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Lemna

About: Lemna is a research topic. Over the lifetime, 813 publications have been published within this topic receiving 19417 citations. The topic is also known as: duckweed.


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Journal ArticleDOI
TL;DR: The measured toxicities of the tested pharmaceuticals shows that acute effect of single substances in the aquatic environment are very unlikely, but it should be kept in mind that considerable combination effects can occur and that toxicity data from chronic studies are needed to assess the environmental risk of drug residues.

890 citations

Journal ArticleDOI
TL;DR: Arsenate proved to be competitive with the highand low-affinity phosphate uptake system and induced transient membrane potential changes of up to 120 mV which were similar to those induced by phosphate and indicated a cotransport mechanism with at least 2H+/H2As04.
Abstract: Interference of arsenate and vanadate with phosphate uptake in Lemna gibba L. was studied by measuring voltage changes and (32P)phosphate uptake. Arsenate proved to be competitive with the highand low-affinity phosphate uptake system. It induced transient membrane potential changes of up to 120 mV which were similar to those induced by phosphate and indicated a cotransport mechanism with at least 2H+/H2As04. The amplitude of the transient arsenate-induced membrane depolarization was strongly influenced by phosphate starvation. A permanent membrane depolarization to the diffusion potential was achieved within 2 to 6 h in P-starved plants. Thus, arsenate is indeed a strongly competitive physiological analogue of phosphate in higher plants. Vanadate was easily transported into L. gibba as concluded from transient Em changes of up to 110 mV. Vanadate interfered only slightly and non-specifically with the two phosphate transport mechanisms. Like phosphate, vanadate uptake seems to be an H+-cotransport mechanism, both with similar optima at pH 6 0. Unlike phosphate uptake, vanadate-linked membrane depolarization was not affected by high intracellular phosphate concentrations. P-starvation did not enhance the weak long-term effect on Em. Hence, vanadate, in contrast to arsenate, is not regarded as a physiological phosphate analogue. The distinct and rapid vanadate-induced and permanent membrane depolarization of Avena sativa, Triticum aestivum and Glycine max leaves was not seen in Lemna nor in leaves of Gossypium hirsutum and Nicotiana tabacum. Plasmalemma-enriched preparations of L. gibba revealed, however, a high vanadate-sensitive ATPase activity (87%). As a possible explanation for these differences it is suggested that the latter plant species have cytosolic vanadate-detoxifying properties, i.e. they can reduce vanadate to vanadyl ions, in contrast to the former group of plant species.

319 citations

Journal ArticleDOI
TL;DR: Using the equations of the linear relationships, the overall fractionation factors between water and the exchanged oxygen and carbon bound-hydrogen of cellulose were estimated and it was indicated that under the three growth conditions about 40, 70, and 100% of oxygens and carbon-bound hydrogens of cellulOSE exchanged with those of water prior to cellulose formation.
Abstract: Lemna gibba L. B3 was grown under heterotrophic, photoheterotrophic, and autotrophic conditions in water having a variety of hydrogen and oxygen isotopic compositions. The slopes of the linear regression lines between the isotopic composition of water and leaf cellulose indicated that under the three growth conditions about 40, 70, and 100% of oxygens and carbon-bound hydrogens of cellulose exchanged with those of water prior to cellulose formation. Using the equations of the linear relationships, we estimated the overall fractionation factors between water and the exchanged oxygen and carbon bound-hydrogen of cellulose. At least two very different isotope effects must determine the hydrogen isotopic composition of Lemna cellulose. One reflects the photosynthetic reduction of NADP, while the second reflects exchange reactions that occur subsequent to NADP reduction. Oxygen isotopic composition of cellulose apparently is determined by a single type of exchange reaction with water. Under different growth conditions, variations in metabolic fluxes affect the hydrogen isotopic composition of cellulose by influencing the extent to which the two isotope effects mentioned above are recorded. The oxygen isotopic composition of cellulose is not affected by such changes in growth conditions.

308 citations

Journal ArticleDOI
TL;DR: It was found that Lemna fronds were able to accumulate both cadmium and copper, but Cu- treated material showed pronounced toxic symptoms at concentrations 1000-fold lower in comparison to Cd, while in Cu-treated fronds neither accumulation of existing proteins nor appearance of any extra protein was observed.

301 citations

Journal ArticleDOI
TL;DR: Promotion of ABA synthesis in Lemna by the two antibiotics and by copper suggests that the plant hormone could be a suitable (additional) indicator for future evaluation of phytotoxicity that results in plant senescence.

284 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202325
202258
202117
202021
201929
201815