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本文论述了孟加拉国吉大港大学校园里,不同年龄(5、10、20年)的羯布罗香(Dipterocarpus turbinatus Gaertn. F)人工林内,距树木基部不同距离(1、2、3、4米)处,外生侵染菌根的水平分布状况.在山的3个部位(顶部、中部和下部)对各人工林外生侵染菌根的侵染进行了测定.在不同水平分布距离处的树下采集了1000cm3的根际土壤样本,不同距离和山高处的外生侵染菌根浸染率差异显著.在5年和10年林龄的人工林内,浸染率随着距树的距离的增加而快速下降,而在20年林龄的人工林内,浸染率随着距树基部距离的增加而急剧增加.山下部20年生人工林内距树4m处的浸染率最高(81.3%),山顶部5年生人工林内距树4m处的浸染率最低(55.33%).图6参32.“,”Garjan (Dipterocarpus turbinatus Gaertn. F) is a highly ectomycorrhizal tree species growing in hilly areas of Bangladesh. The horizontal distributions of ectomycorrhizas (ECM) in different distances (1, 2, 3 & 4m) from the tree base were determined in 5, 10 and 20-year-old D. Turbinatus plantations of Chittagong University Campus (CUC) in 2003. The ECM infection (%) in roots was counted at three hill positions (top, mid and bottom) for each of the plantations. Samples of 1000 cm3 rhizosphere soil were collected from underneath the trees at different horizontal distances. The percentage of infection at different distances and hill elevations varied considerably. In 5 and 10-year-old plantations, the occurrence of infection (%) was rapidly declined with increasing distances,while in 20-year-old plantation, the infection increased sharply with increasing distances from the tree base. The highest infection (81.33%) was found at 4 m distance from the tree at bottom hill in 20-year-old plantation and the lowest (55.33%) at the same distance at the top of the hill in 5-year-old plantation.