Effect of Reduced Water Potential on Imbibition Curve and The Triphasic Pattern of Seeds in Solanaceae Species

This study aimed to analyze the effect of reduced water potential on the imbibition curve and triphasic pattern of seeds in several Solanaceae species. The experiment was conducted at the Seed Physiology and Health Laboratory and the Seed Biology and Biophysics Laboratory, Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, from April to September 2025. The study used seeds from three Solanaceae crops—chili (Capsicum annuum L., varieties Simpatik and Sempurna), tomato (Solanum lycopersicum L., varieties Niki and Rempai), and eggplant (Solanum melongena L., varieties Tangguh and Provita). The seeds were subjected to various levels of osmotic stress using polyethylene glycol (PEG 6000) to simulate water potentials of 0.00, –0.30, –1.90, and –4.10 MPa. Lower water potential in the growing medium reduced the seed’s ability to absorb the water. The triphasic pattern consistently appeared only in chili seeds, whereas in tomatoes and eggplants, it varied across varieties and water potential conditions. The lower water potential made the later the phase I ended, and the longer the phase II lasted. These findings confirm that the standard imbibition pattern cannot be generalized to all seeds, and therefore, the imbibition response is specific to seed type, variety, and germination environment.