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  • 1
    ISSN: 1573-5087
    Keywords: IAA conjugation ; IAA decarboxylation ; HPLC ; Lupinus albus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The products of indole-3-acetic acid (IAA) metabolism by incubating hypocotyl sections and decapitated seedlings of Lupinus albus were investigated. Single treatments using [1-14C]-IAA, [2-14C]-IAA or [5-3H]-IAA and double treatments using [1-14C]-IAA+[5-3H]-IAA were carried out. Extracts from treated plant material were analyzed by paper chromatography (PC), Thin layer chromatography (TLC), and high performance liquid chromatography (HPLC). When hypocotyl sections were incubated in [2-14C]-IAA, several IAA decarboxylation products including indole-3-aldehyde (IA1), indole-3-methanol (IM), 3-hydroxymethyloxindole (HMOx), methyleneoxindole (MOx) and 3,3′-bisindolylmethane (BIM) were detected in the 95% ethanol extract; a latter extraction with 1M NaOH rendered IAA, IM and BIM, suggesting that conjugated auxins were formed in addition to conjugated IM. In sections incubated with [1-14C]-IAA, the 1M NaOH extraction also produced IAA so confirming the formation of conjugated auxins. The same decarboxylation products and two conjugated auxins, indole-3-acetylaspartic acid (IAAsp) and 1-O-(indole-3-acetyl)-β-D-glucose (IAGlu), were detected in the acetonitrile extracts from decapitated seedlings treated with [5-3H]-IAA. After a double isotope treatment ([1-14C]-IAA+[5-3H]-IAA) of decapitated seedlings, the ratio 14C/3H measured in the HPLC fractions of the acetonitrile extracts confirmed the presence of decarboxylation products as well as conjugated auxins.
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  • 2
    ISSN: 1573-5087
    Keywords: 1-aminocyclopropane-1-carboxylic acid ; ethylene ; Lycopersicon esculentum ; polyamines ; ripening ; tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ethylene and polyamine metabolism, both sharing a common precursor, S-adenosylmethionine (SAM), were investigated during detached tomato (Lycopersicon esculentum Mill. nothovar F1 “Lorena”) fruit ripening. Putrescine (PUT) was found to be the major polyamine in the fruits, always over 100 nmols/g FW, while spermidine (SPD) was between 7% and 3% of the level of PUT. Spermine (SPM) was not detected at any stage of ripening. The level of PUT and SPD, did not change significantly during ripening in spite of the almost continuous synthesis of 1-aminocyclopropane-1-carboxylic acid (ACC), the ethylene precursor, and only at the last stage of ripening was a drastic decrease in SPD content observed. The results obtained show that the onset of ACC synthesis and its accumulation within the tissue is not a consequence of a decrease in SPD synthesis.
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  • 3
    ISSN: 1573-5087
    Keywords: Dual-isotope method ; hypocotyl growth ; IAA conjugation ; IAA decarboxylation ; IAA transport ; Lupinus albus ; oscillatory distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The in vivo metabolism of indole-3-acetic acid (IAA) in etiolated hypocotyls of lupin (Lupinus albus L., from Bari, Italy) was investigated by appliying IAA labelled with two radioisotopes ([1-14C]-IAA+[5-3H]-IAA) to the apical end of decapitated seedlings, followed by extraction of the radioactivity in the different regions along the hypocotyl. This method allowed detection of IAA decarboxylation in zones distant from the cut surface and, therefore, containing intact cells. When IAA was added directly in solution to the cut surface, decarboxylation was high especially in those hypocotyl regions where transient accumulations characteristic of the polar transport of IAA occurred. In 10-day-old seedlings such accumulations were observed both in the elongation zone (2nd, 3rd, and 4th cm) and in the non elongating basal zone (8th, 9th and 10th cm). When the IAA, instead, was applied with an agar block deposited on the cut surface, IAA metabolism (decarboxylation as well as conjugation) was increased but almost exclusively in tissues within 10 mm of the cut surface. In both kinds of experiment, the increase in IAA decarboxylation seemed to coincide with a decrease in the transport of IAA, since in the assay without agar the transient accumulations of radioactivity were probably due to a decrease in the transport velocity, while in the assay with agar the transport intensity was much lower than in the assay without agar. These results point to a competitive relationship between IAA metabolism and transport. Consequently, it is suggested that hypocotyl regions that probably use auxin for development processes (e.g., cell elongation and differentiation) may have a more intense IAA metabolism in parallel with their higher IAA concentrations.
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  • 4
    ISSN: 1573-5117
    Keywords: Oligochaeta ; size spectra ; watersheds ; reservoirs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Benthic fauna size distribution, water and sediment composition, and physiographic features of catchments were used to classify ten reservoirs in the Ebro basin, Spain. Three reservoirs (Alloz, Urrunaga and Barasona) diverged from the rest. Environmental factors (water and sediment characteristics) that accounted for the separation of these three reservoirs were directly linked to minor features of the watersheds (high chloride water concentration in Alloz reservoir, iron loading in Barasona reservoir, and Na-rich silicates in sediments from Urrunaga reservoir).
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Planta 167 (1986), S. 76-80 
    ISSN: 1432-2048
    Keywords: Auxin ; Auxin transport ; Lupinus ; Naphtylphthalamic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pH-driven accumulation of [3H]indolyl-3-acetic acid (IAA) has been found to occur in membrane vesicles of lupin (Lupinus albus L.) hypocotyls. Most of this association of auxin with membranes is very sensitive to osmotic shock, high concentrations of permeable weak acids, incubation at 20° C for 20 min and to some ionophores. Long incubation times also depress the ability to accumulate radioactive IAA but this ability can be partially restored by a treatment that presumably reconstitutes the pH gradient across the membranes. Two specific inhibitors of auxin transport, N-1-naphtylphthalamic acid and 2,3,5-triiodobenzoic acid, stimulate net IAA uptake with an optimum at about 10-6 M (pH 5.0). At least two auxin carriers appear to be present in the lupin membrane vesicles. An uptake carrier seems to be saturated at 10-7 M IAA in the presence of N-1-naphtylphthalamic acid, but higher IAA concentrations are needed to saturate an efflux carrier. The uptake carrier also shows a high affinity for IAA and 2,4-dichlorophenoxyacetic acid and a low affinity for 1-naphthylacetic acid.
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  • 6
    ISSN: 1432-2048
    Keywords: Auxin catabolism ; Cytosol (isoperoxidase) ; Indole-3-methanol ; Isoperoxidase, basic ; Lupinus (auxin, isoperoxidase) ; Parenchyma (auxin, isoperoxidase)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nature of the products of the auxin catabolism mediated by both basic and acidic isoperoxidases has been studied. While indole-3-methanol is only a minor product of the oxidation of indole-3-acetic acid catalyzed by extracellular acidic isoperoxidases, it is the only product of the oxidation of indole-3-acetic acid catalyzed by two cytosolic basic isoperoxidases (EC 1.11.1.7) from lupin (Lupinus albus L.) hypocotyls. The putative indole-3-methanol formed by these latter isoperoxidases was isolated and then characterized by mass spectrometry and 1H-nuclear magnetic resonance spectrometry. These results are discussed with respect to the diversity and compartmentation of the catabolism of indole-3-acetic acid in plant tissues.
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  • 7
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The accumulation of both neohesperidin and naringin as major flavonoids in callus cultures of bitter orange (Citrus aurantium) was demonstrated using high performance liquid chromatography with a diode-array detector. The identity of both compounds was confirmed by their corresponding nuclear magnetic resonance spectra. The levels of neohesperidin are higher than those of naringin in callus culture, as they are in immature fruit, and high concentrations of both are found in young tissues such as immature fruits and the outer zone of calli.
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  • 8
    ISSN: 1432-2048
    Keywords: Acid-growth theory ; ATPase ; auxin (uptake, decarboxylation) ; Growth (auxin induced) ; Lupinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The elongation growth of etiolated hypocotyl segments of lupin (Lupinus albus L.) was stimulated by acid pH (4.6 versus 6.5) and by IAA for periods of up to 4 h. After this time, the segments were unable to grow further. In the presence of an optimal IAA concentration (10 μM), acid pH increased the growth rate but had no effect on final growth. With suboptimal IAA (0.1 μM), however, acid pH increased growth in a more than additive way, suggesting a synergistic action between the two factors. This synergism may be explained by the increased IAA uptake and decarboxylation seen at an acid pH. These results reinforce the view that the effects of low pH and IAA on growth are not independent. Vanadate inhibited growth and also IAA uptake and decarboxylation. This inhibitor, therefore, probably inhibits growth not only by decreasing ATPase-mediated acidification but also by decreasing H+-dependent IAA uptake from the apoplasm. This dependence of IAA uptake on ATPase may be mediated by apoplasmic acidification. The amount of IAA decarboxylated increased when the assay conditions favored the growth of segments, indicating that IAA could be destroyed by decarboxylation during the auxin-induced growth.
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  • 9
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The production of the sesquiterpenes nootkatone and valencene by callus cultures of Citrus species is described. The levels of these compounds were examined by gas chromatography-mass spectrometry and their yields were compared with the amounts found in mature fruits. A simultaneous increase and decrease in the levels of nootkatone and valencene, respectively, were observed with the aging of callus cultures of Citrus paradisi. These results suggest that valencene might be a possible precursor of nootkatone in this species. The high level of nootkatone detected in 9-month-old callus cultures of Citrus paradisi might be associated with the corresponding cell morphological changes observed.
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  • 10
    ISSN: 1432-2048
    Keywords: Auxin metabolism, transport ; Elongation growth ; Cortex-stele auxin distribution ; Lupinus (auxin transport) ; Polar auxin transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The transport and metabolism of indole-3-acetic acid (IAA) was studied in etiolated lupin (Lupinus albus L, cv. Multolupa) hypocotyls, following application of dual-isotope-labelled indole-3-acetic acid, [5-3H]IAA plus [1-14C]IAA, to decapitated plants. To study the radial distribution of the transported and metabolized IAA, experiments were carried out with plants in which the stele was separated from the cortex by a glass capillary. After local application of labelled IAA to the cortex, radioactivity remained immobilized in the cortex, near the application point, showing that polar transport cannot occur in the outer tissues. However, following application of IAA to the stele, radioactivity appeared in the cortex in those hypocotyl sections below the first 1 cm (in which the capillary was inserted), and the basipetal IAA movement was similar to that observed after application of IAA to the complete cut surface. In both assays, longitudinal distribution of 14C and 3H in the stele outside the first 1 cm was positively correlated with that of cortex, indicating that there was a lateral migration of IAA from the transport pathway (in the stele) to the outer tissues and that this migration depended on the amount of IAA in the stele. Both tissues (stele and cortex) exhibited intensive IAA metabolism, decarboxylation being higher in the stele than in the cortex while IAA conjugation was the opposite. Decapitation of the seedlings caused a drastic reduction of hypocotyl growth in the 24 h following decapitation, unless the hypocotyls were treated apically with IAA. Thus, exogenous IAA, polarly transported, was able to substitute the endogenous source of auxin (cotyledons plus meristem) to permit hypocotyl growth. It is proposed that IAA escapes from the transporting cells (in the stele) to the outer tissues in order to reach the growth-responsive cells. The IAA metabolism in the outer tissues could generate the IAA gradient necessary for the maintenance of its lateral flow, and consequently the auxin-induced cell elongation.
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