PHOSPHORUS UPTAKE AND GROWTH OF BARLEY AS AFFECTED BY SOIL-TEMPERATURE AND MYCORRHIZAL INFECTION

A glasshouse study was conducted to investigate the effects of soil te mperatures of 20, 15 and 10 degrees C on growth and phosphorus (P) upt ake of barley (Hordeum vulgare L. cv. Galleon) inoculated with Glomus intraradices Schenck and Smith. Vesicular-arbuscular (VA) mycorrhiza f ormation was significantly reduced as the soil temperature decreased. Plant growth depression due to temperature stress was more pronounced in mycorrhizal plants than in nonmycorrhizal plants. The lower the soi l temperature, the higher was the root-shoot ratio. The ratio was also higher in non-mycorrhizal plants than in mycorrhizal plants. Concentr ation of P in roots was influenced by mycorrhiza. Significant interact ion between mycorrhiza and soil temperature was observed for root dry matter and specific P uptake (P uptake per unit weight of root). Compa red to nonmycorrhizal plants, specific P uptake in mycorrhizal plants was higher.