In-vitro cormel formation and changes of biochemical composition in calli during morphogenesis in gladiolus (Gladiolus × grandiflorus)

Abstract

The present investigation was carried out for in-vitro cormel formation and to study the changes of biochemical composition during shoot and root differentiation from callus in gladiolus (Gladiolus × grandifforus L.). Cormel tip was used as explant for in-vitro regeneration on MS media supplemented with different plant growth regulators. Maximum callus formation was observed on MS medium supplemented with 4.0 mg/l 2,4-D with excellent callus growth. The inducted calli were subcultured on MS medium supplemented with 4.0 mg/l BAP and 0.5 mg/l NAA for best shooting followed by on ½ MS medium fortified with 3.0 mg/l IAA for best rooting. After two weeks of root initiation, the whole cluster of rooted plantlets was equally divided into two halves and the divided clusters were subcultured on cormel induction media. The different stages of morphogenesis, viz. non-differentiating callus, differentiating green callus, shoot differentiating callus and root differentiating callus were used for biochemical analysis. Maximum (55.0 %) and earliest (56.0 days) formation of cormels was observed on MS medium supplemented with 4.0 mg/l NAA elevated with 6% sucrose with good cormel size of up to 7.0 mm diameter. Decrease in metabolities like starch, reducing sugars and total phenols while, increase in total soluble proteins was found during shoot and root differentiation. Activities of enzymes, viz. polyphenol oxidase and peroxidase increased during shoot and root differentiation. From the present investigation, it was proved that metabolic and enzymatic activity during in-vitro morphogenesis help gladiolus for rapid organogenesis and multiplication through cormel formation.