Relationships between peroxidases and in vitro bulbification in garlic (Allium sativum L.)

The relationship between in vitro bulbification and peroxidase activities o f garlic (Allium sativum L.) was studied. Two stages could be distinguished during in vitro bulb formation characterized by the peroxidase activity, i soenzymatic patterns especially of the soluble fractions, dry weight, and b ulbification index (BI). The first stage, called the morphogenic stage, sta rted after planting until 30 d of culture with a maximum soluble peroxidase activity, BI = 1-0.5 and low dry weight. At that time axillary buds prefor med at the base of the leaves grew and the in vitro bulb was generated. The second stage (filling in and bulb maturation) started when the BI reached 0.5 at 30 d of the ontogenic cycle, as a result of the bulb assimilate accu mulation phenomenon. During the morphogenic stage the soluble peroxidase ac tivity was maximum and the zymograms showed higher intensity hands. The sec ond stage presented anodic ionic peroxidases and substantial increase in st aining of the anodic covalent peroxidase fraction. The putative role of the different isoforms of peroxidases in relation to the bulbification process is discussed.