Effect Of Benzyladenine Research Articles

A study of the effect of growth regulators and time of plantlet harvest on thein vitromultiplication rate of hardy and hybrid tea roses

The effect of benzyladenine (BA) (0, 0.5, 2.5, 5 and 10 ppm), naphthaleneacetic acid (NAA) (0,0.005,0.01,0.1 and 1 ppm) and time of proliferation (six, eight and ten weeks) on the optimum multiplication conditions for four Rosa hybrida cvs Champlain, John Franklin, John Paul II and Landora were studied. BA and NAA both had a significant effect on the proportion of viable plantlets and on multiplication rates while low or high concentrations of these growth regulators in the medium generally caused a reduction of plant material. The optimum multiplication rate also varied with cultivar and time. Concentrations of NAA above 0.1 ppm decreased the multiplication rate significantly for two of the cultivars. There was no consistent response between multiplication rates and cultivars to concentrations of B A, NAA or even the time of culture, and it is therefore recommended that each of these variates be determined for each cultivar to obtain optimum plantlet yield.

Effect of Benzyladenine on Diurnal Changes in DNA Content per Chloroplast and Chloroplast Replication in Intact Bean Leaves

Effect of Benzyladenine on Diurnal Changes in DNA Content per Chloroplast and Chloroplast Replication in Intact Bean Leaves

The Effects of Benzyladenine on the Accumulation of Messenger RNAs That Encode the Large and Small Subunits of Ribulose-l,5-bisphosphate Carboxylase/oxygenase and Light-Harvesting Chlorophyll a/b Protein in Excised Cucumber Cotyledons

The Effects of Benzyladenine on the Accumulation of Messenger RNAs That Encode the Large and Small Subunits of Ribulose-l,5-bisphosphate Carboxylase/oxygenase and Light-Harvesting Chlorophyll a/b Protein in Excised Cucumber Cotyledons

Benzyladenine-stimulation of nuclear DNA synthesis and cell division in germinating maize

AbstractWe have studied by means of cytology and autoradiography the effect of benzyladenine (BA, a synthetic cytokinin) on DNA metabolism during early maize germination.The data indicate that BA stimulates nuclear DNA replication. The doubling of the amount of nuclear DNA in BA-treated axes occurs earlier than in nontreated axes, and there is a three-fold increase in the mitotic index at 24 h of germination. These results provide further corroboration for the suggestion that the stimulation of DNA synthesis observed relates to a nuclear replicative type of synthesis. Possible mechanisms of action of BA are discussed.

Effect of benzyladenine on DNA metabolism and cell cycle in maize axes

Effect of benzyladenine on DNA metabolism and cell cycle in maize axes

Effect of Benzyladenine on Cell Cycle in Intact Roots. A Cytofluorimetric Approach

Summary Cytofluorimetry following DAPI-staining of the nuclei was used, in combination with autoradiography, to study the effect of benzyladenine on the cell cycle in pea root meristems. When administered to roots of intact two-day-old seedlings, 30 µM benzyladenine induced in the terminal 2 mm a decrease in the labeling and mitotic indices and an increase in the number of nuclei in G2. At the same time, a rapid inhibition of root elongation was also observed. The shift of nuclei towards G2 was particularly evident in the second mm of the root tip zone. We suggest that the primary effect of this supraoptimal benzyladenine concentration might be the promotion of G 1 arrest. The increase of nuclei in G2 might be due to the effect of the G2-factor translocated from the cotyledons, level of which within the tip might increase as a consequence of the rapid inhibition of root elongation induced by the treatment.

Effect of benzyl adenine on the DNA synthesis during early germination of maize embryo axes

The nature of the DNA synthesized during maize germination has been investigated making use of BND-cellulose chromatography, defining early germination as the first 3 h of imbibition; axes have been pulse-labelled for the last 30 min of the incubation period. The pattern of labelled DNA obtained for γ-irradiated axes is typical of a repair-type synthesis whereas that of non-irradiated axes would be defined as a replicative-type synthesis except that it is insensitive to abscisic acid. However, when benzyl adenine is added to these two types of tissues (irradiated and non-irradiated axes) from the beginning of the incubation period, the result is an increase in the label incorporated, enhancing the repair-type pattern in irradiated axes but most important, switching the “replicative patter” of non-irradiated axes to an unambiguous repair-type pattern. This occurs irrespective of whether the pulse-label is given 10, 20 or 30 min bofore the ent of the incubation period. The role of benzyl adenine on early germination and repair synthesis is discussed.

Effect of Benzyladenine on Grain Growth in aestivum wheat

Effect of Benzyladenine on Grain Growth in aestivum wheat

Effects of a brassinosteroid on growth and on H+‐extrusion in isolated radish cotyledons: comparison with the effects of benzyladenine

We investigated the effect of 24‐epibrassinolide (BR) on the cytokinin‐bioassay based on growth of isolated radish (Raphanus sativus L. cv. Tondo Rosso Quarantino) cotyledons. BR stimulated growth of the cotyledons by about 50% when applied at saturating concentrations (3 μM). This effect was much lower than that of saturating concentrations of benzyladenine (BA) which was about 150% at 10 μM BA. The effects of saturating concentrations of BR and BA were additive. BR, but not BA, stimulated H+‐secretion by the cotyledons (measured as acidification of the incubation medium) slightly but reproducibly. These results indicate that the modes of action of the two phytoregulators are at least partially different.BR‐induced stimulation of H+‐secretion was of similar amplitude to that induced by a concentration of fusicoccin (30 nM) such as to stimulate growth to the same extent as BR. These results suggest that BR‐induced stimulation of radish cotyledon growth might depend, at least in part, on BR‐induced acidification of the wall space, similar to that observed on Azuki bean epicotyls and maize roots.

Effect of benzyladenine on the polypeptide pattern of plastids in excised watermelon cotyledons

We have shown in a previous paper that plastids of watermelon (Citrullus vulgaris Schrad., cv. Fairfax) cotyledons differentiate into amyloplasts when the cotyledons are grown in water and into prochloroplasts when they are grown in benzyladenine (BA) solution. In the present work we have tested whether this large difference in development of the plastids is accompanied by equally conspicuous changes in their polypeptide pattern. Cotyledons were grown for 4 days in the dark either on distilled water or on 10−5M BA. Alternatively they were transfered to 10−5M BA after 4 days of growth in water.Plastids of control cotyledons had a rather simple polypeptide pattern. The only prominent protein bands were the two subunits of ribulose bisphosphate carboxylase (EC 4.1.1.39). Contamination with storage protein was present. Plastids from BA‐treated cotyledons had a much more complex polypeptide pattern. No storage protein contamination was observed. Polypeptide bands present only as traces in the control and having molecular weights of 32, 44, 48 and 49 kDa increased in intensity after an exposure of only 6 h to BA. The 32‐kDa band seemed to be most dependent on the presence of the hormone. Contrary to what was observed in plastids, BA seemed to have no influence on the polypeptide pattern of mitochondria.

The Effects of Benzyladenine, Cycloheximide, and Cordycepin on Wilting-Induced Abscisic Acid and Proline Accumulations and Abscisic Acid- and Salt-Induced Proline Accumulation in Barley Leaves

Benzyladenine inhibits proline accumulation in wilted, abscisic acid (ABA)-treated, and salt-shocked barley leaves. It does not affect ABA accumulation or disappearance in wilted leaves. Inhibition of proline accumulation in salt-shocked leaves was observed both when benzyladenine was added at the beginning of or after salt treatment. Cycloheximide (CHX) and cordycepin inhibited both ABA and proline accumulations in wilted barley leaves and proline accumulation in ABA-treated leaves. In salt-shocked leaves, cordycepin inhibited proline accumulation when added after salt treatment but before proline began to accumulate but not when added after the onset of proline accumulation. CHX delayed the accumulation of proline in salt-shocked leaves but, after a period of time, proline accumulated in the CHX-treated leaves at rates comparable to the salt-treated control. This delay and subsequent accumulation was observed when CHX was added before, during, and after salt treatment. However, the earlier in the salt treatment period that CHX was given, the longer was the observed delay. These results are interpreted to indicate that gene activation is involved in proline accumulation in response to wilting, to ABA, and to salt in barley leaves. This gene activation is in addition to the gene activation that is required for ABA accumulation in wilted leaves. If ABA accumulation is required for proline accumulation in wilted barley leaves, then two sets of gene activation are involved in wilting-induced proline accumulation. All of our results are consistent with this possibility but do not prove it. The inhibition of proline accumulation by benzyladenine is probably neither due to an effect on gene activation nor to an effect on the ABA level.

Differential Effects of Benzyladenine and Potassium on Ribulose-l,5-Bisphosphate Carboxylase Synthesis in Detached Cucumber Cotyledons

Summary Excised cucumber (Cucumis sativus L. cv. Ohio) cotyledons were incubated with benzyladenine (BA) and/or KCl in the dark, the dark followed by light or continuous light, and ribulose-1,5-bisphosphate carboxylase (RuBPCase) content was determined immunologically. BA, not KCl, significantly increased RuBPCase content per cotyledon in the dark. On the other hand, KCl, not BA, significantly promoted RuBPCase synthesis in light. BA+KCl enhanced BA or KCl effect on RuBPCase synthesis in both the dark and light. Dark pretreatment with water or KCl produced a lag phase before RuBPCase synthesis occurred on exposure tolight, while pretreatment with BA+KCl eliminated this lag phase. These facts indicate that BA in the dark can act instead of light in RuBPCase synthesis, while KCl increases the light effect on RuBPCase synthesis, and that potassium, cytokinin and light affect RuBPCase gene expression differentially.

Benzyladenine effects on the development of the photosynthetic apparatus in Zea mays: Studies on photosynthetic activity, enzymes and (etio)chloroplast ultrastructure

Primary leaf segments from 8‐day‐old dark‐grown, and from 4‐ and 8‐day‐old light‐grown seedlings of Zea mays L. cv. Fronica, were treated with 10‐bM benzyladenine (BA) in the dark for 14 h. The segments were then studied after an exposure to light for 14 h. Photosynthetic activity (O2 evolution and CO2 fixation) and chlorophyll accumulation were stimulated by BA in dark‐grown leaf segments with etioplastids in the earliest stage of development. In these segments BA stimulated the activities of ribulose‐1,5‐bisphosphate carboxylase (EC 4.1.1.39), phosphoenolpyruvate carboxylase (EC 4.1.1.31), NADP+‐malic enzyme (EC 1.1.1.40) and pyruvate, orthophosphate dikinase (EC 2.7.9.1). In segments taken from 4‐ and 8‐day light‐grown seedlings, BA did not enhance the photosynthetic activity nor the chlorophyll accumulation. The activity of the enzymes mentioned above, was significantly enhanced by the BA‐treatment.BA mainly affected grana stacking in mesophyll cell chloroplasts in primary leaf segments taken from 3‐ to 5‐day light‐grown seedlings. Stroma thylakoid development was stimulated only in leaf segments from 3‐day‐old plants. At the same time BA accelerated grana loss in chloroplasts of bundle sheath cells, a typical phenomenon of development in such chloroplasts. Stroma thylakoid length in these chloroplasts increased by a BA treatment in segments from 3‐ and 4‐day light‐grown plants. A significantly higher number of chloroplasts was only observed with segments taken from 8‐day light‐grown seedlings and treated with BA.The etiochloroplast number in segments taken from 8‐day etiolated plants was significantly higher in BA‐treated segments after 26 h illumination. In etiochloroplasts from both mesophyll and bundle sheath cells, BA enhanced grana stacking after illumination for 4 h or more, whereas stroma membrane length was significantly higher only after 26 h light.It is concluded that the effects of BA depend on the developmental stage. BA accelerates the development of mesophyll and bundle sheath cell (etio)chloroplasts, but does not affect the ultrastructure of mature chloroplasts.

Effect of Benzyladenine on the Promotion of Bud Development and Branching of Picea pungens

Abstract Picea pungens Englm. trees were treated with a single foliar spray of solutions containing 0, 100, 250, 500, and 1000 mM BA at 4 different times as follows during the growing season: 1) dormant trees, 2) at bud break, 3) during stem elongation, 4) summer hardwood, and 5) summer hardwood combined with a pruning. Treatments of 1000 mM at the time of bud break and to pruned summer hardwood trees resulted in an increase in bud number but not a corresponding increase in branch number the following year.

14C]‐Assimilate partitioning in photoperiodically induced seedlings of Pharbitis nil. The effect of benzyladenine

Partitioning of [14C]‐labeled assimilates was studied in relation to photoperiodic floral induction and evocation in one‐week‐old Pharbitis nil Choisy cv. ‘Violet’ seedlings. In plants kept under 16 h photoperiods, one 15 h night induced 100% axillary flowering whereas a 24 h night induced both terminal and axillary flowering. A 15 min night break of red light given 8 h after the beginning of the dark period inhibited flowering. Total [14C]‐assimilate distribution among major sinks (plumules + epicotyl and roots + hypocotyl) from a single source cotyledon was unchanged by one inductive night; however, import of [14C]‐assimilates into shoot apices was increased in induced plants compared to vegegative controls. This increase was several‐fold in plants subjected to a 24 h night. N6‐Benzyladenine (BA) application to cotyledons or plumules under non‐saturating night lengths increased the number of floral buds per plant without affecting the position of the first floral bud (i.e. the speed of induction). The same treatment caused increased label accumulation in induced apices, while it only slightly affected non‐induced ones. The mode of action of BA on flowering through growth stimulation and resulting assimilate mobilization is discussed.

Effects of benzyladenine on bud break of roses

The uppermost axillary buds of some cut-rose cultivars fail to grow following flower harvest, especially in the winter season. In Japan, of the 60 cultivars grown under cover for cut-rose production, cultivar ‘Blue Moon’ syn.Mainzer Fastnacht shows strong dormancy after harvest. The practice of bending the petiole of the uppermost leaf was not effective in breaking dormancy in ‘Blue Moon’. Smearing BA lanoline paste (0.25%) on to the cut surface 0.5 cm above the axillary bud completely broke bud dormancy and hastened growth. Four applications of BA, from early October to March, increased saleable flowers by 78% over the untreated control.

Effect of benzyladenine on development of derooted watermelon seedlings

We have examined the effects of benzyladenine (BA) on derooted watermelon (Citrullus vulgaris Schrad., cv. Fairfax) seedlings with special attention to the cotyledons. The growth regulator was supplied either as a droplet of solution between the cotyledons (application from above) or through the hypocotyl stump (application from below). Application of BA from above stimulates several developmental parameters of cotyledons [growth, lipid breakdown, chlorophyll and carotenoid accumulation, hydroxypyruvate reductase (EC 1.1.1.81.) activity]. The stimulation is much smaller with application from below. Also the distribution of labelled BA changes according to the method of application. The bulk of the label remains in the cotyledons when BA is supplied from above and in the hypocotyl when it is supplied from below. The absolute amount of radioactivity found in the cotyledons after 24 h of treatment is approximately the same in both cases. This seems to indicate that the different effects of the two treatments depend on concentration ratios of BA (or metabolic derivates) between hypocotyl and cotyledons rather than on absolute growth regulator levels.

Effect of Benzyladenine on the Development of Mitochondrial Activities in Imbibed Black Gram Cotyledons

The development of mitochondria was followed in black gram cotyledons cultured on filter paper wetted with water or benzyladenine solution. Treatment with benzyladenine brought about an increase in activities of some mitochondrial enzymes and in respiratory activities of mitochondria. Cycloheximide did not inhibit the increase, although it almost completely inhibited the incorporation of (14)C-leucine into mitochondrial protein. It was inferred that the increase in mitochondrial activity by benzyladenine-treatment was not due to biogenesis of mitochondria but due to an acceleration of activation processes in pre-existing mitochondria. The respiratory control ratio of mitochondria from benzyladenine-treated cotyledons was lower than that of mitochondria from untreated ones. It was also suggested that benzyladenine brought about some qualitative changes in mitochondrial activities.

Mechanism of benzyladenine-induced chlorophyll synthesis in excised cucumber cotyledons

Summary The effect of benzyladenine (BA) on the total chlorophyll content and on endogenous paramagnetic manganese (Mn 2+ ) was studied in excised cucumber cotyledons. BA stimulates the release of manganese from its native bound or complexed state which is evident from a higher amplitude of the Mn 2+ sextet. Enhancement in the amplitude of Mn 2+ sextet may be taken as a parameter for the release of cations from storage bodies., Application of bivalent cations stimulates chlorophyll content under conditions where the concentration of available endogenous cations, measured by the amplitude of Mn 2+ sextet, is low. The stimulation of chlorophyll synthesis appears to be mediated by endogenous cations released under the influence of BA.

Effects of benzyladenine and abscisic acid on superoxide dismutase in fronds of the duckweed Lemna gibba

The growth‐promoting (benzyladenine) and growth‐inhibiting (abscisic acid) plant hormones, when used at concentrations of 0.4 and 4.0 μM, affect the development of superoxide dismutase (SOD) activity of Lemna fronds in opposite ways, the former hormone decreasing the activity and the latter increasing it. The effect of both growth substances is on de novo synthesis of the enzyme. In addition abscisic acid also causes the Zn, Cu and protein contents of the fronds to increase, while benzyladenine has the opposite affect.