Understanding how weed seed germination and emergence respond to environmental factors is critical to determining their adaptive capabilities and potential for infestations, and could also aid in the development of effective control practices. Germination of Ipomoea asarifolia (Desr.) Roem. & Schultz and Stachytarpheta cayennensis (Rich) Vahl. decreased linearly with decreasing osmotic potentials. Also, increasing osmotic stress delayed germination of Ipomoea more than that of Stachytarpheta. Ipomoea germination was insensitive to light, while Stachytarpheta showed a positive photoblastic behavior. Nitrate had a negative effect on germination of Ipomoea seed under both light and dark conditions but stimulated dark germination of Stachytarpheta.... |