حسین صفری

This study was conducted to study germination two species of vetch (Vicia sativa; Vicia pannonica) under temperatures (5, 10, 15, 20, 25, and 30 °C) and different water potentials (0, -2, -4, -6, -8 and -10 bar) at the Vali Asr Rafsanjan University laboratory in completely randomized design arranged as a factorial with four replications. The segmented function was evaluated to describe the relationship between germination rate and temperature. Results showed base temperature for germination of Vicia pannonica was -3.65 to 1.39, optimum temperature 23.99 to 25.57 and ceiling temperature 30 to 58.54 under different water potentials. The biological hours for germination of this specie were 32.29 to 74.97 hours under different water potentials. Also, base temperature for germination of Vicia sativa was -3.54 to 1.39, optimum temperature 22.70 to 25.64 and ceiling temperature 30 to 42.28 under different water potentials. The biological hour requirements for germination of this specie were between 33.10 to 83.54 hours under different water potentials. The results of germination rate in both species showed that with increasing water potential, germination rate decreased. In all of water potentials germination rate increased to 25°C and then decrease. Estimated parameters and the relations can be used to prediction time to germination or emergence in two species of vetch under different water potentials.

Salinity stress is regarded as one of the most important abiotic factors limiting plant growth and agricultural products, particularly in arid and semi-arid regions. Sesame (Sesamum indicum L.) is an important oilseed crop rated moderately salt tolerant and capable of producing profitable crops in saline conditions. Germination and seedling establishment are critical stages in the life cycle of plants especially under stress conditions. Different methodologies have been adopted by plant physiologists in different crops to alleviate salt stress. Seed priming has proven beneficial in this regard in many important agricultural crops. Salicylic acid is one of the physiological processes regulators that it increases resistant of plants to environmental stresses such as salinity stress.
To evaluate the effect of different levels of salinity and seed pretreatment with salicylic acid (SA), on some growth indices and nutrient uptake of sesame (Sesamum indicum L.) seedling, a factorial experiment with completely randomized design and four replicates was conducted in Department of Agronomy, Rafsanjan University of Vali-e- Asr. Factors were seed pretreatment with three levels including, distilled water, 1 mM salicylic acid and 2.5 Mm salicylic acid and salinity at three levels: control (Hoagland standard solution, 2.5 dS.m-1), 6 and 9 dS.m-1. A dry seed treatment (no pretreatment) was also added and considered as control.
Results showed that at 9 dS/m-1both SA concentrations caused significant increase in emergence percentage compared to dry seed and distilled water. Plant leaf area and SPAD values decreased along with salinity in dry seed and distilled water, nevertheless, at 2.5 mM SA, values were not significantly different between 6 and 9 dS.m-1. On the other hand, SA seed pretreatment decreased shoot Na and increased K content, although shoot Mg and P contents were the highest at 1 and 2.5 mM SA, respectively. The effects of SA pretreatment on shoot dry mass was not clear. The highest shoot, root and seedling dry weights were observed at control salinity in dry seed, distilled water and 2.5 mM SA and decreased with salinity level. Seedling dry weight was not significantly lower than control only in 1 mM SA and 9 dS.m-1 salinity.
Generally, in this experiment ameliorative effects of SA pretreatment were more pronounced on seedling survival and some nutrient uptake.

In order to study the effects of priming (control (non-primed), distilled water, 0.1% chitosan and 0.2% chitosan) on seed germination and growth of chickpea seedling, under salinity stress (0, 4, 6 and 8 dS/m) an experiment was conducted in controlled-environment conditions. Results showed salinity stress reduced germination percentage and rate, vigor index, length and dry weights of shoots and roots, K concentration and K/Na ratio, whereas increased Na concentration, proline, total carbohydrate and malondialdehyde content. Seed priming with chitosan increased germination percentage and rate compared to other priming treatments.Vigor index, shoot length, root length and dry weights of shoots were higher in chitosan primed seed compared to control under salinity stress 6 dS/m. The highest K concentration was observed in seed primed with 0.2% chitosan. Also, with the increasing salinity, chitosan decreased Na concentration and malondialdehyde and increased K/Na ratio, proline and total carbohydrate content. Thus, it suggests that main effect priming the chickpea seeds with chitosan was on seedling growth and it don’t effect on increasing germination percentage.

In order to study the effect of chitosan on growth and some biochemical characteristics of chickpea under salinity stress condition a greenhouse experiment was conducted in Vali-e-Asr University of Rafsanjan in 1392، as factorial arrangement in completely randomized design with three replications. Experimental factors included salinity (0، 4، 6 and 8 dS/m) and level of chitosan (0، 0. 1، 0. 2%، all dissolved in 1% acetic acid) along with an additional treatment of distilled water. Results indicated that with increasing salinity malondialdehyde content (0. 834 mM g-1)، proline (0. 254 mg. g-1 FW)، total carbohydrate (10. 48 mg. g-1 FW)، Na+ concentration of shoot (1. 87%)، Na+ concentration of root (2. 05%) were increased while other traits under study were decreased. Chitosan treatment increased shoot height، shoot dry weight and relative water content and decreased malondialdehyde content. Under salinity conditions، chitosan treatment root height، root dry weight، proline and total carbohydrate were increased. Also، chitosan increased K+ concentration and decreased Na+ concentration of shoot under both unstressed and stressed condition. In plants treated with chitosan، K+ concentration of root increased compared with control plants، but the Na+ concentration of root decreased by 7. 14 %. The results of the study indicate that priming the chickpea seeds with chitosan reduce the harmful effects of salinity via either reduction in Na+ absorption or by accumulation of proline، total carbohydrate and K+.