Application Of Benzyladenine Research Articles

The effects of endogenous cytokinin content on benzyladenineenhanced nitrate reductase induction

Foliar application of benzyladenine (BA) has been shown to enhance nitrate‐dependent induction of nitrate reductase (NR; EC 1.6.6.1) in etiolated wheat (Triticum aestivum L.) seedlings. Whether similar enhancement occurs in light‐grown plants, or whether endogenous cytokinin content affects this enhancement is unknown. Since the cytokinin content of etiolated plants probably differs from that of light‐grown seedlings, the NR response of each to exogenous root‐ or shoot‐applied BA in wheat (cv. Red Bob) was examined. Endogenous cytokinins present in untreated control tissues prior to BA application and changes that occurred after a 22 h (12 h dark followed by 10 h of light) period were determined using a combined HPLC‐immunoassay method. Shoot application of BA enhanced the induction of NR in etiolated seedlings in a concentration‐dependent manner but failed to enhance NR induction in light‐grown plants. Root‐applied BA enhanced NR induction in both etiolated and light‐grown seedlings. Endogenous root cytokinin levels were similar in both etiolated and light‐grown plants. In contrast, shoots of 6 day‐old light‐grown seedlings contained at least 20 times the amount of total cytokinins measured in shoots from etiolated plants of the same age. Total cytokinin content of the light‐grown plants diminished after the 22‐h period while that measured in etiolated seedlings increased. The responsiveness of seedlings to BA was correlated with endogenous cytokinin levels in that enhancement of NR induction by exogenous BA was low in tissues which contained high concentrations of cytokinin at the time of BA application. These results may prove useful in interpretation of gene responses to exogenous plant growth regulators.

Modification of Plant Architecture in `Crimson Giant' Easter Cactus with Benzyladenine

Investigations were performed to determine the effects of timing of application and concentration of BA on the vegetative growth of Easter cactus [Rhipsalidopsis gaertneri (Regel) Moran `Crimson Giant']. BA was applied to rooted phylloclades at 27, 37, and/or 47 days after propagation (DAP) at 200 to 1000 mg·liter-1. At 80 DAP, the number and cumulative length of secondary (2°) phylloclades (those developing from the rooted phylloclade) of BA-treated plants exceeded those of the controls. Number and cumulative length of 2° phylloclades increased linearly with increasing BA concentration. At 316 DAP, there were no differences between BA-treated plants and controls in numbers of 2° and apical (terminal) phylloclades. BA also was applied to plants at either 95 or 187 DAP. Treatments included 10, 50, 100, and 200 mg BA/liter and an unsprayed control. Number of new phylloclades (those developing after treatments) and percentage of old phylloclades with new phylloclades increased linearly in response to increasing BA concentration. Relative to the controls, one application of BA at 50, 100, or 200 mg·liter-1 resulted in a ≈50% to 400% increase in total dry weight of new phylloclades accompanied by a ≈4% to 30% decrease in total dry weight of old phylloclades. Branching of mature plants, i.e., with three to five tiers of phylloclades, was significantly affected by timing of application and concentration of BA. BA may be useful for modifying plant architecture of Easter cactus to increase flowering and product marketability. Chemical name used: N- (phenylmethyl) -1H- purine-6-amine[benzyladenine (BA)].

Effects of foliar applied benzyladenine on grain yield and grain protein in wheat (Triticum aestivum L.)

The effects of foliar applications of nitrogen and benzyladenine (BA) on grain yield and grain protein of wheat grown under field conditions were studied over 2 years with 5 cultivars at 2 locations. Nitrogen (N) at 20 kg.ha−1, and BA at 100 or 800 mg.l−1 were applied alone or combined at pre and post-anthesis; applications of BA at 8 mg.l−1 were also made on individual ears in order to study the effect on cell number. Weekly determinations of the chlorophyll content of the flag leaf were conducted after anthesis to study leaf senescence. At harvest, yield, yield components and grain protein percentage were determined. N and BA applications delayed chlorophyll loss in the flag leaf, but modified neither yield nor yield components. Foliarly applied BA increased grain protein in four of the five cultivars tested. It is concluded that delay of the senescence induced by BA might allow more energy to be available for N uptake by the crop leading to an increase in grain protein.

Effects of Application of Benzyladenine to Seedlings of Pinus sylvestris and Pinus nigra

Abstract Greenhouse grown seedlings of Pinus sylvestris L. (Scots pine) and Pinus nigra Arnold. (Austrian pine) were treated with plant growth regulators in a 1% solution of dimethyl sulfoxide. Benzyladenine (BA) induced branching of seedlings of Scots pine. Both Scots pine and Austrian pine seedlings were reduced in height by BA treatments. The addition of gibberellic acid (GA) to the BA treatments had little effect on branching or seedling height. After a second growth cycle the Scots pine seedlings treated with BA were shorter and had more branches while the Austrian pine seedlings were also shorter without an increase in the number of branches.

Seedling Kentucky Bluegrass Growth Responses to Chelated Iron and Biostimulator Materials

AbstractEnhanced growth of seedling turfgrasses with biostimulator materials or chelated Fe could accelerate the rate of establishment. Field experiments in the spring and fall of 1987 and in the greenhouse in the winter of 1988 were designed to measure seedling Kentucky bluegrass (Poa pratensis L.) growth responses to foliar applications of benzyladenine (BA, 6‐benzylaminopurine), propiconazole [1‐{[2‐(2,4‐dichlorophenyl)‐4‐propyl‐1,3‐dioxolan‐2‐yl]methyl}‐l‐(1H‐1,2,4‐triazole], triadimefon [l‐(4‐chlorophenoxy)‐3,3‐dimethyl‐l‐(1H‐1,2,4‐triazol‐1‐yl)‐2‐butanone], or a fortified seaweed extract (SWE, containing 500 µg L−1 of glycol kinetin and 500 µg L−1 gibberellins) applied alone or in combination with chelated Fe (8% Fephosphate citrate). The seaweed extract (0.03 mL product m−2) significantly increased root and shoot growth 6 wk after treatment (WAT) in the spring experiment, and 4 and 6 WAT in the winter greenhouse experiment. The SWE also increased the gross CO2 exchange rate (CER) on a land area basis 4 and 6 WAT in the winter experiment. Propiconazole (42 mg m−2) significantly increased seedling leaf number 6 WAT in the fall experiment. Triadimefon (150 mg m−2)or BA (6 mg m−2)applications generally were not as effective in increasing seedling growth as were the SWE or propiconazole. Foliar Fe applications (112 mg m−2), either alone or in combination with biostimulators, significantly increased root and shoot growth and gross CER on a land area basis 4 and 6 WAT in the winter greenhouse experiment. Applications of Fe increased root dry weight 6 WAT in the spring field experiment. Growth responses to individual biostimulator and Fe combinations were highly variable among experiments, suggesting possible interactions between the growth response mechanisms of the treatments.

Anti-senescence Activity of Chemicals Applied to Kentucky Bluegrass

This study was conducted to determine the potential anti-senescence activity of certain chemicals by monitoring changes in gross. CO2 exchange with senescence of excised leaves of Kentucky bluegrass (Poa pratensis L.). One day following foliar applications of benzyladenine (BA), triadimefon, and propiconazole, with and without chelated Fe (8% Fe phosphate citrate), Kentucky bluegrass leaves were excised, floated on distilled water in petri dishes, and placed in a darkened growth chamber. Gross CO2 exchange rates (CER) were recorded 1, 4, 7, and 10 days after excision (DAE). Foliar applications of Fe, BA, triadimefon, or propiconazole applied alone induced an anti-senescence response. Combinations of Fe with the chemicals delayed excision-induced leaf senescence, but no significant increase in anti-senescence activity was obtained from the Fe and chemical combinations as compared to the materials applied alone. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (benzyladenine, BA); 1-(4-Chlorophenoxy)-3,3-dimethyl-1(1H-1,2,4-triazol-1yl)-2-butanone (triadimefon);1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole (propiconazole).

Rapid Induction of Synthesis and Doubling of Nuclear DNA by Benzyladenine in Intact Bean Leaves

Primary leaves of young and old beam plants (Phaseolus vulgaris L.) were treated with benzyladenine (BA) after cell division had been completed. Changes in the synthesis and amount of DNA in individual nuclei in mesophyll cells shortly after BA application were studied. (...)

Hormones andCuscuta development: IAA uptake transport and metabolism in relation to growth in the absence and presence of applied cytokinin

Transport of 1-14C-IAA in successive stem segments ofCuscuta was strictly basipetal in growing and non growing regions of the vine with a flux velocity of 10–12 mm/h (intercept method). This transport showed a distinct peaked profile, increasing from a low value at 10 mm from the apex to a maximum between 50 and 90 mm before declining to a low value again around 160 mm at which elongation growth ceased. The IAA transport profile paralleled the in vivo growth rate profile, though the latter peaked ahead of transport. A better correlation was observed between the profile of growth responsiveness of the vine to exogenous IAA application and the profile of IAA transport. Growth responsiveness was determined as the differential in growth rate of stem segments in vitro in the absence and presence of growth optimal concentration of IAA (10 μm). Retention of exogenous IAA in the stem was maximal where transport decreased, and this coincided with the region of maximal conjugation of applied 1-14C-IAA to aspartic acid to form indoleacetylaspartate (IAAsp). In addition to aspartate, IAA was conjugated to a small extent to an unidentified compound. IAA destruction by decarboxylation was greatest where transport was low, particularly in the nongrowing region, where lignification occurred (i.e., beyond 180 mm). At concentrations up to 20 μM, a pulse of 1-14C-IAA chased by “cold” IAA moved as a peak (with a peak displacement velocity of 12–18 mm/h) in the “growth” region of the vine, but became diffusionlike where growth either fell off steeply or ceased. At a higher (50 μM) IAA concentration, though uptake was not saturated, transport in the growth region became diffusionlike, indicating saturation of the system. Reduced IAA flux in the region where growth responsiveness to IAA declined coincided with the region of increased IAA conjugation. However, it cannot be concluded whether increased IAA conjugation was the cause or effect of decreased IAA flux. Application of benzyladenine to the vines in vivo, a treatment that elicited haustoria formation by 72 h, resulted in the inhibition of both IAA transport and elongation growth rate in the subapical region. In vitro treatment of vine segments with BA similarly increased IAA retention and decreased IAA transport. IAA loss was suppressed, and conjugation to IAAsp was enhanced.

Manipulating Carnation Petal Senescence II. The Influence of Benzyladenine on Indoleacetic Acid Metabolism and Ethylene Production

Summary Indoleacetic acid (IAA)-induced senescence of isolated carnation ( Dianthus caryophyllus L. cv. Kaly) petals was delayed with the application of benzyladenine (BA). BA reduced the IAA-induced ethylene emanation and retarded the overall rate of (1- 14 C)- and (2- 14 C)-IAA metabolism. In the presence of BA the IAA-induced metabolism that did occur appeared to be largely a result of decarboxylation. It is possible that in the absence of BA, IAA was conjugated rapidly. This could, however, not be substantiated. Using the isolated petal system as a bioassay, reapplication of the major IAA metabolite did not accelerate petal senescence to the degree seen with the application of IAA.

Regulation of Leaf Senescence and Yield in Mungbean (Vigna radiata L. Wilczek)

AbstractFoliar application of benzyladenine at preanthesis stage retarded leaf senescence in mungbean. Chemical spray increased leaf chlorophyll, soluble protein, specific leaf weight, net photosynthetic rate and nitrate reductase activity. Number of pods, grain yield, harvest index and 100‐seed weight were significantly improved by benzyladenine treatment. The possibility of higher pod‐filling and thus, yield by chemical regulation of leaf senescence is evident in mungbean.

Effect of pod removal and plant growth regulators on the growth, development and carbon assimilate distribution in oilseed rape (Brassica napusL.)

SummaryRemoval of basally positioned pods on the terminal inflorescence at anthesis and 6 days thereafter increased the duration of flowering and resulted in the formation of a larger number of smaller pods.Removal at 12 days after anthesis did not affect flower production but increased the number of flowers setting pods. Application of benzyladenine to the apices of intact plants from 8 days but not 14 days after anthesis greatly extended flower but not pod production. Liquid scintillation counting showed that the benzyladenine treatment led to more14C-labelled assimilates moving to the apices.

Cytokinin-promoted Polyribosome Formation in Excised Cucumber Cotyledons

Polyribosome (polysome) levels based on total ribosomal materials in excised etiolated cotyledons of Cucumis sativus L. cv. Ohio were examined during incubation with or without N 6 -benzyladenine (BA) in the dark. Within the first 2 h after excision, polysome levels in both cotyledons with and without BA increased about 5-fold. The polysome level in control cotyledons subsequently declined, approximating the initial level after 12-18h. In BA-treated cotyledons, however, it remained high during the entire period of incubation. BA application to the water-pretreated (18h) cotyledons also increased the polysome level and did not affect RNase activity or RNA content. BA-promoted polysome formation was inhibited by α-amanitin and cordycepin but not by 5-fluorouracil. These results are consistent with the hypothesis that cytokininpromoted polysome formation depends on de novo synthesis of mRNA but not of rRNA.

Axillary Shoot Abscission in Pecan and Its Relationship to Growth Regulators

Abstract The relatively low incidence of axillary shoot development in pecan [Carya illinoensis (Wangenh.) C. Koch] and its detrimental impact on nut productivity prompted: 1) an evaluation of methods to induce axillary shoot morphogenesis, and 2) estimation of levels of endogenous phytohormones in abscising and nonabscising axillary shoots. Retention of developing shoots from 1-year-old terminals was increased three-fold by ringing. Application of benzyladenine (BA) delayed, but did not prevent, shoot abscission, whereas abscisic acid (ABA), indoleacetic acid (IAA), and gibberellic acid (GA3) applications had no detectable effect. Normal morphogenesis of axillary shoots was independent of the presence of developing catkins. Phytohormones tentatively identified in pecan axillary shoots and catkins were IAA, ABA, dihydrozeatin riboside (DHZR), t-zeatin riboside (ZR), trans-zeatin (Z), and dihydrozeatin (DHZ). A possible influence of these substances on budbreak and shoot morphogenesis is discussed. Axillary shoots eventually abscising exhibited a substantially higher level of IAA-like and ABA-like substances than did shoots completing morphogenesis. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine(BA); abscisic acid (ABA); 1H-indole-3-acetic acid (IAA); gibberellic acid (GA,).

Influence of Benzyladenine on Leaf Senescence and Photosynthesis in Sunflower (Helianthus annuus L.)

AbstractThe effect of foliar application of benzyladenine on sunflower leaf senescence, photosynthesis, RuBP carboxylase activity and diffusion resistance was investigated. A considerable drop in photosynthetic rate and rise in diffusion resistance were noted dunng the seed filling period. Benzyladenine application maintained the chlorophyll content and chlorophyll a : b ratio at higher level, enhanced RuBP carboxylase activity and net photosynthesis in both upper and lower leaves. A lower level of diffusion resistance was also observed by benzyladenine application during seed filling period. The results suggested that application of benzyladenine at 30, 60 and 90 days after sowing could help to maintain photosynthesis and assimilate supply to the developing seeds of sunflower.

Effect of Night Temperature on the Activity of Sucrose Phosphate Synthase, Acid Invertase, and Sucrose Synthase in Source and Sink Tissues of Rosa hybrida cv Golden Times

Sucrose phosphate synthase and acid invertase activities in the mature leaves of roses (Rosa hybrida cv Golden Times) were greater in plants grown under a higher night temperature than under a lower temperature regime. In young shoots, the activity of acid invertase was promoted by the lower temperature while that of sucrose synthase was increased at the higher temperature. At both temperatures benzyladenine when applied to the axillary bud stimulated sucrose phosphate synthase activity and advancement of its peak of activity in the leaf subtending to the bud, and also stimulated sucrose synthase activity in the young shoot. At the lower temperature, application of benzyladenine to the axillary bud stimulated acid invertase activity in the young shoot but not in the leaves.

Improving rooting and survival of softwood peach cuttings

With leafy peach ( Prunus persica (L.) Batch) cuttings under mist, the highest rooting percentage, the largest number of roots per rooted cutting and the highest survival rates of the rooted cuttings were obtained by treating the bases of the cuttings for 24 h with a solution of 50 mg l −1 indolyl butyric acid (IBA) + 500 mg l −1 2,3-dichloro-1,4 naphthoquinone (dichlone). However, in the absence of dichlone, an IBA concentration of only 25 mg l −1 was optimal for rooting. Weekly sprays with a mixture of benzyladenine (BA) and naphthaleneacetic acid (NAA) increased the percentage of rooted cuttings in the poorly rooting cultivar ‘15–39’. Treatments to decrease the severe leaf-drop which occurred during the hardening-off period, i.e. weekly sprays with BA + NAA or with an anti-transpirant (TAG), if started at the beginning of the hardening-off period, considerably improved the survival of the rooted cuttings and their cytokinin content. Even more efficient in this respect were weekly sprays with a mixture of benzyladenine and myo-inositol, apparently due to an enhancement in the BA transport to the root system. This explanation is supported by the very marked accumulation of cytokinins in the roots of cuttings which had been sprayed with a mixture of myo-inositol and benzyladenine compared to plants which had been sprayed with benzyladenine alone. On the other hand, application of BA to leaves resulted in the inhibition of the transport of apically applied MI to the bases of the cuttings. Better leaf retention was related to increased levels of sugars in the cuttings. In the newly formed root system of the cuttings, a high cytokinin content was related to a high sugar content.

Cytokinins and Flower Development in Leucospermum

Abstract Flower quality in Leucospermum can be improved by increasing the diameter and length of the reproductive shoot and by increasing floret initiation and capitulum size. During flower induction, endogenous cytokinin levels were low, with mainly “storage” forms of cytokinins being present. However, during flower differentiation, endogenous cytokinin levels increased and most of the activity was in the form of “free” cytokinins. One application of benzyladenine, if applied during the flower induction phase, increased both reproductive shoot diameter and the number of florets per capitulum.

Partial floral evocation by exogenous cytokinin in the long‐day plant Sinapis alba

A single application of benzyladenine (BA) at 4.3 × 10−5M to the shoot apex of vegetative plants of Sinapis alba L. causes an increase of the import of [14C]‐assimilates in the apical bud and of the starch content. BA also produces the breakdown of the vacuoles into smaller vacuolar units and an increase of the mitotic index leading to nearsynchronization of the meristem cell population in G1. All these changes normally occur in the meristem of Sinapis plants during the transition to flowering (full evocation). Other events normally associated with full evocation are not caused by BA which thus produces only partial evocation. The part of evocation produced by BA is different from that caused by high irradiance.

Practical Application of Benzyladenine in Agricultural Production

Practical Application of Benzyladenine in Agricultural Production

Induction of Flowering in Lemna paucicostata by Dicoumarol and 4-Hydroxycoumarin

Dicoumarol, an antagonist of vitamin K, not only promoted the flower-inducing activity of vitamin K5, but also induced flowering in Lemna paucicostata when added alone to the medium. The flower-inducing activity of dicoumarol was comparable to that of benzoic acid and could be greatly intensified by simultaneous application of benzyladenine as was the case with benzoic acid. Warfarin, another antagonist of vitamin K, did not induce flowering. 4-Hydroxycoumarin, a component of dicoumarol, was also active, but coumarin and 7-hydroxycoumarin were not. Dicoumarol had only a slight flower-inducing activity for strains 441 and 6746 under continuous light, but had a strong flower-promoting effect under a near critical photoperiod. That is, the effect of dicoumarol was daylength-dependent.