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Biomedical subjects

T A Thorpe

Publications and source records attributed to T A Thorpe.

5 recordsLinked to original sources

Non-morphogenic metabolism during shoot induction in radiata pine cotyledon explants.

The effects of excision, light and cytokinin (N6-benzyladenine) on 14C-acetate metabolism in cotyledons of Pinus radiata (D. Don) were determined. 14CO2 was released and the distribution of radioactivity into lipids, sugars, organic acids and amino acids was determined. While light and cytokinin generally caused some increase in metabolism, the effect of excision, i.e., wounding, was most pronounced. Specific metabolites examined (citrate, malate, succinate, alanine, aspartate, glutamate and glutamine) were at least 50% greater in 14C-labeling in excised cotyledons as compared to intact seedlings. This enhancement of wound metabolism would mask possible morphogenically-related changes occurring at that time.

Acetates

Changes in isoperoxidases during shoot formation in tobacco callus.

Shoot formation in tobacco (Nicotiana tabacum L.) callus is accompanied by an increase in peroxidase activity which takes a form similar to a sigmoid curve. The "stationary" phase coincides with the period of organ formation. Characteristic changes in isoperoxidase pattern are found in the shoot-forming part of the callus. These changes are different from those in the nonshoot-forming part or in gibberellin-treated tissue, which does not form shoots.

Culture Techniques

Starch accumulation in shoot-forming tobacco callus cultures.

Microscopic histochemical examinations of cultured tobacco callus disclosed a strong correlation between starch accumulation and shoot initiation. The accumulation started before any observable organized development and was heaviest in cells of loci which ultimately gave rise to organ primordia. Treatment of tissue cultures with gibberellin prevented starch accunmulation and organ formation.

Culture Techniques