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.     

EXPERIMENTAL CONTROL OF FLOWERING IN LEMNA. II. SOME EFFECTS OF MEDIUM COMPOSITION,CHELATING AGENTS AND HIGH TEMPERATURES ON FLOWERING IN L. PERPUSILLA 6746

Hillman , William S. (Yale U., New Haven, Conn.) Experimental control of flowering in Lemna. II. Some effects of medium composition, chelating agents and high temperatures on flowering in L. perpusilla 6746. Amer. Jour. Bot. 46(7): 489–495. Illus. 1959.—-L. perpusilla 6746 flowers as a short-day plant on Hutner's medium (containing ethylenediaminetetraacetic acid [EDTA]) at constant temperatures from 25 to 30°C., but eventually flowers also in old cultures under 16 or 24 hr. of light. This old-culture flowering is more pronounced in dilute medium. Flowering is rapid under both long and short days at constant temperatures from 25 to 28°C. in media not containing EDTA; the addition of 10^-5 M EDTA or of similar or higher concentrations of numerous other chelating agents suppresses flowering under long days but not under short (8 hr. light). This effect does not depend on promotion or inhibition of vegetative growth. At 29 to 30°C., a short-day requirement is manifested even in media permitting flowering under long days at the lower temperatures. Temperatures above 31°C. completely inhibit flowering under all conditions. Brief periods of high temperature given to plants under short-day conditions inhibit flowering when given during the dark period but not during the light period. The implications of these observations for the further study of flowering are discussed.     

Effect of Some Chelating Agents on Growth and Antheridial Production in Male Clones of Three Mosses Grown In Vitro

The present work deals with the effect of the chelating agentsethylenediamine-di(o-hydroxyphenylacetic acid) [EDDHA] ethylenediamine tetra acetic acid [EDTA] and their iron salts, salicylicacid and ferric citrate on growth and antheridial productionin male clones of three dioecious mosses: Barbula gregaria,Bryum coronatum and Philonotis turneriana., Barbula and Bryumdevelop antheridia in ordinary cultural conditions on basalmedium, whereas Philonotis remains sterile. In Barbula and BryumEDDHA and EDTA enhance the percentage of fertile gametophytes.Fe-EDDHA and Fe-EDTA increase antheridial production as wellas vegetative growth and the former effect is more striking.In this respect Fe-EDDHA is better than Fe-EDTA for Barbula,whereas the reverse is true for Bryum. Salicylic acid inhibitsantheridial production and vegetative growth. Ferric citrateenhances vegetative growth in all three mosses. In Barbula andBryum it also stimulates antheridial production, and this effectis more marked than that on vegetative growth. None of the chelatestested induces antheridia in Philonotis. antheridial production, Barbula gregaria (Mitt.) Jaeg., Bryum coronatum Schwaegr., Philonotis turneriana (Schwaegr.) Mitt., mosses, chelating agents, bryophyta     

Induction of buds in the moss Bryum pallescens Schleich. ex Schwaegr. by a metal chelate,Fe-EDTA

Abstract

Bryum pallescens remains bud-free on basal medium. Buds are induced in response to Fe-EDTA at all concentrations tested (10^?8 – 10^?4 M); 10^?4 Mbeing optimum. None of the other chelates (EDTA, Fe-EDDHA, SA) tried is effective in eliciting this response.     

EXPERIMENTAL CONTROL OF FLOWERING IN LEMNA. III. A RELATIONSHIP BETWEEN MEDIUM COMPOSITION AND THE OPPOSITE PHOTOPERIODIC RESPONSES OF L. PERPUSILLA 6746 AND L. GIBBA G3

Hillman , William S. (Yale U., New Haven, Conn.) Experimental control of flowering in Lemna. III. A relationship between medium composition and the opposite photoperiodic responses of L. perpusilla 6746 and L. gibba G3. Amer. Jour. Bot. 48(5): 413–419. Illus. 1961.—In a simple Hoagland-type medium, L. perpusilla 6746 flowers, irrespective of daylength; L. gibba G3 does not flower under any daylength, as long as the medium is changed frequently. Ethylenediaminetetraacetic acid (EDTA) prevents the flowering of L. perpusilla in long days but not in short, and brings about the flowering of L. gibba in long days but not in short. The same results are obtained with medium “aged” by the growth in it of L. gibba for several weeks (in any photoperiod) as well as with tartaric acid. The effectiveness of both EDTA and “aged” medium is greater at pH levels near 5 than at 4 or below, probably reflecting action through metal-chelation. These results are most easily interpreted as effects on photoperiodic sensitivity, and suggest a central role of metals in photoperiodism.     

Shoot regeneration,re-flowering and post flowering survival in bamboo inflorescence culture

In vitro grown inflorescences of Bambusa edulis were used to investigate the process of vegetative shoot growth in detail. The findings revealed that auxins and ACC could be significant growth regulators in this process. Overall, auxins [NAA, indolebutyric acid (IBA), and 2,4-dichlorophenoxyacetic acid (2,4-D)] induced inflorescences to grow vegetative shoots. However, the efficiency of shoot regeneration varied. A greater percentage (27.3–34.5) of inflorescences in the 5 mg l⁻¹ NAA, 10 mg l⁻¹ NAA, and 1 mg l⁻¹ 2,4-D treatments formed more vegetative shoots than those exposed to other treatments. IBA promoted shoot regeneration less effectively than NAA and 2,4-D. Fifty percent of regenerated vegetative shoots flowered after 2 months when the medium was supplemented with 5 mg l⁻¹ NAA. All shoots that received 1 mg l⁻¹ 1-amino-cyclopropane-1-carboxylic acid (ACC) flowered in 5 mg l⁻¹ NAA medium. Rooted plantlets were used to examine their survival following in vitro flowering. All plantlets with vegetative shoots, even those with inflorescences, survived and grew.     

Investigations on the effects of metal ions and chelating agents on growth and flowering of Lemna gibba G 3

The effect of different chelating agents on growth and floweringof Lemna gibba G 3 was studied in M and HUTNER'S media. Theincorporation of EDDHA and Fe-EDDHA in the media resulted inprofuse flowering and gibbous character of the fronds. However,EDTA was relatively less effective. It was demonstrated thatthe metal which influenced flowering in L. gibba G 3 was mostlikely copper. (Received August 19, 1970; )     

Lolium multiflorum uptake of iron supplied as different synthetic chelates

The plant availability of Fe from synthetic chelates has not been examined extensively for plants having the second strategy in iron uptake. Since these plants also excrete chelating agents, competition between natural and synthetic ligands is expected. This research was conducted to study the efficiency of different iron-chelates (Fe-EDTA, Fe-DTPA, Fe-EDDHA and a commercial product, Rexene) inLolium multiflorum iron nutrition. Plants were grown in a greenhouse with hydroponic culture using a buffered nutrient solution at pH 8. Initial iron concentration in the nutrient solution was near 0.5 mgl^–1 and solutions were replaced weekly. In an other Fe-EDTA treatment the same amount of chelate was supplied by four additions during each week.Changes of iron concentration in the nutrient solution, harvestable yield, Fe, Mn, Cu and Zn content in plant tissue and chlorophylllevels in leaves are discussed as parameters to evaluate chelate efficacy. Fe-EDDHA, without inorganic iron in the medium was not as effective as the commercial product Rexene, containing Fe-EDDHA and some extra weakly complex iron, which gave the highest yields. Fe-EDTA applied once a week with fresh nutrient solution was less effective than a four part addition as seen from Chl₁/[Fe] ratios.     

Uptake and degradation of EDTA by Escherichia coli

It was found that Escherichia coli exhibited a growth by utilization of Fe(III)EDTA as a sole nitrogen source. No significant growth was detected when Fe(III)EDTA was replaced by EDTA complexes with other metal ions such as Ca²⁺, Co²⁺, Cu²⁺, Mg²⁺, Mn²⁺, and Zn²⁺. When EDTA uptake was measured in the presence of various ions, it was remarkable only when Fe³⁺ was present. The cell extract of E. coli exhibited a significant degradation of EDTA only in the presence of Fe³⁺. It is likely that the capability of E. coli for the growth by utilization of Fe(III)EDTA results from the Fe³⁺-dependent uptake and degradation of EDTA.     

Augmented Phytoextraction of Lead (Pb2+)-Polluted Soils: A Comparative Study of the Effectiveness of Plant Growth Regulators,EDTA, and Plant Growth–Promoting Rhizobacteria

Abstract

The role of gibberellic acid (GA3), indole-3-acetic acid (IAA), plant growth–promoting bacteria (Rhizobium and Azotobacter), and a synthetic chelator (EDTA; ethylenediaminetetraacetic acid) in lead (Pb) phytoextraction was evaluated using Parthenium hysterophorus (dicot, unpalatable noncrop) and Zea mays (monocot food/forage crop) plants at the flowering stage. Various plant parts were analyzed by atomic absorption/flame spectrophotometer for their Pb content. Both plant growth regulators and both growth-promoting bacteria significantly increased the plant growth in Pb-polluted soils, whereas EDTA significantly decreased growth and biomass of both plants. EDTA increased the Pb uptake (μg g^?1 dry biomass), but the total plant Pb accumulation was decreased. GA3 and IAA significantly increased both uptake and translocation, and the maximum total Pb in the entire plant of Parthenium was found with GA3 foliar spray, whereas in Z. mays the total Pb was maximum in the plant treated with GA3 in combination with EDTA, followed by the GA3 foliar spray treatment. Overall, the GA3 foliar application showed superior response compared with all other treatments. Further research is recommended to observe the role of endogenous GA3 levels in correlation with metal phytoextraction in different plants.     

EXPERIMENTAL CONTROL OF FLOWERING IN LEMNA I. GENERAL METHODS. PHOTOPERIODISM IN L. PEPUSILLA 6746

Hillman , William S. (Yale U., New Haven, Conn.) Experimental control of flowering in Lemna. I. General methods. Photoperiodism in L. perpusilla 6746. Amer. Jour. Bot. 46(6): 466–473. Illus. 1959.—Lemna perpusilla strain 6746 flowers as a typical short-day plant when grown aseptically in Hutner's medium (containing ethylenediaminetetraacetic acid, [EDTA]) at 26–28°C. A method is described for quantitatively assaying the degree of flowering in a culture. Maximal flowering takes place under photoperiods of 6–11 hr., and none under photoperiods exceeding 15 hr. The flower-promoting effects of long nights are inhibited by brief interruptions with red light, such interruptions being most effective in the middle of the dark period. A single long night will cause the subsequent production of flowering fronds, but vegetative growth in the culture is resumed after a time. Only frond primordia at a very early stage of development appear to be sensitive to induction. Quantitative flowering experiments lasting a week or less can easily be performed with this plant; it is ideally suited for studies of the effects of light, darkness, temperature, organic compounds and other factors under highly controlled conditions.     

Exogenous Calcium Enhances the Formation of Vegetative Buds,Flowers and Roots in Tobacco Pith Explants Cultured in the Absence of Exogenous Hormones

Pith explants excised from the apical stem internodes of vegetative, flowering, and fruiting tobacco plants were cultured on hormone-free medium in the presence or absence of CaCl₂ (3 mM). The aim was to determine the role of exogenous calcium (Ca²⁺), applied at the concentration normally present in the Murashige and Skoog (1962) medium, in organ formation obtainable in the absence of the exogenous hormonal input. Exclusive formation of vegetative buds was obtained from explants excised from vegetative plants (pure vegetative programme); vegetative buds and flowers (and occasionally roots) on the same sample were obtained from explants from flowering plants (mixed flowering programme); whereas roots, very occasionally associated with vegetative buds and flowers on the same sample, were obtained from explants from fruiting plants (mixed rooting programme). Histological analysis showed that the organs always exhibited indirect regeneration. Exogenous Ca²⁺ promoted the formation of meristemoids and the first phases of their growth into organs, but did not change the realization of the organogenic programme and did not affect callogenesis. Instead, the influence of exogenous Ca²⁺ changed with the programme, when considering the last phases of organ growth (i.e., macroscopic development and elongation), and the appearance of morphological anomalies in the organs.     

Enhanced Phytoremediation Capacity of Chenopodium album L. Grown on Pb-Contaminated Soils Using EDTA and Reduction of Leaching Risk

Leaching of metals due to enhanced mobility during ethylenediaminetetraacetic acid (EDTA)-assisted phytoextraction has been demonstrated as one of the potential hazards associated with this technology. This study was conducted to determine phytoextraction efficiency of Chenopodium album L. for Pb and EDTA-assisted (1.5, 3, and 9 mmol kg^?1) phytoextraction and potential for leaching of Pb. The results demonstrated that BCF_shoot (bioconcentration factor) was relatively higher than the BCF_root. Translocation factor in the shoot was higher than the roots. Thus, plant species would be applicable for Pb phytoextraction. EDTA enhanced translocation of Pb from roots to shoots. Lead content in the plant parts was maximum in the shoot and root of 9EDTA and 3EDTA, respectively. However, there was no significant difference between 3EDTA and 9EDTA. Lead concentration in the plant parts increased significantly from vegetative stage into flowering stage. Lead content taken up by the plant was lowest when EDTA was applied in a single dose. Therefore, application of EDTA in several increments rather than a single split reduced the leaching risk. Totally, optimum phytoextraction was observed when 3 mmol kg^?1 EDTA was added in triple dosage 60 days after the plant cultivation under triple application mode. The results indicated the plant has the potential for Pb phytoextraction, but it should not be used unless the biomass containing such accumulated metal is removed for disposal. Significant improvement over current ETDA-assisted phytoextraction of Pb may be possible but should be implemented cautiously because of environmental risk.     

Effects of chelated iron on oogenesis and vegetative growth of kelp gametophytes (Phaeophyceae)

The supply of iron has been reported to affect gametogenesis in the gametophytes of some species of kelps (order Laminariales). Spores of the kelps Alaria marginata Postels & Ruprecht, Dictyoneurum californicum Ruprecht, Egregia menziesii (Turner) Areschoug, Laminaria setchellii Silva, and Macrocystis pyrifera (L.) C. Agardh were cultured in enriched seawater with and without added chelated iron (Fe‐ethylenediaminetetraacetate) to determine the effects of iron on oogenesis. All species showed a decrease in oogenesis without added Fe‐ethylenediaminetetraacetic acid (EDTA). Gametophytes of E. menziesii showed predominant gametogenesis with or without supplied iron, resulting in all cells being converted to gametes so that vegetative growth did not continue. Vegetative gametophytes were obtained in the other species used. Gametophytes of M. pyrifera did not show any oogenesis without added Fe‐EDTA, while those of L. setchellii, A. marginata and D. californicum were intermediate in their response, showing some gametogenesis without added Fe‐EDTA. When Fe‐EDTA supply was delayed by 6, 13 and 20 days with spores of M. pyrifera, the gametophytes produced fewer eggs, with a greater decrease as the delay grew longer. A range of Fe‐EDTA concentrations was investigated using isolated female gametophytes of two strains of M. pyrifera and one of Macrocystis integrifolia Bory. None of these three strains produced gametes without the addition of Fe‐EDTA. Gametophytes of M. integrifolia required the least amount of added Fe‐EDTA to achieve gametogenesis while gametophytes of M. pyrifera required higher amounts, with the two strains showing somewhat different responses. Iron nutrition appears to be an essential factor for gametogenesis in several species of kelps.     

Gibberellic acid causes earlier flowering and synchronizes fruit ripening of coffee

The effect of 100 mgl^–1 gibberellic acid (GA₃) on flowering and fruit ripening synchrony, fruit set, fruit fresh weight, and vegetative growth were studied for different size classes of coffee (Coffea arabica L. cv. Guatemalan) flower buds. Flower buds that were > 4 mm, but not developed to the candle stage at the time of GA₃ treatment, reached anthesis 20 days earlier than the controls, and their development was independent of precipitation, unlike the controls. Fruit from buds that were treated with GA₃ at the candle stage showed earlier and more synchronous ripening than the control, although no differences in flowering were found during anthesis. Buds that were smaller than 4 mm at the time of treatment did not respond to GA₃ applications. Treatment with GA₃ did not affect fruit set, fresh weight of fruits, or vegetative shoot growth.     

Induction of flowering in Lemna gibba G 3 by Fe-EDDHA

Fe-EDDHA (iron salt of ethylenediamine-di-o-hydroxyphenylaceticacid) induced profuse flowering in Lemna gibba G 3 culturedin HUTNER'S medium. The maximum number of flowering plants wasobserved in a medium supplemented with 5 ppm of this chelate. (Received April 20, 1970; )     

Gibberellin-Growth Retardant Interactions on the Growth and Flowering of Clerodendrum thomsoniae

Gibberellin-growth retardant interactions on the vegetative growth and flowering of the vine Clerodendrum thomsoniae Balf. were studied using both exogenous treatments and biologically testing the acid fraction attained from the plant extract. The growth retardant, ancymidol, greatly retarded stem elongation and markedly increased flowering under inductive environments. Gibberellin A₃ (GA₃) application to the shoot tip stimulated vine growth, prevented flowering under inductive environments, and completely overcame ancymidol-induced effects. In contrast to GA₃, treatment with GA₇ had little effect on vegetative growth but increased flowering under inductive environments. The elevated activity of gibberellin-like compounds, as determined by bioassay, were similar except for a marked increase in levels in ancymidol-treated plants grown under inductive environmental conditions. Microscopic examination of the stem tip indicated that the action of the growth regulators involved the induction of floral buds. Thus, in Clerodendrum, ancymidol appears to stimulate an unknown gibberellin(s) and simultaneously acts antagonistically with GA₃.     

STIMULATION OF GROWTH IN SCENEDESMUS OBLIQUUS (CHLOROPHYCEAE) BY HUMIC ACIDS UNDER IRON LIMITED CONDITIONS1,2

Stimulatory affects of humic acids of molecular weight 30,000 or greater on iron-starved Scenedesmus obliquus (Turp.) Kütz. in association with bacteria were studied by growth and Fe uptake experiments. Humic acids stimulated growth of Fe-starved cells by decreasing the lag phase and extending the growth phase. Humic acids stimulated increased algal growth in medium containing EDTA as well as in medium containing no EDTA, indicating humic acids are not stimulating algal growth under Fe limiting conditions by creating a soluble Fe pool. Humic acids decreased Fe availability to Fe-starved S. obliquus. Iron bound to humic acids is unavailable for uptake by Fe-starved cells indicating growth stimulation is not due to chelation effects alone. Stimulation of growth is not a membrane phenomenon as humic acids show the same stimulatory effect when in contact with cells or separated by dialysis membrane. Humic acids also stimulate growth in the dark, with and without aeration, indicating use as a heterotrophic substrate. A photoheterotrophic mechanism is indicated by increased algal growth caused by illuminating cultures, containing humic acids but excluding CO₂.     

Bacterial Degradation of EDTA

Degradation of EDTA (ethylenediaminetetraacetic acid) or metal–EDTA complexes by cell suspensions of the bacterial strain DSM 9103 was studied. The activity of EDTA degradation was the highest in the phase of active cell growth and decreased considerably in the stationary phase, after substrate depletion in the medium. Exponential-phase cells were incubated in HEPES buffer (pH 7.0) with 1 mM of uncomplexed EDTA or EDTA complexes with Mg²⁺, Ca²⁺, Mn²⁺, Pb²⁺, Co²⁺, Cd²⁺, Zn²⁺, Cu²⁺, or Fe³⁺. The metal–EDTA complexes (Me–EDTA) studied could be divided into three groups according to their degradability. EDTA complexes with stability constants K below 10¹⁶ (log K < 16), such as Mg–EDTA, Ca–EDTA, and Mn–EDTA, as well as uncomplexed EDTA, were degraded by the cell suspensions at a constant rate to completion within 5–10 h of incubation. Me–EDTA complexes with log K above 16 (Zn–EDTA, Co–EDTA, Pb–EDTA, and Cu–EDTA) were not completely degraded during a 24-h incubation, which was possibly due to the toxic effect of the metal ions released. No degradation of Cd–EDTA or Fe(III)–EDTA by cell suspensions of strain DSM 9103 was observed under the conditions studied.     

EDTA activation of H2 photoproduction by Rhodospirillum rubrum

Summary The effect of trace elements (Fe, Ni) and chelating compounds on the activity of hydrogen (H₂) uptake (Hup) hydrogenase, nitrogenase and rate and yield of H₂ photoproduction from l-lactate in photosynthetic cultures of Rhodospirillum rubrum was investigated. Hup activity depended on the availability of Ni²⁺ and was inhibited by EDTA (0.3–0.5 mm ethylenedinitrilotetraacetic acid). Addition of EDTA (0.5 mm) to the culture medium caused a nearly complete inactivation of Hup activity and activation of nitrogenase, which was paralleled by a threefold increase in total H₂ photoproduced from lactate. Hup^– mutants, isolated by transposon Tn5 mutagenesis, produced maximally twofold more H₂ than the wild-type. Experiments with different chelating agents [EDTA, NTA (nitrilotriacetic acid), citrate, isocitrate] and varying concentrations of Fe²⁺ and Fe³⁺ showed that photosynthetic growth and nitrogenase activity of R. rubrum were strongly influenced by the iron supply. It is concluded that EDTA enhanced H₂ photoproduction by (I) inhibition of biosynthesis of Hup hydrogenase and (II) mobilization of iron, thereby activating the biosynthesis of the nitrogenase complex. Correspondence to: M. Kern