铅胁迫对毛白杨组培生根苗生理生化及根尖细胞微管骨架的影响

用50μmol/L硝酸铅对毛白杨组培生根苗进行不同时间的处理,测定叶片超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）4种抗氧化酶活性水平和丙二醛（MDA）含量的变化;并通过间接免疫荧光染色法观察根尖分生区细胞的微管骨架。结果显示：铅能使毛白杨叶片APX和POD活性出现...

EFFECTS OF LEAD STRESS ON BIOCHEMICAL CHARACTERISTICS AND MICROTUBULE CYTOSKELETON ORGANIZATION OF TISSUE CULTURE SEEDLINGS OF Populus tomentosa

The tissue culture seedlings of Populus tomentosa were exposed to lead of 50μmol/L for different treatment times. Biochemical characteristics were determined including superoxide dismutase (SOD), peroxidase (POD),catalase (CAT),ascorbate peroxidase (APX) activities and malondialdehyde (MDA) of leaves and the microtubule organization in the root tip cells of the tissue culture seedlings. Results revealed that activities of APX and POD increased first and then decreased with extension of the exposure time, while SOD and CAT activities did not show any obvious changes. Long time Pb treatment inhibited the activities of all four enzymes and caused lipid peroxidation in the leaves exacerbated. Pb disturbed microtubule structure in interphase and mitotic cells and induced aberrations such as loss of transverse organization of cortical microtubules in their orientation, deflection of the mitotic spindle and abnormal direction of cell division in the root tip cells. These results suggested that, in the antioxidant systems of the tissue culture seedlings of P. tomentosa, SOD and APX play more important roles in Pb resistance, and microtubules in the root tip cells are involved in the responses to lead stress.