Silicon improves the photosynthetic performance of black pepper plants inoculated with Fusarium solani f. sp. piperis

Abstract

This study evaluated the effect of silicon (Si)-supplementation in controlling the fusariosis in two Piper nigrum cultivars (Bragantina and Kottanadan). We hypothesized that susceptible cultivar improves the photosynthetic performance with Si-supplementation. Under greenhouse conditions, six-month-old plants were treated with silicon 30 and 15 d before inoculation with Fusarium solani f. sp. piperis and compared with untreated plants and with healthy control plants. All samples remained photosynthetically active after infection. Chlorophyll content, chlorophyll a fluorescence, and leaf gas-exchange parameters were less affected in Si-supplemented plants as well as healthy control plants. The net carbon assimilation, stomatal conductance, associated with higher internal carbon values suggest that the lower CO2 influx in inoculated plants of Bragantina cultivar was caused by photochemical and biochemical limitations. Si-supplementation reduced the disease severity improving protection, apparently associated with the preservation of photosynthetic performance, especially for Bragantina cultivar.