Germination ecology of invasive common morning-glory (Ipomoea purpurea L.) in Golestan province

Common morning-glory (Ipomoea purpurea L.) is one of the most important harmful weeds in summer crops in Golestan province. Germination is one of the most important stages of plant life and the study of environmental factors affecting the germination of weeds is necessary for their proper management.

In order to investigate the effect of some environmental and management factors on seed germination and emergence of common morning-glory, experiments were conducted in the laboratovar and research greenhouses of the Gorgan University of Agricultural Sciences and Natural Resources in 2017. In this study, common morning-glory response to constant temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ° C), alternating temperature (5:15, 10:20, 15:25, 20:30) , 25:35), high temperature (temperatures of 50, 80 and 100 ° C for 5 and 10 minutes), drought (0, -0.2, -0.4, -0.6, -0.8, -1 MPa), salinity (0, -0.2, -0.4, -0.6, -0.8, -1, -1.2 and -1.4 MPa), pH (4, 5, 6, 7, 8, 9), burial depth (0, 1, 2, 3, 5, 7, 9, 11, 13, 15 and 17 cm) and flooding duration (0, 3, 5 and 7 days) were examined.

Constant and alternating temperatures had a significant effect on the germination percentage of common morning-glory. The highest germination percentage were observed at constant temperatures of 30 and 35 °C and at alternating temperatures of 15: 25 and 20: 30 °C (day / night). Based on the Dent model, Cardinal temperatures of seed germination of this plant including base, optimum upper and lower and ceiling temperatures were 7, 30, 35 and 44 °C, respectively. Germination of of common morning-glory seeds decreased with increasing salinity and drought. The concentrations of sodium chloride and polyethylene glycol, which reduced the germination of this plant by 50%, were equal to -1.06 and -0.45 MPa, respectively. This indicates that this plant is resistant to salinity and there is a possibility of its development in saline lands of the country. Germination of this plant in pHs of neutral and alkaline were significantly higher than acidic pHs. At high temperatures, the percentage of germination and seed viability decreased significantly. The percentage of common morning-glory seed emergence at burial depths of 1 to 7cm were not significantly different (92 to 100%). With increasing depth from 9 to 13 cm, the percentage of emergence decreased significantly and no seeds emerged from a depth of 15 cm. Therefore, the use of non-tillage and low tillage methods can not have much effect on the management of this weed; Unless deeper plowing is used. Results showed that seed germination of this plant is very sensitive to flooding stress.

The results of the present study showed that environmental factors have a significant effect on the germination and emergence of common morning-glory and they can be used in designing effective management scenarios to control of this weed.