Differential responses of oat cultivars to phosphate deprivation: plant growth and acid phosphatase activities

Abstract

The effect of phosphate starvation on growth and acid phosphatases (APases) localization and activity in oat tissues was investigated. Oat cultivars (Avena sativa L.-Arab, Polar, Szakal) were grown for 1-3 weeks in complete nutrient medium (?P) and without phosphate (-P). Pi concentration in plant tissues decreased strongly after culturing on -P medium. Pi deficit reduced shoot growth, stimulated root elongation and increased ratio of root/shoot in all oat cultivars. Pi deficit had a greater impact on growth of oat cv. Polar than other varieties. A decrease in the internal Pi status led to an increase of acid phosphatase activities in extracts from shoots and roots, and in root exudates. The highest activity of secreted APases was observed for oat cv. Arab, during the third week of growth under Pi-deficient conditions. The activity of extracellular APase was high in young, growing zones of roots of -P plants. Histochemical visualization indicated high activity of APases in the epidermis and vascular tissues of -P plants. Pi deficiency increased intracellular APase activity in shoot mainly in oat cv. Polar, whereas APase activity in roots was the highest in oat cv. Szakal. Protein extracts from roots and shoots were run on native discontinuous PAGE to determine which isoform(s) may be affected by Pi deficiency. Three major APase isoforms were detected in all oat plants; one was strongly induced by Pi deficit. The studied oat cultivars differed in terms of acclimation to deficiency of phosphate-used various pools of APases to acquire Pi from external or internal sources.

Legume nodules from nutrient-poor soils exhibit high plasticity of cellular phosphorus recycling and conservation during variable phosphorus supply

“…To determine nodule surface acid phosphatase activity, whole nodules (approximately 3 g fresh weight [fw]) were washed in distilled water, blotted dry and placed into 5ml of incubation medium with substrate mixture (6 mM para-nitrophenylphosphate (pNPP) and 1 mM dithiothreitol (DTT) in 50 mM Na-acetate buffer, pH 5.0), and incubated at 25 °C (Zebrowska et al 2012, Ciereszko et al 2002. After 30 min, 100 µl of the reaction medium was removed and added to 100 µl 1M of NaOH to stop the reaction.…”

The effects of diversified phosphorus nutrition on the growth of oat (Avena sativa L.) and acid phosphatase activity

“…Oat is usually cultured on poor soils, with a low mineral concentration, but its acclimation mechanisms to such environment are not fully understood. Our previous results indicated that oat cultivars differed in terms of acclimation to Pi starvation [38]. In the present study, the effects of differential phosphorus supply (inorganic and organic P or no P) on oat growth and acid phosphatase activity and localization were investigated to estimate the role of these enzymes in oat response to Pi deficiency.…”

“…Oat seedlings (Avena sativa L. ' Arab'), after 7 days of germination (on Petri dishes), were grown hydroponically on nutrient media with contrasting P sources: inorganic phosphate, KH 2 PO 4 (+P, control), lowered Pi concentration to 0.1 of the control (0.1 P), phytic acid (PA) as organic source of P, or without phosphate (−P) in conditions similar to that used by Ciereszko et al [10] and Żebrowska et al [38]. The control nutrient medium contained: Ca(NO 3 …”

“…Acid phosphatase activity was also determined by in vivo activity stain as described by Żebrowska et al [38]. Therefore, intact roots (after 1 week of growth on nutrient media) were rinsed in 0.1 mM Na acetate buffer (pH 5.0) and embedded in 2% agarose with a substrate mixture (0.2% 1-naphthyl phosphate, 0.2% Fast Blue B in 100 mM Na acetate buffer, pH 5.0).…”

Avaliações bioquímicas e fisiológicas para previsão de desordens nutricionais de macronutrientes no desenvolvimento inicial do pinhão-manso

“…Figura 14 -Determinação da atividade da fosfatase ácida em folhas recém-expandidas em plantas de pinhão-manso desenvolvidas em solução completa e com a omissão de P, aos 20, 30, 40 e 120 dias após o início dos tratamentos A alta atividade da enzima fosfatase ácida como resposta adaptativa à baixa disponibilidade de fósforo tem sido observada em diversas culturas (NUNES et al, 2008;GAUME et al, 2010;ZEBROWSKA;BUJNOWSKA;CIERESZKO, 2011). Em condições de baixa disponibilidade de fósforo, as plantas utilizam a fosfatase ácida para promover a desfosforilação de compostos orgânicos disponibilizando fósforo inorgânico para manutenção do metabolismo celular em regiões meristemáticas (TOMSCHA et al, 2004;TRAN;HURLEY;PLAXTON,2010).…”