Effect of microbial-inoculants on growth and biochemical parameters of mango plantlets during bio-hardening

Present investigation was carried out to find out the effects of bio-agents on growth and biochemical changes during bio-hardening of in vitro embryo cultured plantlets of mango genotypes Amrapali, Pusa Arunima and hybrid 8–11. In vitro raised plantlets were subjected to bio-hardening using three microbial, Aspergillus niger and microbial consortium (mixed AMF strains, Nutrilink^®). Plants treated with bio-inculants had 4.8 to 19.98 per cent more plant height compared to control. Similarly, root length, fresh weight, dry weight, leaf number and secondary roots were significantly increased by mycorrhizal inoculation compared to control plants. The histo-chemical studies revealed that the mycorrhizal inoculation resulted in enhanced accumulation of different metabolites such as chlorophyll, total phenols, total sugars, while the proline accumulation was reduced during bio-hardening. The poly-phenol oxidase enzymes like catacholase and cresolase activities were enhanced by microbe inoculation. The mycorrhizal plantlets showed enhanced survival and improved tolerance against stresses experienced during acclimatization phase.