Different Concentrations Of Auxins Research Articles

VEGETATIVE PROPAGATION OFACACIA CATECHU, DALBERGIA SISSOOANDPROSOPIS CINERARIABY CUTTINGS

SUMMARY Mature hardwood and softwood cuttings of Acacia catechu, Dalbergia sissoo and Prosopis cineraria were tested for their capacity to form roots. For P. cineraria coppice shoots were also tried. Cuttings were treated with different concentrations of auxins (IBA and NAA). D. sissoo rooted easily, with a 100 per cent success rate for both hardwood and softwood cuttings irrespective of auxin treatment. A. catechu and P. cineraria were difficult to root, but did root under treatment. Their greatest success rates were 50 per cent (softwood cuttings of A. catechu with 100 mg/l IBA) and 25 per cent (coppice shoots of P. cineraria with 1,000 mg/l IBA) respectively. Auxins did not induce rooting in mature hardwood cuttings of A. catechu or P. cineraria.

MASS PROPAGATION OFDALBERGIA SISSOOBY CUTTINGS: FACTORS AFFECTING THE ROOTING OF CUTTINGS

SUMMARY Mature hardwood and softwood cuttings of Dalbergia sissoo Roxb. were tested for their capacity to root in order to raise seedlings in mass in mist chamber with controlled temperature and humidity. Cuttings were prepared in three seasons, i.e. spring, monsoon and winter, and treated with different concentrations of auxins (IBA and NAA). Rooting ability was influenced by the physiological state of the cutting and the environment in which it was planted. Hardwood and softwood cuttings rooted during spring and monsoon seasons. Auxins triggered/enhanced rooting of cuttings and NAA (100 mg/1) and IBA (100 mg/1) were found to be most effective. Higher concentrations of auxins, i.e. 500 or 1000 mg/1 of IBA/NAA, inhibited or slowed down rooting. Auxin seems to have triggered the growth as well as differentiation of roots. The starch content of the cuttings decreased while proteins and sugars increased with time.

Shift in variability of 2,4-dichlorophenoxyacetic acid-deprived pear cell suspensions

Quiescent 2,4D-dependent pear fruit cells (Pyrus communis L.) were cultured in a bioreactor in the absence of 2,4-Dichlorophenoxyacetic acid. Effects on the ability to divide following transfer into different concentrations of auxin (0; 0.45; 2.3; 4.5; 6.8; 9 μM) are studied and discussed. Changes in cell number and in cell viability during subculture were examined (at all 2,4-D concentrations). In the presence of 2.3, 4.5 and 6.8 μM of 2,4-D, in the standard medium, pear cells undergo a classical growth cycle and cell mortality increased only after 16 days. The level of ploidy estimated by cytophotometry shows, after previous starvation, a significant shift only for 4.5 μM 2,4-D concentration, the value of the usual culture medium of the studied strain.

Is Cell Elongation Regulated by Extracellular Auxin?

AbstractExperiments with isolated epidermal strips of maize coleoptiles, pretreated with auxin and further incubated on sucrose agar containing different concentrations of auxin (indole‐3‐acetic acid, IAA or naphthalene‐1‐acetic acid, NAA) and/or naphthylphthalamic acid (NPA), are described. Preincubation for 2h with 2 . 10−4M IAA or 10−5M NAA in buffer, followed by 30 min wash in buffer results in measurable cell elongation during a subsequent incubation for 6 h on sucrose agar. Addition of 10−4M NPA inhibited the response to auxin and this inhibition could be reversed by providing IAA in addition to NPA. Inner tissue fragments (without outer epidermis) did not respond to external IAA. These results lead to the conclusion that auxin secretion at the outer epidermis may be an essential step in auxin‐regulated coleoptile growth.

Nematocidal activity and .ALPHA.-terthiophene content in marigold callus.

Tissue cultures of marigold (Tagetes patula L.) were established and a high nematocidal activity was detected in n-hexane extracts from the calli. The nematocidal activity varied with callus cell lines that were established on Murashige and Skoog (MS) basal medium supplmented with different concentrations of auxin and cytokinin. The highest nematocidal activity was found in the green solid callus on the medium with 0.1ppm 1-naphthaleneacetic acid. The nematocidal activity and the level of α-terthiophene in the green calli were equivalent to those in the root of intact plants cultivated in vitro. HPLC analysis of n-hexane extracts from several callus cell lines indicated that the nematocidal activity was due predominantly to the level of α-terthiophene but other nematocidal components are also present.

ROOTING OF STEM CUTTINGS OFCASUARINA EQUISETIFOLIAAND THEIR NODULATION

SUUMMARY Juvenile, mature green stem, and mature brown stem/woody cuttings of Casuarina equisetifolia were tested for their capacity to form roots. Cuttings were treated with different concentrations of auxins (IBA, NA A and IA A). Treated cuttings were planted either in soil beds or in water culture jars. Maximum success was achieved with mature green stem cuttings soaked in 50 mg/1 IBA for 3 hrs followed by water culture in V-strength Hoagland's solution minus nitrogen. Inoculating rooted cuttings with a nodule suspension of Frankia gave 84% nodule formation after 3 months.

Callus of Pinus roxburghii (Chir pine) and its cytology

Callus was initiated form different vegetative parts of 3 to 5‐week‐old seedlings of Pinus roxburghii Sargent. Best results were obtained on Murashige and Skoog's revised medium supplemented with 4 mg1−1 NAA or 2,4‐D, 1 mg1−1 kinetin and 15% coconut milk. Callus was grown successfully for more than a year without deterioration in its growth. Growth rate studies on the calli form cytoledon explants were undertaken with different concentrations of auxins and cytokinins. Histogenic differentiation of tracheids ocurred in all the calli, with the formation of bordered pits preceding the reticulate thickenings of the tracherary walls. Cells in the 4 to 12‐week‐old calli were predominantly diploid, though a few polyploid and aneuploid cells were also noticed. Chromosome bridges and laggards were observed in a number of cells.

Rhizogenesis fromNigella sativa protoplasts

Protoplasts were isolated for the first time from cell suspensions ofNigella sativa. These were then cultured in media and observed at regular intervals. Different concentrations of auxin and kinetin were tried with success to obtain root from the callus tissues of the protoplasts.

Effect of Auxin Concentration on the Callus Induction from Various Organs of Rice Seedlings

1. Callus tissues were induced by various concentrations of 2, 4-dichlorophenoxyacetic acid (2, 4-D) from different organs, roots, mesocotyls, internodes, nodes, coleoptiles, leaf sheaths, and epidermal cells of scutellum of Oryza sativa and roots, leaves and stems of Echinochloa crus-galli, Nicotiana tabacum, and Vicia faba. 2. Callus induction is more remarkable in some organs of young rice seedlings than old ones with lower level of 2, 4-D. 3. Different concentrations of 2, 4-D are necessary for callus induction from different organs and diverse species. Tissues and organs in rice seeds, from which callus is able to be induced, are strikingly varied by different concentrations of auxin. 4. The concentration of auxin for callus induction is dependent on a sort of auxins used; IAA, NAA, or 2, 4-D. The difference of auxin concentration for the callus induction corresponds with the difference of auxin activity of the substances used. 5. Effect of kinetin on callus induction in rice seeds is not only undistinct but also repressive. 6. Thiamine is required for growth of rice cultures but it is not essential for callus induction in rice seeds. 7. It is discussed on the effects of the cutting of seedlings on callus induction in rice. 8. The tissues from which the callus is originated in various concentrations of 2, 4-D is histologically investigated on rice seeds and segments excised from the seedlings. Anatomical studies indicated that the initiation of callus in various organs resembled to the initiation of the adventitious root, except for epidermal cells of scutellum. 9. The organ differentiation in rice callus tissues is controled with various concentrations of 2, 4-D. Namely, callus tissues without root-like structures, callus tissues with root-like structures, abnormal roots and normal roots are formed as the concentration decreases.

Studies on the physiology of hyacinth bulbs ( Hyacithus orientalis L.) IV. Hormonal regulation of induction on roots and bulblets in Hyacinthus orientalis L. grown in culture

The purpose of this work was to study the hormonal regulation of root and bublet formation in Hyacinthus orientalis L. grown in culture. Hyacinth bulbs, cv. Lady Derby, a few months old, were cultured on Murashige and Skoog's (MS) medium in 0.6% agar in the presence of different concentrations of auxin (α-naphthaleneacetic acid, NAA) or cytokinin (benzyladenine, BA). The regeneration of roots and bulblets was found to be dependent on the levels of growth substances added to the basic medium (MS). The best combination for bulblet initiation was 1 ppm of NAA and 10 ppm of BA. NAA was the only necessary hormone for callus formation and root differentiation.

Hormonal Control of Xylogenesis in Pith Parenchyma Explants of Lactuca

The time course of xylem differentiation was determined in explants of lettuce pith parenchyma (Lactuca sativa L. cv. Romana) cultured on Murashige and Skoog (1962) medium using different concentrations of auxin (IAA) and one cytokinin (zeatin or kinetin). Increasing levels of auxin from I mg 1−1 to 15 mg 1−1 in the presence of a constant level of a cytokinin (zeatin or kinetin) yielded up to 10 mg 1−1 IAA, an increase in the number of tracheary element formations. Cytokinin concentrations above and below o.1 mg 1−1 interacting with an optimal xylogenic amount of auxin inhibited xylogenesis. The IAA (10 mg 1−1)-zeatin (0.1 mg 1−1) treatment produced the greatest number of tracheids, while kinetin compared to zeatin did not produce such an effect. The different effectiveness of zeatin and kinetin in inducing tracheary element formations was not due to a different capacity of the two cytokinins to stimulate cell division but it seems likely that zeatin, because of interaction with IAA, is more active than kinetin in the determination of the dividing cells in a specific type of cytodifferentiation. The IAA (10 mg 1−1)-zeatin (0.1 mg 1−1) treatment produced about 6.9 per cent tracheids with respect to cell division while IAA (10 mg 1−1)-kinetin (0.1 mg 1−1) produced 4.2 per cent. These results are discussed with reference to the problems of hormonal control of xylem differentiation.

Differences in ploidy and degree of intercellular contact in differentiating and non-differentiating sycamore calluses.

ABSTRACT Comparisons have been made between a sycamore callus (S4) isolated in 1970 and one first isolated in 1958 (S2). Incubation of S4 on media containing different concentrations of auxin and kinetin showed that the ratio of the hormones was the factor which controlled the growth pattern within the tissue. High ratios of auxin: cytokinin favoured a white friable tissue, whereas a compact callus with a much harder texture was formed at low ratios. Roots were differentiated at intermediate values. Callus (S2) has not been induced to undergo cellular differentiation. No soluble factors which were capable of stimulating differentiation in S2 were produced during the differentiation of S4, and S2 did not affect the ability of S4 to form roots. Divisions seen in suspension cultures of S4 callus were mainly diploid; the cells of S2 were predominantly tetrapioid. When S2 suspensions were grown in the cytokinin-free medium used for S4 a considerable number of diploid cells were seen. A number of S2 clones have been isolated and all these developed chloroplasts on exposure to continuous light and, when grown on the medium used to induce differentiation in S4, five of them showed a growth pattern in which the cells were more closely packed than is usually the case in S2 callus. A greater degree of cell contact has also been induced by including polyethylene glycol in the medium and so restricting the availability of water to the callus. Under these conditions the cells must have a greater capacity for interaction with one another. The effect of tissue texture on the extent of cell contact and adhesion between the cells is discussed in relation to the composition of the plant cell wall and ideas on the totipotency of plant tissue cultures.

Multicompartment analysis of the response of lupin hypocotyl segments to the addition and removal of indolyl-3-acetic acid

The typical growth rate curve of the response of lupin hypocotyl to auxin is discussed and explanations suggested for the different parts of the curve. Two alternatives are shown to be able to account for the latent period after auxin addition. One is a linear series of compartments with the transport between compartments similar to allosteric activation in enzyme kinetics and the other alternative is an unmixed compartment (transport delay). Computer simulation is used to test different models to determine whether any model quantitatively predicts the observed results. An example (and variations) of a model is given that predicts much of the experimental results. The model is tested under different conditions such as the addition of different concentrations of auxin, and different times of cycloheximide pretreatment, and on removal from different auxin concentrations. The results of the computer simulations are then compared with experimental results and the model improved to overcome discrepancies. The usefulness of computer simulation in an experimental study is discussed.

Efficient Plant Regeneration from Cotyledon and Midrib Derived Callus in Eggplant (<i>Solanum melongena</i> L.)

Somatic embryos were obtained from cotyledon and midrib explants of Solanum melongena L., cultivar Loda. For callus induction, medium was supplemented with different concentrations of auxin singly or in combination with BAP. The best callusing 83-85% was obtained from both of the explants cultured on MS medium containing 2.0 mgl-1NAA + 0.05 mgl-1BAP. Somatic embryogenesis and shoot regeneration was achieved after transferring the calli to MS medium supplemented with BAP, GA3, NAA and Zeatin. Cotyledon derived calli showed better performance (87%) for regeneration than that of midrib (82%) when sub cultured on MS medium having 2.0 mgl-1 Zeatin + 1.0 mgl-1 BAP. For root induction, MS + 3.0 mgl-1 IBA was proved to be better treatment for average number (14-15) and mean length (12 cm) of roots than those of other treatments. 
 
 Key words: Eggplant; cotyledon; midrib; callus induction; somatic embryo
 
 J. bio-sci. 14: 1-9, 2006

<i>In vitro</i> Plant Regeneration from Axillary Buds of <i>Asparagus racemosus</i> Wild, a Medicinal Plant

An efficient method was developed for regeneration of Asparagus racemosus Wild, from axillary explants. MS media supplemented with different concentrations of cytokinin (BAP) alone or in combination of different concentrations of auxin (NAA or IBA) was tested for their efficiency in multiple shoot induction. High frequency of multiple shoot regeneration was achieved on MS medium supplemented with BAP (0.1mg/l) and NAA (0.05 mg/l). When shoots were well developed they were dissected and subcultured on the same medium to promote more multiple shoots. Eighteen to twenty shoots were obtained on this medium. The shoots were rooted best on half MS medium supplemented with 0.05 mg/l BAP and 1.0 mg/l IBA. Among the five levels of pH tested, 5.7 was the best for multiple shoot proliferation. The result presented here proved to be suitable for the rapid propagation system of A. racemosus. Key words: Asparagus racemosus; Medicinal plant; Rapid proliferation; Multiple shoots; Auxins and Cytokinins DOI: 10.3329/bjsir.v45i3.6534Bangladesh J. Sci. Ind. Res. 45(3), 255-260, 2010

<i>In Vitro</i> Indirect Plantlet Regeneration from Hypocotyl Segments and Cotyledonary Explant Derived Calli in Lady's Finger (<i>Abelmoschus esculentus</i> L. Monech)

An experiment was conducted to develop an efficient protocol for in vitro regeneration of plantlets from hypocotyl segments and cotyledonary explants of Abelmoschus esculentus L. Monech. In this investigation the cultivar OK-285 of Abelmoschus esculentus L. Monech was used. At first somatic embryogenic calli were induced using MS medium supplemented with different concentrations of auxin and cytokinin singly or in combination. The cotyledonary explants showed the best callus induction rate (87.9%) in MS medium containing 1.5mgl-l 2.4-D + 0.1mgl-l BAP hormonal concentration while hypocotyl segments showed 82.6% callus induction rate in the same medium. For shoot formation, calli were subcultured on MS solid medium and the hypocotyl segments showed the best result (72.1%) in MS medium containing 2.0 mgl-l BAP + 0.1 mgl-l IAA and the mean number of shoots per callus was recorded 4.2. For root induction from shoots MS and ½MS media were used. The highest 63.5% microshoots initiated roots in ½ MS + 0.1 mgl-l IBA medium and the highest mean number of root was 4.8. Rooted shoots were acclimated and successfully established into soil under natural condition with 70% survival. Key words: Abelmoschus esculentus, hypocotyl segments and cotyledon, embryogenic calli, regeneration. DOI:10.3329/jbs.v16i0.3741 J. bio-sci. 16: 49-57, 2008

High Frequency <i>In Vitro</i> Propagation of <i>Adhatoda vasica</i> Nees through Shoot Tip and Nodal Explants Culture

An efficient protocol for in vitro propagation of Adhatoda vasica Nees was established using shoot tip and nodal explants from field grown mature plant. Proliferation of multiple shoots was achieved on MS medium supplemented with different concentrations and combinations of cytokinins (0.5-4.0 mg/l) and auxins (0.1-1.0 mg/l). Maximum number of shoots per explant (13.0) was obtained on MS medium supplemented with 2.0 mg/l BAP + 0.2 mg/l NAA. Among two types of explants used in this study, nodal explants showed better response in respect of multiple shoot production. The elongated shoots were excised and subcultured for rooting on MS medium supplemented with different concentrations of auxins (IBA and NAA). Highest 80% rooting was achieved; and three to four roots per shoot were recorded in medium with 1.0 mg/l IBA within 4 weeks of culture. The in vitro raised plantlets were acclimatized and successfully transferred to natural condition in pot. The regenerated plants were healthy, uniform and identical to the donor plants and the survival percentage was 80%. Key words: Micropropagation, Adhatoda vasica, shoot tip, nodal explant. DOI:10.3329/jbs.v16i0.3739 J. bio-sci. 16: 35-39, 2008

A Photokymograph for the Analysis of the Avena Test

1. With an automatic photokymograph, the procedure of curvature in the Avena test was investigated. In general, when auxin was applied unilaterally there was little or no effect for about 20 minutes, after which curvature set in and continued at a constant rate for about an hour, then diminished or reversed, depending on the treatment. 2. It was found that increasing the auxin concentration inside the plant decreased the sensitivity to unilaterally applied auxin. This explains the increase in sensitivity after decapitation, since the auxin content decreases after removal of the tip. 3. To study this process in detail, the effect of the i.d.p. (length of interval between decapitation and putting on of the agar block) and the number of decapitations was followed for different concentrations of auxin. 4. For all concentrations up to maximum angle concentration, the sensitivity increased rapidly for the first 30 minutes i.d.p., increased gradually until 200-240 minutes i.d.p., then gradually decreased. 5. But the maximum angle concentration fell off rapidly for the first 100 minutes i.d.p. 6. For i.d.p. longer than 100 minutes, a second decapitation just before putting on causes: (a) the reaction to maximum angle concentration to be doubled; (b) the reaction to extremely low concentration to be slightly decreased, even to the extent of sometimes giving small positive angles; (c) more uniform reactions. 7. A modified standard Avena test is recommended: (a) an i.d.p. of 3-4 hours; (b) a second decapitation 20-40 minutes before putting on; (c) photographs at 90 minutes after putting on. 8. Besides the regeneration effect which reverses the curvatures at 130 minutes after decapitation for i.d.p. of less than 50 minutes, there is also a pseudo-regeneration effect for longer i.d.p. which also balances or reverses curvature at 80-90 minutes after putting on. 9. This effect, and certain others (decreases of maximum angle concentration with increasing i.d.p., and positive angles if low concentration auxin-agar blocks are put on soon after decapitation) cannot be explained by geotropism, lateral auxin transport, or aging. Thus it is tentatively proposed that they may be due to food factor distribution.