Office: Pereira Hall 100; Life Sciences Building 215
Phillippa Drennan is a Professor of Biology at Loyola Marymount University.
University of Natal: Ph.D., Biology 1987
University of Natal: B.Sc., Biology 1981
University of Natal: B.Sc., Biology 1980
Areas of Expertise (5)
Industry Expertise (3)
Thirty years ago, Philippa Drennan joined her colleague John Waggoner in a study of Joshua trees in the Mojave Desert. His initial research that concerned the distribution of Joshua trees within a range of altitudes in the remote desert became long-term monitoring of new growth and flowering of specific trees. Changes in climate and environment have affected the trees, and Drennan describes here what they have observed through their research in the Mojave National Preserve.
Green roofs offer a variety of ecological benefits that include decreased storm water runoff, reduced pollutant loading of storm water, and reduced urban heat island effects. This study investigated suitable plant species for green roofs in southern California. Four treatments were selected: plant species native to southern California, with and without irrigation; and plant species typical of green roof industries, with and without irrigation.
The fan-shaped leaves of the resurrection plant Myrothamnus flabellifolius Welw. fold during episodes of drought and consequent desiccation of the tissue. The leaf teeth of M. flabellifolius have several features characteristic of hydathodes. Tracheary elements from the three vein endings that converge in each leaf tooth subtend and extend into a cluster of cells significantly smaller than those of the adjacent mesophyll.
Park S. Nobel pioneered the coupling of cellular physical chemistry with plant physiology, providing a sound physicochemical interpretation of the laws of diffusion to a rapidly expanding field of plant physiological ecology. His classical textbook is the only one of its kind to provide an extensive array of quantitative problems and solutions in the field of plant biophysics and ecophysiology, extending from the molecular to the ecological level. In this festschrift, former graduate students and postdocs, as well as colleagues of Prof. Nobel present a series of reviews that include scales from sub-cellular to global, and topics that range from desert succulent biology to the physiology of alpine plants, encompassing basic research and applications in agronomy and conservation biology.
Sand verbenas (Abronia spp., Nyctaginaceae) are difficult to germinate in the laboratory. This hinders conservation and restoration efforts for Abronia spp. some of which are rare and others of which have been displaced from dune environments by invasive species and human activities. The possibility that ethylene (supplied as the liquid ethephon) could promote germination was investigated for Abronia fragrans, Abronia maritima, Abronia umbellata, and Abronia villosa.
1. Root elongation as a function of soil temperature was determined for the CAM succulent Opuntia ficus-indica, under three different day/night air temperatures (15 °C/5 °C, 25 °C/15 °C and 35 °C/25 °C) and an ambient (360 μmol mol–1) vs a doubled CO2 concentration (720 μmol mol–1) at 25°C/15 °C, the optimum temperature for net CO2 uptake.2.
The salt excreting glands on both the adaxial and the abaxial surfaces of a sequential developmental series of leaves of Avicennia marina were studied at the light microscopic and ultrastructural level. Scanning electron and light microscopy have shown that there is a decrease in the total number of glands on the adaxial and abaxial surfaces as the leaf matures.