RESEARCH ARTICLE
Acid Phosphatases Activity and Growth of Barley, Oat, Rye and Wheat Plants as Affected by Pi Deficiency

The influence of phosphorus deficit on the growth of plants and acid phosphatases activity in leaves and roots of barley seedlings (Hordeum vulgare L.), as well as oat (Avena sativa L.), rye (Secale cereale L.) and wheat plants (Triticum vulgare L.) was studied.

Plants were cultured three weeks in a nutrient media: complete (control, +P) or without phosphorus (-P). The growth on -P medium significantly affected the inorganic phosphate (Pi) content in plants tissues. Pi deficit decreased shoots growth but ratio of root/shoot was higher for -P plants when compared to control. The root elongation was enhanced under Pi deficiency - in -P oat and barley more intensive elongation was observed than in other plants. On the other hand, inhibition of shoot growth was more pronounced for -P rye and wheat. Pi-deficient plants showed higher activity of acid phosphatases in tissue extracts and in exudates from roots than +P plants.

Extracellular acid phosphatases activity increased the most for -P rye and wheat plants. Acid phosphatases secretion was intensive in growing parts of Pi-deficient roots. The activity of enzymes secreted by -P roots of all studied plants was higher than intracellular acid phosphatases.

Our results indicated that wheat is more sensitive to the Pi deficiency at the early stage of growth than other plants, whereas oat is rather resistant to Pi deficit. The results suggested that acid phosphatases played an important role in acclimation of studied crop plants to moderate Pi deficiency.