Growth characteristics of an exotic plant Ipomoea hederacea Jacq. under different environmental conditions

摘要

This study was carried out to investigate the differences in germination and growth of Ipomoea hederacea Jacq. under various temperatures, seeding depths and levels of shading and soil moisture so that more effective methods of weed management might be developed. Because I. hederacea can remain dormant for over one year, our best results were obtained when seeds were soaked in sulfuric acid for 15 min in order to break the dormancy. The ideal temperature for germination of I. hederacea was between 25°C and 35°C which produced the highest levels of germination (70%). In lower temperature conditions at 15°C, I. hederacea seeds also germinated at 33%. The germination rate of I. hederacea was the highest at 72-84% at 1, 2 and 3 cm seeding depths. However, the germination rate was still 3% when seeds were planted at 20 cm. In addition, mesocotyle lengths increased as seeding depths increased. I. hederacea seeds germinated at a higher rate in 20% shade condition than in non-shade condition (control).Although germination rates were reduced by increasing shade levels, germination rates under 90% shade condition were still as high as 50%. Germination rates were 73-93% in soil with 30, 60 and 80% moisture and even in poor germination conditions where the soil was at 100% saturation, seeds still germinated at a rate of 13%. Overall, I. hederacea had potentail for germination and growth under bad environmental conditions. Due to the germination and growth characteristics of I. hederacea, this weed I. hederacea may be difficult to control in crop fields.