Differential Effects of Potassium Chloride on Vascular Tissues, Morphological Traits and Germination of Tomato with Sperm Swarm-based Nutrient Optimization

Potassium chloride (KCl)-induced stress has been predominantly tested on higher crops such as cotton, rice, and wheat. What open agriculture needs now is the extended understanding of possible contributions and detrimental effects of KCl dynamics to tomato as this is one of the major crops consumed worldwide. In this study, the impacts of KCl on the three Philippine tomato (Solanum lycopersicum) genotypes namely, Perlas, Diamante Max F1, and Mica, in separate mesocosms were visualized and measured based on morphological, vascular tissues, and germination variability responses. Three KCl treatments were deployed, which are control (Tc, 0.05 mM), deficit (Td, 0.025 mM), and excess (Te, 0.5 mM), in 3 replicates. KCl-deficit treatment showed improvement in germination rate and vigor index and deteriorated Timson germination index for tomato seedlings. Excess KCl treatment distinctively promotes a higher root (R) to shoot (S) length ratio for Perlas variant with rusty red-orange root color. R/S length increases from control, deficit to excess KCl and R/S fresh and dry weights quadratically increase from control, excess to deficit KCl. The inconsistency of Td and Te treatments to provide equally productive outcomes across the 3 genotypes on the first 37 days after sowing led to the use of 3 bio-inspired algorithms namely, moth-flame, sperm-swarm, and jellyfish swarm optimizers, in determining the most suitable KCl concentration for growth promotion. Multigene symbolic genetic programming was used in constructing the fitness models of five phytomorphological phenotypes namely, root and shoot lengths and weights and leaf count, as functions of KCl concentration and cultivation period. Light microscopy showed that sperm swarm-optimized KCl (0.038 μM) widens the diameter of xylem and phloem vessels in the vegetative stage which is important as they are responsible for transporting nutrients, water, and photosynthesis by-products. Hence, KCl is an essential micronutrient that could alter the growth of crops.