Authors: B J Hawkins S Robbins
Publish Date: 2014/03/31
Volume: 380, Issue: 1-2, Pages: 315-325
Abstract
Cupressaceae species thrive on calcareous soils and accumulate calcium Ca in their tissues High nitrification rates occur in soils under these species and many prefer nitrate NO3 as a nitrogen N source We tested the hypothesis that high levels of available Ca enhance NO3 uptake to a greater degree in Cupressaceae than Pinaceae using seedlings of Thuja plicata and Callitropsis Chamaecyparis nootkatensis compared with Pseudotsgua menziesii and Tsuga heterophyllaSeedling growth and longterm N uptake were measured in a 2 × 2 factorial experiment supplying Ca and NO3 at 50 μM low or 1000 μM high Shortterm measures of Ca2+ NO3 − and NH4 + net flux in seedling roots were made in the same four test solutions using microelectrodesIn T plicata C nootkatensis and P menziesii 50 μmol Ca2+ supply resulted in greater growth and N content than 1000 μmol Ca2+ Shortterm NO3 − uptake was greater in the low Ca treatment for T plicata and P menziesii but the high Ca treatment for T heterophylla Ca treatment had no significant effect on net NO3 − flux in C nootkatensis With high Ca significant net Ca2+ efflux was observed from P menziesii and T heterophylla roots but Ca2+ uptake occurred in C nootkatensisWe wish to thank David D’Amore and Paul Hennon USDA Forest Service for the inspiration to initiate this study and for thoughtful comments and suggestions on an early draft of this manuscript Thanks also to Marty Kranabetter for his review of the manuscript Funding for this work was provided by the Canadian Natural Sciences and Engineering Research Council
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