Protuberances tentatively identified as buds were initiated on callus proliferating from the bases of excised terminal buds of Psychotria punctata (Rubiaceae) cultured on media containing 10(-4) and 10(-5)M zeatin. Only those cultures maintained in a greenhouse during mid-summer formed such buds. A high cytokinin concentration together with one or more specific environmental conditions appear to be required for their formation. In contrast, large nodule-bearing shoots developed directly from terminal buds when these were excised during the fall and cultured on the same medium in controlled environment chambers providing temperatures and light intensities lower than in the greenhouse. Zeatin was required for shoot development on this medium; little development occurred in its absence. Shoot development occurred in both 8- and 16-hr days in the chambers; it did not occur in darkness, in continuous, predominantly incandescent light, or in the greenhouse.
Proceedings of the Iowa Academy of Science
© Copyright 1976 by the Iowa Academy of Science, Inc.
Edwards, Wayne J. and LaMotte, Clifford E.
"Bud Formation and Shoot Development In Vitro: Observations on Stem and Bud Explants of Psychotria punctata (Rubiaceae),"
Proceedings of the Iowa Academy of Science: Vol. 83:
, Article 5.
Available at: http://scholarworks.uni.edu/pias/vol83/iss4/5