Ecophysiological Studies on the Seed Germination and Antioxidant activities of Gnaphalium purpureum L.

• Main Authors: Li-Ting Huang, 黃笠庭
• Other Authors: Chin-Jin Hou
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/26944787990002185537

碩士 === 國立嘉義大學 === 農藝學系研究所 === 97 === The purpose of this study would like to know seed ecophysiology of the upland field weed of Gnaphalium purpureum L. in Taiwan, including the annual changes of the seed germinability and the seed germination affected by various environment factors. The second purpose of this study would like to determine antioxidant activities of G. purpureum L.. The seeds were collected in Chiayi and buried into a 10 cm-deep upland soil, and then harvested monthly for two years. Seed germinative percentage was tested under six different temperature regimes or buried into soil of 0.1 cm in depth. It was found that the germinative rate of tested seeds was lower at 30/25℃ than the other treatments in the beginning of the experiment with light treatment. The high germinative ability of buried seeds was observed while they were incubated at 15/10, 20/15, 25/20, 23/13 and 30/20℃ with light treatment and that was changed with seasonal fluctuation. However, seed germination at all temperature regimes was lower at the beginning with dark treatment. The tested seeds had stronger conditional dormancy at 30/25 and 30/20℃ with germinative percentage near zero. Germinative abilities of tested seeds among other four temperatures were similar with light treatment, but all seed germinative abilities with dark treatment were lower than that with light treatment. Field experiments of buried seeds and fresh seeds showed that of the seed germination mainly occurred in winter. However, the high temperature from late spring to early autumn refarded seed germination. The seed germination of G. purpureum L. under alternate temperatures was highest among under constant temperatures. The germinative percentage reaches 90.33 % at 25/20℃ as highest among all treatments. Both of the germinative percentage at 25/20℃ reach 80 % and upward as highest under the experiments of osmotic potentials and salt stress. Seeds of G. purpureum L. can germinate at osmotic potentials between 0 MPa and -0.2 MPa, and it can germinate at salt stress between 0 % and 0.4 %. Both of the germinative percentage reach 80 % and upward as highest under white light and red light. Seeds were insensitive under other light qualities, and the germinative percentage reaches 21.33 % as lowest under dark. The germination of pH 6 with 25/20℃ was highest among all treatments. Both of the contents at total phenols and total flavones were highest in the period before blooming. Scavenging activity of the period before blooming on the DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical was highest. Chelating capacity of the period after blooming was highest.