【摘要】 为探明烟草青枯菌在不同杂草根部的寄生和腐生状况以及冬季在杂草根部的消长和传病能力,采用抗利福平青枯菌接种烟草诱发青枯病,将不同的带菌杂草根埋入无病盆土并移栽烟草监测青枯病发生,同时以含利福平的选择性培养基对49种杂草根、杂草的不同部位、病土中杂草烂根和冬季病土中杂草根作带菌测定。腋花蓼、香附子等7种杂草根感青枯菌;无芒稗、龙葵等18种根为中感;黄鹌菜、稗草等24种根为低感。鬼针草和商陆仅根表带菌;早熟禾和无芒稗等6种根内外带菌;牛筋草和马齿苋等3种根、茎、叶带菌。青枯菌能在牛筋草和水蓼等8种杂草的烂根中高度腐生,在无芒稗和座地菊等7种烂根中中度腐生,在石龙芮和稀签等6种烂根中低度腐生。红辣蓼等7种杂草均能诱发烟草青枯病,其中红辣蓼、空心莲子草等4种杂草带菌的根传病能力强,发病率85.7%~100%。烟草青枯菌能在杂草根部定殖,根腐烂时能继续生长繁殖,并且能在早熟禾等6种杂草根部安全越冬,成为翌年有效的初侵染源,引发烟草青枯病,其中看麦娘处理的发病早且重,这是导致烟草青枯病发生与流行的一个重要因素。更多还原

【Abstract】 Parasitism and saprophytism of Ralstonia Solanacearum in different weeds were studied to provide basis for preventing tobacco bacterial wilt. Growth and decline trends and infectivity ability of the bacteria in winter were monitored. Disease was induced by inoculating tobacco seedlings with rifampicin-resistant R. solanacearum. Bacteria in 49 weed roots in tobacco planting land.Weed roots from infected soil in winter were determined using a selective culture medium containing rifampicin. The occurrence of tobacco bacterial wilt was monitored by planting tobacco seedlings in pots with uninfected soil. 7 weeds such as Polygonum plebeium R.Br and Cyperus rotundus L. were susceptible, 18 such as Pospalum orbiculare Forst. and Solanum mgrum L. were moderately susceptible,while 24 weeds such as Youngia japonica(Linn.) DC and Echinochloa crusgalli(L.) Beauv. were low susceptible. R.Solanacearum were just noted on the root surface of Bidens bipinnata L. and Phytolacca acinosa Raxb., but were both noted in vivo and in vitro of6 weed roots such as Poa annua L. and Pospalum orbiculare Forst..3 weeds, i.e. Eleusine indica(L.) Gaertn and Portutulaca oleracea.R.Solanacearum was highly saprophytic in 8 rotten roots such as Eleusine indica(L.) Gaertn and Polygonum hydropiper L., moderately saprophytic in 7 rotten roots such as Pospalum orbiculare Forst. and Soliva anthemifolia(Juss), low saprophytic in 6 rotten roots such as Ranunculus sceleratus L. and Siegesbeckia orientalis L. Result showed R.Solanacearum can overwinter in roots of 6 annual weeds and then cause tobacco bacterial wilt in the following year. The disease occurrence can be induced by 7 weeds, while the disease was early and serious in Alopecurus aequalis Sobol. 4 weeds such as Polygonum orientale L. and Altemanthera philoxeroides(Mart)Griseb had the strongest infectivity ability, the morbidity was 85.7% ~ 100%. R. Solanacearum can colonize in weed roots, then proliferate during root decay and overwinter in the weed roots such as Alopecurus aequalis Sobol, and finally become the effective resources of primary infection. It was an important factor that caused the occurrence and epidemic of tobacco bacterial wilt.更多还原