Effect of environmental factors on the germination and growth of Parthenium hysterophorus and Rumex crispus.
Germination is the key feature for the establishment of weeds in agro-ecosystem. To confirm this, a laboratory experiment was performed to investigate the impact of temperature and salinity on germination and seedlings attributes of two foremost weeds i.e. Parthenium hysterophorus and Rumex crispus. The sterilized seeds of both tested weeds were grown on Petri-dishes inside a growth chamber. The temperatures (15, 25 and 40°C) and NaCl concentrations (0, 100, 200, 300, 400, 500 and 600 mM) were applied. The statistically prominent effect of salinity and temperature was observed on germination and growth-related variables of both the weeds. The optimum temperature for growth and germination related variables of P. hysterophorus and R. crispus was found to be 25°C. By increasing (40°C) or decreasing (15°C) the temperature, reduction in germination and growth traits of both tested weeds was noted. In case of NaCl concentrations, R. crispus proved slightly more susceptible to salinity compared to P. hysterophorus. Both the species (P. hysterophorus and R. crispus) showed fair tolerance against salinity up to 100 mM of NaCl, however, above this concentration a significant reduction in germination were observed and was completely inhibited at 500 and 600 mM NaCl, respectively. A significant decline in growth was perceived with an increase in NaCl concentration. Conclusively, it was revealed that the establishment of both tested weeds was influenced significantly by temperature and NaCl concentrations. Thus the growth pattern, competitive ability, infestation and spread of these weeds can be correlated with the temperature and salinity for their control in agro-ecosystems.