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Full-Text Articles in Life Sciences

Evaluating Relationships Between Mercury Concentrations In Air And In Spanish Moss (Tillandsia Usneoides L.), Kathryn T. Sutton Jan 2012

Evaluating Relationships Between Mercury Concentrations In Air And In Spanish Moss (Tillandsia Usneoides L.), Kathryn T. Sutton

Electronic Theses and Dissertations

Mercury is a potent neurotoxin that is transported globally in vapor form. A major source of mercury contamination to soil, water, and biota is atmospheric deposition. Therefore, comprehensive monitoring of atmospheric concentrations is important. Limitations of conventional atmospheric measurement techniques include high cost and lack of temporal or spatial integration. Bioindicators, however, may serve as an integrative tool to add to conventional mercury measurement techniques. Spanish moss (Tillandsia usneoides L.) is a potential bioindicator of atmospheric mercury concentration in the southeastern United States because it is an abundant epiphyte that absorbs and accumulates atmospheric pollutants. A study was conducted in …


The Jeweled Armor Of Tillandsia—Multifaceted Or Elongated Trichomes Provide Photoprotection, Simon Pierce Dec 2007

The Jeweled Armor Of Tillandsia—Multifaceted Or Elongated Trichomes Provide Photoprotection, Simon Pierce

Aliso: A Journal of Systematic and Floristic Botany

Foliar trichomes of gray-leaved Tillandsioideae (Bromeliaceae) are highly reflective, suggesting a role in protecting the leaf against direct sunlight in exposed niches. The performance of photosystem II, as denoted by the chlorophyll fluorescence characteristic Fv /Fm , was determined for seven Tillandsia species and Vriesea barclayana that were exposed to excessive light, with trichomes either present or removed. Additionally, trichome structure and interaction with light was recorded using extended depth-of-field photomicrography, and reflectance quantified using a novel photographic technique. Trichomes of mesomorphic Type IV life forms (T. cryptantha, T. cyanea) and of the intermediate life …


Photosynthesis Of Arid And Subtropical Succulent Plants, Irwin P. Ting Jan 1989

Photosynthesis Of Arid And Subtropical Succulent Plants, Irwin P. Ting

Aliso: A Journal of Systematic and Floristic Botany

The hypothesis of Crassulacean acid metabolism (CAM) is that it is a physiological adaptation to arid or otherwise dry habitats. Stomata are closed during the day and open at night when the evaporative demand is low. Thus exogenous CO2 is fixed at night with relatively little water loss. CAM is typically found in succulents occurring in desert and dry Mediterranean regions, but not in the cold deserts of Asia. Recently, it has become known that many arid tropical succulent plants are CAM as well, particularly those growing epiphytically. The vegetation of St. John, U.S. Virgin Islands, ranges from desertlike …