Production of Thiophenes in Calli and Suspension Cultures of Tagetes patula L. as Influenced by Light/Dark Succession

POLI F., Tosi B., DALL'OLIO G. & BRUNI A. 1992. Production of thiophenes in calli and suspension cultures of Tagetes patula L. as influenced by light/dark succession. — Phyton (Horn, Austria) 31 (2): 257-262, 3 figures. English with German summary. HPTLC-densitometry was used to evaluate thiophene accumulation in leaf calli and cell suspension of Tagetes patula. Calli obtained from 7-8 weeks old leaves were subcultured in supplemented MS for many months. The secondary calli showed 4 to 6-fold higher fresh weight increment in 2 weeks while the tertiary ones only doubled their weight in the same period. A considerable increase of thiophene production (about 16.5 -fold) was obtained growing calli under successive light/dark periods. Repeated subculturing of callus tissues resulted in a slow decline of the thiophene yield. Under the same conditions, cell suspension cultures did not exhibit an appreciable increment in thiophene content which decreased with subculturing.