Hydroxymethylglutaryl Coenzyme A Reductase in Fusarium oxysporum

Both growth and theanine accumulation in tea callus cultures were improved by the combination of 4 mg/liter benzyladenine and 2mg/liter indol-3-butyric acid, but were strongly inhibited by the addition of 2,4-dichlorophenoxyacetic acid. The optimum initial concentration of carbon source was 30g/liter sucrose. Upon the addition of more than 30 g/liter of sucrose, the callus fresh weight was increased, but the theanine formation was not improved.     

Enzymic synthesis of 1-O-indol-3-ylacetyl-beta-D-glucose and indol-3-ylacetyl-myo-inositol.

An enzyme fraction from extracts of immature kernels of Zea mays catalyses the formation of 1-O-indol-3-ylacetyl-beta-D-glucose from indol-3-ylacetic acid and UDP-glucose. A second enzyme fraction catalyses the formation of indol-3-ylacetyl-myo-inositol from 1-O-indol-3-ylacetyl-beta-D-glucose and myo-inositol. To our knowledge, this is the first example of hydroxy-group acylation by a 1-O-acyl sugar. The following reaction sequence is proposed: Indol-3-ylacetic acid + UDP-glucose leads to indol-3-ylacetylglucose + UDP (1) Indol-3-ylacetylglucose + myo-inositol leads to indol-3-ylacetyl-myo-inositol + glucose (2) The enzyme catalysing reaction (1) is called UDP-glucose:indol-3-ylacetate glucosyl-transferase (indol-3-ylacetylglucose synthase), and that catalysing reaction (2) is indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (indol-3-ylacetyl-myo-inositol synthase). We further show that indol-3-ylacetylglucose synthase is specific for UDP-glucose and, at the stage of purity tested, the enzyme will use either indol-3-ylacetic acid or naphthalene-1-acetic acid, but not 2.4-dichlorophenoxyacetic acid, as glucose acceptor. The indol-3-ylacetyl-myo-inositol synthase is specific for indol-3-ylacetyl-glucose and will not use naphthalene-1-acetylglucose as substrate, and it is specific for myo-inositol among the alcohol acceptors tested. Thus, of the auxins tested, only indol-3-ylacetic acid forms the myo-inositol ester.     

Auxin binding in roots: A comparison between maize roots and coleoptiles

Auxin binding onto membrane fractions of primary roots of maize seedlings has been demonstrated using naphth-1yl-acetic acid (NAA) and indol-3yl-acetic acid (IAA) as ligands. This binding is compared with the already well characterized interaction between auxins and coleoptile membranes. The results indicate that while kinetic parameters are of the same order for root and coleoptile binding, a number of differences occur with respect to location in cells and relative affinity. The possible significance of the existence of such binding sites in root cells is discussed in relation to auxin action.Abbreviations 4-Cl-PA 4-chlorophenoxyacetic acid - EDTA ethylene diamine tetracetic acid - IAA indol-3yl-acetic acid - MCPA 2-methyl-4-chlorophenoxyacetic acid - NAA naphth-1yl-acetic acid - 2-NAA naphth-2yl-acetic acid - Tris 2-amino-2-(hydroxymethyl) propane-1,3 diol - TIBA 2,3,5 triiodobenzoic acid - NPA naphthylphthalamic acid - PCIB 4-chlorophenoxyisobutyric acid - PCPP 4-chlorophenoxyisopropionic acid - 2,4-D 2,4-dichlorophenoxyacetic acid     

Hormonal Control of Morphogenesis in Leaf Explants of Perilla frutescens Britton var. crispa Decaisne f. viridi-crispa Makino

Leaf discs of Perilla frutescens var. crispa f. viridi-crispawere cultured on a defined medium to investigate factors influencingbud and root formation, callus induction, somatic embryogenesis,and floral bud formation. Addition of naphthalene-acetic acid(NAA) to the culture medium caused compact callus whereas 2,4-dichlorophenoxyacetic acid (2,4-D) promoted soft and friable callus formationon the surface of the explants. Benzyladenine, when appliedwith auxin, suppressed callus and root formation. Somatic embryogenesisoccurred, when the explants were first grown on nutrient mediumcontaining 2,4-D and organic elements, and then transferredto the 2,4-D free medium. Treatments with cytokinins, N-phenyl-N'-(4-pyridyl)urea and its derivatives induced bud formation. A low concentrationof NAA and naphthoxy-acetic acid promoted bud development. Occasionalfloral bud formation was observed depending on the originalleaf positions on mother plants from which the leaf discs wereexcised. A gradient of floral bud forming capacity along thestem was noted. Perilla frutescens, tissue culture, embryogenesis, morphogenesis, benzyl adenine, kinetin, naphthalene-acetic acid, naphthoxy-acetic acid, 2,4-dichlorophenoxy acetic acid, indol-3yl-acetic acid, cytokinins, auxins     

Effect of auxins on flower formation in coffee (Coffea arabica L.)

With the aim to reduce the period of flowering and of fruit maturation, we investigated the effect of auxins on flower formation. For these experiments we used young decapitated plants with two plagiotropic branches. Both the auxins, indol-3-ylacetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D), retarded flower formation in coffee, the latter one being more effective. The effects of 2,4-D if applied on only one of the two plagiotropic branches can be observed only in this treated one. Furthermore, the auxins seem to act in coffee plant directly by affecting flower formation and not indirectly by inducing endogenous ethylene production.     

Short-term Effects of Some Chemicals on Cambial Activity

Aqueous solutions of indol-3yl-acetic acid (IAA), 1-naphthyl-aceticacid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), gibberellicacid (GA), 6-furfuryl-aminopurine (FAP), myo-inositol, and sucrosewere applied singly and in mixtures to the apical ends of disbuddedstem segments of willow. After 4 weeks all substances had hadsome effect on differentiation of xylem from cambial derivatives.The production of potential xylem cells, as well as their differentiationwere most markedly enhanced when IAA, GA, and FAP were appliedtogether, although the response was further augmented by additionof inositol or sucrose. The action of the substances when appliedas mixtures was often synergistic. This means that it is difficultto assess the role of different chemicals in xylem productionby extrapolation from experiments involving the applicationof single substances.     

Regulation of root formation by auxin-ethylene interaction in pea stem cuttings

The possibility was investigated that the inhibition of rooting in pea ( Pisum sativum L. cv. Weibull's Marma) cuttings caused by low indol-3yl-acetic acid (IAA) concentrations is due to ethylene produced as a result of IAA treatment. Treatment with 10 uμ IAA reduced the number of roots to about 50% of the control and increased ethylene production in the stem bases by about 20 times the control value during the two first days of treatment. Ethylene-releasing compounds (ethephon and 1-amino-cyclopropane-1-carboxylic acid, ACC), in concentrations giving a similar ethylene release, inhibited rooting to the same extent or more strongly than IAA. These results indicate that IAA-induced ethylene is at least responsible for the negative component in IAA action on root formation in pea cuttings. A higher IAA concentration (100 μ) and indol-3yl-butyric acid efficiently counteracted the negative effect of ethylene on root formation.     

Tracheary Element Differentiation Induced in Isolated Cylinders of Lettuce Pith: a Bipolar Gradient Technique

To study the influence of morphogenetic gradients on vasculardifferentiation patterns, a new technique was developed whichallows different substances to be applied at opposite ends ofa tissue block. It yielded information on the mobility of particularmorphogens and on the dependence of callus formation and trachearyelement differentiation on their presence. Application of indol-3ylacetic acid (1AA) (10 mg l^–1), zeatin (0.1 mg l^–1)and sucrose (3 per cent, w/v) in various combinations to theends of cylindrical explants of lettuce pith (Lactuca sativaL.) showed that (a) callus formation was stimulated by IAA,whereas induction of tracheary elements required both IAA andzeatin; (b) callus was confined to a few millimetres at theends of the explants, and tracheary elements occurred mainlywithin the callus; (c) sucrose or its metabolic products diffusedthe 10 mm length of the explants, while IAA and zeatin wereeffective only close to the application site; and (d) some callusand tracheary elements formed when no sucrose was applied, butboth increased with sucrose application, though inhibition oftracheary elements formation occurred with high sucrose concentrations. differentiation, pith explant, tissue culture, xylogenesis, indol-3yl acetic acid, sucrose, zeatin, lettuce, Lactuca sativa     

Anther culture of papaya (Carica papaya L.)

Papaya (Carica papaya L.) anther containing microspores in tetrad to early-binucleate stages were successfully cultured on 1/2 strength MS salts and vitamins with full strength Na-Fe-EDTA supplemented with 2 mg/l NAA, 1 mg/l BA and 6% sucrose for callus initiation and formation. Highest frequencies of callus induction were obtained when anthers at the uninucleate stage were cultured in the dark. Haploid plantlets and pollen-derived embryoids were obtained from anthers cultured at the uninucleate stage on solidified MS medium containing 3% sucrose without any growth regulators under a low light intensity (1,500 lux). Large quantities of embryoids were obtained when the original embryoids were transferred to MS medium with 3% sucrose and no growth regulators. Cytology of root tips of embryoid-derived plants confirmed the haploid chromosome number of 9 indicating that the embryoids originated from pollen.Abbreviations MS Murashige and Skoog (1962) - MAA naphthaleneacetic acid - BA 6-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid     

Rapid clonal propagation of Pinellia ternata by tissue culture

Adventitious buds or protocorm-like bodies were regenerated directly from excised explants without intervening callus. Differences in the ability of regeneration were observed among different plant organs with bulbils showing the highest regenerative ability followed by leaf blade and petiole. Ability of vegetative propagation of bulbil could be maintained by alternate solid-and liquid-medium culture. Theoretically, 1.7×10²⁷ plantlets could be produced from a single bulbil by this technique within one year based on the production and rapid growth of protocorm-like bodies and adventitious buds. Concentration of MS salts, NAA and sucrose influenced not only root formation from the differentiated adventitious buds, but also root number and length. For root formation, the best combination was one-half strength MS salts with 3–5% sucrose and 1 mg/l NAA. The high survival rate of 96% was recorded when plantlets were transplanted into a mixture of vermiculite:loam soil:peat moss (1:2:1). Plants from in vitro culture were morphological similar to field-grown plants. The acute toxicity of crude extracts from protocorm-like bodies was about one-fourth that of extracts from tubers of field-grown plants when tested with white mice. Tissue culture has potential for clonal propagation of Pinellia ternata plants for commercial use.Abbreviations MS Murashige and Skoog (1962) - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA -naphthaleneacetic acid - BA 6-benzylaminopurine     

2,4-Dichlorophenoxy acetic acid and indoleacetic acid partially counteract inhibition of organogenesis by difluoromethylornithine

Difluoromethylornithine (DFMO) is a well known inhibitor of putrescine biosynthesis that has been reported to interact in varying ways with auxins such as indoleacetic acid (IAA) and 2,4-dichlorophenoxy acetic acid (2,4-D). In the present report DFMO is shown to inhibit root formation in isolated hypocotyl segments of Euphorbia esula L. (leafy spurge) grown in the dark on solidified nutrient media in Petri dishes. Shoot formation was only slightly inhibited by DFMO and only on media with salts and vitamins diluted 10-fold. 2,4-D inhibited both root and shoot formation in full strength or diluted media. Simultaneous application of both compounds resulted in partial reversal of root inhibition, but only at 450 n M 2,4-D, the highest concentration used. In both media IAA also partially reversed DFMO effects on root formation. The effects of DFMO, 2,4-D or IAA on root (or shoot) formation do not appear to be closely related to endogenous content of the polyamines determined by high performance liquid chromatography.     

白蕊草组织培养和快速繁殖的研究

通过对白蕊草组织培养的培养基种类,激素配比,添加物汁液,碳源的研究,得出适合白蕊草侧芽分化生长的最佳培养基为MS＋6－BA2.0mg/L＋NAA0．5mg/L 狗牙根汁液。诱导愈伤组织以2,4－D浓度在0.5mg/L-2mg/L之间最佳。碳源以蔗糖,浓度3％最佳。生根实验表明：较低浓度的生长素不利于生根,最佳生根培养基为MS＋6－BA0.5mg/L NAA2mg/L 狗牙根汁液或MS＋6－BA0.5mg/L IBA2mg/L 狗牙根汁液。     

Growth Hormones and Propagation of Cymbidium in vitro

Protocorms of Cymbidium (Orchidaceae) were grown on solid or liquid medium with macro-nutrients according to Wimber (van Raalte 1967) and iron, micro-nutrients and vitamins according to Nitsch (1968) the medium also contained 2% sucrose. The effects of 1) the auxins; indol-3yl-acetic acid (IAA), α-naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D); 2) the cytokinins; 6-furfurylaminopurine (kinetin) and benzyladenine (BA) and 3) the gibberellin; gibberellic acid (GA) were examined alone or in combinations. IAA had no effect alone. NAA resulted in optimal fresh weight at 10 μM and the protocorms were vigorous, but lighter green than usual. 2,4-D caused a high weight increase at 1 μM, but the protocorms were abnormal. Higher concentrations of NAA and 2,4-D inhibited chlorophyll synthesis. On solid medium kinetin (100 μM) induced a growth of many small shoots, but had no effect on the fresh weight. In liquid medium, kinetin promoted a callus formation and fresh weight increase. BA had effects similar to kinetin, but at lower concentrations. GA alone promoted shoot and leaf growth. Combinations of kinetin and NAA resulted in a maximal fresh weight increase at kinetin concentrations one tenth of the NAA concentrations. The optimal growth and the best development occurred at 10 μM NAA and 1 μM kinetin. NAA and kinetin together could limit the shoot and leaf growth induced by GA.     

The indirect role of 2,4-D in the maintenance of apical dominance in decapitated sunflower seedlings (Helianthus annuus L.)

When sufficient 2,4-D to maintain apical dominance for at least 21d was applied to the cut stem interface of sunflower seedlings which had been decapitated in the epicotyl, it could not be detected in the vicinity of the inhibited axillary buds 7d after application. Rather the 2,4-D concentrated at the stump apex where it was associated with formation of meristematic tissue. The results indicate an indirect role for 2,4-D in the maintenance of apical dominance in this system, possibly involving the induced meristematic activity.Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid - [¹⁴C]2,4-D 2,4-dichlorophenoxy[2-¹⁴C]acetic acid - IAA indol-3-yl-acetic acid     

Somatic embryogenesis,organogenesis and callus growth kinetics of flax

The effects of plant growth regulators (PGR) on calli induction, morphogenesis and somatic embryogenesis of flax were studied. The organogenic and callus formation capacity were assessed for different types of source explants. Root and shoot explants were equally good material for calli production but the former produced calli without shoot regeneration capacity. Under the experimental conditions tested, 2,4-dichlorophenoxyacetic acid (2,4-D) + zeatin was the most efficient PGR combination on calli induction and biomass production. The calli were green but with no rhizogenic capacity. In contrast, and at similar concentrations, indole-3-butyric acid (IBA) + kinetin induced white or pale green friable calli with a good root regeneration capacity (60%). A factorial experiment with different combinations of 2,4-D + zeatin + gibberellic acid (GA₃) levels revealed that the direction of explant differentiation was determined by specific PGR interactions and concentrations. The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l^?1 in the induction medium. The induction and development of somatic embryos from flax explants was possible in a range of 2,4-D + zeatin concentrations surrounding 0.4 mg l^?1 2,4-D and 1.6 mg l^?1 zeatin, the most efficient growth regulator combination.     

Auxin-stimulated ATPase in membrane fractions from pumpkin hypocotyls (Cucurbita maxima L.)

Membrane fractions from Cucurbita maxima hypocotyls were isolated in a medium which inhibits the action of endogenous phospholipases. After removal of soluble phosphatases by Sepharose 2B-CL column chromatography, an auxin-stimulated ATPase activity was found in membrane fractions from linear sucrose gradients. In the presence of 10^-4 M phenylacetic acid (PAA), the stimulation by indol-3-acetic acid (IAA) exhibited a bimodal concentration dependence with maximal stimulation of about 50% at 10^-6 M IAA. Without PAA, only a high concentration of 10^-4 M IAA was stimulatory, whereas 10^-6 M IAA had no apparent effect and 10^-8 M IAA exhibited weak inhibition. PAA alone had only weak or no effects. The effects of IAA must be considered as hormone-specific. The ATPase activity in the presence of 10^-4 M PAA was activated only by 2,4-dichlorophenoxyacetic acid (2,4-D), an active auxin analogue, but not by the inactive stereoisomers, 2,3-D and 3,5-D. Comparison with marker enzyme profiles suggested that part of the auxin-stimulated ATPase was localized on plasma membranes as well as other compartments. Thus, the auxin-stimulated ATPase may become a useful tool in the investigation of the mechanism of action of auxin.Abbrevations 2,4-D 2,4-dichlorophenoxyacetic acid - 2,3-D 2,3-dichlorophenoxyacetic acid - 3,5-D 3,5-dichlorophenoxyacetic acid - IAA indol-3-acetic acid - PAA phenylacetic acid - MES (2-(N-morpholino))-ethanesulfonic acid - EDTA ethylenediamine tetraacetic acid     

Effects of macronutrients on growth and rosmarinic acid formation in cell suspension cultures of Anchusa officinalis

The influence of various macronutrients on growth and RA formation in cell suspension cultures of Anchusa officinalis has been investigated. Factors tested included sucrose concentration, alternate carbon sources, nitrate, phosphate and calcium concentration. The optimum concentration of sucrose was 3%. Fructose, glucose or their 1:1 mixture were also suitable carbon sources. The optimum concentrations of nitrate (15 mM), phosphate (3 mM) and calcium (0.25 mM) were, respectively, 3/5, 3x, and 1/4 those in normal B5 medium, when tested separately. These concentrations improved not only the yield of RA but also cell growth to a similar degree (10%–50%). Studies on the combined effects of these optimum macronutrient concentrations in B5 medium showed that RA production is inhibited by 2,4-D-containing revised medium but stimulated by NAA-containing revised medium.Abbreviations RA rosmarinic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-napthaleneacetic acid     

贯叶金丝桃组织培养的研究

分别以甘肃天水贯叶金丝桃的幼根、幼茎、幼叶为外植体．在1／2MS培养基上附加各类激素,进行贯叶金丝桃的组培实验。研究发现各外植体的增殖速率由高到低分别为幼茎、幼根、幼叶,且得到贯叶金丝桃组培各阶段的最佳培养基成分。诱导愈伤组织的培养基为1／2MS 1．3～1．6mg／L BA 0．2mg／L NAA;培养基1／2MS 1．3～1．6mg／L BA 0．15mg／L NAA有利于不定芽的形成;诱导不定根的培养基为l／2MS IBA0．5～O．8mg／L 蔗糖2．0％。向1／2MS培养基中添加不同的生长素(IAA,IBA,NAA,2．4-D)．在不同浓度梯度的培养基上进行诱导贯叶金丝桃的愈伤组织及不定根的试验,结果表明：生长素IAA,IBA既可诱导愈伤组织,又可以诱导不定根的产生。生长素NAA,2,4-D可诱导产生愈伤组织,但对不定根的诱导作用较差。     

In vitro studies on Pea (Pisum sativum L.): I. Callus formation,regeneration and rooting

Abstract

Callus production, shoot formation via organogenesis and rooting of the regenerated shoots are reported in an Egyptian variety of Pisum sativum L. Calli were initiated from hypocotyl, leaf, root and mature embryo explants when cultured on MS medium containing B5 vitamins and supplemented with 2 mg/l 2,4-D+1 mg/l kin. Among the different types of explants, hypocotyl showed best potential for callus proliferation. Hypocotyl, leaf and immature cotyledon explants were used for shoot organogenesis. The best results of shoot formation were achieved when hypocotyl explants were cultured on MS-medium supplemented with 2 mg/l BA+1 mg/l NAA. However, immature cotyledon explants showed the highest frequency of shoot formation with 1 mg/l BA. Data of in vitro rooting showed that maximum root frequency occurred on culture medium containing half strength of MS salts, 40 g/l sucrose and 2 mg/l NAA.     

Plant growth regulators and adventitious root development in relation to auxin

Adventitious root formation in stem cuttings of mung bean was enhanced by ethrel, which had an additive effect when employed simultaneously with indolebutyric acid (IBA). Abscisic acid (ABA) did not influence the number of roots per cutting whereas gibberellic acid (GA₃) and kinetin were without effect on rooting at lower concentrations but were inhibitory at higher concentrations. Nevertheless, all three of these chemicals showed synergistic interactions with IBA and/or indol-3-ylacetic acid (IAA) and thereby significantly promoted root formation. A localised application of morphactin to the epicotyl of cuttings totally inhibited root production irrespective of which of the foregoing growth regulators were suppliedvia the hypocotyl. Morphactin application also prevented root formation in cuttings treated with vitamin D₂. The various growth regulators employed had differing effects on growth of roots but there was no simple relationship between their effects on root formation and subsequent root growth.