Interaction of abscisic acid and auxins in rooting of cuttings

Abscisic acid (ABA) at optimum concentrations promoted rootingof Phaseolus aureus ROXB. and Lycopersicon esculentum MILL,stem cuttings. In combination with IAA (indole-3-acetic acid)ABA has mostly given additive effects. Synergistic effect ofABA was noted on IBA (-indolebutyric acid)-induced rooting ofLycopersicon cuttings. Rooting of Phaseolus vulgaris L. cuttingscompletely failed when ABA (50 mg/liter) was applied in combinationwith IBA or NAA (-naphthaleneacetic acid). The results suggestthat abscisic acid may be an important natural regulator ofrooting in cuttings. (Received March 19, 1970; )     

The effects of a fogging system on the physiological status and rooting capacity of leafy cuttings of woody species

The early responses of leafy stem cuttings of Prunus and Castanea species with differing rooting abilities were assessed in a fog system using fluorescence measurements. Different types of cuttings of each species were used: cherry Prunus (‘GiSelA 5’, Prunus cerasus × Prunus canescens—148/2) and chestnut Castanea (‘Marsol’ and ‘Maraval’, Castanea crenata × Castanea sativa). The physiological status of cuttings in the early initiation phase was compared to the rooting results. For all cuttings, fluorescence measurements revealed a close-to-optimum photochemical efficiency, indicating that physiological stress (severance, water, etc.) was minimal. In cherry, the potential photochemical efficiency (Fv/Fm) differed slightly between terminal and basal cherry cuttings, being lower in the basal ones at the time of severance. Later in the propagation process, the differences were smaller. The photochemical efficiency did not differ between two ‘difficult-to-root’ Castanea clones, nor was it dependent on the length of the cuttings. The high rooting capacity of long Castanea cuttings (50 cm) indicated that physiological stress could be minimized under a fogging system. An erratum to this article can be found at     

Endogeneous levels of indole-3-acetic acid and abscisic acid during the rooting of Cotinus coggygria cuttings taken at different times of the year

Cuttings of Cotinus coggyria cv Royal Purple rooted well in the spring but not at all later in the season. Levels of free and conjugated IAA and ABA were measured in cuttings taken at different times of the year. Hormones were measured in the leaf, the upper stem and the lower stem (rooting zone). In cuttings taken in early June the level of IAA was much higher than that of conjugated IAA. In late July the opposite was found. No significant differences in ABA levels were found although the ABA/IAA ratio changed dramatically.     

The effect of Fe-EDDHA and of ascorbic acid on in vitro rooting of the peach rootstock GF-677 explants

The objective of this research was to study the effect of the chelated form of the iron salt of ethylenediamine di-o-hydroxyphenylacetic acid (Fe-EDDHA) (6% Fe) on in vitro rooting of the rootstock GF-677. The iron salt of ethylenediamine tetraacetic acid (Fe-EDTA) (12% Fe) of the MS basic medium was replaced by Fe-EDDHA, which was applied in three concentrations: 93.5, 187.0 and 280 mg l⁻¹ (5.6, 11.2 and 16.8 mg l⁻¹ Fe, respectively). For each treatment of Fe-EDDHA, the effect of ascorbic acid added in four concentrations (0, 0.1, 1.0 and 10 mg l⁻¹) was studied. After 4 weeks of culture, the explants growing on the medium with 280 mg l⁻¹ Fe-EDDHA gave the best rooting results. Regarding ascorbic acid, no clear stimulating effect on rooting was found.     

Synergistic effect of gibberellic acid and indole-3-acetic acid on rooting in stem cuttings of Abelmoschus esculentus Moench

Indole-3-acetic acid (IAA) and gibberellic acid (GA₃) enhanced the formation of roots on the stem cuttings of Abelmoschus esculentus. The effect increased considerably when both IAA and GA₃ were applied together.     

Shoot RNA, cambrial activity and indolebutyric acid effectivity in seasonal rooting of juvenile and mature Ficus pumila cuttings

The seasonal influence on adventitious root formation was studied in woody leaf bud cuttings of Ficus pumila L., creeping fig. Juvenile cuttings rooted easily, whereas only mature cuttings treated with indolebutyric acid (IBA) exceeded 30% rooting. Greater rooting occurred in IBA-treated juvenile and mature cuttings than controls, regardless of the month each experiment was initiated. Seasonal changes influenced rooting in all treatments except IBA treated juvenile cuttings where percentage rooting was not affected. Higher vascular cambial activity and shoot RNA levels occurred in juvenile and mature forms during peak rooting periods. Highest RNA was recorded with juvenile materials during maximum rooting periods, while lowest RNA was observed in mature shoots during low rooting intervals.     

Levels of endogenous indole-3-acetic acid and indole-3-acetyl-aspartic acid during adventitious rooting in avocado microcuttings

Quantification of endogenous IAA and lAAsp was carried out duringadventitious root formation in avocado microcuttings. Both auxinand conjugate were monitored in control cuttings (rooted inthe absence of auxin) as well as in cuttings treated with arooting promotor (IBA) or an auxin transport inhibitor (TIBA).Additionally, a histological study to follow root differentiationwas carried out. In control cuttings IAA levels remained constantthroughout the rooting process, however, in IB A-treated cuttingsIAA levels increased 2-fold during the first 6 d. Addition of200 µM TIBA induced a slight decrease of IAA levels andinhibited root formation. As for IAAsp levels, both control and IBA-treated cuttings showeda big increase before root differentiation occurred and as theprocess went on, a progressive decrease took place. However,in TIBA-treated cuttings IAAsp levels not only did not increasebut diminished progressively during the process. The role ofauxin conjugates during the rooting process of avocado is discussed. Key words: Avocado, IAA, IAAsp, rooting     

Indole-3-butyric acid and myo-inositol impacts on in vitro rooting of the cherry rootstocks CAB-6P and Gisela 6

The present study investigates the effects of indole-3-butyric acid (IBA) alone and in combination with myo-inositol on in vitro rooting and biochemical responses in the cherry rootstocks CAB-6P (Prunus cerasus L.) and Gisela 6 (Prunus cerasus × Prunus canescens). For the CAB-6P rootstock, the best results for root number (6.31), fresh mass (FM), dry mass (DM), and rooting percentage (100 %) were obtained on Murashige and Skoog (MS) medium with 2 mg dm^?3 IBA and maximum root length (30.57 mm) was obtained at 1 mg dm^?3 IBA. Myo-inositol suppressed the positive effects of IBA on root length. In the Gisela 6 explants, the inclusion of 2 mg dm^?3 IBA together with 0.5 mg dm^?3 of myo-inositol in the culture medium significantly enhanced root number (9.91) and root FM and DM. The root length was maximum in the combination of the lowest IBA and myo-inositol concentrations (0.5 mg dm^?3). The rooting percentage was the greatest (100 %) with the application of 1 mg dm^?3 IBA alone. In both explants, the application of IBA alone or in combination with myo-inositol resulted in a lower leaf proline content in comparison with the control (without growth regulators). The maximum leaf chlorophyll content was at 1 mg dm^?3 IBA in the CAB-6P whereas at 2 mg dm^?3 IBA and 1 mg dm^?3 myo-inositol in Gisela 6. Addition of myo-inositol mostly increased sugar content in comparison with control or IBA alone in both rootstocks.     

Ethylene accelerates the breakdown of cytokinins and thereby stimulates rooting in Norway spruce hypocotyl cuttings

Cuttings were taken from 4-week-old seedlings of Norway spruce ( Picea abies L. Karst.) raised at two different irradiation levels. Rooting experiments showed that root formation was increased by the ethylene formed by adding 1-aminocyclopropane-1-carboxylic acid ACC or Ethrel, especially in the slowly rooting cuttings grown under high light (HL). Cobaltousion. an ethylene synthesis inhibitor, delayed rooting, especially in the easily rooted cuttings grown under low light (LL).
Compounds isolated from the cuttings using immunoaffinity chromatography, on a column with antibodies against cytokinins, and separated by HPLC decreased in amount during the first week of the rooting period. An increase in ethylene production accelerated this process, especially in cuttings grown under HL, whereas cobaltous ion delayed it. We suggest that ethylene stimulates rooting by enhancing the degradation of cytokinins.     

Levels of endogenous indole-3-acetic acid and indole-3-acetylaspartic acid during adventitious root formation in pea cuttings

Levels of endogenous indole-3-acetic acid (IAA) and indole-3-acetylaspartic acid (IAAsp) were monitored in various parts of leafy cuttings of pea ( Pisum sativum L. cv. Marma) during the course of adventitious root formation. IAA and IAAsp were identified by combined gas chromatography—mass spectrometry, and the quantitations were performed by means of high performance liquid chromatography with spectrofluorometric detection. IAA levels in the root forming tissue of the stem base, the upper part of the stem base (where no roots were formed), and the shoot apex remained constant during the period studied and were similar to levels occurring in the intact seedling. A reduction of the IAA level in the root regenerating zone, achieved by removing the shoot apex, resulted in almost complete inhibition of root formation. The IAAsp level in the shoot apex also remained constant, whereas in the stem base it increased 6-fold during the first 3 days. These results show that root initiation may occur without increased IAA levels in the root regenerating zone. It is concluded that the steady-state concentration is maintained by basipetal IAA transport from the shoot apex and by conjugation of excessive IAA with aspartic acid, thereby preventing accumulation of IAA in the tissue.     

Interaction of paclobutrazol and indole-3-butyric acid in relation to rooting of mung bean (Vigna radiata) cuttings

Paclobutrazol (PB) only slightly stimulated the rooting of mung bean cuttings but, interestingly, the number of adventitious roots formed was dramatically increased when PB was used together with indole-3-butyric acid (IBA). Application of PB in the first phase of root formation, when root initials are induced, caused the greatest enhancement of the promotive effect of IBA on rooting. Investigation of the effect of PB on uptake, transport and metabolism of [5^-3H]-IBA in mung bean cuttings revealed some changes in the rate of metabolism of IBA in comparison with control cuttings. PB was found to be involved in the partitioning of carbohydrates along the cuttings. Application of sucrose, like PB to the base of IBA-treated cuttings enhanced the effect of IBA. The patterns of the effects of PB and IBA, separately and together, on rooting were similar in defoliated and intact cuttings, however the number of roots was much lower in the defoliated cuttings, which lacked a source of assimilates. PB counteracted the effect of GA₃ in the upper regions of the cuttings and seemed to increase the sink capacity at the base of the cuttings. The results of the present study clearly demonstrated the enhancing influence of PB on IBA stimulation of the rooting of mung bean cuttings. It is suggested that PB may affect the rate of metabolism of IBA during rooting and the status of the local sink, in the base of the cuttings, thus partially contributing to the enhancement of the rooting-promotive effect of IBA.     

Biosynthesis of phenolic compounds in first internodes of sorghum: lignin and related products

Lignin biosynthesis in excised tissues of Sorghum vulgare variety Wheatland milo incubated in air with and without prior infiltration with H₂O was presumably limited by H₂O₂ production and was dependent upon an endogenous substrate, probably starch. In solution culture without shaking, this conversion of endogenous material was partially blocked at some step prior to p-hydroxycinnamic acid. The synthesis was light independent and continued protein synthesis was not required. The accumulation of lignin products was paralleled by an increase in dhurrin, alkaline sensitive esters of p-hydroxycinnamic, ferulic and sinapic acids, and flavin coenzymes, especially flavin-adenine dinucleotide. There was no detectable evidence of competition for substrates with other phenols such as anthocyanins or with the growth of adventitious roots. There was evidence, however, of mechanisms limiting lignification in the first internode in the intact seedling. Comparisons are made with lignin production in comparable tissues of Phleum.     

Distribution of quinic acid derivatives and other phenolic compounds in Brazilian propolis

The quinic acid derivatives (including 4-feruoyl quinic and 5-ferruoyl quinic acids characterized for first time in propolis samples) and other phenolic compounds were quantified in thirteen Brazilian propolis samples by HPLC analysis. For chemometrical analysis, the distribution of quinic acid derivatives and other phenolic compounds were considered. The results suggest that the Brazilian propolis with floral origin from Citrus sp. have the highest concentration of the quinic acid derivatives (between 11.0 to 58.4 mg/mg of the dried crude hydroalcoholic extract) and therefore would probably show a more effective hepatoprotective activity.     

Effect of imidazole compounds on the activity of adenosine-3', 5'-monophosphoric acid phosphodiesterase]

The effect of 24 imidazol derivatives on the activity of phosphodiesterase (3', 5'-AMP-phosphohydrolase; KF3.1.4.1) was studied in the experiments with the homogenates of the rat brain and of the Rana temporaria skeletal muscles. Imidazol derivatives could produce both the activating and inhibitory influence on the enzyme. Imidazol and seven of its alkyl-substituted derivatives activated the phosphodiesterase. TTFB (tetrachloro-2-trifluoromethylbenzimidazol) produced the greatest inhibitory effect among the inhibitors on the phosphodiesterase activity.     

Effects of cotton rootstock on endogenous cytokinins and abscisic acid in xylem sap and leaves in relation to leaf senescence

Leaf senescence varies greatly among cotton cultivars, possiblydue to their root characteristics, particularly the root-sourcedcytokinins and abscisic acid (ABA). Early-senescence (K1) andlate-senescence (K2) lines, were reciprocally or self-graftedto examine the effects of rootstock on leaf senescence and endogenoushormones in both leaves and xylem sap. The results indicatethat the graft of K1 scion onto K2 rootstock (K1/K2) alleviatedleaf senescence with enhanced photosynthetic (Pn) rate, increasedlevels of chlorophyll (Chl) and total soluble protein (TSP),concurrently with reduced malondialdehyde (MDA) contents inthe fourth leaf on the main-stem. The graft of K2 scion ontoK1 rootstock enhanced leaf senescence with reduced Pn, Chl,and TSP, and increased MDA, compared with their respective self-graftedcontrol plants (K1/K1 and K2/K2). Reciprocally grafted plantsdiffered significantly from their self-grafted control plantsin levels of zeatin and its riboside (Z+ZR), isopentenyl andits adenine (iP+iPA), and ABA, but not in those of dihydrozeatinand its riboside (DHZ+DHZR) in leaves in late season, whichwas consistent with variations in leaf senescence between reciprocallyand self-grafted plants. The results suggest that leaf senescenceis closely associated with reduced accumulation of Z+ZR, andiP+iPA rather than DHZ+DHZR, or enhanced ABA in leaves of cotton.Genotypic variation in leaf senescence may result from the differencein root characteristics, particularly in Z+ZR, iP+iPA, and ABAwhich are regulated by the root system directly or indirectly. Key words: Abscisic acid, cotton, cytokinins, grafting, leaf senescence Received 23 October 2007; Revised 17 January 2008 Accepted 23 January 2008     

Cyclic adenosine-3',5'-phosphate and guanosine-3',5'-phosphate in mouse plasma during administration of chemical compounds with different degrees of radioprotective effectiveness

A study was made of seven radioprotective agents of different chemical classes (sulfur-containing, indolylalkylamines, and imidazol, urea and pyridasine derivatives) and also of their six structural analogs without radioprotective properties on the content of cyclic nucleotides in blood plasma and on the postirradiation survival of mice. There was a correlation between the ability of the preparations to increase the level of cyclic adenosine-3',5'-monophosphate and their radioprotective properties; with guanosine-3',5'-monophosphate, this correlation was absent.     

The phenolic, 3,4-dihydroxybenzoic acid,is an endogenous regulator of rooting in <Emphasis Type="Italic">Protea cynaroides</Emphasis>

Analysis of stem extracts identified large quantities of 3,4-dihydroxybenzoic acid and other similar phenolics. The exogenous application of 3,4-dihydroxybenzoic acid on Protea cynaroides explants in vitro significantly increased the root mass at 100 mg l⁻¹, but not at lower concentrations, while root inhibition was observed at 500 mg l⁻¹. HPLC analysis of cuttings during vegetative propagation showed a considerable increase in 3,4-dihydroxybenzoic acid levels from initial planting to when root formation took place, indicating for the first time that 3,4-dihydroxybenzoic acid may be an important phenolic compound in regulating root formation in P. cynaroides cuttings. HPLC analysis also identified caffeic, ferulic, gallic and salicylic acids in the cuttings.