The influence of sublethal concentrations of sulfur dioxide on morphology, growth and product yield of the duckweed Lemna minor L.

Oecologia ◽  
1976 ◽  
Vol 23 (3) ◽  
pp. 201-209 ◽  
Author(s):  
H. Fankhauser ◽  
Chr. Brunold ◽  
K. H. Erismann
Keyword(s):  
Sulfur Dioxide ◽  
Lemna Minor ◽  
Product Yield ◽  
Sublethal Concentrations

Sulfur dioxide as a sulfur source in duckweeds (Lemna minor L.)

1976 ◽  
Vol 32 (3) ◽  
pp. 296-297 ◽  
Author(s):  
Chr. Brunold ◽  
K. H. Erismann
Keyword(s):  
Sulfur Dioxide ◽  
Lemna Minor ◽  
Sulfur Source

Effets physiologiques de l'atrazine à doses sublétales sur Lemna minor L. IV. Influence sur la composition lipidique

1979 ◽  
Vol 57 (9) ◽  
pp. 1015-1020 ◽  
Author(s):  
G. Grenier ◽  
J. P. Marier ◽  
G. Beaumont
Keyword(s):  
Fatty Acids ◽  
Linolenic Acid ◽  
Acid Content ◽  
Neutral Lipids ◽  
Lemna Minor ◽  
Fatty Acid Content ◽  
Linoleic Acid Content ◽  
Gas Liquid Chromatography ◽  
Total Fatty Acids ◽  
Sublethal Concentrations

The lipids and the fatty acids of duck weed (Lemna minor L.), cultivated aseptically during 5, 10, or 15 days in mineral solution containing sublethal concentrations of atrazine (0.05 to 0.75 ppm), were analysed by thin-layer and gas–liquid chromatography. All concentrations of atrazine used, independently of age of plants, increased the total fatty acid content, except for 5-day plants at 0.50 and 0.75 ppm atrazine where a decrease in total fatty acids was observed. α-Linolenic acid content increased while linoleic acid content decreased. Sublethal concentrations of atrazine increased the percentage of monogalactosyldiacylglycerol compared with total phospholipids and total neutral lipids. Monogalactosyldiacylglycerol was the main lipid involved in the α-linolenic acid increase observed in the total fatty acids. The increase in α-linolenic acid and in monogalactosyldiacylglycerol in the presence of sublethal concentrations of atrazine is an indication that these treatments maintain intact and fully functional chloroplast membranes.

Lipid synthesis by isolated duckweed (Lemna minor) chloroplasts in the presence of a sublethal concentration of atrazine

1989 ◽  
Vol 67 (8) ◽  
pp. 2261-2265 ◽  
Author(s):  
Gilles Grenier ◽  
Luce Proteau ◽  
Gaston Beaumont
Keyword(s):  
Linolenic Acid ◽  
Lemna Minor ◽  
Specific Radioactivity ◽  
Lipid Synthesis ◽  
Thylakoid Membranes ◽  
Sublethal Concentration ◽  
In Vivo Studies ◽  
High Level ◽  
Sublethal Concentrations

We have examined the effects of a sublethal concentration of atrazine on the incorporation of sodium-[U-14C] acetate into isolated chloroplast lipids of Lemna minor. A high level of [14C]-acetate was incorporated into diacylgalactosylglycerol (DGG) and diacylglycerol (DAG). Consequently, the conversion of phosphatide acid to DAG and that of DAG to DGG seems to be as active in L. minor (an "18:3-plant") as in "16:3-plants." Chloroplast lipids from atrazine-treated plants were more extensively labelled with [14C]-acetate than the control plants. These results are in agreement with our previous in vivo studies which suggest that sublethal concentrations of atrazine stimulate the lipid metabolism of L. minor to form more thylakoid membranes. Furthermore, the specific radioactivity of linolenic acid was the highest in DAG and the lowest in DGG. These data suggest that desaturation of linoleic acid to linolenic acid mainly occurs before the galactosylation of DAG to form DGG in L. minor.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

Elemental Analysis of Phloem Tissue in Lemna Minor Root Tips

1980 ◽  
Vol 38 ◽  
pp. 798-799
Author(s):  
Patrick Echlin ◽  
Thomas Hayes ◽  
Clifford Lai ◽  
Greg Hook
Keyword(s):  
Vascular Tissue ◽  
Lemna Minor ◽  
Atomic Weight ◽  
Companion Cell ◽  
Root Tips ◽  
Phloem Tissue ◽  
Cell Stage ◽  
Phloem Parenchyma ◽  
Parenchyma Cells ◽  
Xylem Element

Studies (1—4) have shown that it is possible to distinguish different stages of phloem tissue differentiation in the developing roots of Lemna minor by examination in the transmission, scanning, and optical microscopes. A disorganized meristem, immediately behind the root-cap, gives rise to the vascular tissue, which consists of single central xylem element surrounded by a ring of phloem parenchyma cells. This ring of cells is first seen at the 4-5 cell stage, but increases to as many as 11 cells by repeated radial anticlinal divisions. At some point, usually at or shortly after the 8 cell stage, two phloem parenchyma cells located opposite each other on the ring of cells, undergo an unsynchronized, periclinal division to give rise to the sieve element and companion cell. Because of the limited number of cells involved, this developmental sequence offers a relatively simple system in which some of the factors underlying cell division and differentiation may be investigated, including the distribution of diffusible low atomic weight elements within individual cells of the phloem tissue.

The Determination of Sulfur Dioxide-Correction

1917 ◽  
Vol 9 (12) ◽  
pp. 1148-1148
Author(s):  
James Withrow
Keyword(s):  
Sulfur Dioxide
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