海南岛几种绿肥作物丛枝病病原体的电子显微镜研究

 在广东省海南岛发现几种绿肥植物:巴西苜蓿、卵叶山蚂蝗、暗紫莱豆、爪哇大豆罹患了植物黄化病害。病株表现症状:植株矮化、枝叶丛生、叶变小、普遍退绿或黄化。电子显微镜观察发现,在病株叶柄韧皮部筛管细胞超薄切片中,存在大量的类菌原体(MLO)。这些菌体形态多样,有些可见菌体内纤维状样核酸物质,有的菌体正处于二分裂、或发芽状态。这些MLO大小分别为170~800nm、170~700nm、250~650nm、375~770nm。由于在病株中发现有MLO存在,而健株中则没有。可以初步认为四种绿肥植物丛枝病是由MLO所致。

AN ELECTRON MICROSCOPIC STUDY ON THE PATHOGENS OF THE WITCHES' BROOM DISEASE OF SEVERAL GREEN MANURE CROPS IN HAINAN ISLAND

In Hainan Island of Guangdong Province,a yellow type disease occurred on Desmodium ovalifolium Wall,Stylosanthes gracilis H.B.K,Phaseolus atropurpureus W.Siratro,and Glycine javanica D.The diseased plant exhibited severe stunting,excessive proliferation of shoots and the formation of witches' broom.Electron microscopic observations of the ultrathin sections of the phloem tissue from the infected leaf vein revealed mycoplasma-like organisms(MLOS) in the sieve tubes.The pleomorplic MLO were around 170-800 nm(Stylosanthes gracilis H.B.K),170-700 nm(Desmodium ovalifolium Wall),250-650 nm(Phaselus atropurpureus W.Siratro),and 375-770 nm(Glycine javanica L.),some with nucleic acid strands and some apparently undergoing binary fission or budding.
Since these MLO were found in diseased plants but not in healthy controls,the causal agents of the witches' broom diseases of these green manure crops may be mycoplasma-like organisms in nature.