Effects of Gibberellic Acid (GA3) Foliar Application on Growth Characteristics and Essential Oil of Lavender (Lavandula officinalis Chaix.)

An experiment was carried out to investigate the effects of different concentrations of gibberellic acid (GA₃) as foliar application on growth and essential oil content and yield of lavender based on randomized complete block design with five treatments and four replications. The treatments consisted of different concentrations of gibberellic acid (T₂=100, T₃=200 and T₄=300 mg/l), formulated (tablet) gibberellic acid (T₅) and the control (T₁=0). Essential oil of dried shoots and flowering stalks were extracted by hydro-distillation method using Clevenger type apparatus. Essential oil yield was calculated in milliliters per square meter based on the essential oil content. The results showed that the highest essential oil content and yield of both shoots and flowers belonged to the 300 mg/l GA₃ application. Fresh and dry weight of leaves and stem attained their highest quantities at 300 mg/l GA₃ application as well. In contrast, there was significant difference between treatments regarding flowering stalk (inflorescence) fresh and dry weight and the greatest amount for this trait was recorded in the control. GA₃ application at 300 mg/l significantly (P<0.05) affected flower bearing plants and the highest number for this trait belonged to the highest level of GA₃ i.e. 300 mg/l. Like with many of traits, the maximal plant height was also belonged to T4 treatment. Overally, considering the whole results it seems that 300 mg/l GA₃ was the most appropriate treatment for foliar spray of lavender plants regarding growth characteristics, essential oil content and yield.
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h�f `-_ le='mso-spacerun:yes'>  T<sub>2</sub>،  200 میلی­گرم در لیتر=   T<sub>3</sub>و300 میلی گرم در لیتر=T<sub>4</sub>) و تیمار پاششی حاصل از قرص جیبرلین ((T<sub>5</sub> به علاوه تیمار شاهد (T<sub>1</sub>) بود. اسانس شاخساره و گل آذین با استفاده از کلونجر استخراج و عملکرد آن در اندام­های فوق الذکر بر حسب میلی­لیتر به متر مربع محاسبه گردید. نتایج نشان دادند بیشترین محتوا و عملکرد اسانس در تیمار 300 میلی­گرم در لیتر اسید جیبرلیک بدست آمد. وزن تر و خشک برگ­ها و ساقه در تیمار 300 میلی گرم در لیتر بیشترین مقدار بود. از لحاظ وزن­تر و خشک گل­آذین اختلاف بین تیمارها معنی­دار بود و بیشترین مقدار در تیمار شاهد مشاهده گردید. از نظر تعداد گیاهان گل دهنده اختلاف معنی­داری بین تیمارها دیده شد و بیشترین تعداد گیاهان گل دهنده مربوط به تیمار 300 میلی گرم در لیتر اسید جیبرلیک بود. ارتفاع گیاهان نیز در تیمار 300 میلی گرم در لیتر اسید جیبرلیک به حداکثر رسید. بنابراین افزایش غلظت اسید جیبرلیک به عنوان تنظیم کننده رشد گیاهی تا 300 میلی­گرم هم باعث افزایش محتوا و هم عملکرد اسانس اسطوخودوس گردید.  43: Q���
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Baher  ZF, Mirza M, Ghorbanli M and RezaiiMB, 2002. The influence of water stress on plant height, herbal and essential oil yield and composition in Saturja hortensis L. Flovour and Fragrance Journal, 17: 275 – 277.
Bannayan M, Nadjafi F, Azizi M, Tabrizi L and Rastgoo M, 2008. Yield and seed quality of Plantago ovata and Nigella sativa under different irrigation treatments. Industrial Crops and Products, 27: 11–16.
Baricevic D, Umek A, Kreft S, Maticic B and Zupancic A, 1999. Effect of water stress and nitrogen fertilization on the content of hyoscyamine and scopolamine in root of deadly nightshade (Atropa belladonna). Environmental Botany, 42: 17 – 24.
Bryant JP, Chapin III, FS and Klein DR, 1983. Carbon / nutrient balance of boreal plants in relation to vertebrate herbivory. Oikos, 40: 357 – 368.
Charles DJ, Joly RJ and Simon JE, 1990. Effect of osmotic stress on the essential oil content and composition of peppermint. Phytochemistry, 29 (9): 2837 – 2840.
Charles D, Simon J and Widrelechner M, 1995. Characterization of essential oil of fruits of Anethun graveolens L. Journal of Essential Oil Research, 7: 1 – 11.
Gershenzon J, 1984. Changes in levels of plant secondary metabolites under water and nutrient stress. In: B.N. Timmermann, C. Steelink, and F.A. Leowus, (eds.), Phytochemical adaptation to stress, Plenum Press, New York., pp.273 – 320.
Herms DA and Mattson WJ, 1992. The dilemma of plants: To grow or defend. Quart. Rev. Biol. 67: 283 – 325.
Hornok L, 1980. Effect of nutrition supply on yield of dill (Anethun graveolens L.) and its essential oil content. Acta Horticulture, 96: 337.
Houpalahti R, Lahtinen R, Hiltunen R and Laskso I, 1998. Studies on the essential oil of dill  herb (Anethun graveolens L.). Flavour and Fragrance Journal, 3 (3): 121.
Kruger H and Hammer K, 1996. A new chemotype of  Anethun graveolens L. Journal of Essential Oil Research, 8 (2):  205.
Letchamo W and Gosselin A, 1996. Transpiration, essential oil glands, epicuticular wax and morphology of Thymus vulgaris are influenced by light intensity and water supply. Journal of Horticultural Science, 71 (1): 123 – 134.
Lorio PL, 1986. Growth - differentiation balance: A basis for understanding southern pin beetle-tree interaction. Forest Ecology Management, 14: 259 – 273.
Mahram G, Kadry H, Thabet C, Olem N, Azizi M, Shiff J, Wong L and Liv N, 1992. GC/MS analysis of volatile oil of fruits of Anethun graveolens L. International Journal of Pharmacognoy, 30 (2): 130.
Rhizopoulous S and Diamatoglon S, 1991. Water stress induced diurnal variations in leaf water relations, stomatal conductance, soluble sugars, lipids and essential oil content of Origanum majorana L. Journal of Horticultural Science, 66 (1): 119 – 125.
Simon JE, Bubenheim RD, Joly RJ and Chares DJ, 1992. Water stress induced alteration in essential oil content and composition of  sweet basil. Journal of Essential Oil Research. 4: 71 – 75.
Tuomi J, Niemela P, Haukioja E and Neuvonen S, 1984. Nutrient stress an explan- at ion for plant anti - herbivore responses to defoliation. Oecologia, 61: 208–210.