Document Type : Original Article
Authors
1 Lecturer, Department of Agronomy and Plant Breeding, Payame Noor University, Iran
2 PhD students of Weed Science, Ferdowsi University, Mashhad, Iran
3 Associated Professor of Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Birjand., Birjand, Iran
4 MSc in Weed Science
5 PhD student of Weed Science, Ferdowsi University, Mashhad, Iran
Abstract
Seed dormancy is one of the major obstacles against evaluating the effect of different environmental factors on germination characteristics of weed seeds. In order to realize the type of Mesquite seed dormancy, an experiment was conducted based on completely randomized design (CRD) with twelve treatments and four replications. Treatments were six different times of seed soaking in sulfuric acid 95-98% (10, 20, 30 40, 50 and 60 minutes), mechanical scarification with sandpaper for 5 minutes, seed soaking in distilled water for 24 and 48 hours and soaking seeds in boiling water (95-98 °C) for 5 and 10 minutes as well as a control treatment. Results showed that all chemical and mechanical scarification treatments resulted in mesquite germination and the highestgermination rate, root and stem length, and root and stem fresh weight were observed in the treatment of seed soaking in sulfuric acid for 60 minutes. Moreover, in order to study the effect of salinity and drought stress on germination characteristic of mesquite, two separate experiments were conducted as completely randomized design (CRD) with four replications. Treatments included different osmotic and matric potentials at four levels (-0.3, -5, -10 and -15 bars) as well as a control treatment (0 (distilled water). Results showed more negative osmotic and matric potentials significantly (p≤ 0.001) decreased the germination percentage and rate in comparison with the control, and this reduction was greater with the drought stress. The parameter X50 of the three-parameter logistic model showed that the 50% reduction in maximum germination percentage of mesquite occurred at -16.23 and -6.26 bar of osmotic and matric potentials, respectively, which indicated a greater sensitivity of this species to drought stress.
Keywords
)