1,720,985 research outputs found
Ultrastructural features and production of canthaxanthin in a Chlorophyta isolated from Gondwana lake (Victoria Land, Antarctica).
No full textGrowth and ultrastructural responses of a green filamentous microalga isolated from Southern Ocean (Terra Nova Bay, Ross Sea) to variation in irradiance.
No full textSuitable reference genes for accurate gene expression analysis in Papaver rhoeas under 2,4-D herbicide stress
No full textUltrastructural and cytochemical study on Plocamium cartilagineum (L.) Dixon (Gigartinales, Rhodophyta)
No full textSome observation on photoautotrophic picoplancton of Terra Nova Bay (Ross-Sea - Antarctic) during the austral summer 1989-90.
No full text
The picoplankton in Antarctic lakes of Northern Victoria Land during summer 1989-90
No full textPhotoautotrophic picoplankton is reported from some lakes located near the Italian Antarctic station of Terra Nova. Observations, carried out by both flow cytometry on water samples and electron microscopy on micro-organisms in cultures from each lake, have confirmed the occurrence in all the environments studied of this fraction accounting, in several cases, for more than the 50% of the phytoplankton, measured as chlorophyll. Cultures of the picoplankton fraction from these waters contained known prokaryotic (Synechococcus) and eukaryotic (Chlorella) genera as well as two unidentified entities, possibly prochlorophytes
Characterisation of ALS genes in the polyploid species Schoenoplectus mucronatus and implications for resistance management
No full textSeven different mutant ACCase alleles (1781-Leu, 1999-Leu, 2041-Asn, 2041-Val, 2078-Gly, 2088-Arg and 2096-Ala) and 13 combinations with two types of mutation were detected in the pinoxaden-resistant plants. The 1781-Leu allele appears to confer a dominant resistance to pinoxaden, clodinafop, haloxyfop, sethoxydim and clethodim at 60 g AI ha(-1) . The 2041-Asn and 2041-Val alleles are associated with dominant or partially dominant resistance to FOPs, no substantial resistance to DIMs and a moderate resistance to pinoxaden. The 2088-Arg allele endows a partially dominant resistance to clodinafop, sethoxydim and most likely to pinoxaden. In addition, non-target-site resistance mechanisms seem to be involved in pinoxaden resistance
A European biotype of Amaranthus retroflexus cross-resistant to ALS inhibitors and response to alternative herbicides
No full textAn acetolactate synthase (ALS)-resistant Amaranthus
retroflexus biotype was collected in a soyabean crop
after repeated exposure to imazethapyr and thifensulfuron-
methyl in north-eastern Italy. Studies were conducted
to characterise the resistance status and
determine alternative post-emergence herbicides for
controlling this biotype. Whole-plant bioassay revealed
that the GR50 values were 1898- and 293-fold higher
than those observed for the biotype susceptible to
imazethapyr and imazamox respectively. The biotype
also displayed high cross-resistance to sulfonylureas.
Molecular analysis demonstrated that a single nucleotide
substitution had occurred in domain B (TGG to
TTG at position 574), conferring a change from the
amino acid tryptophan to leucine in the resistant
biotype. However, herbicides with other modes of action
(PSII, 4-HPPD and PPO inhibitors) provided excellent
control. The GR50 ratios for metribuzin, terbuthylazine
and mesotrione were close to 1 and treatments with
fomesafen gave 100% control of both susceptible and
resistant biotypes at the recommended field dose. This
study documents the first case of an imidazolinone and
ALS-resistant biotype in European crops and identifies
the post-emergence herbicide options available for
managing this troublesome weed in soyabean crops.
Alternative management strategies are also discussed
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