The seed germination and seedling growth of pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee cv. Hanxiao） were not significantly inhibited until the concentration of NaCl was increased to 150 mm...The seed germination and seedling growth of pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee cv. Hanxiao） were not significantly inhibited until the concentration of NaCl was increased to 150 mmol/L. Treatment of pakchoi seeds with exogenous 5-aminolevulinic acid （ALA）, at concentrations ranging from 0.01 to 10.00 mg/L, promoted seed germination when seeds were stressed by salinity, whereas levulinic acid （LA）, an inhibitor of ALA dehydrase, significantly inhibited seed germination and seedling growth, suggesting that metabolism of ALA into porphyrin compounds was necessary for seed germination and seedling growth. Determination of respiratory rate during seed germination showed that ALA increased seed respiration under both normal conditions and salt stress. Furthermore, salt stress decreased levels of endogenous ALA, as well as heme, in etiolated seedlings. More salt-tolerant cultivars of pakchoi contained higher relative levels of endogenous ALA and heme under conditions of salt stress. These results indicate that salt stress may inhibit the biosynthesis of endogenous ALA and then heme, which is necessary for seed germination, and treatment of seeds with exogenous ALA prior to germination may be associated with the biosynthesis of heme.展开更多
中文的"图书馆权利"一词源自对美国图书馆协会《图书馆权利法案》英文"Library Bill of Rights"的翻译,大约于1980年开始在中国出现。2004年,我国大陆第一次将"图书馆权利"的主要内容列入全国图书馆学专...中文的"图书馆权利"一词源自对美国图书馆协会《图书馆权利法案》英文"Library Bill of Rights"的翻译,大约于1980年开始在中国出现。2004年,我国大陆第一次将"图书馆权利"的主要内容列入全国图书馆学专业统编教材《信息资源共享》,其后程焕文正式提出"图书馆权利"这个术语,并因此而使"图书馆权利"一词在我国图书馆界广泛传播和流行。目前,我国图书馆学界对"图书馆权利"一词的正宗性一直存在着分歧:一种观点认为"图书馆权利"一词用词不正宗,不宜使用;另一种观点认为"图书馆权利"这个词是一个非常正宗的汉语词汇,应该没有异议。文章认为:美国图书馆协会《图书馆权利法案》的英文名称"Library Bill ofRights"沿用了英文习惯用法,在英语语境中并不会产生歧义,随着"图书馆权利"理念的进一步广泛传播,"图书馆权利"一词也将成为一个简单明了和民众喜闻乐见的正宗中文专门术语。展开更多
基金the Overseas Scholarship Foundation of the Chinese Education Department，国家自然科学基金
文摘The seed germination and seedling growth of pakchoi （Brassica campestris ssp. chinensis var. communis Tsen et Lee cv. Hanxiao） were not significantly inhibited until the concentration of NaCl was increased to 150 mmol/L. Treatment of pakchoi seeds with exogenous 5-aminolevulinic acid （ALA）, at concentrations ranging from 0.01 to 10.00 mg/L, promoted seed germination when seeds were stressed by salinity, whereas levulinic acid （LA）, an inhibitor of ALA dehydrase, significantly inhibited seed germination and seedling growth, suggesting that metabolism of ALA into porphyrin compounds was necessary for seed germination and seedling growth. Determination of respiratory rate during seed germination showed that ALA increased seed respiration under both normal conditions and salt stress. Furthermore, salt stress decreased levels of endogenous ALA, as well as heme, in etiolated seedlings. More salt-tolerant cultivars of pakchoi contained higher relative levels of endogenous ALA and heme under conditions of salt stress. These results indicate that salt stress may inhibit the biosynthesis of endogenous ALA and then heme, which is necessary for seed germination, and treatment of seeds with exogenous ALA prior to germination may be associated with the biosynthesis of heme.
文摘中文的"图书馆权利"一词源自对美国图书馆协会《图书馆权利法案》英文"Library Bill of Rights"的翻译,大约于1980年开始在中国出现。2004年,我国大陆第一次将"图书馆权利"的主要内容列入全国图书馆学专业统编教材《信息资源共享》,其后程焕文正式提出"图书馆权利"这个术语,并因此而使"图书馆权利"一词在我国图书馆界广泛传播和流行。目前,我国图书馆学界对"图书馆权利"一词的正宗性一直存在着分歧:一种观点认为"图书馆权利"一词用词不正宗,不宜使用;另一种观点认为"图书馆权利"这个词是一个非常正宗的汉语词汇,应该没有异议。文章认为:美国图书馆协会《图书馆权利法案》的英文名称"Library Bill ofRights"沿用了英文习惯用法,在英语语境中并不会产生歧义,随着"图书馆权利"理念的进一步广泛传播,"图书馆权利"一词也将成为一个简单明了和民众喜闻乐见的正宗中文专门术语。
