Effect Of Cold Stratification And Temperature On Seed Germination Of Two Types Of Plant Of The Alpine Meadow

Seeds germination are affected by many factors,and temperature is one of the most important ecological factors. This paper describes the germination characters of gramineous species and leguminosae species from the alpine meadow on the eastern of Qinghai-Tibet plateau. Seeds of 25 gramineous species and 19 leguminosae species were stored in darkness for 18 weeks at 5℃in the laboratory and 18 weeks at room temperature (about 20±l℃) before germination tests,the other trail is each species were tested in darkness for 50 days with four different temperature regimes (a 12-h day at 20℃and a 12-h night at 5℃, a 12-h day at 15℃and a 12-h night at 5℃, a 12-h day at 25℃and a 12-h night at 10℃, a 12-h day at 25℃and a 12-h night at 15℃). These temperature regimes have relevance to field conditions. Cold stratification removed seed germination characters differences in most gramineous species. Of the 25 gramineous species examined, 28% species germinated higher after cold stratification than room temperature storation, 40% lower, and 32% similiar. In addition, of the 19 leguminosae species, only Caragana brevifolia and Astragalus weigoldianus germinated lower after cold stratification than room temperature storation; Oxytropis longipedunculata and O.latibracteata germinated equally after two storation conditions; and the other species germinated higher after cold stratification than room temperature storation. At different temperature regimes, 56% gramineous species germinated higher at the amplitude of 15℃than 10℃and only 2 species (Bromus japonica and Ptilagrostis dichotoma) germinated higher at the amplitude of 10℃than 15℃. In addition, some of gramineous species are sensitive to daily maximum(or minimum) temperture. 7 leguminosae species germinated higher at the amplitude of 10℃than 15℃; some leguminosae species didn't germinate at the daily maximum temperature of 25℃; and seed germination seemed to be independent of temperature amplitude. In a word, seeds germination of leguminosae species were more influenced by cold stratification, but weren't sensitive to different alternating temperature. Seeds germination of gramineous species were removed by cold stratification, and were more sensitive to different alternating temperature than leguminosae species.