Spring Growth Variation in Pioneer and Fibrous Roots in Abies sachalinensis Seedlings from Provenances with Contrasting Snow Cover Environments

Premise of research.In boreal forests with snow-covered conditions, local adaptation in spring root exploration can be expected due to soil freezing or competition for the fundamental niche.However, few studies have investigated adaptive strategies for acquiring soil space and resources after snowmelt. Methodology.To conduct a common garden trial, Abies sachalinensis was used as a representative boreal conifer species with local adaptation.Five-year-old seedlings derived from an eastern provenance with low snow cover and a northern provenance with high snow cover were grown for two years in a common garden in a high snow-cover region.Seedlings were dug up in early spring just after snowmelt and late spring after one month had passed to evaluate patterns of spring root growth.Pioneer roots exploring soil space and fibrous roots acquiring soil resources were collected, and specific root length and relative central cylinder thickness were measured.Pivotal results.In pioneer roots, a significant increase in specific root length and a decrease in relative central cylinder thickness from early to late spring were observed only in the northern provenance.These results demonstrated that the pioneer roots in the northern provenance were more responsive to spring soil conditions than those in the eastern provenance.In fibrous roots, the decline rate in specific root length from early to late spring averaged approximately 14% in the northern provenance versus 37% in the eastern provenance.This intraspecific difference may be induced by the plastic responses in the low snow-cover provenance to the condition of a high snow-cover region. 3Conclusions.Our results indicated that the plasticity of the number and specific root length of pioneer roots was related to local adaptation.The rate of soil space exploration by pioneer roots might be relevant to adaptation to the spring soil environments with various snow-covered conditions.

Hali tarjima qilinmagan