Assimilation of Organic phosphorus in Lolium multiflorum.

Plants are known to have limited capacity to utilize organic phosphorus (P) forms despite their abundance in soil. Gulf and Marshall ryegrass (Lolium multiflorum), which accumulates P in their shoots, were grown aseptically in agar-nutrient medium enriched with different organic P  substrates (GMP, AMP, ATP and IHP) to study the pattern of growth, P accumulation and the activities of root phytase and phosphomonoesterase. Plants exhibited a differential pattern of growth in respect of the substrates, with minimum growth in the GMP- and maximum growth in the IHP- supplemented media. Both ryegrasses accumulated P up to 1% (shoot dry weight) depending on the type of organic P in the media. The pattern of phytase and phosphomonoesterase activities in these grasses was interesting. The enzyme activities of plants grown in IHP-enriched media were either equal to or higher than controls that were grown in the media devoid of any P source.