35 research outputs found
The vegetation of South Africa, Lesotho and Swaziland
Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected] En WysbegeerteGeografie En Omgewingstudi
Coastal Vegetation of South Africa
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Impacts of Vegetation Cover on Surface-Groundwater Flows and Solute Interactions in a Semi-Arid Saline Floodplain: A Case Study of the Lower Murray River, Australia
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Manufacturing doubt about endocrine disrupter science - A rebuttal of industry-sponsored critical comments on the UNEP/WHO report "State of the Science of Endocrine Disrupting Chemicals 2012"
We present a detailed response to the critique of "State of the Science of Endocrine Disrupting Chemicals 2012" (UNEP/WHO, 2013) by financial stakeholders, authored by Lamb et al. (2014). Lamb et al.'s claim that UNEP/WHO (2013) does not provide a balanced perspective on endocrine disruption is based on incomplete and misleading quoting of the report through omission of qualifying statements and inaccurate description of study objectives, results and conclusions. Lamb et al. define extremely narrow standards for synthesizing evidence which are then used to dismiss the UNEP/WHO 2013 report as flawed. We show that Lamb et al. misuse conceptual frameworks for assessing causality, especially the Bradford-Hill criteria, by ignoring the fundamental problems that exist with inferring causality from empirical observations. We conclude that Lamb et al.'s attempt of deconstructing the UNEP/WHO (2013) report is not particularly erudite and that their critique is not intended to be convincing to the scientific community, but to confuse the scientific data. Consequently, it promotes misinterpretation of the UNEP/WHO (2013) report by non-specialists, bureaucrats, politicians and other decision makers not intimately familiar with the topic of endocrine disruption and therefore susceptible to false generalizations of bias and subjectivity
A Coastal Seawater Temperature Dataset for Biogeographical Studies: Large Biases between In Situ and Remotely-Sensed Data Sets around the Coast of South Africa
Molecular and Physiological Adaptations of Tea Plant in Response to Low Light and UV Stress
The sensory quality, economic value, and health functions of tea liquor
depend on several metabolites in leaves of tea (Camellia sinensis L.), such as polyphenols
(the most representative quality- and function-related compounds, especially
catechins), caffeine, amino acids, aroma compounds, vitamins, and
carbohydrates. The biosynthesis of these molecules is significantly affected by both
management practices in the field and environmental factors, such as shading and
ultraviolet (UV) stress. In this chapter, therefore, we review existing literature reporting
the effects of shade and UV irradiances on tea plants with the aim to reappraise
morphological, biochemical, physiological, and molecular responses found in this
species. Cultivation of tea plants under shade can (i) induce anatomical and ultrastructural
adaptations; (ii) influence leaf color, providing characteristic vivid greenness
due to incremented chlorophyll content; (iii) decrease the risk of photoinhibition;
and finally (iv) improve the quality of tea beverages by causing the reduction of the
concentration of phenylpropanoids and caffeine (which contribute to astringency)
while increasing the level of amino acids (the compounds that contribute to sweetness).
However, the shade practice in tea is still subjected to controversy, and the
correct managing of the shade practice is essential. Elevated UV irradiances, especially
UV-B, can alter the plant morphology and affect several biochemical and
physiological processes; most plant species respond to UV in a dose dependent manner.
Protracted exposition to low UV-B doses (similar to UV peaks actually perceive
by plants in the ambient) leads to an enhancement of phenylpropanoid metabolism
and in particular stimulates the biosynthesis of UV-protecting flavonoids (mainly
catechins). Conversely, UV-B doses much higher than those usually experienced in
natural environment lead to the downregulation of the phenylpropanoid metabolism
likely due to irreversible (to some extent) UV-triggered damages. The understandings
of the reactions of tea plants to different light conditions, including situations of
low light and high UV, are of pivotal importance to enhance both plant yield and tea
quality by âdrivingâ the accumulation of desired compounds in tea leaves