三七种苗的带菌检测及消毒处理效果

Testing of Panax notoginseng seedling-borne fungi and disinfection effect of chlorine-containing disinfectants

为了明确三七种苗传带根腐病菌情况,通过稀释涂板法对分别采自云南省文山市和砚山县的一年生三七种苗传带真菌情况进行了检测。结果表明,不同来源地三七种苗块根表面均能分离获得三七根腐病主要病原真菌Cylindrocarpon spp.),但其样品带菌量有所差异,根表传带柱孢菌数量在4.0×104~2.3×105cfu/根范围内;检测三七块根部不同组织内部带菌情况,发现须根、剪口和块根皮层均带有柱孢菌,带菌率最高达20%,而在芽尖和茎基部组织均未检测到柱孢菌。为进一步比较不同表面消毒剂处理对三七种苗的消毒效果及对幼苗的安全性影响,通过次氯酸钠表面消毒处理种苗后,其块根带菌总量降低93.8%,根表柱孢菌数量降低75.5%;次氯酸钠、过氧乙酸、二氯异氰尿酸钠及氯溴异氰尿酸等4种活性氯消毒剂对三七种苗的处理效果表明,在一定浓度下4种消毒剂对引起三七根腐病的柱孢菌C-3均有较好的杀灭作用,但其药剂的有效杀菌浓度及其作用时间有差异;综合消毒效果及对三七种苗安全性测试结果分析,50%氯溴异氰尿酸的1 000倍液处理10 min为三七种苗消毒处理的最安全有效的方法。

Root rot is one of the most detrimental diseases which can cause significant yield loss and quality reduction of Panax notoginseng(Burk.) F. H. Chen. The root rot fungal pathogens associated with one-year-old P. notoginseng seedlings were investigated by spread plate methods. Cylindrocarpon spp. isolates were found in all samples from Wenshan and Yanshan county of Yunnan province. However, the quantity of Cylindrocarpon spp. was different among these samples,ranging from 4.0×10~4 to 2.3×10~5 CFU per root. Moreover, Cylindrocarpon spp. isolates were obtained in the fibrous root,rhizome, and root cortex of seedlings, and the isolation rates were up to 20%. Nevertheless, there was no Cylindrocarpon spp. isolate founded in sprout and caudex of all samples. The disinfectant effect and safety of four disinfectants were tested on P. notoginseng seedlings. After surface disinfection with sodium hypochlorite, the total amount of fungal isolates in the rhizome and root cortex could be reduced by 93.8% and 75.5%. The Cylindrocarpon destructans isolate C-3 could be significantly inhibited by four chlorine-containing disinfectants, which were sodium hypochlorite, peracetic acid, sodium dichloroisocyanurate, and chloroisobromine cyanuric acid. But the effective concentration and the contact times were different. Based on the disinfectant effects and safety test results, it is one of the safest and most effective methods to disinfect seedlings with 50% chloroisobromine cyanuric acid 1000-fold dilution for 10 minutes.