采用高效解磷菌P19 和P7(解无机磷)以及YP17(解有机磷),研究不同浓度单一及混合解磷菌处理对巨尾桉(Eucalyptus grandis Hill ex Maiden ×E. urophylla S. T. Blake)幼苗干质量、氮和钾含量的影响以及叶片磷含量的动态变化。结果表明:用5×10⁶ 、2×10⁶ 和1×10⁶CFU·mL^-1解磷菌单一及混合处理后,巨尾桉幼苗的地上部分和地下部分干质量、总干质量以及氮含量总体上高于空白对照(CKB )和供磷对照(CKP,添加18 mg·kg^-1 KH₂ PO₄ ),且总体上差异显著(P<0. 05),而仅少数处理组的幼苗钾含量显著高于CKB 和CKP。随处理时间延长,不同解磷菌处理组的叶片磷含量呈现不同的变化趋势,但不同月份间叶片磷含量差异极显著(P<0. 01);各处理组的叶片磷含量平均值均高于CKB,且混菌处理组总体上高于单菌处理组。方差分析结果表明:不同解磷菌和不同菌液浓度对幼苗总干质量的影响效应均有显著差异;二者对幼苗氮含量有极显著或显著影响,但二者的交互作用对幼苗氮含量无显著影响(P>0. 05);不同解磷菌、不同菌液浓度及二者间的交互作用对幼苗钾含量均有极显著影响;不同解磷菌、不同菌液浓度、不同时间及三者间的交互作用对叶片磷含量均有极显著影响。多重比较结果表明:P19-YP17、P7-YP17 和P7-P19 处理对幼苗氮含量和叶片磷含量平均值的提升作用明显,YP17、P19-YP17 和P7-P19 处理对幼苗总干质量平均值的提升作用明显,不同解磷菌对幼苗钾含量平均值无显著提升作用;不同菌液浓度下幼苗的总干质量、氮和钾含量以及叶片磷含量的平均值总体上显著高于CKB,其中,中浓度(2×10⁶CFU·mL^-1)和低浓度(1×106 CFU·mL^-1) 菌液处理对叶片磷含量以及幼苗氮和钾含量平均值的提升作用明显。综合分析结果显示:P19-YP17、P7-YP17 和P19-YP17 解磷菌混合处理对巨尾桉幼苗生长有明显的促进作用,可作为混合解磷菌剂加以进一步开发研究。

Taking high-efficiency phosphate-solubilizing bacterium P19 and P7 (solubilizing inorganic phosphorus) and YP17 (solubilizing organic phosphorus), effects of single and mixed treatments of phosphate-solubilizing bacterium on dry weight and contents of nitrogen (N) and potassium (K) in seedling and dynamic change in phosphorus (P) content in leaf of Eucalyptus grandis Hill ex Maiden×E. urophylla S. T. Blake were researched. The results show that after treated by single and mixed phosphate-solubilizing bacteria with 5×10⁶, 2×10⁶ and 1×10⁶ CFU·mL^-1, dry weights of above-and under-ground parts, total dry weight, N content in seedling of E. grandis ×E. urophylla are totally higher than those in the blank control (CKB) and the control supplied with P (CKP, adding 18 mg·kg^-1 KH₂PO₄), and differences are totally significant (P<0. 05), while K content in seedling in only a few treatment groups is significantly higher than that in CKB and CKP. With prolonging of treatment time, change trends of P content in leaf in different treatment groups of phosphate-solubilizing bacterium are different, while there are obviously significant differences (P<0. 01) in P content in leaf among different months. The average value of P content in leaf in all treatment groups is higher than that in CKB, and that in the mixed bacterium treatment group is totally higher than that in the single bacterium treatment group. The result of variance analysis shows that effects of different phosphate-solubilizing bacteria and bacterium concentrations on total dry weight of seedling have significant differences, their effects on N content in seedling are obviously significant or significant, but their interaction on N content in seedling is not significant ( P > 0. 05 ). Effects of different phosphate-solubilizing bacteria and bacterium concentrations, and their interaction on K content in seedling are obviously significant. Effects of different phosphate-solubilizing bacteria, bacterium concentrations and times, and their interaction on P content in leaf are obviously significant. The result of multiple comparison shows that P19-YP17, P7-YP17 and P7-P19 treatments have obvious promotion effects on average values of N content in seedling and P content in leaf and YP17, P19-YP17 and P7-P19 treatments do on average total dry weight of seedling, and different phosphate-solubilizing bacteria have no significant promotion effect on average K content in seedling. Under different bacterium concentrations, average values of total dry weight, N and K contents in seedling, and P content in leaf are generally significantly higher than those in CKB, in which, bacterium treatments with middle concentration (2×10⁶ CFU·mL^-1) and low concentration (1×10⁶ CFU·mL^-1) have obvious promotion effect on average values of P content in leaf and N and K contents in seedling. The comprehensive analysis result shows that mixed treatments of phosphate-solubilizing bacterium of P19-YP17, P7-YP17 and P19-YP17 have obvious promotion effect on seedling growth of E. grandis ×E. urophylla, and can be developed as mixed phosphate-solubilizing bacteria and need to be researched deeply.