Augé RM, Foster JG, Loescher WH, Stodola A.W . 1992. Symplastic sugar and free amino acid molality of Rosa roots with regard to mycorrhizal colonization and drought. Symbiosis 12: 1-17. Mycorrhizal symbiosis can alter amino acid concentrations of plant roots, but little is known about the extent to which this occurs in mycorrhizal roots of droughted plants. Our objective was to determine if symplastic molalities of free amino acids or sugars are affected similarly in mycorrhizal and nonmychorrizal roots with exposure to drougth. Comparably sized rose plants (Rosa hybrida L. cv.. Love) were produced by colonizing them with Glomus intraradices Schenck & Smith or giving uncolonized plants supplemental P fertilization. Plants were kept well-watered or were exposed to four to five drought cycles for a total of 21 days. Mycorrhizal colonization and drought interacted in modifying free amino acid and sugar pools in roots . Regardless of treatment, amino acid pools of roots consisted primarily of asparagine. Asparagine and total measured amino acids were almost three times as high in nonmychorrizal that in mychorrhizal roots. Compared with droughted nonmychorrizal roots, droughted mycorrhizal roots had more fructose and glucose but less sucrose, asparagine, aspartic acid, glutamic acid, glutamine, glycine+arginine (which co-eluted), serine, threonine and lysine. These amino acids and sugars accounted for one-third to two-thirds of total symplastic osmolality.