Citrullus colocynthis is one of the major medic plants and it has many medical values. This plant adopts in desert regions and specifically in sand dunes. Forasmuch as seeds of this plant germinate not easily, so in this research tried to study about effect of different treatments for breaking seed dormancy, germination stimulus and growth of Citrullus colocynthis seeds. The treatments were include sulfuric acid 98% in 20 and 40 minutes time intervals, potassium nitrate 0.2% within 72 hours, hot water in 90 centigrade degree during 10 minutes and scratching by sand paper. For comparing this treatments and normal germination is used distilled water for control. Experiments were performed in a completely randomized design with four repetitions and six treatments. Results of variance analysis and mean comparison showed that there are significant statistical differences (0.01 levels) between treatments for percentage and velocity of germination, length of the Root and Shoot. The maximum percentage and velocity of germination and length of the Shoot obtain in scratching by sand paper treatment and results of other treatments were in lower level than this one. According to got results determined that scratching is the most suitable method for dominance on seed dormancy of Citrullus colocynthis species.

Seed priming technique has been known to improve germination and seedling emergence under different environment stresses. The objective of this study was to evaluate the effectiveness of seed priming in improving the seed germination and seedling vigor of Agropyron elongatum and Bromus inermis in response to five concentrations of the allelopathic extract of Thymus kotschyanus (0, 5%, 25%, 50% and 75%) under laboratory conditions. Pretreatments included gibberellic acid (250, 500 and 1000 ppm), potassium nitrate (0.1%, 0.2% and 0.3%) and salicylic acid (100, 200 and 300 mg/L). This experiment was carried out as a factorial experiment based on a completely randomized design with four replications. The results showed that seed germination, germination speed and seedling vigor were significantly decreased (P < 0.01) by increasing extract concentrations of Thymus kotschyanus allelopathic compounds in unprimed seed (control) compared with primed seeds. Seed priming enhanced germination percentage, germination speed and initial growth. Overall, the results of this study showed that the response of both species to pretreatment of seeds was positive. Therefore, pretreatments of seeds with the aforementioned chemical stimulators before planting can significantly reduce the negative effect of allelopathic compounds in Thymus kotschyanus during the germination stage and contribute to plant establishment by increasing germination speed and growth of embryos.

Bio19 with 50.5% contribution, followed by Bio8 and Bio2 with 30% and 11.4% contributions, respectively. The best Maxent model included seven variables, 4 feature types (linear, quadratic, product, and hinge), and had a test AUC value of 0.894. The current potential distribution indicated that 8% of Iran's drylands are suitable for growing D. mucronata and this area could decrease to 5.2% under representative concentration pathway (RCP) 4.5, and 3.1% under RCP 8.5 due to climate change. Our results suggest that D. mucronata may lose overall about 2.8% and 4.9% of its current distribution under RCP 4.5 and RCP 8.5, respectively, by 2050. There would be only 0.7 and 0.2% gains under RCP 4.5 and 8.5, respectively. The species would locally disappear between 1500-and 2000-m elevation under RCP 4.5 and 8.5, respectively. The establishment of some stations for monitoring the changes in transition zone or lost areas especially on the southeastern parts of Zagros Mountain can help in detecting changes in the future. Additionally, stable habitats may be good target areas for future conservation planning. Keywords Climate change • Habitat loss • Maxent • Species distribution modeling • Zagros MountainsHighlights • Daphne mucronata Royle is an important medicinal plant in the Zagros mountains in the Middle East. • About 8% of Iran's drylands are suitable for growing Daphne mucronata. • D. mucronata may lose about 2.8 to 4.9% of its current habitat under future climate scenarios. • The species would locally disappear between 1500 and 2000 m elevation under future climate. • Results can be used to re-introduce D. mucronata and monitor suitable habitats.

Toleration of germination and embryonic growth stage to heavy elements is as a key of plant establishment under limited conditions. In this study effects of two heavy metals, cadmium and copper sulfate and their interplays were evaluated on germination and growth of A. elongatum. Therefore A. elongatum seeds after disinfectant, placed on watman paper and influenced by cadmium (10, 20 and 30 mg L ). Distilled water was used as control treatment. Each treatment had 4 replications and there were 25 seeds for each replication. Germination of seeds was evaluated everyday and growth index was determined by measuring of root length, shoot length, seedling length and seed vigurity index. Results indicated that there weren't significant differences among the treatment of germination percentage and speed but length of roots, length of shoots, length of seedling and vigurity index reduced significantly by application of these heavy metals. Root length reduced from 6.2 cm in the control to 2.4 cm at 30 mg L -1 Cd solution but it reduced from 6.3 cm in the control to 4.1 cm at 30 mg L -1 Cu solution. Shoot length was reduced from 9.2 cm in the control to 4.6cm at 30 mg L -1 Cd solution and reduced from 9.4cm in control to 5.6 cm at 30 mg/L Cu solution.