Temporal impact of infection with Sclerotinia sclerotiorum on important physiological and biochemical variables of tomato plants

A study was undertaken to determine the effect of infection with Sclerotinia sclerotiorum on the biochemical and physiological characteristics in relation to days after inoculation, and the subsequent impact on the plant growth variables of tomato, Lycopersicon esculentum cv. Pusa Ruby. The levels of chlorophyll, phenol, protein, peroxidase, polyphenol oxidase activity, stomatal conductance, photosynthesis, and transpiration were studied on alternate days up to one month of inoculation. Chlorophyll content in infected plants decreased with the progress of time when compared to uninfected plants. The biochemical variables such as leaf phenol, polyphenol oxidase, peroxidase and plant proteins increased in the fungus inoculated plants. The rates of photosynthesis, transpiration, and stomatal conductance fluctuated slightly over time in healthy plants, while in infected plants, the rates of photosynthesis and transpiration both gradually decreased over time. The physiological variables fluctuated mostly between 17 and 21 days after inoculation, thereafter the values of the variables stabilized. The study has demonstrated that inoculation of S. sclerotiorum substantially influenced vital physiological and biochemical processes of the host plants, which ultimately led to chlorosis and reduced plant growth.