Pressure gradients along whole culms and leaf sheaths, and other aspects of humidity-induced gas transport in Phragmites australis.

Emergent aquatic macrophytes growing in waterlogged anaerobic sediments overlain by deep water require particularly efficient ventilating systems. In Phragmites australis (Cav.) Trin.

Plant-environment interactions: Accumulation of hypericin in dark glands of Hypericum perforatum.

Background And Aims: Hypericum perforatum is a perennial herbaceous plant and an extract from this plant has a significant antidepressant effect when administered to humans. The plant is characterized by its secretory glands, also known as dark glands, which are mainly visible on leaves and flowers. The current study evaluates the influence of several environmental factors and developmental stages of the plant on the accumulation and synthesis of hypericin and pseudohypericin (Hy-G), the major bioactive constituents, in H.

Melatonin in Glycyrrhiza uralensis: response of plant roots to spectral quality of light and UV-B radiation.

Melatonin (N-acetyl-5-methoxytryptamine) is known to be synthesized and secreted by the pineal gland in vertebrates. Evidence for the occurrence of melatonin in the roots of Glycyrrhiza uralensis plants and the response of this plant to the spectral quality of light including red, blue and white light (control) and UV-B radiation (280-315 nm) for the synthesis of melatonin were investigated. Melatonin was extracted and quantified in seed, root, leaf and stem tissues and results revealed that the root tissues contained the highest concentration of melatonin; melatonin concentrations also increased with plant development.

Genetic diversity in seed populations of Echinacea purpurea controls the capacity for regeneration, route of morphogenesis and phytochemical composition.

The production of new varieties and higher quality products from Echinacea spp. requires a greater understanding of the regulation of plant growth and the production of specific phytometabolites. The current studies were designed to generate elite varieties of Echinacea purpurea based on regeneration efficiency and chemical profile.

Spectral quality and UV-B stress stimulate glycyrrhizin concentration of Glycyrrhiza uralensis in hydroponic and pot system.

Glycyrrhizin, the major bioactive component of Glycyrrhiza uralensis, is widely used as a natural sweetener. Recently glycyrrhizin has been shown to have anti-tumor activity, highly active in inhibiting replication of HIV-1 and SARS-associated virus and exhibits a number of pharmacological effects. The principle objective of the current study was to evaluate the effects of different spectral quality including red, blue, white and UV-B radiation on the production of glycyrrhizin, in a controlled environment.