Germination Response and Seedling Growth of Hirschfeldia incana Under Different Osmotic Stress and Temperature Conditions

Abstract

Hirschfeldia incana is a highly adaptable weed species commonly found in agricultural and disturbed environments, where it competes aggressively with cultivated crops for water, nutrients, and space. Its successful establishment and persistence are strongly influenced by environmental factors such as temperature and water availability. Understanding the germination ecology and seedling growth responses of this species under stress conditions is essential for predicting its spread and developing effective weed management strategies. The present study investigated the effects of different osmotic stress levels and temperature regimes on the germination and early seedling growth of Hirschfeldia incana. Laboratory experiments were conducted under controlled conditions using a range of osmotic potentials and temperature treatments to evaluate seed germination percentage, germination rate, seedling vigor, root length, and shoot development. The results demonstrated that both osmotic stress and temperature significantly affected germination and seedling growth parameters. Maximum germination and vigorous seedling growth were observed under moderate temperature conditions with low osmotic stress, while severe water stress substantially reduced germination percentage and delayed seedling emergence. High osmotic stress also inhibited root and shoot elongation, indicating reduced physiological activity under limited moisture conditions. Temperature influenced the tolerance of seeds to osmotic stress, with optimal germination occurring within a specific temperature range, whereas extremely low or high temperatures negatively affected seed performance. Despite reductions under stress conditions, a proportion of seeds remained capable of germination, demonstrating the ecological adaptability of H. incana to fluctuating environmental conditions. The findings provide valuable insights into the stress tolerance mechanisms and establishment potential of this weed species in agricultural systems. Understanding these ecological responses is important for designing integrated weed management strategies aimed at limiting weed establishment and reducing competition with cultivated crops under changing climatic conditions.