Mycorrhization alters root morphology, leaf starch and nutrient content of micropropagated banana under water stress

Abstract

The influence of mycorrhizal inoculation under water stress was studied to observe the effect of different mycorrhizal strains on the root morphology in banana and its consequence on starch and nutrient content of in vitro derived banana leaves. We assessed per cent root colonization, number of roots per plant, root length, root fresh weight, root dry weight and its effect on leaf starch content of micropropagated banana plantlets during hardening at 20, 40 and 60 days after mycorrhizal inoculation. The effect of mycorrhization on leaf nutrient (N, P, and K) was recorded at the end of the hardening period. Four treatments including control were replicated four times and 10 plants per replication were maintained in completely randomized design (CRD). Significant increase in number of roots, root fresh and dry weight of mycorrhized banana plantlets was recorded at 20, 40 and 60 days after inoculation over control. Though the numbers of roots remain significantly less in banana plantlets without mycorrhization, the root length was highest throughout the experimental period. Changes in root morphology of mycorrhized plantlets under water stress plays an important role in improved growth as number of lateral roots increase surface area for nutrient and water absorption. Significantly less leaf starch content after 20 days of inoculation in mycorrhizal plantlets were observed which increased significantly after 40 days of inoculation and continued up to 60 days. Foliar N, P, K content was also found to be significantly high in the mycorrhizal plantlets as compared to non-mycorrhized plantlets at 60 days after inoculation.