Germination Response of Lactuca serriola to Temperature, Light, and Osmotic Stress Under Laboratory Conditions

Abstract

Germination response of Lactuca serriola was evaluated under varying temperature, light regimes, and osmotic stress conditions to understand its adaptive germination behavior in fluctuating environments. Laboratory experiments were conducted under controlled growth chamber conditions, where seeds were exposed to different temperature ranges, photoperiod treatments (light and dark), and osmotic potentials simulated using polyethylene glycol solutions. Results indicated that germination was strongly influenced by temperature, with optimal germination occurring under moderate thermal conditions, while extreme low and high temperatures significantly reduced germination percentage and delayed germination onset. Light exposure played a critical role in regulating germination, with higher germination rates observed under light conditions compared to complete darkness, indicating positive photoblastic behavior. Osmotic stress markedly inhibited germination by reducing water uptake and delaying metabolic activation, with increasing stress intensity leading to progressive declines in germination percentage. Interaction effects among temperature, light, and osmotic potential revealed that favorable thermal and light conditions partially mitigated moderate water stress effects. The study highlights the ecological adaptability of L. serriola seeds to environmental variability, contributing to its success as a widespread weed species. These findings provide important insights into germination ecology and support the development of predictive models for weed emergence under changing environmental conditions in agricultural ecosystems.