Large changes in indole-3-acetic acid (IAA) levels occur during growth of Lemna gibba G-3 in sterile culture. The levels of IAA were measured in plants during a 45 day growth cycle using HPLC and isotope dilution analysis followed by selected ion current monitoring GC-MS analysis with (13)C(6)-IAA as the internal standard. Even though the rate of plant growth remained constant over the entire g...

Auxin is the mobile signal controlling the rate of growth and specific aspects of the development of plants. It has been known for over a century that auxins act as the messenger linking plant development to specific environmental changes. An often overlooked aspect of how this is accomplished is the effect of the environment on metabolism of the major plant auxin, indole-3-acetic acid (IAA). W...

In chemical regulation, e.g. the EU Water Framework Directive, REACH, or the Pesticide Directive, standardized ecotoxicological tests are applied to evaluate and rank the hazard of compounds and for deriving environmental quality standards (EQS). Standardized test methods prescribe fixed testing conditions e.g. specific temperature, pH, light intensity etc. However, environmental conditions und...

Placing light-grown Lemna gibba L. G-3 into the dark results in a changed pattern of protein synthesis. Although the amount of protein in the tissue and the over-all rate of incorporation of [(35)S]methionine into protein does not significantly decline during four days of darkness, the rate of synthesis of three polypeptides declines dramatically. One of these polypeptides is the chlorophyll a/...

Antibiotic residues have been found in environmental samples, such as water, soil, and even food, usually come from wastewater, presenting human health risks. This study aimed to improve the elimination of antibiotics tetracycline (Tet) chloramphenicol (Chlor) by modifying three factors: contact time (3–7 days), plant biomass (10–14 g), antibiotic concentration (5–15 mg/L Tet 10–20 Chlor). An a...

Two small regions of the promoter of an Lhcb gene encoding a light-harvesting chlorophyll a/b protein were identified as essential in conferring phytochrome responsiveness by using a transient expression assay. Initially, 5' deletion analysis of cabAB19, an Lhcb2 gene of Lemna, showed that sequences within the region from -174 to -104 relative to the start of transcription were necessary for ph...