Ecophysiological studies on the seeds of Amaranthus viridis L. and A.spinosus L.

• Main Authors: Ching-hsiu Wu, 吳晶綉
• Other Authors: Ruey-shing Lee
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/28128946470307462450

碩士 === 國立嘉義大學 === 農學研究所 === 91 === Summary Amaranthus spp. distributed widely throughout the temperature and tropical regions in the world.Both Amaranthus viridis L.and Amaranthus spinosus L. are annual weeds in Taiwan. This thesis was aimed to investigate the annual changes of germinability of the buried seeds of these species. The environmental factors affecting seed germination and seedling emergence of both species were also studied . The freshly harvested seeds of A. viridis L.and A. spinosus L. were conditional dormancy.The seeds high germination percentages at different temperature regimes one month after buring in the soil. A. viridis L.seed had low germination one lear after buring in the soil.It might be a type of short period of persistent seed.However, A. spinosus L.seed had low germination 10 months after buring in the soil. It might be a type of transient seed. The optimum temperatures for germination of b oth A. viridis L.and A. spinosus L. seeds were between 20℃and 40℃. Germination of these species reduced when the water potentials of the medium were below —0.4 Mpa. The days reguired for cotyledon appearance of A. viridis L.and A. spinosus L. were decreased at optimum temperature（35/30℃）and the cotyledon appearance of A. spinosus L. delayed with the temperatures decreased .The germination percentage of A. viridis L.decreased at the concentration of 0.6% NaCl solution and no germination was observed at the concentrations of 1.2%NaCl solution for A. viridis L. and 1.6% NaCl solution for A. spinosus L. respectively . Both nondormant seeds of A. viridis L.and A. spinosus L. responded moderately to pH values . Germination percentages were above 80% in solutions with pH 4 to pH 10. The emergence percentages decreased significantly beyond 0.5~3 cm deep burial in soil for both A. viridis L.and A. spinosus L. Germination percentages both fresh and nondormant seeds of A. viridis L. were higher than those of A. spinosus L. at different light treatments .The germination percentages of both A. viridis L. and A. spinosus L. decreased at dark ness. A shorter duration of light exposure for A. viridis L. seeds was reguired to reach high germination than that for A. spinosus L. seeds . Germination percentages of both A. viridis L. and A. spinosus L. were above 80% under the condition with O2 added , wihle those were less than 40% under partial anaerobic condition. Key words : seed ecology、environmental factors Amaranthus viridis L.、 Amaranthus spinosus L.。