Secondary metabolism responses in two Pisum sativum L. cultivars cultivated under Fe deficiency conditions
The present study was carried out to investigate the Fe deficiency effect on the secondary metabolism responses in two Pisum sativum cultivars characterized by different tolerance to Fe deficiency. Previous study investigating the physiological responses to Fe deficiency in these two pea cultivars showed that Kelvedon was more tolerant than Lincoln. Both cultivars were grown in the absence or presence of Fe with the addition of bicarbonate for twelve days. Higher concentrations of phenols and flavonoids were observed in Fe-deficient tissues of both cultivars; however, the increase was greater in the tolerant cultivar than in the susceptible one. The activity of shikimate pathway enzymes tested was more enhanced in the tolerant cultivar. In addition, lipid peroxidation and H2O2 concentrations were more increased in the susceptible cultivar when compared with the tolerant one. Peroxidase activity was increased in the tolerant cultivar grown under bicarbonate supply, while a considerable diminution was observed in the susceptible one, suggesting the involvement of this antioxidant enzyme in the tolerance of pea to Fe deficiency. The lignifying peroxidases activity was more decreased in Lincoln than in Kelvedon, especially in the presence of bicarbonate. Our data suggest that the tolerance of Kelvedon was related to its ability to modulate the phenolic metabolism pathway and to enhance the antioxidant potentials.
Key words: Iron deficiency, bicarbonate, phenolic metabolism, antioxidative enzymes, Pisum sativum.