Enhanced Root and Stem Growth and Physiological Changes in Pinus bungeana Zucc. Seedlings by Microbial Inoculant Application

Yi-Ming Liu, Zheng Fang, Zhao-Hui Liu, Hai-Bo Lan , Ye-Hong Cu, Tong-Guo Gao, Marja Roitto, Ai-Fang Wang

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Background and Objectives: As an extensively used tree species in landscaping and afforestation in China, lacebark pine (Pinus bungeana Zucc.) seedlings are in high demand. However, the small number of fine roots and the low growth rate of lacebark pine seedlings increase the risks encountered during transplant and extend the nursery time for outplanting. We aimed to find out whether a microbial inoculant would promote root growth and accordingly, shorten the nursery cultivation time. Materials and Methods: One-year-old lacebark pine seedlings were treated with the inoculant Bacillus subtilis 8-32 six times from June to September. At each application time, five treatments of undiluted microbial inoculants (UM), 30 times diluted microbial inoculants (30 DM), 40 times diluted microbial inoculants (40 DM), 50 times diluted microbial inoculants (50 DM), and distilled water as a control (CTRL) were administered to the seedlings. In the end, all the seedlings were harvested to measure the root growth, aboveground growth, and the physiological indices. Results: Root and stem growth was enhanced by the inoculants in terms of the increased number of root tips, the length and surface area of the roots, the biomass of the roots and stems, as well as the increase in height and basal stem diameter. The chlorophyll a/b of the needles was increased, in spite of the fact that the total chlorophyll content was decreased by the microbial inoculant treatments at the end of the growth phase. Meanwhile, the maximum photochemical efficiency (F-v/F-m) of the needles was increased by the inoculant treatments. The soluble sugar content was additionally translocated into the stems in the UM treatment, suggesting the change in carbon allocation. The content of available potassium, phosphorus, and ammonium nitrogen in the potting soil was increased in the 30 DM group, and the content of soil organic matter was increased in all the inoculant treatments. Conclusions: The microbial inoculant Bacillus subtilis 8-32, in appropriate concentrations, could be applied to promote root and shoot growth and improve the seedling quality of the lacebark pine during cultivation.
Original languageEnglish
JournalForests
Volume13
Issue number11
Number of pages14
ISSN1999-4907
DOIs
Publication statusPublished - Nov 2022
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 11831 Plant biology
  • Biomass
  • Chlorophyll content
  • Chlorophyll fluorescence
  • Microbial agent
  • Non-structural carbohydrate
  • Root
  • Soil nutrients

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