عنوان مقاله [English]
Introduction: Growth regulators play a vital role in developmental stages of plants and their use can be improved the yield of crops. One of the most important compounds that used as growth regulators in recent years is Salicylic acid. The application of salicylic acid in the activation of systemic acquired resistance, and metabolite synthesis and antioxidant enzymes has been proved. Also, salicylic acid as a natural compound has potential to prevent ethylene production and its effect. In order to evaluate the effect of salicylic acid in different concentration on yield and oils content of Ziziphora, a split plot experiment with three replications during 2014-2015 in the farm of Agricultural Faculty of Shirvan and Ferdowsi University of Mashhad laboratories was conducted.
Material and Methods:This research was conducted during 2014-2015 in field conditions in a split plot design in time,at Shirvan Agricultural Research Station(latitude º40 / 37, longitude º93 / 57 and with a height of 1097 m above sea level) and in labrovatory Department of Horticultural Sciences, Ferdowsi University of Mashhad. Each plot had an area of 4 square meters in furrow planting way which the distance between rows were 50 cm and on rows 15 cm and were carried out on 25 March 2014. IMediately after planting, irrigation was done, and after 20 days which the seeds germinated as well, second irrigation was done. Irrigation and weed controls also be done manually once a week. Salicylic acid (Sigma Aldrich, 99.5%) in the three phases of plant growth (vegetative growth, during vegetative growth and flowering time), at concentrations (0, 10-2, 10-4 and 10-6 M) in three repeats were sprayed. The first spraying (the growth)on 3 April 2014, the second spraying (during growth) on 4 May and the third one (at the time of flowering) was conducted in early June 2014. Plant harvesting was done on 20 July. In order to measure the dry weight of plants, the samples were dried for a week in shade condition. Essential oil content was determined using 30 grams dry sample in 500 ml of water by hydrodistillation using Clevenger for 4. For biochemical characteristics first samples extract were obtained. To prepare extracts, dry samples were milled then one gram of each sample was transferred to the 50 ml Erlen and 10 ml of 80%methanol was added and shaked for 24 hours. After 24 hours the extract was filtered using filter paper then used for measuring phenols, flavonoids and antioxidant activity.
Phenol measurment: phenolic content was measured using the Folin reagent. In 5.0 mL of each extract (10 milligrams per ml) 5.2 ml Folin reagent was added. After 5 minutes, 300 ml of a molar solution of sodium carbonate is added and for 30 minutes in a bath that was 40 °C. The sample absorbance at 760 nm was measured by a spectrophotometer against the blank. Gallic acid was used as the standard for calibration curve.
Flavonoids measurement: Flavonoid content of the samples were measured using aluminum chloride reagent. In 5.0 ml of methanol extract (10 milligrams per ml), 5.1 ml of methanol, 1.0 ml of 10% aluminum chloride, 1.0 ml of a molar potassium acetate and 8.2 ml of distilled water was added. The mixture kept in dark for 30 minutes and absorbance at a wavelength of 415 nm was read against the blank. Quercetin was used as the standard for calibration curve evaluation. JMP statistical software was used to analyze the data.
Results and Discussion: Based on the results application of salicylic acid affect fresh and dry weight, plant height, phenol and flavonoid content significantly ( P