Dynamics of endogenous cytokinins during the growth cycle of a hormone-autotrophic genetic tumor line of tobacco

• Published in: Plant physiology (Bethesda) Vol. 94; no. 3; pp. 1084 - 1089
• Main Authors: Nandi, S.K. (C.S.I.R. Complex, Himachal Pradesh, India), Palni, L.M.S, Parker, C.W
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.11.1990
• Subjects: 550201 - Biochemistry- Tracer Techniques; BASIC BIOLOGICAL SCIENCES; BIOASSAY; BIOCHEMICAL REACTION KINETICS; Biological and medical sciences; BODY; Callus; CARCINOGENESIS; CITOCININAS; CULTIVO DE TEJIDOS; CULTURE DE TISSU; Cultured cells; CYTOKININE; Cytokinins; Development and Growth Regulation; DIAGNOSTIC TECHNIQUES; Fundamental and applied biological sciences. Psychology; GENETICA; GENETIQUE; Growth regulators; HIBRIDOS; HYBRIDE; HYDROGEN COMPOUNDS; IMMUNOASSAY; IMMUNOLOGY; IN VITRO; INDICE DE CRECIMIENTO; ISOTOPE APPLICATIONS; KINETICS; MAGNOLIOPHYTA; MAGNOLIOPSIDA; MEDIO DE CULTIVO; Metabolism; MILIEU DE CULTURE; NEOPLASMAS; NEOPLASME; NICOTIANA; Nucleotides; ORGANOGENESE; ORGANOGENESIS; PATHOGENESIS; PHYSIOLOGY; Plant cells; PLANT DISEASES; Plant gall; PLANT GROWTH REGULATORS; Plant physiology and development; PLANT TISSUES; PLANTS; RADIOASSAY; RADIOIMMUNOASSAY; RADIOIMMUNODETECTION; RADIOIMMUNOLOGY; REACTION KINETICS; SINTOMAS; Subcultures; SYMPTOME; TAUX DE CROISSANCE; TISSUES; TRACER TECHNIQUES; TRITIUM COMPOUNDS; Tumors; Callus; Nicotiana; Tissue culture; Cytokinin; Assay; Dicotyledones; Radioimmunoassay; Angiospermae; Industrial crop; Plant growth substance; Tumor; Spermatophyta; Solanaceae
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.94.3.1084

The profile of endogenous cytokinins in a genetic tumor line of tobacco, namely, Nicotiana glauca (Grah.) X Nicotiana langsdorffii (Weinm.), following 1 to 10 weeks of growth on solid medium was determined by radioimmunoassay. 3H-labeled cytokinins of high specific activity were added during tissue extraction to correct for the purification losses. Following subculture (of 4-week-old tissues when their cytokinin content is high) onto fresh medium the total cytokinin content continued to be high during the first week (1470 picomoles per gram fresh weight) when the tissue fresh weight remained essentially unchanged (lag phase). The cytokinin levels then declined by about half in 2- and 3-week-old tissues (626 and 675 picomoles per gram fresh weight, respectively), a period when rapid increase in tissue fresh weight was recorded. Increments of 840% and 2780% over initial fresh weight were obtained in 2- and 3-week-old cultures, respectively. The cytokinin content then increased to initial high levels in 4-week-old tissues (1384 picomoles per gram fresh weight) after which it gradually declined with tissue age. The lowest cytokinin levels (432 picomoles per gram fresh weight) were observed in 10-week-old tissues. Maximal tissue fresh weight (4030% increase over initial fresh weight) was recorded in 5-week-old cultures after which it decreased slowly to 77.5% of the highest tissue fresh weight in 10-week-old cultures. Zeatin appeared to be the dominant endogenous cytokinin in tissues of all ages. Other cytokinins quantified were dihydrozeatin, zeatin riboside, and dihydrozeatin riboside; the values may include contributions from aglucones derived from the hydrolysis of corresponding omicron-glucosides, since the entire basic fraction was treated with beta-glucosidase before analysis. In addition the levels of isopentenyladenine, isopentenyladenosine, and the nucleotides of zeatin riboside, dihydrozeatin riboside, and isopentenyladenosine were also determined