Zn^(2+)在菹草叶片中的积累及其植物毒理学效应

以广泛分布的沉水植物———菹草为研究对象,通过添加不同浓度Zn2+(0、5、10、15和20 mg.L-1)的10%Hoagland营养液培养7 d,分析Zn2+在水生植物中的积累及其诱导产生的毒理学作用。结果发现:随着培养液中Zn2+浓度的增加,(1)菹草叶片中Zn2+含量极显著上升。(2)Zn2+处理使菹草产生明显的矿质营养失衡症状,主要表现为显著增加了对Fe2+的吸收和降低了对P5+和Na+的吸收。(3)光合色素中,叶绿素a和b、类胡萝卜素先升后降,分别在5、5和10 mg.L-1处理浓度时最多;叶绿素a/b一直下降。(4)GSH含量在5 mg.L-1时达到峰值后减少,而AsA则为逐渐降低。(5)各处理浓度都使ATP和可溶性蛋白含量明显减少。(6)电镜观察发现,正常条件下Ca2+主要分布在胞间隙和液泡中,细胞基质中较少;添加Zn2+后,胞间隙和液泡中的Ca2+逐渐进入细胞质,使细胞质中Ca2+浓度明显升高,在质膜内侧、细胞核和叶绿体中都出现大量呈圆环状的黑色钙颗粒。综合分析认为,AsA对Zn2+胁迫反应最敏感,Zn2+对菹草产生毒害的临界浓度为5~10 mg.L-1。

植物内生细菌对利福平的抗性及紫外诱变研究

[目的]从植物体内分离筛选内生细菌,了解其在植物体内的定殖动态。[方法]选用5株植物内生细菌H1、DP1、CJL1、DJL12和YC1作为出发菌株,在明确其对利福平的抗性水平后,对抗性较低的H1菌株和DLJ12菌株进行紫外诱变试验。[结果]经初筛,5种植物内生菌在不含利福平的平板上生长良好,其中H1、DLJ12在浓度10μg/ml的利福平下均不能生存,其他3个菌种均能在浓度50μg/ml的利福平下生存。诱导后得到了抗利福平浓度达到80μg/ml的DLJ12菌株。[结论]该研究可为开发利用内生细菌提供理论和实践依据。

植物内生细菌对利福平的抗性及紫外诱变研究(英文)

The study aimed to isolate and screen endophytic bacteria from the plant in order to understand their colonization dynamics in plants. [Method] 5 kinds of endophytic bacteda including H1, DP1, CJL1, DJL12 and YC1 were selected as the original strains, and conducted UV mutagenesis studies on H1 and DJL12 with weak resistance, while the resistance of them against rifampicin was confirmed. [Result] Through preliminary screening, five kinds of endophytic bacteria could grew well in the plate without rifampin, among them, H1 and DLJ12 were unable to survive under 10 μg/ml concentration of rifampicin, and the other three strains could survive under 50 μg/ml concentration of rifampicin. After UV mutagenesis, DLJ12 strain with dfampicin resistance concentration of 80 μg/ml was obtained. [ Conclusion] The study could provide theoretical and practical basis for development and utilization of endophytic bacteria.