engleski

Lodging related stem anatomy and guaiacol peroxidases in two barley cultivars

Background and aims: Peroxidases are heme-containing glycoproteins involved in many physiological processes such as auxin metabolism, call wall modification (e.g. lignification, suberinization), defense against pathogens, senescence, salt and heavy matals tolerance. In the present study, two barley cultivars, Scarlet and Astor, were compared in order to investigate the differences in the lodging resistence between them. The main goal of our study was to examine the structure, peroxidase activity and isoenzyme profiles in first three internodes, with special reference to lignification processes. Methods: Microscopy analysis was done on semi-thin methacrylate embedded sections stained with Toluidine blue. Also, lignin was detected in fresh free-hand sections with phloroglucinol. The activity of guaiacol peroxidases was determined spectrophotometrically. The expression of peroxidase isoenzymes was investigated by isoelectric focusing (IEF). Key results: Analysis of lodging resistance revealed approximately three times higher lodging for cv. Scarlet than for cv. Astor. Barley stem of cultivar Astor had continuous layers of epidermal and hypodermal cells with lignified cell wals. The layer of cells below the hypodermis showed certain lignification in cell walls, as well. The stem of cv. Scarlet showed loose parenchyma cells inserted in the layer of cells with lignified walls. Total activity of guaiacol peroxidases was significatntly higher in cv. Astor than in cv. Scarlet for all three internodes. In cv. Astor three peroxidase isoenzymes were found, while an additional isoform appeared in c. Scarlet. Conclusions: It can be concluded that better lodging resistance of cv. Astor was related with more intensive stem lignification as well as with higher values of peroxidase activity and different isoenzymes pattern.

Hordeum vulgare; Lodging; GPOD; Stem anatomy

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