Response of invasive Solanum elaeagnifolium Cav. seed germination and growth to different conditions and environmental factors.
Germination abilities endorsed the successful invasion and establishment regularly of Silverleaf nightshade (Solanum elaeagnifolium Cav.) to be one of the most serious invasive weeds in the world. Therefore, their seed sets were exposed to different thermogradient temperatures and light/dark regimes with and without chemical and physical treatments to determine the germination requirements and conditions. The percentage of seed germination is generally low and reached the optimum at alternating temperature regimes of 20/30°C (32.8%), followed by 15/25°C (31.5%) and 20/25°C (30.0%), respectively under 12/12 (day/night) within four weeks. While it failed to germinate at constant temperatures. The superlative treatment was achieved from combined heat at 100oC with gibberellic acid at 1000 ppm reached 65% of seed germination over the control. Time exposure and concentration of various chemical and physical promotors have significant effects on germination and breaking their seed dormancy. S. elaeagnifolium seed germination was diminished progressively to ≤ 3000 ppm of NaCl but their growth has more enough resistance. While the range of 8 to 9 pH is preferential to the maximum germination. We concluded that alternating temperatures are basic requirements of S. elaeagnifolium seed germination while it seems a moderate tolerance to salinity and drought stresses. This knowledge will encourage effective methods for management tactics of S. elaeagnifolium.