MODULATION OF MINERAL AND FREE FATTY-ACID PROFILES DURING THIDIAZURONMEDIATED SOMATIC EMBRYOGENESIS IN PEANUTS (ARACHIS-HYPOGEAE L.)

Seedlings grown in the presence of thidiazuron (TDZ: N-phenyl-N'-(1,2, 3-thiadiazol-yl) urea) exhibited symptoms of severe metabolic disrupti ons including stunted growth, darkly coloured leaves, swollen green co tyledons and an inhibited growth of the root system with an enlarged p rimary root and few secondary roots. After two weeks of exposure to TD Z, somatic embryos developed at the hypocotyledonary notch region of t he cultured seedlings. An analysis of the nutritional status of regene rating seedlings revealed significant increases in the accumulation of sodium, copper and zinc within the treated seeds after only a 24h per iod of culture on TDZ supplemented media. Thidiazuron supplementation of the culture medium was also found to increase the total lipid compo nent of the seeds with increases in the major structural free fatty ac ids and the ratio of unsaturated:saturated free fatty acids. Alteratio n of nutrient availability and structural free fatty-acid profiles, af fecting both cellular functions and growth patterns, seems to be part of the mode of action of TDZ and may play an important role in the ind uction of regeneration.