缺钾胁迫对连作草莓生长和土传病害的影响

 以草莓‘红颜’品种为试材，设缺K（K+ 48.75 mg · L^-1，缺量水平）、1/2K（K+ 415.58 mg · L^-1，半量水平）和全量K（K+ 782.41 mg · L^-1，正常水平）营养液处理，对缺钾胁迫与草莓连作障碍的关系进行了探讨。结果表明，缺钾处理显著抑制二茬草莓植株地下部分和地上部分的生长，其中缺K 的长势最弱，1/2K 比全量K 的长势强；缺K 二茬植株根系分泌物对草莓组培苗生长有显著影响，表现为低浓度（1%、2%）根系分泌物促进幼苗侧根和茎叶生长，高浓度（4%）则抑制根系生长。不同浓度钾营养液处理的三茬植株分别接种尖孢镰刀菌和大丽轮枝菌后，在不同时期比未经过连作的基质对照发病都严重。缺K 三茬植株发病最重，接菌后10 d 时病情指数就高达75，全量K 三茬植株发病次之，1/2K 三茬植株发病相对较轻。因此，缺K 环境会加重草莓的连作障碍，适宜的K 量对草莓连作障碍的防治有重要意义。

Influence of K-deficiency Stress on Plant Growth of Strawberry and Soil-borne Disease Under Continuous Cultivation

Use strawberry cultivar‘Benihoppe’as test material. The purpose of this study was toinvestigate the relations of K-deficiency stress with continuous cropping obstacles of strawberry. Theresults showed that the growth of shoot and root was inhibited，when strawberry plants were replanted infirst-crop substrates with K-deficiency（K+ 48.75 mg · L^-1），1/2K（K+ 415.58 mg · L^-1）and normal K（K+782.41 mg · L^-1）treatments compared with control group. The plants with K-deficiency treatment had theworst growth，while the growth of plants with 1/2K treatment was better than that with 1K treatment. Rootexudates of second-crop plants with K-deficiency treatment had a significant influence on growth of thetissue cultural plantlets. The low concentration（1%，2%）promoted laterals growth and shoot growth andhigh concentration（4%）inhibited root growth. When second-crop substrates were used to replantstrawberry plants and inoculated by Fusarium oxysporum and Verticillium dahliae，the diseases ofthird-crop strawberry plants were worse at different periods than that of control group. The disease ofplants with K-deficiency treatment was the most serious，resulting in a 75 disease index after 10 days. 1/2Ktreatment had lower disease index than normal K treatment. In conclusion，continuous cropping obstaclesof strawberry can be worse under the K-deficiency stress and appropriate K concentration had an importantrole in preventing continuous cropping obstacles.