Journal article
Understanding Trichoderma in the root system of Pinus radiata: associations between rhizosphere colonisation and growth promotion for commercially grown seedlings

Publication Details
Hohmann, P.; Jones, E.; Hill, R.; Stewart, A.
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Fungal Biology
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Two Trichoderma isolates (T. hamatum LU592 and T. atroviride LU132) were tested for their ability to promote the growth and health of commercially grown Pinus radiata seedlings. The colonisation behaviour of the two isolates was investigated to relate rhizosphere com- petence and root penetration to subsequent effects on plant performance. Trichoderma ha- matum LU592 was shown to enhance several plant health and growth parameters. The isolate significantly reduced seedling mortality by up to 29 %, and promoted the growth of shoots (e.g. height by up to 16 %) and roots (e.g. dry weight by up to 31 %). The introduc- tion of LU592 as either seed coat or spray application equally improved seedling health and growth demonstrating the suitability of both application methods for pine nursery situa- tions. However, clear differences in rhizosphere colonisation and root penetration between the two application methods highlighted the need for more research on the impact of inoculum densities. When spray-applied, LU592 was found to be the predominant Tricho- derma strain in the plant root system, including bulk potting mix, rhizosphere and endorhi- zosphere. In contrast, T. atroviride LU132 was shown to colonise the root system poorly, and no biological impact on P. radiata seedlings was detected. This is the first report to demon- strate rhizosphere competence as a useful indicator for determining Trichoderma bio-inoculants for P. radiata. High indigenous Trichoderma populations with similar popula- tion dynamics to the introduced strains revealed the limitations of the dilution plating technique, but this constraint was alleviated to some extent by the use of techniques for morphological and molecular identification of the introduced isolates.

Ecology, Health and growth promotion, Pinus radiata, Population dynamics, Rhizosphere competence, Root penetration, Tree nursery, Trichoderma atroviride, Trichoderma hamatum


Last updated on 2019-25-07 at 11:19