缺锌胁迫下玉米叶片出现类似细胞凋亡现象  

Cell apoptosis in maize leaves possibly induced by zinc deficiency stress

作　　者：王盛锋[1,2] 汪洪 WANG Sheng-feng;WANG Hong(Key Laboratory of Plant Nutrition and Fertilizer,Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Key Laboratory of Crop Specific Fertilizer,Ministry of Agriculture and Rural Affairs/Xinyangfeng Agricultural Technology Co.Ltd,Beijing 100070,China)

机构地区：[1]农业农村部植物营养与肥料重点开放实验室/中国农业科学院农业资源与农业区划研究所,北京100081 [2]农业农村部作物专用肥料重点实验室/新洋丰农业科技股份有限公司,北京100070

出　　处：《植物营养与肥料学报》2023年第8期1423-1434,共12页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(31372138,31071855);国家重点基础研究发展计划项目(2013CB127402)。

摘　　要：【目的】植物缺锌表现为叶片脉间失绿、枯萎黄化、局部细胞死亡等。通过分析缺锌玉米营养学性状和细胞凋亡特异性指标,揭示缺锌是否会导致玉米出现细胞凋亡的特征。【方法】选择‘郑单958’和‘农大108’两个玉米品种,进行水培试验。设置不施锌(0μmol/L)和供锌(1μmol/L)两个处理,在玉米幼苗生长5、10、15和20天时,取样测定幼苗地上部和根部生物量和锌含量;利用光学显微镜和电子显微镜观察叶片细胞结构;利用琼脂糖凝胶电泳进行叶片DNA梯状条带分析,利用DAPI(4',6-二脒基-2-苯基吲哚)荧光染色研究叶片细胞DNA降解特征;利用试剂盒测定Caspase-3酶活性。【结果】缺锌玉米植株生长矮小,新叶基部发白,地上部锌含量下降,生物量降低,叶肉细胞体积变小、收缩;叶肉细胞核膜出现皱缩,核内染色质凝集固缩,趋向核膜边缘,向外周聚集,形成周边化;维管束鞘细胞核结构变形、萎缩,呈不规则状。DAPI染色可见缺锌叶片细胞的细胞核变形、弥散,碎片增多。琼脂糖凝胶电泳发现,缺锌培养15天时,叶片中DNA出现降解,呈现拖尾(DNA ladder),郑单958叶片DNA受破坏较农大108更为严重;缺锌培养20天时,农大108叶片中类Caspase-3酶活性显著升高,而郑单958叶片中类Caspase-3酶活性在缺锌培养15天时表现出升高趋势。【结论】缺锌导致玉米叶片细胞出现了类似细胞凋亡的形态与生理学特征。【Objectives】Zn deficiency is a common limiting factor for crop growth and grain quality.Typical Zn deficiency symptoms are expressed as leaf chlorosis and necrosis.We tried to reveal whether Zn deficient causes the display of morphological and biochemical features of cell apoptosis in maize leaves.【Methods】Maize cultivars Nongda 108 and Zhengdan 958 were chosen as the tested crops to carry out a hydroponic culture experiment.The Zn concentration in the nutrient solution was set up as 0 and 1.0μmol/L,to represent Zn deficient and normal Zn supply.At 5,10,15 and 20 days of treatment,the seedlings were harvested for the determination of growth,biomass,and Zn content;the leaf tissue and cell microstructure were observed under optical microscopy and electronic microscopy,and the DNA ladder in leaves was measured by agarose gel electrophoresis.The DNA degradation characteristics of leaf cells were determined with DAPI(4',6-diamidino-2-phenylindole)staining technique;the enzyme activity of caspase-3 was determined by the kit.【Results】Zn deficiency significantly decreased shoot dry matter weight and Zn concentration.Under Zn deficiency,leaf cells shrined,cell spaces became narrow and irregularity were visible;the membrane of leaf mesophyll cell nucleus wrinkled,chromatin dispersed toward the edge of nuclear membrane and condensed peripherally;the nuclear structure of the bundle sheath cells deformed and shriveled,showing a irregular shape.The images of DAPI fluorescent staining also showed irregular leaf cell nuclei structure and increased nuclear fragmentations under Zn deficiency.The“DNA ladder”in leaf Zn deficient cells were visualized in bands of agarose gel electrophoresis,revealing the DNA breakdown in Zn deficient leaves.Zn deficiency induced the increase of caspase-3 activity in Nongda 108 leaves at 20 days and in Zhengdan 958 leaves at 15 days of Zn deficient treatment.【Conclusions】Zn deficiency could induce the maize leaf cells to apoptosis.

关 键 词：缺锌 玉米 叶片 细胞凋亡 

分 类 号：S513[农业科学—作物学]