Effect of Temperature and Drought Stress on Germination of Slender Amaranth (Amaranthus viridis L.) and Prostrate Pigweed (Amaranthus blitoides S. Watson) Seeds
Majallah-i ḥifāẓat-i giyāhān
Slender amaranth (Amaranthus viridis L.) and prostrate pigweed (Amaranthus blitoides S. Watson) are two common weeds in vegetables and summer crop fields of Iran. The two Amaranthus species have all the attributes required by ecologically successful annual weeds: rapid growth, early reproduction and continuous seed production. Knowledge of the germination requirements of these weeds will helps determine the proper conditions for germination and emergence and allow better management of them.
... gement of them. Water and temperature are determining factors for seed germination of weed. Both factors can, separately or jointly, affect the germination percentage and germination rate. Water stress is one of the main constraints on plant growth and the most common environmental stresses around the world. Water stress affects the different aspects of plant growth and causes reduction and delay in seed germination. Seed germination of all plant species requires a minimum of water to be absorbed and swelled and that is why osmotic potential should not be less than a certain amount. Materials and Methods: Seeds were harvested from vegetable fields of Karaj. For breaking dormancy, seeds were treated with concentrated sulfuric acid for two minutes. Two experiments were conducted at Islamic Azad University, Science and Research Branch, Ecology lab, in 2016. First experiment was based on completely randomized design with 4 replications .The seeds were treated with different temperatures (5, 10, 15, 20, 25, 30, 35, 40 and 45oC). Germination percentage and germination rate were measured and seed were considered to have germinated with the emergence of the radical. Intersected lines model is used to determine the cardinal temperature. Second experiment was conducted to determine the effects of simulated dry conditions (use PEG) and temperature on seed germination of slender amaranth and prostrate pigweed. Exposure to polyethylene glycol (PEG-6000) solutions has been effectively used to mimic drought stress with limited metabolic interf [...]