Plant Tissue Cult. 8(1) : 139-147, 1998 (December)

Polyethylene Glycol and Sucrose Concentrations After Lipids Accumulation in Somatic Embryos of Indian Mustard (Brassica juncea L. Czern and Coss)

Anita Kumari, G. S. Cheema¹ and S. K. Munshi

Department of Biochemistry, Punjab Agricultural University, Ludhiana-141 004, India

Key words: Brassica juncea, Hypocotyl, Somatic embryos, Lipid biosynthesis, Enzyme assays

Abastract

The dry matter and lipid content of hypocotyl derived somatic embryos of Indian mustard (Brassica juncea L.) increased significantly (P < 0.05) with 10% polyethylene glycol 6000 (PEG) as compared to control. The values were higher at d 30 than d 15 after culture. The lipid content in treated embryos increased with 2 and 5% sucrose when combined with 10% PEG through enhanced activity of acetyl CoA carboxylase and the rate of 1-¹⁴C-acetate incorporation into lipids at d 15-the stage of maximum lipid biosynthesis. Besides, these conditions stimulated the utilization of starch making soluble sugars available for the lipid biosynthesis. PEG increased wax content of somatic embryos but the addition of sucrose in PEG mediated cultures caused a significant decrease in the proportion of wax in the lipids. Triacylglycerols content in the somatic embryos increased significantly with maximum at d 30 when 10% sucrose and PEG were added to the medium. A decrease in the proportion of 16 : 0, 18 : 0 and 22 : 1 and corresponding increase in 18 : 1, 18 : 2 and 18 : 3 occurred in somatic embryos at d 15 using PEG in the culture medium indicating that fatty levels can be manipulated by altering the conditions of culture medium.

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