Studying the Effect of Foliar Application of Methanol and Ethanol on Morphological and Biochemical Characteristics of Sweet Basil (Ocimum basilicum c.v. Keshkeni luvelou)

The side effects of chemical drugs has resulted in more attention of human to use medicinal plants and extract their ingredients for treated of many diseases. Iranian plateau have been introduced as an origin of many medicinal plants and according to the needs of pharmaceutical, food and cosmetic industries to medicinal plants as a raw materials, necessity of cultivation of medicinal plant species in the country is quite clear, because dependency to natural products and the indiscriminate exploitation of them will be extinction of this species. Basil (Ocimum basilicum) is a medicinal plant of the family of Lamiaceae, which it is very important in pharmaceutical industry, food and traditional medicine. Due to serious problems in the past decades resulting excessive application of chemical inputs and plant growth regulators to enhance agricultural production, nowadays, the need for new technologies to produce safe food and to protect environment has been of great interest to the international community. In this regard, the application of alcohols, especially ethanol and methanol solutions, to improve the performance of plants in the agricultural systems are important. Alcohols are the most important compounds in organic chemistry and they have wide frequency in the nature and are easily produced in the industry and chemical laboratories. In addition, use of foliar application of methanol and ethanol on the aerial parts of different plants propound as one of the newest strategies to increase growth and their yield. The objective of this experiment was evaluation of methanol and ethanol spraying effects on morphological and biochemical characteristics of sweet basil (Ocimum basilicum L.).
This experiment was carried out as completely randomized design with three replications at the Faculty of Agriculture, Ferdowsi University of Mashhad, in 2015. Plants were foliar treated with four levels of ethanol (0, 10, 20 and 40% v/v), methanol (0, 10, 20 and 40% v/v), the same mixture of methanol and ethanol (5, 15 and 25% v/v), and control (without spraying).
The results of variance analysis showed that the effect of foliar application had significant effect on measured indices, so that 40% methanol in the most of morphological characters is superior to the other levels. Alcohol treatments are effective to the growth and development of the vegetative organs of plants. Also, alcohol treatments can increase the carbohydrate accumulation and carbon dioxide concentration. Also, foliar application of methanol along with methanol that produces at leaves by pectin methyl esterase enzyme in cell wall development processes can increase cytokine in production and stimulation plant growth. In the biochemical traits, the most of antioxidant activity, phenol, carotenoids and chlorophyll b related to interaction of foliar application of methanol and ethanol 25%. Methanol increases turgor pressure, sugar content, cell swelling and helps to leaves development and increasing of chlorophyll and carotenoid content. Foliar application of methanol lead to increasing of FBPase enzyme activity such as enzymes that involve in control photosynthetic process. Ethanol converts to formaldehyde after penetrating to plant tissue and finally converts to carbon dioxide. Produced carbon dioxide increases internal concentration of that at leaf and causes to increase of photosynthetic efficiency. Also the most of total chlorophyll and chlorophyll a with 20% ethanol treatment and the most level of sugar were achieved by foliar application with 10% methanol.
Generally in this study it can be concluded that foliar application of methanol and ethanol as a carbon source and biostimulant can increase the biomass and yield of Basil.