GERMINATION PATTERNS ON GRASSES PRESENT AT THE CHIHUAHUAN DESERT

Background: Germination characteristics of grasses are the bases for explain possible adaptation to environmental changes, as well as invasive behavior. Hypotheses: Each species has germination characteristics that can explain its establishment success in grassland. Studied species: Bouteloua curtipendula, B. dactyloides, B. eriopoda, B. gracilis, B. hirsuta, B. repens, B. rigidiseta, Chloris virgata, Digitaria californica, Eragrostis curvula, E. echinochloidea, E. lehmanniana, E. superba, Heteropogon contortus, Hilaria mutica, Leptochloa dubia, Melinis repens, Muhlenbergia emersleyi, M. macroura, M. rigida, Pappophorum bicolor, and Pennisetum ciliare (16 native species and six exotic species). Study area and dates: Chihuahuan desert grasslands, 2019. Methods: Germination test at 28 degrees C at constant moisture and in the dark. Response variables were number of seed germinated, time of germination and length of root and shoot. Based on those, range, time, velocity, index of germination ad root:shoot ratio were calculated. Results: Germination range was <= 4 days on 18 species. The highest values (P < 0.05) were 7.8 germinated seed per day and 3.3 of germination index. Eleven species had a value <= 1 of R:S at one week age. Conclusions: E. curvula, B. curtipendula, L. dubia, and D. californica showed one or more adaptations that place them with potential for a rapid establishment in arid zones. However, the invasive aliens E. lehmanniana and Melinis repens possibly have other strategies that facilitate their establishment.