Mycorrhizas and drought resistance of Picea sitchensis (Bong.) Carr

II. In conditions of adequate nutrition



    1. Institute of Ecology and Resource Management, University of Edinburgh, The King's Buildings, Edinburgh EH9 3JU, UK, and Institute of Terrestrial Ecology, Bush Estate, UK
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    • Suonenjoki Research Station, Finnish Forest Research Institute, 77600 Suonenjoki, Finland.


Mycorrhizal [Paxillus involutus (Batsch) Fr.] and non–mycorrhizal Sitka spruce [Picea sitchensis (Bong.) Carr.] seedlings were grown to comparable size and with comparable shoot N, P and K concentrations in a perlite nutrient solution culture. Shoot water potentials of mycorrhizal and non–mycorrhizal seedlings were related to the moisture content of the substrate during a drying cycle. At any given substrate moisture content, mycorrhizal plants had significantly lower water potentials than non–mycorrhizal plants, the difference being about O.l MPa. In a factorial experiment there was no effect of mycorrhizal infection on stomatal conductance or net photosynthetic rate in either well–watered or droughted seedlings.