نشریه بوم شناسی گیاهان زراعی
سال پانزدهم شماره 3 (پیاپی 57، پاییز 1398)

To investigation the effect of carbon nanotubes (CNTs) seed priming to enhance seed germination quantity and quality of corn hybrids under drought stress, an experiment was conducted as factorial based on completely randomized design at Seed Technology Laboratory of Shahed University, Tehran, Iran. Drought stress induced by -0.5 and -1 Mpa polyethylene glycol solution on Fajr and Dehghan maize hybrids and the seeds primed by 25 and 50 mg/L CNTs. Nano-priming under drought stress was effective on germination percentage and rate, weight and length, chlorophyll a, b, and total chlorophyll and carotenoid contents of maize seedlings. Application of 25 mg/L CTNs at -1 Mpa drought stress effectively enhanced germination percentage of maize seed. Also, application of 50 mg/L CTNs improved photosynthetic pigmentation at -1 Mpa drought stress. Generally, CTNs priming improved seed germination traits and photosynthetic pigmentation of maize seedlings under drought stress conditions. Therefore, priming by 25 mg/L CTNs is recommended to improve maize seeds germination indices in arid and semi-arid regions.

Novel integrated system of greenhouse and saltwater evaporation pond is a recently developed idea to provide the possibility of producing freshwater and crop growth in arid and semi-arid areas using saltwater. The system greatly reduces the water requirement of the crop in cultivating environment controlling atmospheric conditions and increasing relative humidity to saturation point. To evaluate the effect of saltwater evaporation pond dimensions on basil water requirements in greenhouse condition of the proposed system, a pilot project was done using pond dimensions of 1, 2, and 3 meter in southeast of Tehran. The average daily requirements of the basil in pilot projects of numbers 1, 2, and 3 in two cultivation periods were measured as 2.4, 1.9, and 0.8 mm, respectively which were significantly different. Increasing the length of saltwater evaporation pond in the system improved system capability to reduce crop water requirement. Therefore, implementation of larger ponds is recommended in commercial scale of this integrated system.

Sufficient soil fertilization is one of the main requirements for production of barley improvment. To study the effect of different organic fertilizers on yield and yield components of barley cv. Reyhan, an experiment was conducted based on randomized complete block design with three replications with 16 fertilizer compounds. Barley morphological traits, yield and yield components were measured. Treatments were included wood vinegar, 5, 10, and 150/00 as soil application, azocompost, zeolite, wood vinegar, 5, 10, and 150/00 as foliar spraying, wood vinegar, 5 and 100/00 + azocompost, wood vinegar, 5 and 100/00 + zeolite, humic acid, wood vinegar, 5 and 100/00 + humic acid. Application of wood vinegar at 50/00 rate + zeolite significantly increased leaf area and plant dry weight. Also, using vinegar at 100/00 rate + zeolite significantly increased spike length and grain yield. Application of vinegar at the rate of 100/00 with zeolite is recommended in barley cultivation.

To study the effect of nano-chelated iron and potassium foliar spraying on quality and quantity of damask rose essential oil and morpho-physiological characteristics, an experiment was conducted based on randomized complete block design in 2018 at Medicinal Plant Research Farm of Islamic Azad University, Miyaneh Branch. One year after the complete establishment of damask rose and during the blooming stage, plants were sprayed three times at intervals of 10 days by 0.5, 1 and 1.5 g/L nano chelated iron and potassium. The traits evaluated in this experiment were leaf fresh and dry weights, flower fresh weight, leaf length and width, chlorophyll content, flower and receptacle diameter, petal number, plant height, essential oil quantity and quality. Application of nano-chelated iron increased the leaf fresh and dry weights. The highest and the lowest percentages of essential oil were observed in nano-chelated potassium at 1 g/L (0.2%) and nano-chelated potassium at 1.5 g/L (0.06%), respectively. 18 combinations were identified in essential oil of damask rose and the highest components were determined in citronellol, geraniol, tricosane, nonadecane and henicosane. The citronellol (27.3%) and geraniol (14.17%) was obtained from nano-chelated potassium at 1 gr/L and highest nonadecane (3.12%) and tricosane (21.17%) was obtained from nano-chelated iron at 1.5 g/L. The highest amount of henicosane (21.53%) was obtained in control treatment. Therefore, nano-chelated potassium at 1 g/L. can be used to give the highest essential oil yield and extraction of citronelol and geraniol, which are one of the most important economic compounds in damask rose.

Changes in the history of the first frost of autumn and the last frost in the spring could be a serious threat to gardeners and farmers. The purpose of this study is to know how this change will be in the future period (2015-2068) compared to the base period (1961-2014) at Gorgan Station. For this purpose, daily data of the Gorgan Minimum Temperature Station was obtained at the observation period from the Golestan Meteorological Office. Then NCEP data, CanESM_RCP_26, RCP_45, RCP 85 were downloaded from Canada's Climate Change site, and using SDSM software, the minimum temperature data for the next period was generated for the three scenarios. Then, the date of the beginning and the end of the glacial to date of Julius was calculated and fitted with SMADA software with different statistical distributions and, using more suitable distributions, the probability of occurrence of freezing days was calculated. The results of this study indicate that the glacial period in the observation period is 75 days. it is also 46 days for the upcoming period in the optimistic scenario. It includes 39 days in the intermediate period and 31 days in the pessimistic scenario, which results in a significant decrease in the duration of the ice period and the increase of the period Growth of plants in the course of the future, which requires more vigilance of planners to deal with the destructive effects of climate change.

Salinity is one of the most abiotic stress that cased reduce the yield of crops. Quinoa has role importance in human nutrition and have a high resistance to salinity stress. In order to investigate the effects of salinity stress on germination characteristics of quinoa cultivar Q26, experiment was conducted based a complete randomized design (CRD) with four replication. The treatments consisted of different concentrations of sodium chloride (NaCl) (0,4, 8,12,16,20, 30and40 dS/m) on the germination seed of quinoa under laboratory conditions. Salinity haveundesirable effects ontraits study such as germination percentage, germination rate, shoot and root length, shoot and root dry weight, stem-to-root ratio (Coefficient of Allometry), germination uniformity and time to 50 percent germination.The percent germinationsignificantly reduce in 30 dS/m salinity,but many traits reduced in concentration 40 dS/m of NaCl. The percentage of germination was not significant between control and 30 dS/m treatment, but at 40 dS/m concentration reduced to 75 percent. With increase salinity levels, time to 50 percent germination increased significantly. Germination rate also reduced significantly by salinity levels.The shoot-to-root ratio decreased with increasing salinity up to 20 dS/m but reached a maximum at 30 dS/m The results showed that quinoa cultivar Q26 has high resistance to salinity stress in germination stage,therefore it can be said that thiscultivar have a good resistance to 30 dS/mof sodium chlorideand can be thebest cultivar for saline conditionafter field evaluation and appropriate climate.