Growth and nutrition of mycorrhizal guayule plants*

Abstract

SUMMARYSynthesis of mycorrhiza in guayule plants was achieved by inoculation of 8‐day‐old seedlings with hyphae and chlamydospores of an undescribed Glomus species. There was a five‐fold increase in total dry weight of 30‐day‐old mycorrhizal‐ compared to nonmycorrhizal‐guayule grown in sterile loamy‐sand without additional fertiliser. Thirty‐day‐old, inoculated‐ and uninoculated‐seedlings were transplanted to sterile or unsterile soil and grown an additional 60 days. The greatest total dry weight of guayule was attained by inoculated transplants grown in sterile soil. Inoculated transplants increased two‐ to three‐fold in total dry weight compared to uninoculated transplants, both grown in unsterile soil. After 90 days, uninoculated plants grown in unsterile soil had formed mycorrhizae with resident vesicular‐arbuscular mycorrhizal fungi to the same extent as inoculated‐plants grown in unsterile soil. Total mineral uptake increased in inoculated guayule, irrespective of soil treatment or the presence of resident VA mycorrhizal fungi.