• Journal of Forest and Environmental Science
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• v.25 no.2
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• pp.111-118
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• 2009

Multiple shoot induction and plant regeneration using apical bud and nodal explants of 100 year old tree of Anthocephalus cadamba, an important sacred and medicinal tree in India was achieved for the first time. Aseptic explants cultured in Murashige and Skoog (MS) medium augmented with different concentrations of BAP (0.1, 0.5, 1.0, 2.5, 5.0 and 10 mg/l), when maintained for 60 days, healthy shoots were induced in presence of BAP (1 mg/l). Lower concentrations of BAP (0.1 - 0.5 mg/l) induced only one shoot per explant. Increase in number of shoots per explant was observed in presence of higher concentrations of BAP (2.5, 5.0 and 10 mg/l). However, elongation of shoots was completely inhibited. Bud break and shoot regeneration was largely associated with seasonal factors. Apical buds cultured during June to August exhibited early bud break within two weeks of initial culture. In rest of the months, bud break and shoot regeneration was very slow irrespective of the various concentrations of BAP used in the medium. Explants sourced from three different maturity levels of shoots indicated that actively growing shoots from the mother plant with 1 - 2 nodal segments was more suitable for culture initiation than the explants collected from mature shoots at dormant stage. Regenerated shoots with 2 - 3 pairs of leaves when transferred to half strength MS medium fortified with IBA (1 mg/l), 60% of the shoots induced healthy roots, indicating the possibility of large scale micropropagation.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.94-99
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• 1997

When the leaf and stem tissues of Rehmannia glutinosa were cultured on MS medium with plant growth regulators, shoots were regenerated on MS medium with TDZ(0.01 to $2.0{\mu}M$), and root initiation was better on MS medium treated with NAA(0.01 to 2.0mg/$\iota$). On $B_5$ medium, shoot regeneration was better on medium with TDZ than those with Quincrac, NAA, and 2.4-D. The addition of Quincrac, NAA, and 2.4-D inhibited shoot regeneration on MS medium, but promoted shoot regeneration on $B_5$ medium. Shoot regeneration and growth was better on MS medium with the combination treatments of 2.4-D 0.01mg/$\iota$ and TDZ 0.01, 0.1 and $2{\mu}M$ compared with other treatments. Also shoot regeneration and growth on B_5 medium showed the similar results to that on MS medium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.14-25
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• 2006

Response of grain yield and milled-rice protein content to nitrogen (N) rates at various growth stages is critical for quantifying real-time and real-amount of applied N requirement for target grain yield and protein content. An experiment including 10 N rate treatments at transplanting, tillering and panicle initiation stages with four rice cultivars in 2003, 6 N treatments with two rice cultivars in 2004 and 2005 was conducted. Increase of N rates at PIS significantly increased both grain yield and milled-rice protein content but increase of N rates at tillering stage significantly increased grain yield but not milledrice protein content. Therefore, high grain yield and low milled-rice protein content would be difficult to obtain only by adjusting N rates at PIS. Internal N use efficiency (INUE) was 60.5 kg grain/kg N accumulation on an average over N treatments, cultivars, and experimental years, showing considerable reduction especially at high shoot N accumulation in the experimental year of low sunshine duration. Milled-rice protein content tended to increase almost linearly with increasing shoot N accumulation, but it revealed big variation even at the same shoot N accumulation at harvest. Milled-rice protein content decreased with increasing INUE. N accumulation in the milled rice increased at an almost constant proportion of 45.5 percent of the shoot N accumulated at harvest, showing slight decresing proportion with the increasing shoot N accumulation.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.195-200
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• 1998

Callus induction from leaf and stem explants of Arabidopsis thaliana was successfully obtained when leaf explants were cultured on MS medium containing 2.0 mg/L 2,4-D in the dark and also, when stem explants were cultured on CP medium containing 0.5 mg/L 2,4-D and 0.1 mg/L BAP. Explant-derived sliced calli were suspension-subcultured every week in CP liquid medium with 0.5 mg/L 2,4-D and 0.1 mg/L BAP in the dark, and shoot-forming cell clusters of nodular, pale yellow and knobby type were selected after 7-8 weeks of culture. Shoots were initiated from the green spots of the selected shoot forming calli cultured on MS regeneration medium containing 0.05 mg/L IAA, 7.0 mg/L 2-iP and 30 g/L sucrose under continous illumination for four weeks. Shoot regeneration frequency (calli regenerating at least one shoot) was more than 50%. For plant regeneration, excised shoots were trnasferred to hormone free medium for root initiation after 4 weeks of culture. The regenerants were bolting after 2 weeks of culture and formed in vitro flowering buds within bracts after 4 weeks of culture.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.207-213
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• 1997

This study was conducted to correlate changes in plant growth and flowering behavior with inhibition of gibberellin synthesis following application of GA biosynthesis inhibitor. Two sorghum genotypes, wild-type and phyB-1(phytochrome B mutant) which grow fast and flowers early relative to the wild-type, were used. Both growth and floral initiation of these two genotypes were greatly affected by ancymidol concentration increased. However, these growth inhibition and delayed flowering are almost completely overcome by simultaneous applications of 31.6ppm $GA_3$. The ability of $GA_3$ to reverse the effect of the inhibition on both growth and floral initiation in sorghum suggests a role for native GAs in sorghum flowering. This result was contrast to the fact that in some long day plants GA biosynthesis inhibitors will inhibit shoot elongation but not floral initiation. In sorghum, inhibition of vegetative growth by GA biosynthesis inhibitor is accompanied by a delay in flowering. Ten ppm of ancymidol treatments drastically reduced all early-13-hydroxylation pathway GAs($GA_{12}$, $GA_{53}$, $GA_{19}$, $GA_{20}$, $GA_3$, and $GA_8$) levels.

• The Journal of Natural Sciences
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• v.4
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• pp.143-159
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• 1991

In order to investigate the micropropagation of Pelargonium, 2 cultivars of P. peltatum 'Pouletta' and P. zonale 'Pinto Red' were cultured in vitro on the MS basal medium supplemented with various concentrations of growth regulators. It attempted to study the induction of callus and the differentiation of organs from leaf disc, petiole segments, stem segments. hypocotyle segments and flower stalk segments. The results are summarized as follows; A. As for the initiation of callus, stem explant was proved to be the most suitable one among various explants of P. zonale 'Pinto Red'. The medium was supplemented with 1.0mg/1 BAP and 1.0mg/1 NAA. As NAA concentration increased, callus formation was enhanced, but higher concentration of NAA inhibited callus fromation. Leaf and hypocotyle explants showed less callus formation than stem and petiole explants. B. In P. zonale 'Pinto Red' petiole culture, the condition of cullus culture such as hormone concentration resulted in affecting shoots differentiation. The best result of shoots formation from the callus reculture were obtained from the combination of 0.5-1.0mg/1 BAP and 0.1-1.0mg/1 NAA when the callus was cultured in 1.0mg/1 BAP and 0.05mg/1 NAA. When the callus was cultured in medium without BAP, the shoot was not differentiated in subculture regardless to BAP and NAA concentration. and only callus was formed. C. Poly-phenol substance was observed in MS medium supplemented without PVP, in which callus was not formed from the leaf of P. peltatum 'Rouletta'. Polyphenol substance was not observed in MS medium supplemented with PVP, in which callus formation was increased. D. The callus formation of P. peltatum 'Rouletta' showed the stem explant being best result. The best result particularly in the stem explant among others. The optimal hormonal concentration was 0.1mg/1 NAA and 5.0mg/1 BAP. The shoot formation was observed at 0.05mg/1 NAA and 1.0mg/1 BAP, 0.1mg/1 NAA and 5.0mg/1 BAP. The shoot was malformed and the tissue recultured turned necrotic.

• Korean Journal of Plant Resources
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• v.23 no.1
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• pp.7-13
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• 2010

This experiment was conducted to establish the micropropagation of Calanthe discolor through multiple shoot formation from the culture of leaf, corm and root explants. Frequency of adventitious shoot formation from leaf explants was higher than those of corms and root explants. Frequency of adventitious shoot formation on medium with various concentrations of BA (0. 1.0, 3.0, and 5.0 mg/L) and NAA (0, 0.1, 0.5, and 1.0 mg/L) was tested. The maximun induction of adventitious shoot was obtained on half strength Murashige and Skoog (MS) medium supplemented with 3.0 mg/L BA and 1.0 mg/L NAA after 6 weeks of culture. Multiple shoots were transferred onto half strength MS medium with various concentrations of GA3 (0, 0.1, 0.5, 1.0, 3.0, and 5.0 mg/L). The number and length of multiple shoots on medium were highest on medium with 3.0 mg/L GA3. All the adventitious shoot grew well and rooted on half strength MS medium with 3.0 mg/L NAA. The plantlets were acclimatized up to 100% on sand with TKS-II or pearlite with TKS-II.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.176-176
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• 2017

Hydropriming had positive effects on the time for germination to reach 50%, the germination index, the time to final germination percentage, and the number of uniform seedlings with enlarged cotyledons in in vitro germination of small watermelon. In addition, the highest shoot initiation was obtained from hydroprimed cotyledonary nodes ($95{\pm}6%$), followed by non-primed cotyledonary nodes ($78{\pm}6%$), hydroprimed cotyledons ($72{\pm}4%$), and non-primed cotyledons ($48{\pm}4%$). Meanwhile, no shoots were initiated from hypocotyls. The total number of shoots that initiated from cotyledonary nodes and cotyledon explants was insignificant, indicating that both cotyledons and cotyledonary node were good sources for the in vitro culture. Choosing explant sources that favor tetraploidy should be the key for producing higher polyploidy plants; a total of 10.5% of tetraploid regenerants were entirely identified from cotyledon explants. Cotyledons with highly differentiated cells might show higher variations than cotyledonary nodes with more preexisting meristematic cells. Cells of cotyledon tissue might undergo changes in ploidy level during differentiation of the culture, or it might be that some of the variations were already present in the tissues of the donor plant. Morphological changes in fruit length of tetraploid regenerants are genotype-dependent.

• Journal of Crop Science and Biotechnology
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• v.10 no.1
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• pp.33-38
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• 2007

Nitrogen management at the panicle initiation stage(PI) should be fine-tuned for securing a concurrent high yield and high quality rice production. For calibration and testing of the recommendation models of N topdressing rates at PI for target grain yield and protein content of rice, three split-split-plot design experiments including five rice cultivars and various N rates were conducted at the experimental farm of Seoul National University, Korea from 2003 to 2005. Data from the first two years of experiments were used to calibrate models to predict grain yield and milled-rice protein content using shoot fresh weight(FW), chlorophyll meter value(SPAD), and the N topdressing rate(Npi) at PI by stepwise multiple regression. The calibrated models explained 85 and 87% of the variation in grain yield and protein content, respectively. The calibrated models were used to recommend Npi for the target protein content of 6.8%, with FW and SPAD measured for each plot in 2005. The recommended N rate treatment was characterized by an average protein content of 6.74%(similar to the target protein content), reduced the coefficient of variation in protein content to 2.5%(compared to 4.6% of the fixed rate treatment), and increased grain yield. In the recommended N rate treatments for the target protein content of 6.8%, grain yield was highly dependent on FW and SPAD at PI. In conclusion, the models for N topdressing rate recommendation at PI were successful under present experimental conditions. However, additional testing under more variable environmental conditions should be performed before universal application of such models.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.1
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• pp.35-38
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• 2001

When root initiation ratio of cut Birdsfoot trefoil (Lotus corniculatus L.) stems was examined in several medium conditions containing different IBA concentration, the higher IBA contration of medium was elucidated superior then lower IBA concentration. Highest root initiation ratio was confirmed at 2.5 mg/$\ell$ of IBA and the ratio was 90~95%. When the stems from regenerated shoots from callus were treated at 8 kinds of medium for 12 days, the root iniation result was 9 (45%) at 1/2 SH-0 medium, 10 (50%) at SH-0 medium, 10 (50%) at SH-0.5IBA medium, 10 (50%) at SH-1.0IBA medium, 13 (65%) at SH-1.5IBA medium, 14 (70%) at SH-2.0IBA medium, 19 (95%) at SH-2.5IBA medium and 14 (70%) at SH-3.0IBA medium.