不同浓度NO_3^-胁迫下黄瓜幼苗根系分生区细胞内Ca^(2+)分布变化的差异  

The Differences of Subcellular Ca^(2+) Distribution in Root Meristem Region of Cucumber Seedling Under Different NO_3^- Concentrations Stress

作　　者：杨凤娟[1,2] 魏珉[1,2] 苏秀荣[3] 王秀峰[1,2] 

机构地区：[1]山东农业大学,作物生物学国家重点实验室,山东泰安271018 [2]山东农业大学园艺科学与工程学院,山东泰安271018 [3]山东农业大学化学与材料科学学院,山东泰安271018

出　　处：《园艺学报》2009年第9期1291-1298,共8页Acta Horticulturae Sinica

基　　金：国家自然科学基金项目(30471187;30871705);山东农业大学中青年创新基金项目(23472)

摘　　要：以‘新泰密刺’黄瓜为试材,采用焦锑酸钙沉淀的电镜细胞化学方法,研究不同浓度NO3-胁迫下黄瓜幼苗根系分生区细胞内Ca2+的分布变化,以期为探讨不同浓度NO3-胁迫下细胞内Ca2+行为特征与黄瓜对NO3-适应性之间的关系。结果表明,对照生长条件下(14mmol.L-1NO3-),黄瓜根系分生区细胞内Ca2+主要出现在细胞膜和小液泡内,线粒体、细胞质和细胞核及核仁内也有少量的较小颗粒钙沉淀。而其它浓度NO3-胁迫下,其根系分生区细胞内Ca2+定位分布变化明显。在56和140mmol.L-1NO3-浓度下,Ca2+有向细胞基质分布的趋势,其细胞间隙、细胞质和线粒体中亦出现大量钙沉淀颗粒。且不同处理浓度下,线粒体和小液泡数量及结构变化较大。而当NO3-浓度达182mmol.L-1时,根系分生区各细胞器内钙沉淀颗粒明显减少,此时Ca2+的变化是各细胞器及膜系统遭严重破坏的结果。综上可知,黄瓜幼苗可通过根系分生区液泡内Ca2+向细胞基质分布变化,来增加对高浓度NO3-胁迫的抗性。The changes of calcium level in root meristem region of cucumber seedling （ ＇ Xintai Mici＇ ） under different NO3^- concentrations stress were determined by the improved cytochemical method of calcium pyroantimonate precipitation. After 7 days of treatment, under optimum NO3^- （ 14 mmol· L^-1 ） conditions, calcium antimonite deposits, which indicates calcium distribution, were mainly localized in cell membrane and vacuoles, as a storeroom of Ca^2＋ , and smaller amounts of calcium precipitates randomly resided in mitochondria, cytoplasm and nucleus. But under excessive NO3^- stress, the distribution of Ca^2＋ in subcellular was changed greatly. After 7 days treated with 56 and 140 mmol· L^-1 NO3^- , Ca^2＋ level in the intercellular spaces, cytoplasm and mitochondria elevated. With the increasing NO3^- concentrations, the shape and amount of mitochondria and vacuoles were changed greatly. Higher NO3^- concentrations （ 182 mmol · L^-1 ） caused a series of disorders of metabolic processes and serious damages of membrane system of organelles in cucumber seedling roots, thus, Ca^2＋ deposits in each compartments became smaller significantly. The result indicated that the change of Ca^2＋ from vacuoles to hyaloplasm can reduce the NO3^- stress in cucumber seedlings.

关 键 词：黄瓜 NO3^-浓度 焦锑酸钙沉淀 细胞生物化学 钙离子 

分 类 号：S633.1[农业科学—蔬菜学] Q945.78[农业科学—园艺学]