Effect of calcium silicate on number of trichomes, leaf thickness and chlorophyll in tomato

Silicon plays a role in alleviating biotic and abiotic stress in plants. A similar mechanism also acts against insects by inducing the formation of the trichomes and changing leaf structure. However, there are few studies on the role and effects of silicon on leaf structure. In previous studies, silicon protects plants from pathogens and insects and improves growth under stress conditions. This study looks at the effects of calcium silicate on salicylic acid content, chlorophyll content, the number of trichomes, and thickness of tomato leaves. The experimental design was a completely randomized design with five treatments and 10 replications. Calcium silicate was added to the planting media at 0, 62.5, 125, 187.5 and 250 kg ha^‑1, seven days after transplanting (DAT). Leaves at position three to five from the shoot apex at 60 DAT were collected and analyzed for chlorophyll and salicylic acid content. The number of trichomes examined at the leaf margin, leaf blade, lower leaf vein, and upper leaf vein. Leaf thickness measured via cross-section with and without the vascular bundle. The concentration of calcium silicate at 250 kg ha^‑1 increased the number of trichome at the leaf margin, leaf blade, lower leaf vein, and upper leaf vein by 25, 40, 41 and 23%, respectively, compared to the control treatment. The lower leaf vein had a higher number of trichomes compared to the other leaf sectors examined. In addition, calcium silicate at 187.5 kg ha^‑1 enhanced leaf thickness by 43% and total chlorophyll content by 13% compared with the control treatment. Furthermore, calcium silicate did not result in a significant increase in leaf salicylic content compared to the control treatment.