Analysis of the Developmental Regulation of the Cyanogenic Compounds in Seedlings of Two Lines of \u3cem\u3eLinum usitatissimum\u3c/em\u3e L.

The developmental profiles and tissue distribution of the four cyanogenic compounds in seedlings of two developmentally contrasting inbred lines of flax (Linum usitatissimum L.) were examined using HPLC. During germination, the isoleucine-derived compound, neolinustatin, was hydrolysed faster in the more vigorous of the two lines. Furthermore, in this line, the neolinustatin content was higher in seeds and the accumulation of the other isoleucine-derived compound, lotaustralin, was also higher in the cotyledons of seedlings. In contrast, with one exception, the hydrolysis and accumulation of the valine-derived compounds, linustatin and linamarin, was the same in both lines. Differences in the levels of the compounds during germination, and in the hypocotyls, are interpreted as evidence for the involvement of transient levels of hydrogen cyanide in the autocatalytic regulation of ethylene production

Evaluating the Potential of Using 5-Azacytidine as an Epimutagen

A number of early flowering lines were induced when 5-azacytidine was applied to germinating flax (Linum usitatissimum L.) seed. The genetics of these lines indicate that the induced changes are epigenetic and probably result from demethylation of the genomic DNA at loci that affect flowering age. Although the growth and development of three stable early flowering lines are altered and the percentage of filled seed was reduced in all three lines compared with controls, measures of seed productivity demonstrated that harvest index was unaffected in two of the lines. In the third, harvest index was lower than normal and both seed set per capsule and seed mass per 100 seed were reduced. Furthermore, six generations after induction this line began to display relatively high levels of polyembryony. The late appearance of this twinning and other aspects related to working with lines induced by 5-azacytidine and using 5-azacytidine as an epimutagen are discussed

Preliminary Characterization of Peroxidase Isozymes Isolated from Two Flax Genotrophs

Four peroxidase (EC 1.11.1.7) isozymes were isolated from each of two flax genotrophs. All four isozymes were glycoproteins and all exhibited indoleacetic acid (IAA) oxidase activity. The percentage purity of two of the isozymes was very high; these isozymes differed in percentage carbohydrate and in peroxidase and IAA oxidase specific activities. Three of the isozymes displayed molecular weight values of about 43 000; for the fourth, molecular weight was considerably higher. Corresponding isozymes from the genotrophs and from two other flax genotypes displayed molecular weight differences which corresponded to electrophoretic relative mobility differences. Enzyme yield per unit fresh weight was higher for one genotroph than the other, and the balance between peroxidase activity and IAA oxidase activity between the genotrophs was different

Measurement of Activity of Peroxidase Isoenzymes in Flax (\u3cem\u3eLinum usitatissimum\u3c/em\u3e)

Peroxidase isoenzynles may be separated on acrylamide gels and then detected by supplying the substrate in an appropriate reaction system. One such system frequently used contains guaiacol as the hydrogen donor, although this compound has certain drawbacks. Ways of circumventing these drawbacks are suggested, so that quantitative estimates of the activity of individual peroxidase isoenzymes may be obtained

Isolation of Peroxidase Isozymes from Two Flax Genotypes by Column Chromatography

Isolation of the four major peroxidase isozymes (isozymes 1, 2, 3, and 4) of two flax genotypes was achieved by modifying the procedure used by Shannon et al. (1966) for the isolation of horseradish peroxidase isozymes. The net positive and net negative charges of isozymes 1, 2, and 4 were different. Isozyme 3 resembled isozyme 4 in charge but differed in apparent molecular weight. The chromatographic elution profiles of both genotypes were the same. Anionic gel electrophoresis demonstrated that after isolation and repurification, relative mobility differences existed between the corresponding isozymes of the two genotypes for all four isozymes

Influence of soil type and natural Zn chelates on flax response, tensile properties and soil Zn availability

A greenhouse experiment was conducted on weakly acidic and calcareous soils to evaluate the relative efficiencies of three natural Zn chelates [Zn-aminelignosulphonate (Zn-AML), Zn-polyhydroxyphenylcarboxylate (Zn-PHP) and Zn-S,S-ethylenediaminedisuccinate (Zn-S,S-EDDS)] applied to a crop textile flax (Linum ussitatisimum L.) at application rates of 0, 5 and 10 mg Zn kg−1. In the flax plant, the following parameters were determined: dry matter yield, soluble and total Zn concentrations in leaf and stem, chlorophyll, crude fibre, and tensile properties. For the different soil samples, the following parameters were determined: available Zn (DTPA-AB and Mehlich-3 extractable Zn), easily leachable Zn (BaCl2-extractable Zn), the distribution of Zn fractions, pH and redox potential. On the basis of the use of added Zn by flax, or Zn utilization, it would seem recommendable to apply Zn-S,S-EDDS at the low Zn rate in both soils. In contrast, adding the high Zn rate of this chelate to the weakly acidic soil produced an excessive Zn concentration in the plant, which caused a significant decrease in both dry matter yield and chlorophyll content. Furthermore, assessing available Zn with the DTPA-AB method proved the best way of estimating the level of excess Zn in flax plants. The soluble Zn concentration, which was established with 2-(N-morpholino)ethanesulfonic acid reagent (MES), of plant fresh and dry matter could be used as an alternative way of diagnosing the nutritional status of Zn in flax plants. In this experiment, the highest soil pHs were associated with the lowest redox potentials, which coincided with the smallest amounts of available Zn and water soluble Zn in soil, and the lowest levels of Zn uptake by flax plants

Nature, origin, transport and deposition of andosol parent material in south-central Chile (36-42°S)

Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in CATENA 73 (2008): 10-22, doi:10.1016/j.catena.2007.08.003.The andosols of south-central Chile (36-42°S) are developed on yellow-brown loams that cover the region with a thickness of several meters. In the literature, several hypotheses concerning the nature, origin, mode of transport and deposition of the andosol parent material have been advanced but no general agreement has been found. In this paper, we test these hypotheses by analyzing new representative outcrops located around Icalma (38°50’S) and Puyehue (40°40’S) lakes by a plurimethodological approach. Our data demonstrate that the andosol parent material has the typical mineralogical and geochemical signature of the regional volcanism and that these deposits are postglacial in age. The grain size of the deposits and the morphology of the coarse grains evidence that most of these particles haven’t been re-transported by wind but are direct volcanic ash falls deposited throughout the Late Glacial and Holocene. Because of the prevailing westerly winds, most of them have been transported to the East. Following the deposition of the volcanic particles, weathering and pedogenetic processes have transformed part of the volcanic glasses and plagioclases into allophane and have wiped out the original layering. This work demonstrates that most of the andosols that occur in the Andes and in the eastern part of the Intermediate Depression of south-central Chile are developed on volcanic ashes directly deposited by successive volcanic eruptions throughout the Late Glacial and Holocene.This research is supported by the Belgian OSTC project EV/12/10B "A continuous Holocene record of ENSO variability in southern Chile"