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1.
Maria de Lourdes Lucio Ferrarese Osvaldo Ferrarese-Filho JoĂo Domingos Rodrigues 《Acta Physiologiae Plantarum》2000,22(2):121-124
Ferulic acid uptake by soybean root in nutrient culture was investigated by the depletion method at different concentrations,
temperatures and pH. Results showed that soybean roots absorbed this compound at greater rates in the concentrations between
0.05-mM and 1.0-mM and it was concentration dependent. Ferulic acid uptake was unaffected at pH 4.5 or 6.0 but reduced at
pH 7.0. At pH 6.0, uptake rates decreased significantly with increasing temperature of nutrient solution. 相似文献
2.
Indol-3yl-acetic acid was identified in extracts of sterile roots of Zeamays seedlings by means of TLC, chromogenic reactions, GLC and GC-MS. 相似文献
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As the first part of a comprehensive study of the hormonal control of lateral root initiation and development, the effect of surgical treatments such as removal of the root tip, one or more cotyledons, the young epicotyl, or combination of these treatments, on the induction and emergence of lateral roots on the primary root of pea seedlings has been examined. Results show that removal of the root tip leads to a rapid but transitory increase in the number of lateral primordia, the largest number arising in the most apical segment of decapitated roots suggesting the accumulation of acropetally moving promoter substances in this region. The cotyledons appear to be the main source of promoter substances for both the induction and emergence of lateral roots, although one or more promoters also appear to be produced in the epicotyl. The data further indicate that the root tip is possibly the source of a substance which moves basipetally and interacts with acropetally moving promoters to regulate the zone for lateral primordia initiation; the root tip also appears to be the source of a powerful inhibitor of lateral root emergence. 相似文献
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For some foodstuffs, determination of the mycotoxin ochratoxin A (OTA) requires time consuming clean up by means of solid
phase extraction (SPE). Therefore a system for automated SPE was tested for cleaning up roasted coffee as a possible way of
shortening preparation time. Validation of the method in accordance to the so called “Concept '98” led to a LOD of 0.2 μg/kg
and a recovery rate of 92%. By using the described procedure with samples of roasted coffee the OTA contents varied between
the LOD and 3.4 μg/kg. This method was also used to determine ochratoxin A in liquorice roots, ginger and valerian.
Presented at the 26th Mykotoxin Workshop in Herrsching, Germany, May 17–19, 2004 相似文献
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Nalini M. Nadkarni 《Oecologia》1994,100(1-2):94-97
Some of the proximate factors that would induce aboveground stems to produce adventitious roots were investigated experimentally on Senecio cooperi, a tropical cloud forest tree. Stem segments were air-layered with different treatments to promote root formation, and the number of roots initiated and rates of root growth were monitored for 20 weeks. Treatments were the application of wet epiphytes or dry epiphytes plus associated humus, sponges wetted with either water or nutrient solutions, or dry sponges. Controls (stem segments with nothing applied) were also monitored. Numbers of adventitious roots formed and rates of subsequent root growth differed among treatments. Wet epiphyte/humus and nutrient solutions were most effective in producing roots, which suggests that epiphytes and the nutrients they intercept and retain within the canopy may cue adjacent host tissue to exploit this resource. 相似文献
9.
P. Nick 《Plant biology (Stuttgart, Germany)》1997,110(4):291-297
The crown roots in the coleoptilar node of maize emerge asymmetrically: emergence at the dorsal flank of the node (opposite to the caryopsis) precedes emergence at the ventral flank (facing the caryopsis). This asymmetry can be altered by phototropic stimulation: emergence of crown roots is delayed in the lighted flank and promoted in the shaded flank causing an inversion of the endogenous asymmetry. The curvature induced by the phototropic stimulation is transient, the effect on crown root emergence, in contrast, persists. This stable effect is not a consequence of curvature per se and becomes irreversibly fixed between one and two hours after stimulation. The emergence of crown roots depends on directional signalling from the coleoptile to the node. The data are discussed in terms of a stable blue light induced transverse polarity of the coleoptile that can imprint a stable asymmetry upon the coleoptilar node guiding the emergence of crown roots. 相似文献
10.
Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum) 总被引:8,自引:1,他引:7
Protein, amino acids and ammonium were the main forms of soluble soil nitrogen in the soil solution of a subtropical heathland (wallum). After fire, soil ammonium and nitrate increased 90- and 60-fold, respectively. Despite this increase in nitrate availability after fire, wallum species exhibited uniformly low nitrate reductase activities and low leaf and xylem nitrate. During waterlogging soil amino acids increased, particularly γ-aminobutyric acid (GABA) which accounted for over 50% of amino nitrogen. Non-mycorrhizal wallum species were significantly (P < 0.05) 15N-enriched (0.3–4.3‰) compared to species with mycorrhizal associations (ericoid-type, ecto-, va-mycorrhizal) which were strongly depleted in 15N (-6.3 to -1.8‰). Lignotubers and roots had δ15N signatures similar to that of the leaves of respective species. The exceptions were fine roots of ecto-, ecto/va-, and ericoid type mycorrhizal species which were enriched in 15N (0.1–2.4‰). The 515N signatures of δ15Ntotal soil N and δ15Nsoil NH4+ were in the range 3.7–4.5‰, whereas δ15Nsoil NO3? was significantly (P < 0.05) more enriched in 15N (9.2–9.8‰). It is proposed that there is discrimination against 15N during transfer of nitrogen from fungal to plant partner. Roots of selected species incorporated nitrogen sources in the order of preference: ammonium > glycine > nitrate. The exception were proteoid roots of Hakea (Proteaceae) which incorporated equal amounts of glycine and ammonium. 相似文献