Augé RM, Schekel KA, Wample RL. 1986. Greater leaf conductance of VA mycorrhizal rose plants is not related to phosphorus nutrition. New Phytologist 103: 107-116. Plants of Rosa hybrida L. cv. 'Samantha', grown with high or low phosphorus (P) fertilization, were inoculated with Glomus intraradices Schenck & Smith, G. deserticola Trappe, Bloss & Menge, or left non-mycorrhizal. All plants except the low-P non-mycorrhizal group had similar tissue dry weights, leaf and root surface areas, growth ratios, stomatal characteristics and P contents. The higher rate of P fertilization increased plant dry weight three-fold and leaf area four-fold in non-mycorrhizal plants, but had no effect on growth characteristics of mycorrhizal plants except for a depression of colonization levels. Under well-watered conditions (75-90% and 45-50% relative soil water content), low-P mycorrhizal plants displayed greater leaf conductance than both high-P mycorrhizal and non-mycorrhizal plants. Leaf water potential was similar in colonized and uncolonized roses. Fungal species did not differ significantly in their influence on leaf water potential or leaf conductance.