摘要
海带人工育苗工作是发展海带栽培事业的一个重要环节,在人工控制的循环海水系统中,确保大量密集海带幼苗的正常生长乃是一项复杂的任务,其中病害问题尤为重要。近年来,全国不少育苗单位在育苗过程中普遍发生脱苗和烂苗现象,时常影响正常供苗。在严重的情况下,可以发展成为毁灭性灾难,甚至使整个育苗工作完全失败,往往因为苗源不足给海带栽培事业的发展带来损失。本研究工作的前两篇报告阐述了褐藻酸降解菌是海带藻体上的主要定居者和优势菌群,即使在不附加任何其他营养的条件下,这些细菌也能以海带藻体作为基质良好地生长。
The young sporophytes of Laminaria are cultivated in sporeling culture station at a temperature of about 8-10℃.It happened sometimes that the sporophytes died or fell off from the cords due to a destructive disease,especially in the later stage.In serious cases the disease virtually destroyed the entire crop.For a long time the main cause of this disease was unknown and production of sporelings always suffered severely from this disease for the lake of preventive measures.We found that the alginic acid decomposing bacteria were the dominants on cultivated Laminaria.Evidence showed that many isolates could grow well on the living blades of Laminaria without any additional nutrients and degrade the blades by enzymatic action.Contact infection experiment showed that the rotting and detaching of young sporophytes could be resulted from the inoculation of these bacteria in a density of 108 cells per ml sea water.It has proved that in certain eases the alginic acid decomposing bacteria can infect cultivated young sporophytes and even detach them from the stalk.Owing to inefficient management,some Laminaria sporeling culture systems had actually changed into microbial chemostat.The flourishing growth of these bacterial populations deponds on enrichment conditions,such as the presence of an abundance of Laminaria sporophytes,constant temperature,suitable nutrients and circulating sea water system,etc.These bacteria were mostly concentrated on the sporophytes and had become important members of the microbial flora in the culture system.About 400 strains of alginic acid decomposing bacteria isolated from culture systems were studied.All of them are characterized by having a similar appearance of colony with a cloudy zone around it,producing no pigment and degrading algmate actively.Most of them belong to genus Pseudomonas and are very different from strains isolated from natural sea water.They can grow well at 15-25℃,but retard at 4℃.It is important to prevent the multiplication of these bacteria in culture system.In case of spore collection and cultivation of sporelings,it is necessary to select the healthy mature sporophytes,to discard the decayed parts of the blades carefully,to keep a suitable density of sporelings on cords,to maintain the temperature at about 6-8℃ constantly,to filter culture sea water completely,to remove any falling sporophytes in time,to wash the sporelings,culture pools and circulating system thoroughly and to replace the culture sea water twice a week without delay.The addition of erythromycin at 5 o.u./ml to the sea water showed obviously inhibitory effect on these bacteria,therefore it is possible to prevent Laminaria sporophytes from the rot disease by this kind of antibiotic.
作者
陈
刘秀云
刘秀珍
于义德
杨肇惠
邱淑怀
Chen Dou;Liu Xiuyun;Liu Xiuzhen;Yang Zhaohui;Qiu Shuhuai(Institute of Oceanology,Academia Sinica,Qingdao;Sansha Sporeling Culture Station,Fujian Province)
出处
《海洋与湖沼》
1984年第6期581-589,共9页
Oceanologia Et Limnologia Sinica
