جستجوی مقالات مرتبط با کلیدواژه "rangeland plants" در نشریات گروه "اکولوژی"

Aboveground net primary production (ANPP) is one of the crucially characteristics of rangeland ecosystems and it is importance in the cycle of materials and energy in these ecosystems. The aim of present study was investigate the ANPP of life forms (grasses, forbs, and shrubs), and total ANPP; then modeling of life forms and total ANPP by using precipitation and temperature in Siahpoush and Ganjgah mountain rangelands of Kowsar County, Ardabil Province. Seven sampling sites were determined at different altitudes and in each site according to the vegetation pattern of the representative regions were considered as three transects (100 m) in each site and 10 plots were considered for ANPP evaluation in each transects. The relationship between climate factors classes (precipitation and temperature), and the ANPP were analyzed using one way Anova and Duncan analysis. The ANPP maps were simulated using linear regression in ArcMap10.0. The results show a significant relationship (p>0.05) between the life forms and total ANPP with precipitation and temperature factors. The accuracy (RMSE) of simulated maps for ANPP of grasses, forbs, shrubs and total ANPP was 0.07, 0.08, 0.14 and 0.06, respectively. The present study results can be used in balance between supply and demand of rangelands production.

Smyrniopsis aucheri BOISS is an herbaceous species of Apiaceae family which seed germination is difficult. Therefore, to restore the natural habitats of this plant, it is necessary to provide information about the length and the factors that affecting seed dormancy of this plant. In order to study effect of the duration of chilling and temperature on seed dormancy and seedling establishment of Smyrniopsis aucheri, this experiment was conducted as factorial in a randomized design. Factors were included the pre-chilling duration in 7 levels (0, 10, 20, 30, 40, 50 and 60 days), level of chilling (with and without chilling) and temperature in 4 levels (5, 10, 15 and 20 ° C).The results showed that the combination of chilling and temperature treatment had the highest effect on stimulation of seed germination under certain conditions, and chilling treatment less than 30 days had no significant effect on seed germination. The results showed that chilling at 5 ° C for 60 days, was the most effective treatment on breaking dormancy in S.aucheri. Germination percentage (51.9%), germination rate and seed vigor increased significantly in this treatment, compared to control treatment. In relation to growth indices, the results showed that chilling 20 ° C for 60 days was the most effective treatment on seedling growth indices. Overall, according to the results, In order to improve the seedling establishment of Smyrniopsis aucheri, the use of chilling for 60 days, which markedly enhanced all of the seedling establishment indices, is recommended.