Journal Article

Drought effects on fine-root and ectomycorrhizal-root biomass in managed Pinus oaxacana Mirov stands in Oaxaca, Mexico

Valdes, M, Vogt, K.A, Gomez-Cardenas, M, Juarez, M, Asbjornsen, H

2006

Overview

The effects of a severe drought on fine-root and ectomycorrhizal biomass were investigated in a forest ecosystem dominated by Pinus oaxacana located in Oaxaca, Mexico. Root cores were collected during both the wet and dry seasons of 1998 and 1999 from three sites subjected to different forest management treatments in 1990 and assessed for total fine-root biomass and ectomycorrhizal-root biomass. Additionally, a bioassay experiment with P. oaxacana seedlings was conducted to assess the ectomycorrhizal inoculum potential of the soil for each of the three stands. Results indicated that biomasses of both fine roots and ectomycorrhizal roots were reduced by almost 60% in the drought year compared to the nondrought year. There were no significant differences in ectomycorrhizal and fine-root biomass between the wet and dry seasons. Further, the proportion of total root biomass consisting of ectomycorrhizal roots did not vary between years or seasons. These results suggest that both total fine-root biomass and ectomycorrhizal-root biomass are strongly affected by severe drought in these high-elevation tropical pine forests, and that these responses outweigh seasonal effects. Forest management practices in these tropical pine forests should consider the effects of drought on the capacity of P. oaxacana to maintain sufficient levels of ectomycorrhizae especially when there is a potential for synergistic interactions between multiple disturbances that may lead to more severe stress in the host plant and subsequent reductions in ectomycorrhizal colonization.

• Publisher: Springer,Springer Nature B.V
• Subject: Bioassays / Biological and medical sciences / Biomass / Coniferous forests / Disasters / Drought / drought tolerance / Dry season / ectomycorrhizae / Forest ecosystems / Forest management / Forest practices / forest soils / forest trees / Fundamental and applied biological sciences. Psychology / growth & development / Herbivores / Mexico / microbiology / Mycorrhizae / Mycorrhizae - growth & development / mycorrhizal fungi / Parasitism and symbiosis / Pinus / Pinus - growth & development / Pinus - microbiology / Pinus oaxacana / Plant physiology and development / Plant Roots / Plant Roots - growth & development / Plant Roots - microbiology / Rainy season / Roots / Seasons / Seedlings / soil water content / Symbiosis / tree growth / water stress