Temporal impact of root-knot nematode infection on some important biochemical and physiological characters of tomato

摘要

Abstract The study was made to examine the temporal impact of infection with Meloidogyne incognita (root-knot nematode) on the biochemical and physiological responses of tomato plants with regard to plant growth variables, photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll contents, phenol contents, protein contents, polyphenol oxidase activity and peroxidase activity. The physiological and biochemical parameters were determined on alternate days during first month of nematode inoculation. The chlorophyll contents decreased in infected plants with the progress of time in comparison to non-infected plants. In infected plants, the leaf protein, peroxidases, and polyphenol-oxidase showed a maximum increase of 17.4, 19.2, and 21 on 17th, 19th and 21th day of inoculation over respective controls. In healthy plants, photosynthesis rate, transpiration rate and stomatal conductance marginally increased, but in the infected plants, the photosynthesis rate significantly decreased, whereas the transpiration rate and stomatal conductance increased with the progress of time with a maximum of 20, 19.4 and 17.6 increase on 21th, 23th, and 25thday. Overall, the decrease or increase was greatest during 17–21 days after inoculation and thereafter, the physiological variables remained significantly unchanged. The study has shown that the nematode infection caused notable alterations in the biochemical and physiological characters of the host plants, which resulted into reduced plant growth of tomato.