Effect of Low and High Temperature Regimes on Seed Dormancy and Germination of Ricimus Communis (Castor Oil plant) using Thermal Time Method

The seed is an important stage in the higher plant life cycle with respect to its survival as a species.It is the dispersal unit of the plant, which is able to survive the period between seed maturation and the establishment of the next generation as a seedling after it has germinated.For this survival, the seed, mainly in a dry state, is well equipped to sustain extended periods of unfavorable conditions (Finch-Savage and Leubner-Metzger, 2021).To optimize germination over time, the seed enters a dormant state.Dormancy prevents pre-harvest germination as well.Numerous studies have been performed to better understand how germination is controlled by various environmental factors and applied chemicals.However, still very little is known about the process by which the embryo emerges from the seed to complete germination and how embryo emergence is blocked in dormant seeds (Bewley, 2022).Castor oil plant is an economically important crop known for its oil-rich seeds, which are used in various industrial and pharmaceutical applications.Seed dormancy and germination are key stages in the life cycle of castor oil plants, and their successful completion is essential for crop establishment and yield potential (Singh and Singh, 2021).However, temperature fluctuations, especially extreme temperatures, can disrupt these processes and affect seedling emergence and crop performance (Gummerson, 2022).The thermal time model, based on the concept of accumulated heat units required for seed dormancy release and germination, provides a quantitative framework for studying temperature