• Korean Journal of Microbiology
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• v.10 no.3
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• pp.117-127
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• 1972

To study the effect of IAA on the growth of Chlorella, the alage wre cultured on the media for six days by bubbling $_{2}$ enriched air under 10K lux at 20-$25^{\circ}C$. The culture media were made by adding a concentration of $10^{-3}$M, $10^{-4}$M, and 0M(as a control) IAA to the standard media. During the period of culture, Chlorella was smapled for the given time of interval and photosynthetic and respiratory activities were measured by Warburg manometer and change of chemical components of Chlorella was determined by spectrophotometry after the Chlorella cell was fractionated by Schmidt-Thannhauser method. 1) Photosynthetic and respiratory activities were enhanced by IAA ; especially the enhancement of respiratory activity was so remarkable. 2) As to the chemical components of Chlorella, carbohydrates and amino acids were reduced a little but phosphate, RNA, DNA, and protein were increased by $10^{-3}$M IAA ; the increase of RNA, in particular, was noticable. 3) The above results suggest that the enhancement of growth of Chlorella, by IAA and ATP induced by respiratory activity accelerated with IAA enhanced RNA synthesis, resulting in an increase of protein synthesis.

• Journal of Plant Biology
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• v.27 no.2
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• pp.43-50
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• 1984

Effects of IAA on the elongation and cell wall hlysocidase activities were investigated in excised rape (Brassica napus L. cv. Yongdang) hypocotyl segments. IAA promoted the elongation of rape hypocotyl segments. In rape hypocotyls, the first 10-mm segments from the hook exhibited maximal elongation and the capacity of elongation was gradually decreased with increasing distance of each 10-mm from the hook. A good correlation has been obtained between the magnitude of endogenous growth and the activities of $\alpha$, $\beta$-glucosidase and $\alpha$, $\beta$-galactosidase. However, exogenous application of IAA did not seem to enhance the tissue with IAA resulted in acidification of the incubation medium. From these data, we can conclude that IAA seems to enhance elongation of the tissue segments, at least in part, by releasing hydrogen ion into cell wall, some of which may participate in the cell wall extension process, but does not seem to trigger the activation of $\alpha$, $\beta$-glucosidase and $\alpha$, $\beta$-galactosidase.

• Journal of Life Science
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• v.32 no.11
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• pp.872-881
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• 2022

In this study, we optimized the composition of the indole-3-acetic acid (IAA) production medium using response surface methodology on Pantoea agglomerans SRCM 119864 isolated from soil. IAA-producing P. aglomerans SRCM 119864 was identified by 16S rRNA gene sequencing. There are 11 intermediate components known to affect IAA production, hence the effect of each component on IAA production was investigated using a Plackett-Burman design (PBD). Based on the PBD, sucrose, tryptone, and sodium chloride were selected as the main factors that enhanced the IAA production at optimal L-tryptophan concentration. The predicted maximum IAA production (64.34 mg/l) was obtained for a concentration of sucrose of 13.38 g/l, of tryptone of 18.34 g/l, of sodium chloride of 9.71 g/l, and of L-tryptophan of 6.25 g/l using a the hybrid design experimental model. In the experiment, the nutrient broth medium supplemented with 0.1% L-tryptophan as the basal medium produced 45.24 mg/l of IAA, whereas the optimized medium produced 65.40 mg/l of IAA, resulting in a 44.56% increase in efficiency. It was confirmed that the IAA production of the designed optimal composition medium was very similar to the predicted IAA production. The statistical significance and suitability of the experimental model were verified through analysis of variance (ANOVA). Therefore, in this study, we determined the optimal growth medium concentration for the maximum production of IAA, which can contribute to sustainable agriculture and increase crop yield.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.9-14
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• 2010

This study was conducted to examine the effects of IAA and kinetin on induction of gemmae and gametophytes in Hypnum plumaeforme moss during tissue culture. Explants were obtained from sterilized gametophyte tips cultured on solid basal medium containing Knop's major salts and Nitsch and Nitsch's trace elements. After culture, inoculated gametophyte tip produced protonema firstly, changed to new gametophytes after four weeks. Aseptic gametophytes were chopped and inoculated on the same media containing 0.01, 0.1, 1 and $10{\mu}M$ of IAA and kinetin. As a result, secondary protonemata as well as protonemal gemmae were formed from gametophytes. But protonemal gemmae formation was varied according to the concentration of IAA and kinetin. Lower concentration of IAA and kinetin promoted gemma formation and bud induction. Especially, $0.01{\mu}M$ of kinetin showed the highest frequency of bud and gemma production. All the materials, obtained from $0.01{\mu}M$ kinetin medium, were subcultured to media supplemented with 0.01, 0.1, 1 and $10{\mu}M$ of IAA and kinetin again to induce gametophytes. After subculture, protonema and calli were developed from secondary protonema, and induced gametophytes finally. IAA regulated induction and growth of gametophytes, and kinetin influenced gemma formation and gametophyte induction also. All aspects of development of this moss species were governed by the external growth regulators.

• Applied Biological Chemistry
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• v.15 no.3
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• pp.181-186
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• 1972

Wheat coleoptile sections were treated with either $1.5{\times}10^{-5}M$ ABA or $5×10^{-5}M$ IAA in vitro, the results may be summarized as follows, 1. The treatmert of IAA decreased the level of high molecular weight RNA F2 and F3 but that with ABA increased the F4 level. 2. IAA caused an increased activity of G2 isozyme, while ABA suppressed the activity of G3 isozyme. 3. The results may suggest that there may exist common effects of IAA and ABA on RNA and RNase. 4. The latent RNase activity caused by SH blocking reagent (p-hydroxymercury benzoate, Pb et al) was not observed.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.38-43
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• 1994

The effect of thidiazuron on callus growth and shoot regeneration of Solanumspecies was very positive. Increasing concentrations of thidiazuron stimulated callus growth of Solanum ptycanthum and Solanum nigrum. Shoot regeneration of S. ptycanthum and S. nigrum was greater on medium with thidiazuron than that with IAA and BA. Thidiazuron at $0.5{\mu}M$ or above increased the number of shoots regenerated from S. ptycanthum calli compared to the IAA with BA. High concentrations of thidiazuron $( >I{\mu}M)$ increased the number of shoots than BA or low levels of thidiazuron and IAA or BA The addition of IAA to thidiazuron media reduced S. ptycanthum shoot formation.

• Journal of Plant Biology
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• v.35 no.4
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• pp.409-414
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• 1992

Effect of quercetin, a kind of natural plant flavonoids, on auxin-induced ethylene production in barley coleoptiles was studied. Auxin-induced ethylene production was apparently stimulated by quercetin. This stimulatory effect of quercetin appeared after 4 h of incubation period. Ethylene production was stimulated 200% over the control after 8 h of incubation by $3{\times}10^{-5}\;M$ quercetin. The quercetin effect was most prominent at $10^{-4}\;M$ of IAA. Ethylene production induced by the synthetic auxin, 2,4-D and NAA, was not significantly affected by quercetin. Also ACC-based ethylene production was unaffected by the flavonoid. In an effort to elucidate mechanisms of quercetin action on auxin-induced ethylene production, the effect of quercetin on 1M metabolism was studied. Data obtained from these experiments indicate that quercetin treatment resulted in about 90% inhibition of IAA oxidase activity. IAA ($3{\times}10^{-5}\;M$) conjugation was found to be not affected by quercetin. This results suggest that the stimulatory effect of quercetin on auxin-induced ethylene production may be due to the fact that quercetin inhibits 1M oxidase activity, thus increasing the free IAA level.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.235-244
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• 2004

In this study, we compared the levels of methylotrophic bacterial community diversity in the leaf samples of 19 rice cultivars collected from three regions of Korea. Nineteen pink pigmented isolates showing characteristic growth on methanol were obtained. Physiological and biochemical characters of each isolate were examined according to methods described in Bergey's Manual of Systematic Bacteriology. When phylotypes were defined by performing numerical analysis of 37 characteristics, four distinct clusters were formed. The two reference strains, Methylobacterium extorquens AM1 and Methylobacterium fujisawaense KACC10744 were found to group under cluster IV and cluster III respectively. Cluster I diverged on the basis of nitrate reduction and four isolates showed tolerance upto 0.5 M NaCl concentrations. Two strains in cluster I and III were found to possess methane utilizing properties. Most of the isolates in all the four clusters utilized monosaccharides, disaccharide and polyols as carbon source. When the isolates were subjected for indole-3-acetic acid (IAA) analysis in the presence of L-tryptophan, only 8 isolates exhibited IAA production. In addition, the nitrogen source in the medium was found to influence the IAA production. Addition of $(NH_4)_2SO_4$ in the medium led to a 2 to 30 fold increase in the indole synthesis. However, $KNO_3$, $NH_4NO_3$ and $NH_4Cl$ substitution did not significantly stimulate the synthesis of IAA in the growth medium. Result of gnotobiotic root elongation assay significantly increased roots and shoots lengths, and number of lateral roots, which is mediated by IAA production in the culture medium. The rice seedlings primary roots from seeds treated with methylotrophic isolates were on average 27 to 56% longer than the roots from seeds treated with the uninoculated seeds. In addition, application of different high concentrations of authentic IAA ($400g\;mL^{-1}$) to roots of rice seedlings inhibited root growth. However, the IAA concentration from 10 to $200g\;mL^{-1}$, IAA promoted root growth of rice seedlings. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

• Korean Journal of Plant Tissue Culture
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• v.25 no.2
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• pp.75-80
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• 1998

Disbudded epicotyl cuttings from light-grown 6-day-old seedings of Vigna angularis Owhi et Ohashi were preincubated in $2\;\times\;10^{-4}M$ IAA solution for 48 hr to promote adventitious root formation in upright or inverted direction and then incubated in upright direction for 96 hr. Adventitious root formation occurred only at the morphological base of the cuttings which were preincubated in upright direction, while at the both ends in inverted direction. IAA treatment enhanced the adventitious root formation in all cuttings regardless of their orientation during preincubation. To elucidate localized root development, the activity of enzymes involved in root initiation and development was measured 24 hr, 48 hr, and 148 hr after epicotyl incubation. IAA oxidase, peroxidase and catalase were assayed in the apical, middle and basal segment of the epicotyls, and their fresh weight and length were measured. Elongation occurred the most in the upper segment of the epicotyl while fresh weight gain was the most in the basal segment. At root initiation phase, 24 hr after incubation IAA peroxidase and catalase activities appeared high at rooting zone while IAA oxidase activity was low at both ends, IAA oxidase and peroxidase activities declined at the rooting zone during the adventitious root formation at 48 ht. Inversion of cuttings during preincubation caused a chrange of enzyme activities along their epicotyl cuttings. Only peroxidase activity showed a high correlation with root initiation. Therefore, the biochemical change is highly correlated with change in IAA level in the rooting zone of the epicotyl, resulting in root formation in unusual rooting zone of epicotyl.

• Journal of Plant Biology
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• v.31 no.3
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• pp.239-247
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• 1988

Spermidine, spermine and IAA promoted an increase in $\beta$-1, 4-endoglucanase activity in hypocotyls of Glycine max. The optimal concentration for the increase of the enzyme activity was 10-6 M for spermidine, 10-8 M for spermine and 10-6 M for IAA. However, IAA had innocuous effect on arginine decarboxylase and ornithine decarboxylase activites, and the content of polyamine. Such cumulative results suggest that the increase in $\beta$-1, 4-endoglucanase activity by IAA is not attributed by the effect on the biosynthesis of polyamine by IAA but spermidine, spermine and IAA induce cell wall loosening and therefore extension growth of cells.