Effect of arbuscular mycorrhizal inoculation on growth, mineral nutrient uptake, photosynthesis and antioxidant activities of black pepper cuttings

Abstract

Arbuscular mycorrhizal (AM) fungi are one of most important soil microorganisms that can form mycorrhizal symbiosis with most of the terrestrial plants. In the present study, the effect of arbuscular mycorrhizal fungi inoculation on root colonization, growth, nutrition, photosynthetic gas exchange and antioxidant activities of black pepper cuttings were evaluated under polyhouse conditions. The single node cuttings of black pepper were grown in the presence and absence of AM combinations for 150 days under poly house. AM inoculated plants showed significantly higher mycorrhizal root colonization (95%) and spore numbers (312/50 g of sample). The effect of AM fungi was more prominent in improving root biomass than above ground biomass. Nutrient accumulations were higher in AM inoculated plants rather than uninoculated black pepper plants. Amount of acid phosphatase and dehydrogenase activity were significantly higher in AM inoculated soils. Net photosynthetic rate and stomatal conductance of AM colonized black pepper leaves were found to be significantly greater than uninoculated plants. The influence of AM was more prominent on poly phenol oxidase and β-glucanase activity in leaves than roots. In principal component analysis the scatter plot revealed variations of the effects of arbuscular mycorrhizal fungi on growth of black pepper cuttings. Based on these results, AM inoculation at the earlier stage of plant development could improve symbiosis, and increased plant growth in the nursery which may improve the performance after planting in the field.