Low Concentration Of NAA Research Articles

Serial brain imaging analysis of stroke-like episodes in MELAS

We report 2 patients of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and consider the pathophysiology of stroke-like lesions, using magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) on MRI, perfusion imaging on MRI, and 1H magnetic resonance spectroscopy ( 1H-MRS). In Patient 1, T2-weighted imaging (T2-WI) on MRI at onset and even at 44 days after onset of the stroke-like episode showed high intensity in left parietal, temporal, and occipital lobe lesions. In the temporal lobe lesion, the apparent diffusion coefficient (ADC) at 44 days after onset was higher (average: 1.219 × 10 −3 mm 2/s) than that in a normal region (average: 0.796 × 10 −3 mm 2/s). 1H-MRS of the left parietal lobe lesion at the same day showed a decrease in N-acetylaspartate/(creatine + phosphocreatine) (NAA/Cr) (0.43) and a peak in lactate. 1H-MRS of the contralateral side at the same day showed NAA/Cr (1.57) and no peak in lactate. Thereafter, ADC gradually decreased and NAA/Cr gradually increased, and the peak in lactate disappeared in the lesion. In Patient 2, T2-WI at onset showed high intensity in bilateral occipital lobe lesions. In the left occipital lobe lesion, ADC at the same day was higher (1.082 × 10 −3 mm 2/s) than that in a normal region (average: 0.841 × 10 −3 mm 2/s). 1H-MRS of the left occipital lobe lesion at the same day showed a decrease of NAA (3.0 mM) and a peak in lactate (13.1 mM) (measured by LCModel). In 1H-MRS of the normal left parietooccipital lobe at 4 months before onset, NAA was 7.6 mM and there was no peak in lactate (0 mM). Perfusion imaging at onset showed high intensity in bilateral occipital lobes, which indicated hyperperfusion in stroke-like lesions. Thereafter, ADC gradually decreased and the peak in lactate partially decreased, and the low concentration of NAA persisted (regardless of the partial recovery) in the lesion. These results suggest that the stroke-like episodes is related to vasogenic edema, hyperperfusion, and neuronal damage. Acute oxidative phosphorylation defect may have a crucial role in the pathophysiology of stroke-like episodes.

Effects of Growth Regulators on Direct Flowering of Isolated Ginseng Buds in vitro

An in vitro method for obtaining gingseng inflorescences directly from explants of gingseng (Panax ginseng) is reported. Isolated shoot-buds of somatic embryo-derived plantlets ginseng were used as explants and incubated in B5 medium supplemented with 1 mg l−1 benzyladenine (BA) and 1 mg l−1 gibberellic acid (GA3). About 15% of the buds flowered directly without developing vegetative organs. Cytokinin was found to be the key factor for inducing these isolated buds to proliferate and flower, but both these processes also occurred when benzyladenine (BA) was replaced by thidiazuron (TDZ). The optimal concentration of TDZ for obtaining the best ratios of bud proliferation and total flowering was 0.1 mg l−1, while the highest number of vegetative shoots was obtained in medium supplemented with 1 mg l−1 GA3 and 0.1 mg l−1 TDZ. The explant elongated abnormally in the presence of 10 mg l−1 GA3. Although a low concentration (1 mg l−1) of NAA increased the bud proliferation ratio in the medium supplemented with 0.1 mg l−1 TDZ and 1 mg l−1 GA3, a high concentration (5 mg l−1) of NAA reduced the bud proliferation ratio and inhibited the flowering.

In vitro propagation of Aconitum balfourii Stapf.: an important aconite of the Himalayan alpines

SummarySmall leaf segments, obtained from in vitro sprouted axillary buds, have been used to develop an ef®cient micropropagation protocol for Aconitum balfourii Stapf., an important medicinal herb of the Indian Himalayan alpines. Following the induction of callus from cultured leaf segments on Murashige and Skoog (1962; MS) medium containing 4.5.mM 6-benzyladenine (BA) and 26.9.mM a-naphthaleneacetic acid (NAA), the highest values for shoot induction were obtained on the same medium supplemented with the same concentration (4.5.mM) of BA and a lower concentration of NAA (1.4.mM). These individual shoots could be further multiplied easily, with maximum shoot proliferation obtained on MS medium containing 1.1.mM BA only. The shoots obtained either directly from the callus or after multiplication on the above medium, were found to root ef®ciently on MS medium supplemented with 12.3.mM indole-3-butyric acid (IBA). After in vitro hardening in the culture room, the plantlets were transplanted to a greenhouse where the growth of plants was normal. Comparison of mitotic chromosome numbers of root tip cells, protein pro®le and alkaloid content of tubers of in vitro raised and seed grown plants of comparable age showed equal number of chromosomes, identical protein pro®le and similar amounts of diterpenoid alkaloids (aconitine and pseudoaconitine). This paper is the ®rst report describing a complete regeneration protocol, along with quantitative data, for A. balfourii using in vitro methods.

In vitro organogenesis from leaflet explants in Bacopa monnieri Linn., an important medicinal plant

Regeneration of both shoot bud and root was achieved from leaflet explants in Bacopa monnieri cultured on MS medium supplemented with graded doses of BA and NAA. The proximal portion of leaflet gave better response in terms of both percentage frequency and number of shoots per explant in comparison to the middle and distal parts. Maximum in vitro regeneration of plantlets was achieved on the medium containing higher concentration of BA (10 mm) and lower concentration of NAA (1.0 mm). In vitro raised plantlets were successfully hardened and transferred to the field. 100% plantlets survived when transferred to the field.

Effects of auxin on growth and ripening of mesocarp discs of peach fruit

A bio-assay system using the mesocarp discs of peach fruit ( Prunus persica L. cv. Akatsuki) was developed, and the effects of auxin on the physiology of fruit tissues were investigated at different stages of development (FWI: initial period of exponential growth, FWII: period of slow growth, and FWIII: second period of exponential growth). Auxin promoted both the enlargement of discs as well as ripening processes such as softening and anthocyanin formation. In particular, discs at FWI and FWII enlarged remarkably after four weeks of incubation with NAA. The highest value of the weight of FWI discs was observed at 10 μM of NAA; that of FWII discs was at 1 μM. Weights were compared between discs that were incubated with and without NAA. NAA-incubated discs reached to 3.1-fold in the FWI stage and 2.7-fold in the FWII stage. Discs at each stage of development lost their firmness with increasing concentrations of NAA up to 100 μM. There was a significant difference in anthocyanin formation between light- and dark-incubated discs. Anthocyanin formation at the surface of the discs was enhanced by high concentrations of NAA and light, whereas that inside of the discs was enhanced by darkness and low concentrations of NAA. These multiple effects of auxin on growth and the ripening process of fruit tissue may be caused by multiple mechanisms of auxin action as influenced by the stage of fruit tissue growth and environmental conditions.

Isolation by differential display and characterization of a tobacco auxin-responsive cDNA Nt-gh3, related to GH3

By use of differential display, we have isolated a new early auxin-responsive cDNA in Nicotiana tabacum. Nt-gh3 had 70% identity with the unique GH3 sequence isolated in soybean by Hagen et al. [Planta 162 (1984) 147–153] and is thus the first reported cDNA related to this gene until now. Nt-gh3 mRNA accumulates within a short time after auxin treatment, responds to very low concentrations of NAA (as little as 10 −9 M) and specifically to active auxins. Nt-gh3 mRNA is demonstrated to be one of the most relevant early molecular markers of primary auxin response.

In VitroPropagation ofRauvolfia serpentinathrough Tissue Culture

Multiple shoots were induced from nodal segments and shoot apices of Rauvolfia serpentina and MS medium containing 1.0 mg/l BA and 0.1 mg/l NAA was found to give the best shoot proliferation rate. Callus formed at cut bases of the explants which produced shoots when subcultured on media containing low concentration of BA (0.5 or 0.1 mg/l) and NAA (0.1 mg/l). The in vitro proliferated shoots were rooted and later transferred to the soil.

Effects of Cold Treatment, BA and GA3 on Enlargement and Leaf Emergence of In Vitro Cultured Bulblets of Lilium japonicum Thunb.

While bulblets of Lilium japonicum Thunb. were being multiplied by tissue culture, the number of leaves emerging from the bulblets gradually decreased as the culture period was prolonged; finally, bulblets developed no leaves. Dormant bulblets which had been cultured in vitro for more than 15 months were exposed to 2°C or treated with BA or GA3.1. Bulblets incubated at 2°C to break dormancy and subsequently cultured at 20°C developed scale leaves and enlarged. Thus, dormancy prevents leaf emergence and reduces the rate of bulblet enlargement.2. Bulblets cultured on medium with 2 mg•liter-1 BA or 9.5 or 30 mg•liter-1 GA3 formed leaves. However, leaf emergence was suppressed when the bulblets were transferred to medium with low concentrations of NAA (0.01 mg•liter-1) and BA (0.001 mg•liter-1), indicating that BA and GA3 stimulate leaf emergence directly and do not break dormancy.

Production of plantlets from Aegle marmelos nucellar callus

Techniques have been developed for the regeneration of Aegle marmelos from nucellar explants. Slow-growing calli were induced from nucellar explants excised from 90-120 d-old developing fruits. The medium consisted of Murashige and Skoog formulation containing 40 g/l sucrose, 400 mg/l casein hydrolysate, 5 mg/l 1-naphthaleneacetic acid and 1 mg/l kinetin. The basal medium with high concentration (1-5 mg/l) of N6-benzyladenine (BA) and low concentration (0.1 mg/l) of NAA was suitable for regeneration of shoots from 3-month-old calli. Addition of 1 mg/l gibberellic acid (GA3) favoured shoot growth. Callus-derived shoots produced roots and developed into plantlets when transferred to half-strength MS medium supplemented with 0.5 mg/l indole-3-butyric acid (IBA) and 0.5 mg/l NAA. Approximately 5 months were required for the full regenerative process.

Effects of Auxin, Cytokinin and Nitrogen Concentration on Morphogenesis of Tissue-cultured Shoot Apex of Chinese Yam (Dioscorea opposita Thunb.).

Most shoot apices of Chinese yam (Dioscorea opposita Thunb. cv. Nagaimo) developed into shoots in modified Murashige-Skoog (MS) medium in which the nitrogen level was reduced to one tenth of the recommended concentration and containing 0 to 0.1 mg•liter-1 NAA and 0.1 mg•liter-1 BA. Bases of shoot apices developed friable calli in a medium supplemented with 1.0 mg•liter-1 NAA. The composition of the basal medium had little effect on shoot formation, but morphogenic calli were produced by excised apices on a medium having 1 to 2 mg•liter-1 BA and low concentration of NAA. Morphogenic callus resembled shoot primordium in that adventitious buds were formed on its surface. When morphogenic calli were subcultured on MS medium containing 0 to 0.1 mg•liter-1 BA and 0.01 to 0.1 mg•liter-1 NAA, a large number of plantlets were regenerated.

Role of ethylene in auxin‐induced flower bud formation in tobacco explants

The effect of ethytene on in vitro flower bud formation in thin‐layer explants from tobacco pendicels (Nicotiana tabacum L. cv. Samsun) was studied Endogenous ethylene production was stimulated by l‐minocyclopropanc‐l‐carhoxylic acid (ACT), and inhibited by aminoethoxyviny lglycine (AVG). resulting in higher and lower ethylene accumulation. respectively. In the presence of an elevated ethylene concentration, the number of flower buds formed after 7 days of culture in explants was increased, compared with the control. Treatment with AVG or with AgNO3 which blocks ethylene action resulted in decreased bud numbers after 7 days of culture. A different effect of ethylene was visible after 14 days of culture, when regeneration was complete. Treatment with AgNO3 led to more bud regeneration, and increasing ethylene concentrations to lower bud numbers. The endogenous production of ethylene was enhanced by high concentrations of 1‐naphthaleneacetic acid (NAA).The inhibitory effect of applied ethylene was almost 100% in explants cultured at low concentrations of NAA (below 1 μM). but hardly visible at high concentrations (4.5 μM). As a consequence, the optimal NAA concentration shifted to a higher value in the presence of ethylene. These results are interpreted as a reduction in tissue sensitivity to auxin and in regenerative capability by ethylene. The effect of ethylene on auxin action is not exerted at the level of hormone concentration. Neither NAA uptake nor conversion to conjugates was effected by ethylene.

Metabolic Changes and Alkaloid Production in Habituated and Non-habituated Cells of Catharanthus roseus Grown in Hormone-free Medium. Comparing Hormone-deprived Non-habituated Cells with Habituated Cells

Summary Habituated cells of Catharanthus roseus (Apocynaceae) selected from an auxin-dependent line accumulated alkaloid in higher amounts than did the non-habituated cells grown in their maintenance medium. Ajmalicine and serpentine contents could be enhanced in both cell lines by feeding the indole alkaloid precursor secologanin or low concentrations of IAA or NAA. However the production remained low in the habituated cells as compared to that of non-autotrophic cells grown in a hormone-free production medium. By comparing the evolution of pH values, the levels of some cellular components and the activities of strictosidine synthase and tryptophan decarboxylase in habituated cells and non-habituated cells grown either in their maintenance medium (with auxin) or in a hormone-free medium, we present evidence that enhancement of alkaloid production in auxin depleted cells might be due to a combination of several factors including a better coordination between tryptamine and secologanine supplies and an increase of vacuolar accumulation capacities.

Induction and subculture of bud forming tissues from twig sections of Chamaecyparis pisifera, var. filifera.

Callus with multiple buds (CMB) consisting of callus and many buds in which the multiplication of buds was associated with callus growth was induced from the sections of twigs on an agar medium in an ornamental conifer, Chamaecyparis pisifera, var. finifera Beissn. A devised medium containing half strength of Murashige and Skoog's minerals, vitamins, inositol, amino acids, sucrose, 1mg/l BA and 0.3mg/l IAA (SF-medium) was favored to induce CMB. CMB is able to be subcultured on SF-medium without a decrease in capacity to form buds for more than 5 years. Buds in various developmental stages were observed in CMB depending on the length of culture period. Buds with scale-like leaves in CMB were observed in the regular subculture cycle. Needle leaves appeared in the buds of CMB with prolonged culture more than about 2 months on SF-medium without regular subculture. Buds developed into shoots when buds were isolated from CMB and cultured on SF-medium with low concentration of NAA or IBA, 0.03-0.1mg/l.

In vitro plant regeneration of Hedychium roxburghii blume through rhizome-meristem culture

Full grown plants have been raised successfully in vitro by culturing meristems excised from rhizome of Hedychium roxburghii Blume on Murashige and Skoog's medium supplemented with NAA and kinetin. Zeatin associated with IAA stimulated the development of buds on the basal region of the stem. A low concentration of NAA (0.2 mg.1-1) enhanced the root formation on young excised buds.

ブドウ‘巨峰’の腋芽茎頂培養におけるナフタレン酢酸及びベンジールアデニンの好適濃度について

Investigations were carried out to determine the appropriate concentration of α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BA) for the regeneration of intact plants and multishoot formation from the apex culture of axillary-buds (0.25_??_0.3mm) of ‘Kyoho’ vines.1. To enhance the survival rate, a preliminary test was performed using various modified Murashige and Skoog (MS) media. The survival rate of inoculated apex was highest (higher than 80%) in a modified MS medium containing one tenth amount of nitrogen, 0.1mg/l NAA, 1.0mg/l BA, 30g/l sucrose, and 7.0g/l agar. Therefore, this modified MS medium was adapted in this study.2. The effect of BA was very marked in the stage from the greening and enlargement of inoculated plantlets to the development of shoots and multishoot formation (stages 1_??_3); The optimum concentration was found to be 1mg/l in all the stages. In view of the fact that supplementation with 1mg/l NAA resulted in callus formation from plantlets and inhibition of shoot formation, either the concentration of NAA should be lower than 0.1mg/l, or no NAA should be supplemented.3. Supplementation with BA at the forth stage enhanced callus formation, but inhibited rooting from the basal part of shoots. This stage was, therefore, carried out without supplementing with BA. NAA promoted the elongation of shoots at a low concentration (0.05mg/l or less), making potting easy. Rooting rate was high, but the elongation of shoots were poor when supplemented with 0.1mg/l NAA or more. The rooted shoots were, therefore, transferred to a medium containing either no NAA or a low concentration of NAA to ensure elongation before potting.4. Intact plants of ‘Kyoho’ vines were regenerated successfully from apex culture by supplementing a modified MS medium with NAA and BA.

Growth and Plantlet Regeneration in Tissue Cultures of Some Indian Millets: Paspalum scrobiculatum L., Eleusine coracanaGaertn. and Pennisetum typhoideumPers.

Summary Somatic tissue cultures of Paspalum scrobiculatum, Eleusine coracana and Pennisetum typhoideum established on MS medium containing CM and 2,4-D developed shoot buds on abrupt withdrawal of 2,4-D from the medium or its substitution by low concentrations of NAA or IA A. Addition of the cytokinins SD 8339 (6-benzyl-9-tetrahydropyraneadenine) and kinetin in the medium significantly promoted shoot bud induction. Complete plantlets could be raised on culture of excised young shoot buds in a rooting medium which grew to maturity as pot plants, when transplanted.

Pistil development in Cleome flowers III. Effects of growth-regulating substances on flower buds of Cleome iberidella Welw. ex Oliv. Grown in vitro

Pistil development in flower buds of Cleome iberidellaWelw. ex Oliv., grown in vitro, is strongly stimulated by specific cytokinins, viz. zeatin and BA; kinetin is less active and 2iP ineffective. In the presence of zeatin, low concentrations of NAA stimulate pistil development, whereas higher concentrations are inhibitory.

Morphogenic investigations on tissue cultures of Panicum miliaceum

Summary Somatic tissue cultures of Panicum miliaceum have been established on MS medium with 2,4-D and CM. Shoot buds developed on abrupt withdrawal of 2,4-D from the medium or, its substitution by low concentrations of NAA or IAA. Plantlets were obtained by excising young shoot buds and transferring them on to a nutrient medium supplemented with CM and NAA. They were successfully raised as pot plants which grew to maturity, flowered and set seeds.

Organogenesis in the meristem tissue cultures of cymbidiums. II

Protocorm-Pieces of Cymbidium pumilum ROLFE and rhizome-tips of Cymbidium goeringii REICHB. F. were cultured aseptically in the dark. Chemical control of the organ formation in these cultures was studied. The results obtained were summarized as follows:1) Cymbidium pumilum; On the basal medium (KNUDSON C+NITSCH microelement) shoots were formed in a half of samples after 8 weeks, while no root was formed. Addition of NAA markedly affected their organ formation. Low concentrations of NAA (below 0.1mg/l) promoted shoot formation. With increasing concentration from 0.1 to 0.6mg/l, root arose and the number of shoot decreased. Root formation was most abundant at 0.6mg/l, where root formation scarcely occurred. Still higher concentration suppressed completely both shoot and root formation. Shoot formation was also improved respectively by addition of 0.01mg/l 2, 4-D, 0.01 mg/l gibberellin, 10-3M L-arginine, 10-3M L-aspartic acid and 1mg/l ascorbic acid. Addition of kinetin showed no remarkable effect.2) Cymbidium goeringii; Rhizome-tips of C. goeringii cultured on the basal medium always developed into rhizomes without shoot formation. Addition of 10mg/l kinetin led most of samples to shoot formation. Whereas low concentration of NAA tends to promote the growth of shoot in combination with 10mg/l kintin, high concentration of NAA tends to counteract the stimulating effect of kinetin on the shoot formation. Incorporation of 10-3M L-arginine and L-aspartic acid stimulated shoot formation slightly. Growth of rhizome was improved by addition of 10-3M L-tryptophan and 0.1mg/l biotin to some extent.

Morphological studies on adventitious root formation in cuttings II

The experiment was carried out to see the effects of basipetally moving endogenous substances on the root primordium differentiation of Portulaca cuttings and to determine whether the exogenously applied IAA or NAA acts as the substitute of the substances.One side of the stem of the cutting was cut out at a slight distance from basal end for the purpose of blocking downward movement of root promoting substances, and then an agar block containing various concentrations of IAA or NAA was inserted into the cut-out portion. The experiments were conducted in two cases: one with leaves and the other without leaves.Root initiation at the base of the cutting was observed morphologically in order to see the difference between the side under the cut and the intact side.1. The formation of the root primordia was inhibited by removing the leaves from cuttings. Furthermore, the root primordia were not formed at all at the side under the cut portion, but the advancing tendency to form root primordia were somehow exhibited by the application of IAA or NAA to the cut-out portion.2. On the cuttings with leaves, the formation of the root primordia was also inhibited at the side under the cut portion, but it was promoted a little by treatments with a low concentration of IAA or NAA.3. On the cuttings with leaves, many root primordia were formed at the opposite side of the cut-out portion and a tendency to promote the formation of the root primordia was shown by the application of IAA to the cut-out portion. In this case, IAA at a concentration of 10-11M was more effective than the other concentrations.4. Most of the root primordia were formed near the cut-end of cuttings by IAA or NAA applied to the cut-out portion.5. On the cuttings with leaves, IAA or NAA applied to the cut-out portion promoted the formation of the root primordia at the medullary ray.