Identification off AsA on phloem

Fig. ? Fig.1 1 shows HPLC chromatograms of potato source leaf phloem exudates collected from severed petioles in buffer containing either EDTA or CaCl₂. Total AsA (AsA_t; L -ascorbic acid + dehydroascorbic acid) appeared as the largest peak of absorbance at 2cuatro5 nm retained by the column in both cases. ₂ instead of EDTA, all exudate derived peaks were strongly reduced due to the reduction in exudation caused by callose gelation . In experiments to test the stability of authentic AsA (final concentration 0.1 ?M) in the presence of EDTA or CaCl₂ exudation buffers less than 5% oxidation was observed in either case over 90 min (data not shown). AsA localisation to the vascular tissue was confirmed histochemically in sections of potato stems and tubers incubated with ethanolic AgNO₃ at 3°C (Fig. ? (Fig.2). 2 ). Intense deposition of metallic silver was observed in the vasculature of stems. Read More Whenever exudates was basically compiled throughout the presence regarding CaCl