Thin layer chromatography of plant phospholipids of Zea mays (L.) un-der the action of the phytohormone kinetin in different aeration condi-tions

Abstract

Under extreme weather conditions, crops are exposed to excess rainfall, causing the acute oxygen starvation of plants. The treatment of plants with phytohormones started in order to increase plant resistance to stresses. Using thin layer chromatography, the effect of the phytohormone kinetin on the content of plant phospholipids was studied under different aeration conditions. A kinetin solution (10 mg l-1) was injected into the etiolated maize seedlings separated from the roots by the suction method with a transpiration current and seedlings were transferred to aeration conditions, hypoxia or carbon dioxide (9 hours). Control plants were not treated with kinetin. Samples were fixed with boiling isopropanol and extracted with a hexane:isopropanol mixture (3:2). After purification from non-lipid impurities, lipids were evaporated and dissolved in chloroform. Phospholipids were isolated on silica gel W plates and further separated into classes on silica gel 60G plates. (“Merk”, Germany). It was found that the content of total phospholipids in maize seedlings decreased to 84.9% under hypoxic conditions and to 54.5% in CO2. If plants were pre-treated with kinetin, the content of total phospholipids practically did not change (96.2%), and in CO2 it increased to 88.5%. When plants were treated with kinetin under aeration conditions, the content of phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatilylethanolamium (PEA) increased, and phosphatidylglycerol (PG) decreased by almost 40%. Under conditions of oxygen deficiency, changes in the composition of phospholipids were different. The content of PS and PC in seedlings increased by1.5-2.0 times, and the content of PG and PEA decreased to 27.2% and 20.0% of the control. Treatment of maize seedlings with kinetin reduced the effect of gaseous media on the content of all analysed classes of phospholipids in plants, this was especially evident in CO2. Thus, it can be considered proven that the protective effect of kinetin is realized due to the ability of this phytohormone to maintain the optimal content and ratio of phospholipid components characteristic of a given tissue in plants exposed to various unfavourable environmental factors, including oxygen deficiency and high concentrations of carbon dioxide.