解磷菌肥不同施用方式对马尾松家系苗木根系生长及磷素营养的影响

Effects of different application modes of phosphorussolubilizing bacterial fertilizer on seedling root growth and phosphorus nutrition of Pinus massoniana families

为了探讨解磷菌肥分区施入对低磷胁迫下马尾松磷营养状况的影响,该文设置了局部和均匀施用解磷菌肥(PSB肥)的盆栽接种试验,并利用WinRHIZO Pro STD1600+根系图像分析软件、H_(2)SO_(4)-H_(2)O_(2)消煮和钼锑抗比色法研究了马尾松不同家系根系形态参数和苗木磷素吸收量对PSB肥不同施用方式的响应。结果表明:(1)局部和均匀施用PSB肥均对马尾松生长影响显著,局部施用较均匀显著增加了苗木苗高、地径、根冠比、根系和整株干物质量等主要生长指标。(2)局部施用PSB肥苗木根长、根表面积、根体积和根尖数显著增加,而均匀施用根系各参数有所增加但差异不显著;局部施用较均匀0<根系直径(D)≤0.5 mm的细根根长增加了近2倍。两种处理根系生长的差异与局部施用PSB肥造成了土壤磷素的异质性分布有关。(3)与均匀施用PSB肥相比,局部施用显著增加了苗木根、茎、叶及整株磷素吸收量。相关性分析表明,苗木磷素吸收量与根系形态参数、D≤1.0 mm根系根长呈显著正相关。说明局部施用PSB肥通过诱导根系的生长促进苗木对磷素的吸收。(4)马尾松不同家系对施用PSB肥的响应存在差异。亲本为耐低磷种源的22号家系对局部施用PSB肥较敏感,其各生长指标均显著高于10号和50号家系。综上所述,低磷环境下局部施用PSB肥较均匀施用对马尾松幼苗生长和磷素吸收的影响更加显著,该研究结果可为磷匮乏立地上马尾松人工林的管理提供参考和指导。

In order to study the effect of different application modes of phosphorus-solubilizing bacterial fertilizer(PSB fertilizer) on seedling phosphorus nutrition of Pinus massoniana,a pot inoculation experiment with local and evenly application of PSB fertilizer was set up.We studied the responses of P uptake and root growth of different P.massoniana families under different PSB fertilizer treatments through using WinRHIZO Pro STD1600+ root image analysis software and Molybdenum antimony colorimetric method.The results were as follows:(1)Inoculating PSB fertilizer had a significant effect on growth of P.massoniana seedlings.The main growth indexes,such as seedling height,ground diameter,root dry matter weight,root/shoot and whole plant dry matter weight,significantly increased under local treatment.(2)Local treatment significantly increased the root length,root surface area,root volume and root tip number of seedlings.The root length of 0<root diameter(D)≤0.5 mm fine roots under local treatment was nearly three times of that under evenly treatment.Differences of root growth were related to the heterogeneous distribution of soil P caused by localized application of PSB fertilizer under the two treatments.(3) Inoculating PSB fertilizer significantly increased the P uptake of root,stem,leave and whole plant,and the local treatment was significantly higher than evenly treatment.Correlation analysis showed that P uptake of seedlings was significantly positively correlated with root morphological parameters and root length of D≤1.0 mm.This indicated that local treatment promoted P uptake by inducing root growth.(4)Due to the genetic background,the families of P.massoniana showed different performance under application of PSB fertilizer.The low phophorus tolerance provenance No.22 was a much sensitive family,and all growth indexes were significantly higher than those of No.10 and No.50 families.In conclusion,local application of PSB fertilizer significantly promoted the growth and P uptake of P.massoniana families under low P environment,and this study provides guidances for the management of P.massoniana plantation under P poor sites.