XYLEM-RESIDING BACTERIA IN ALFALFA ROOTS
XYLEM-RESIDING BACTERIA IN ALFALFA ROOTS
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DOI：
10.1139/m87-175
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发表时间：
1987-11-01
影响因子：
2.8
通讯作者：
ANTOUN, H
中科院分区：
文献类型：
--
作者：
GAGNE, S;RICHARD, C;ANTOUN, H
从无症状的田间种植的苜蓿植物的根和冠木质部中始终分离出细菌。大多数测试的植物含有不止一种细菌属。假单胞菌属占已鉴定的 387 个分离株中的 52%，荧光假单胞菌是分离出最常见的细菌。大约 23% 的分离株是欧文氏菌样细菌。细菌数量范围为 6.0 倍。 103 至 4.3 倍。 104 CFU/g 新鲜木质部，并且不受植物年龄、品种或采样地点的影响。 Iroquois 和 Titan 品种的表面灭菌种子不含细菌，而 Apica 和 Saranac 品种的种子中分别只有 3% 和 5% 含有细菌。在温室实验中，将双抗生素抗性细菌接种到人为受伤的苜蓿植物完整根部的土壤和茬上。当根受伤时，根木质部细菌的发病率最高。与完整植物相比，当植物受伤（茬或根）时，细菌数量（CFU/克鲜重）最高。结果表明，细菌是根木质部的正常居民，它们进入木质部的主要途径是自然的根伤口和收获后留下的植物残茬。
Bacteria were consistently isolated from the root and crown xylem of symptomless field-grown alfalfa plants. Most of the plants tested contained more than one bacterial genus. Pseudomonas spp. accounted for 52% of the 387 isolates identified and the fluorescent pseudomonads were the most frequent bacteria isolated. About 23% of the isolates were Erwinia-like bacteria. Bacterial population ranged from 6.0 .times. 103 to 4.3 .times. 104 CFU/g of fresh xylem, and was not affected by plant age or cultivar or by the sampling locations. The surface-sterilized seeds of the cultivars Iroquois and Titan were bacteria free and only 3 and 5% of the seeds of the cultivars Apica and Saranac, respectively, contained bacteria. In a greenhouse experiment, double antibotic resistant bacteria were inoculated into the soil of artificially wounded and intact roots of alfalfa plants, and on the stubble. The highest incidence of bacteria in the root xylem occurred when the roots were wounded. The highest numbers of bacteria (CFU/g fresh weight) were found when plants were wounded (stubble or roots) as compared with intact plants. The results suggest that bacteria are normal residents of the root xylem and that their main avenues of entrance to the xylem are natural root wounds and plant stubbles remaining after harvest.