In Vitro Callussing and Xylogenesis of Allium sativum L

Callus culture for Allium sativum L. was established from shoot buds dissected out from the cores of cloves. Callus was induced through inoculation of explants in MS basal media supplemented with 2,4-D, 1 mg l-1 . The callus was maintained through subsequent subcultures by transferring to fresh MS media supplemented with MS media with Kin 0.1 mg l-1 in addition to 2,4-D. Callus tissue from the third sub-culture was analyzed from Day 1 through Day 27; for mitosis, mitotic index, cell viability, cell death, cell differentiation and generation of hydrogen peroxide. Whereas the frequencies of cells with chromosome aberrations or micronucleus in callus tissue was negligible, the incidence of hyperpolid cells were more common, which suggested genetic instability. Furthermore, generation of hydrogen peroxide indicated that the callus tissue was under oxidative stress that perhaps triggered cellular differentiation or xylogenesis. The present in vitro system, seemed to be an ideal system for study of vascular tissue differentiation, particularly xylogenesis.