| In order to explore the effects of different application methods of actinomycetes on growth and physiological characteristics of late-sown winter wheat, using Chang 6990 as the test variety and Streptomyces roche (D74) as the test microbial agent, five treatments were set up in the field: T1(seed coating plus spraying D74 at jointing and filling stage), T2 (seed coating plus spraying D74 at jointing stage and clean water at filling stage), T3 (seed coating plus spraying clean water at jointing and filling stage), T4 (spraying D74 at jointing and filling stage without seed coating), and CK (spraying clean water at jointing and filling stage without seed coating). The differences of wheat yield and its components, phenotypic traits, photosynthetic characteristics and dry matter accumulation among the treatments were compared and analyzed. The results showed that the yield of late-sown wheat treated with actinomycetes increased in different degrees by 7.35%-25.00% compared with that of CK, ranking as T4>T1>T2>T3>CK, among which T1 and T4 showed significantly higher yield than CK did (P<0.05). There were no significant differences in plant height among different treatments (P>0.05), and the panicle length, grains per spike, and 1 000-grain weight of T1 and T4 were significantly higher than those of CK, while the grains per spike and 1 000-grain weight of T2 treatment were also higher. The application of actinomycetes mainly affected the photosynthetic efficiency of late-sown wheat at the late filling stage. From 28 d to 35 d after anthesis, the net photosynthetic rate of flag leaf of T1 and T4, the relative content of chlorophyll (SPAD) and nitrogen content of flag leaf of T1, T2, T3 and T4, and the leaf area index of T1, T2, and T4 were significantly higher than those of CK. The dry matter translocation amount before anthesis and the contribution rate of dry matter translocation amount before anthesis to grains of late-sown wheat decreased after using actinomycetes, yet the differences among treatments were not significant. The dry matter accumulation amount after anthesis in T1, T2, and T4 was increased significantly by 37.93%, 29.42%, and 50.92% compared with that of CK. The contribution of dry matter assimilation amount after anthesis to grain also increased, yet there were no significant differences among treatments. Based on the comprehensive analysis, the use of actinomycetes effectively increased the photosynthetic sustainability of late-sown wheat, delayed leaf senescence, improved dry matter accumulation after anthesis, promoted ear development and grain filling, increased the grains per spike and 1 000-grain weight, and thus increased the yield. Among the treatments, the effect of seed coating with actinomycetes was not obvious, while the effect of spraying actinomycetes on the leaf surface was outstanding. Spraying actinomycetes on leaves at jointing and filling stage had the best effect. |
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