Effect of Iron and Auxins on Peroxidase Activity and Rooting Performance of Three Citrus Rootstocks In Vitro

Abstract

The effects of FeCl₃, Fe‐EDDHA and Fe‐EDTA as iron sources at 5.6 ppm, as well as their combined effect with the auxins IBA and α‐NAA on rooting capacity and total peroxidase activity of three Citrus rootstocks (Swingle Citrumelo, C. taiwanica, and C. aurantium) in vitro were studied for eight weeks. No root or callus formation was observed in the presence of IBA independently of the Fe source, or in the absence of Fe in the culture medium independently of the hormone used. Low rooting percentage obtained by FeCl₃, while the best results were obtained using Fe‐EDDHA as Fe source. The time of root appearance was also influenced by the different sources of Fe as well as by the kind of the rootstock. In the presence of Fe‐EDTA plantlets survived for four weeks and then died. Total peroxidase activity declined sharply shortly before root appearance, but the decline was less pronounced shortly before callus formation (in some cases of FeCl₃ treatment).

Keywords:

• Iron
• Auxin
• Peroxidase
• Rooting
• Citrus
• In vitro