PHOSPHORUS UPTAKE AND UTILIZATION IN WILD AND CULTIVATED OATS (AVENA SPP)

In a solution culture experiment, the growth and nutrient uptake of wild oat plants (Avena fatua L.) was compared with that of cultivated oat plants (Avena sativa L. cv. Pennlo) at both low (5-mu-M P) and high (100-mu-M P) levels of phosphate. Solution phosphate depletions and plant growth variables were measured through daily solution sampling and destructive tissue harvests. Wild oat produced more root mass and accumulated P more rapidly than the cultivar in both low and high P levels. Wild oat plants also produced significantly more dry matter for a given accumulation of P than the cultivated oat plants in both low and high P solutions. We conclude that wild oat is likely to be competitively superior to the Pennlo cultivar under conditions of moderate P limitation due to its greater allocation of dry matter to roots and higher P use efficiency.