(n.) A genus (Lemna) of small plants, seen floating in great quantity on the surface of stagnant pools fresh water, and supposed to furnish food for ducks; -- called also duckmeat.
Example Sentences:
(1) Duckweed commonly refers to a group of floating, flowering plants of the family Lemnaceae.
(2) Evidence for the sequence of duckweed (Lemna minor) chloroplast 5S rRNA was derived from the analysis of partial and complete enzymic digests of the 32P-labelled molecule.
(3) Growth inhibition of duckweed could be achieved at approx 20 ppb terbutryne in steady state.
(4) The period of the circadian rhythm of uptake of K+ by Lemna gibba strain G3 (duckweed), cultured in a flow medium, was shortened by continuous application of 0.5 mM tetraethylammonium chloride (TEA), which functions as a K+ channel blocker in both animal and plant cells.
(5) Spirodela (Duckweed) was thus used to ascertain the response of the nucleocytoplasmic (nc) and plastid ribosomal RNA metabolisms to partial and total carbon deprivation.
(6) The possible sequence of the chloroplast 5S rRNA from three other flowering plants was deduced by complete digestion with T1 ribonuclease and comparison of the sequences of the oligonucleotide products with homologous sequences in the duckweed 5S rRNA.
(7) Many duckweed species have been studied, primarily of the Lemna and Spirodela genera.
(8) Radioactivity from d-[l-(14)C]glucosamine is incorporated into ethanol-insoluble compounds of high molecular weight in a number of plant tissues, including roots of corn (Zea mays), callus cells of sycamore (Acer pseudoplatanus), axenic cultures of duckweed (Lemna minor) and germinating seedlings of corn, broad bean (Vicia faba) and barley (Hordeum vulgare).
(9) Duckweed and algae represent different levels of complexity in the plant kingdom.
(10) Values for the half-life of Lemna minor (duckweed) protein determined by the new method are compared with values obtained by other methods.
(11) Herbicidal effectiveness of terbutryne-EVA formulation has been investigated in a laboratory-scale simulated flow system device with duckweed plants (Lemna minor) as test organism.
(12) Thus the specific activity of the duckweed enzyme is more than two orders of magnitude higher than that of the enzyme from rat testes.
(13) In the short, single-screen film Lock Again, there is a marvellous sequence in which two young men in sailor's uniforms - both of whom look as if they have been in a fight - ferry an imperious girl across a pond thick with duckweed in a rowing boat.
(14) A new method is described for measuring environmental stress through the use of the duckweed (Lemna minor) rhizosphere.
(15) Differences in duckweed test methodology occur with regard to test types, test vessels, control tests, nutrient media, end points, and applications.
(16) Other studies, however, indicate that duckweed plants are as sensitive to toxicity as other aquatic species.
(17) Duckweed (Spirodela oligorrhiza, Kurz) is a sensitive indicator of 1,1'-alkyl-4,4'-bipyridylium salt (viologen) herbicidal potency.
(18) Duckweed plants are fast growing and widely distributed.
(19) Orellanine, a toxic principle of Cortinarius orellanus Fr., efficiently inhibited the photosynthetic activity of duckweed, Lemna minor L., at a concentration of 0.4 mM.
(20) The present paper deals with the separation of cells from soluble compounds of blood by means of exclusion chromatography using a recently described vesicular packing material made from the cell wall framework of the small duckweed Wolffia arrhiza.
Milkweed
Definition:
(n.) Any plant of the genera Asclepias and Acerates, abounding in a milky juice, and having its seed attached to a long silky down; silkweed. The name is also applied to several other plants with a milky juice, as to several kinds of spurge.
Example Sentences:
(1) Experimental vein severance renders milkweed leaves edible to generalist herbivores that do not show vein-cutting behaviors and ordinarily ignore milkweeds in nature.
(2) Many mandibulate insects that feed on milkweeds, or other latex-producing plants, cut leaf veins before feeding distal to the cuts.
(3) The significance of these findings are discussed in light of the recent discovery that the C28-ecdysone, makisterone A, is the predominant molting hormone inthe embryonated egg of the milkweed bug.
(4) Chromosomal fragments and translocations induced by x-rays in the sperm of adult milkweed bugs, Oncopeltus fasciatus (Dallas), were detected in the meiotic cells of F(1), F(2), and F(3), males and caused high levels of sterility in lintreated progeny.
(5) The WWF, which carries out the census of the Mexican colonies in co-ordination with the Mexican government, says the extensive use of herbicides is wiping out vast quantities of the milkweed that provides the butterflies with their main food source and breeding grounds.
(6) But research by Lundgren and his team also found that 60% of the milkweed in their South Dakota study area was contaminated by the pesticide, which even at low levels causes monarch larvae to grow much more slowly and reach much smaller size.
(7) Polinnators are important to a huge portion of our food supply ... anything that flowers.” One reason for the decrease is a drop in the amount of milkweed, which monarch larvae eat, Lundgren said.
(8) Significant amounts of immunoreactive cardiac glycoside were found to be present in the ornamental shrubs: yellow oleander (Thevetia peruviana); oleander (Nerium oleander); wintersweet (Carissa spectabilis); bushman's poison (Carissa acokanthera); sea-mango (Cerbera manghas); and frangipani (Plumeria rubra); and in the milkweeds: redheaded cotton-bush (Asclepias curassavica); balloon cotton (Asclepias fruiticosa); king's crown (Calotropis procera); and rubber vine (Cryptostegia grandifolia).
(9) Several aromatic terpenoid ethers possess a high degree of morpho-genetic activity when assayed on the yellow mealworm Tenebrio molitor L. and the milkweed bug Oncopeltus fasciatus (Dallas).
(10) Cortisol increased growth and differentiation in the large milkweed insect (Oncopeltus fasciatus).
(11) Analysis of the sterols of the milkweed bug, Oncopeltus fasciatus (Dallas) and dietary sunflowerseeds revealed that there is little, if any, conversion of dietary C28 OR C29 phytosterols to cholesterol in this phytophagous insect.
(12) In order to determine whether the genes coding for ribosomal RNA (rRNA) are amplified in the telotrophic ovary of the milkweed bug Oncopeltus fasciatus, the percentages of the genome coding for ribosomal RNA in somatic cells, spermatogenic cells, ovarian follicles, and nurse cells were compared.
(13) The use of herbicides destroying milkweed is directly linked to the mass cultivation in the great plain states of the US of genetically modified soybean and corn crops with inbuilt resistance to chemicals that the rest of the plants in the areas sprayed do not have.
(14) We have analyzed electron micrographs of chromatin-associated fiber arrays from embryos of the milkweed bug, Oncopeltus fasciatus.
(15) Scientists are extremely concerned that monarch populations are declining because the caterpillar's only food source – milkweed – is being eradicated.
(16) The persistence of these fragments through numerous generations of cells confirmed the holokinetic nature of the milkweed bug chromosomes.
(17) SK Films, the American distributor, is encouraging audiences to grow milkweed and also to create their own butterfly gardens by selling seed-packets in cinemas.