Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nurs...Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nursery.The experiment was established in the nursery of the Institute of Forestry and Environmental Sciences.University of Chittagong, Chittagong, Bangladesh. Results revealed that Nail clipping in one side of the seed （at the distal end of the seed） （T4） provides the highest （50%） seed germination. The second highest germination （42%） was obtained for the seeds treated with immersion in cold water for 24 h （T1）. Germination was completely inhibited when the seeds immersed in boiled water for 30 s followed in cold water soaking for 24 h. Other germination parameter and initial morphological growth and biomass production of the seedlings was also higher for the treatments T4and Ti in comparison to the control （Ta）treatment. Pre-sowing treatments of T4 e.g. Nail clipping in one side of the seed （at the distal end of the seed） and T1 （Seeds immersed in cold water for 24 h） may be recommended for maximum germination and initial vigorous seedlings growth of Albizia sarnan in the nursery.展开更多
Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have r...Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have received a large amount of exogenous nitrogen （N） input from the adjacent agricultural land because of fertilization. In the present study, the effects of nitrogen additions on seed germination and seedling biomass of Calamagrostis angustifolia in freshwater marsh were tested in a greenhouse study. Seed bank soil was exposed to different N additions （0, 5, 10, 20 and 40 g/m^2） under non-flooded water regime. Results revealed that, low level of N additions （less than 10 g/m^2） did not significantly affect the species richness and seedling density, while the seedling biomass at 5 g/m^2 of N addition was higher than other nutrient conditions. But species richness, seedling emergence and biomass decreased significantly at high level of N additions （20-40 g/m^2）. The responses were species-specific. High level of N additions had negative impacts on seed germination, seedling growth and biomass of dominant species Eleocharis ovata, Calamagrostis angustifolia, duncus effusus in the seed bank. To protect and restore the wetland vegetation community in the Sanjiang plain, fertilization, irrigation and land management strategies will need to be implemented to reduce the nutrient input from the agricultural land to the wetlands.展开更多
文摘Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nursery.The experiment was established in the nursery of the Institute of Forestry and Environmental Sciences.University of Chittagong, Chittagong, Bangladesh. Results revealed that Nail clipping in one side of the seed （at the distal end of the seed） （T4） provides the highest （50%） seed germination. The second highest germination （42%） was obtained for the seeds treated with immersion in cold water for 24 h （T1）. Germination was completely inhibited when the seeds immersed in boiled water for 30 s followed in cold water soaking for 24 h. Other germination parameter and initial morphological growth and biomass production of the seedlings was also higher for the treatments T4and Ti in comparison to the control （Ta）treatment. Pre-sowing treatments of T4 e.g. Nail clipping in one side of the seed （at the distal end of the seed） and T1 （Seeds immersed in cold water for 24 h） may be recommended for maximum germination and initial vigorous seedlings growth of Albizia sarnan in the nursery.
文摘Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have received a large amount of exogenous nitrogen （N） input from the adjacent agricultural land because of fertilization. In the present study, the effects of nitrogen additions on seed germination and seedling biomass of Calamagrostis angustifolia in freshwater marsh were tested in a greenhouse study. Seed bank soil was exposed to different N additions （0, 5, 10, 20 and 40 g/m^2） under non-flooded water regime. Results revealed that, low level of N additions （less than 10 g/m^2） did not significantly affect the species richness and seedling density, while the seedling biomass at 5 g/m^2 of N addition was higher than other nutrient conditions. But species richness, seedling emergence and biomass decreased significantly at high level of N additions （20-40 g/m^2）. The responses were species-specific. High level of N additions had negative impacts on seed germination, seedling growth and biomass of dominant species Eleocharis ovata, Calamagrostis angustifolia, duncus effusus in the seed bank. To protect and restore the wetland vegetation community in the Sanjiang plain, fertilization, irrigation and land management strategies will need to be implemented to reduce the nutrient input from the agricultural land to the wetlands.
