© 1998 Heron Publishing—Victoria, Canada
Growth and development of the arborescent cactus Stenocereus queretaroensis in a subtropical semiarid environment, including effects of gibberellic acid
Eulogio Pimienta (1), Gerardo Hernandez (1), Alejandro Domingues (1) and Park S. Nobel (2, 3)
1. Departamento de Ecología, Centro de Ciencias Biologicas y Agropecuarias, Universidad de Guadalajara, Las Agujas, Zapopan,
Jalisco, 45110, México / 2. Department of Biology, University of California, Los Angeles, CA 90095-1606, USA / 3. Author to whom correspondence should be addressed (psnobel@biology.ucla.edu) / Received February 7, 1997
Summary
In Stenocereus queretaroensis (Weber) Buxbaum, an arborescent cactus cultivated in Jalisco, Mexico, for its fruits but studied here in wild populations,
stem extension occurred in the autumn at the beginning of the dry season, flowering and fruiting occurred in the spring at
the end of the dry season, and new roots grew in the summer during the wet season. The asynchrony of vegetative and reproductive
growth reduces competitive sink effects, which may be advantageous for wild populations growing in infertile rocky soils.
Seasonal patterns of sugars in the roots and especially the stems of S. queretaroensis were closely related to the main phenological stages, becoming lower in concentration during periods of major stem extension.
Cessation of stem extension occurred in 100-year-old plants for which injection of GA3 reinitiated such growth. Isolated chlorenchyma cylinders had maximum extension in a bathing solution containing 0.1 μM gibberellic
acid.
Keywords:
phenology, photosynthetic photon flux, pitayos, soluble sugars, stem extension.
