Assimilation of nitrogen dioxide in response to fumigation with 15 N-labelled nitrogen dioxide was studied in 217 plant taxa. The taxa included 50 wild herbaceous plants collected from roadsides (42 genera, 15 families), 60 cultivated herbaceous plants (55 genera, 30 families) and 107 cultivated woody plants (74 genera, 45 families). Two parameters, the 'NO 2 -N content', or NO 2 -derived reduced nitrogen content in fumigated plant leaves (mg N g -1 dry weight), and the 'NO 2 -utilization index', or percentage of the NO 2 -derived reduced nitrogen in the total reduced nitrogen, were determined. The NO 2 -N content differed 657-fold between the highest (Eucalyptus viminalis; 6·57) and lowest (Tillandsia ionantha and T. caput-medusae; 0·01) values in the 217 taxa; 62-fold in a family (Theaceae) and 26-fold in a species (Solidago altissima). Nine species had NO 2 -utilization indices greater than 10%, of which Magnolia kobus, Eucalyptus viminalis, Populus nigra, Nicotiana tabacum and Erechtites hieracifolia had NO 2 -N contents > 4·9. These plants can be considered 'NO 2 -philic' because in them NO 2 -nitrogen has an important function(s). The Compositae and Myrtaceae had high values for both parameters, whereas the monocots and gymnosperms had low ones. These findings suggest that the metabolic pathway of NO 2 -nitrogen differs among plant species. The information presented here will be useful for creating a novel vegetation technology to reduce the atmospheric concentration of nitrogen dioxide.
Temperature and photoperiod are important determinants of the time from emergence to flowering in soybean [Glycine max (L.) Merr.]. A linear and a logistic model have been developed independently for describing the development rate to flowering (a high development rate means a short time to flowering). Field experiments on Arredondo fine sand soil (loamy, siliceous hyperthermic Grossarenic Paleudult) at Gainesville, FL, during 3 yr using a range of sowing dates in each year provided data to evaluate each model. In the first 2 yr, 13 cultivars were grown from 17 sowing dates. The linear model was found to represent adequately these 2 yr of data, but the logistic model was somewhat superior for 12 of the 13 cultivars. The coefficients derived for each model from the first 2 yr of study were used to predict flowering date in the 3rd yr. Both models gave accurate predictions of flowering date, although the larger discrepancies between predictions and observations were obtained with the linear model. Assuming an adequate data base to evaluate the coefficients in each model, either model was able to predict soybean flowering date.
A high density culture method was devised to improve the yield of berberine from highly productive cells of Coptis japonica. By adjusting aeration and stirring, Coptis cells were cultured at densities of up to 75 g dm-3 (dry weight) in a culture tank fitted with a hollow-paddle type stirrer.Whereas a maximum density of 30 g dmP3 of C. japonica cells could be used in ordinary batch culture, 48 g dm-3 could be used in a fed-batch culture in which the amounts of the nutrients in the medium were made proportional to the density of the inoculum. Moreover, in fed-batch culture done with modified medium, the composition of which had been determined from the amounts of components incorporated in cells grown at the usual density for ordinary batch culture, the cell yield was improved to 55 g dm-3 and the berberine yield to 3.5 g dm-'.
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