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 to investigate the relations of K-deficiency stress with continuous cropping obstacles of strawberry. The results showed that the growth of shoot and root was inhibited，when strawberry plants were replanted in first-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 the worst growth，while the growth of plants with 1/2K treatment was better than that with 1K treatment. Root exudates of second-crop plants with K-deficiency treatment had a significant influence on growth of the tissue cultural plantlets. The low concentration（1%，2%）promoted laterals growth and shoot growth and high concentration（4%）inhibited root growth. When second-crop substrates were used to replant strawberry plants and inoculated by Fusarium oxysporum and Verticillium dahliae，the diseases of third-crop strawberry plants were worse at different periods than that of control group. The disease of plants with K-deficiency treatment was the most serious，resulting in a 75 disease index after 10 days. 1/2K treatment had lower disease index than normal K treatment. In conclusion，continuous cropping obstacles of strawberry can be worse under the K-deficiency stress and appropriate K concentration had an important role in preventing continuous cropping obstacles.