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Plant Sciences

1995

Selected Works

Articles 1 - 4 of 4

Full-Text Articles in Life Sciences

A Second Nitrogenase In Vegetative Cells Of A Heterocyst-Forming Cyanobacterium, T Thiel, E M. Lyons, J C. Erker, A Ernst Sep 1995

A Second Nitrogenase In Vegetative Cells Of A Heterocyst-Forming Cyanobacterium, T Thiel, E M. Lyons, J C. Erker, A Ernst

Teresa Thiel

In many filamentous cyanobacteria nitrogen fixation occurs in differentiated cells called heterocysts. Filamentous strains that do not form heterocysts may fix nitrogen in vegetative cells, primarily under anaerobic conditions. We describe here two functional Mo-dependent nitrogenases in a single organism, the cyanobacterium Anabaena variabilis. Using a lacZ reporter with a fluorescent beta-galactoside substrate for in situ localization of gene expression, we have shown that the two clusters of nif genes are expressed independently. One nitrogenase functions only in heterocysts under either aerobic or anaerobic growth conditions, whereas the second nitrogenase functions only under anaerobic conditions in vegetative cells and heterocysts. …

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Clonal-By-Environment Interactions Influence Isoflavonoid Accumulation In Cicer Milkvetch, Andrew W. Lenssen, C. E. Townsend, S. S. Martin May 1995

Clonal-By-Environment Interactions Influence Isoflavonoid Accumulation In Cicer Milkvetch, Andrew W. Lenssen, C. E. Townsend, S. S. Martin

Andrew W. Lenssen

Cicer milkvetch (Astragalus cicer L.) is a perennial, nonbloatinducing forage legume adapted to temperate environments. For unknown reasons, however, ruminants grazing cicer milkvetch in pure stands have become photosensitized, or sunburned, in some environments, Isoflavonoids are involved with diverse biological activities, including estrogenism, disease resistance, and, potentially, photosensitization. We conducted a series of studies from 1991 to 1993 to identify factors that influence the accumulation of isoflavonoids. In separate greenhouse studies, elicited leaflets from the parental clones of ‘Monarch’ and. ‘Windsor’ cicer milkvetch were analyzed for isoflavonoid accumulation. Growth chamber studies were conducted to investigate the clonal variability of leaflet …

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Pollination Of The Crown Imperial Fritillaria Imperialis By Great Tits Parus Major, Winfried S. Peters, Michael Pirl, Gerhard Gottsberger, Dieter Stefan Peters Feb 1995

Pollination Of The Crown Imperial Fritillaria Imperialis By Great Tits Parus Major, Winfried S. Peters, Michael Pirl, Gerhard Gottsberger, Dieter Stefan Peters

Winfried S. Peters

Visitations of flowers of the Crown Imperial by Great Tits at two different locations in Hessen, Germany, in 1990 and 1993 are described. The observations prove that flowers were visited because of the nectar; most likely pollination occurs during this visits. Similar reports from Europe are discussed. The significance of specific interactions including ecological generalists such as the Great Tit is considered in the context of the phylogenetic reconstruction of the development of co-adaptive syndroms.

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Swine Waste Disposal Dilemma, Robert Mikkelsen Jan 1995

Swine Waste Disposal Dilemma, Robert Mikkelsen

Robert Mikkelsen

The swine industry has grown rapidly in North Carolina in the past decade, with the majority of the growth occurring in a few counties in the Coastal Plain region of the state. With this expansion has come the problem of swine waste disposal. Mr. Blevins, a local farmer in this region, has been raising swine since 1985. The swine waste on his farm is collected in an anaerobic lagoon and then irrigated onto a bermudagrass (Cynodon dactylon(L.) Pers.) pasture where cattle are fed using intensive rotational grazing techniques. A study of Mr. Blevins' farm revealed very high nitrate concentrations in …

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