absorbed by the root system was transferred to different organ and accumulated there.The selenium content in different organs increased with the maturing of the organ, and in harvest time of seeding stage, selenium content of each organ is: root >leaf >stem. Most part of the selenium absorbed by the plant was converted intoorganic selenium by anabolism, and the content in soluble biological macromolecules is: protein >polysaccharide >nucleic acid. The selenium content in different types of protein is: salt-soluble protein >water-soluble protein >gliadin >alkali-soluble protein. In the leaf blade, the protein-selenium is little, but it is also the main mode of binding. Brassica Napus endurance ability with the selenium in the environment was related to the method which selenium was provided and increase with the mature and the ability of soil to keep the selenium within proper selenium concentration. The biological effect of selenium on the Brassica Napus conforms to the general dose rule of microelement. Within the low concentration (21.0mgSe.kg-1 soil in soil culture, 15.0 mgSe.kg-1 soil in liquid culture),with the selenium concentration increaseing;there will be the following changes: the deoxidation ability of root system increases and so does the content of chloroplast and protein; per oxidation product MDA decreases. Under the same situation, selenium has many functions as obviously promoting the growth and development, keeping high vigor, slowing ghee senescence, improving the quality. However, high concentration selenium can change the indexes above mentioned conversely and even take the toxic effect on the Brassica Napus growth. Fractionally precipitation was chosen from many separation methods developed to extract the protein containing selenium in Brassica Napus. This method provided the basis to the further purification of the protein containing selenium.Accordi更多还原