• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.109-115
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• 2000

Effects of the heavy-ion ($^{14}$ N or $^{20}$ Ne) beam irradiation on the response of anthers, growth of calli, germination of seeds, and the early growth after the germination of tobacco (Nicotiana tabacum L. cv. BY-4) were investigated. Anthers precultured for 10 days before the irradiation became brown without callus or shoot induction over 20 Gy of $^{14}$ N and $^{20}$ Ne ion beam irradiation. Relative growth rate of the cultured calli was reduced by the irradiation and became brown significantly 2 weeks after the $^{14}$ N and $^{20}$ Ne ion beam irradiation over 50 Gy. The increased intensity of the heavy-ion ($^{14}$ N, $^{20}$ Ne) beam irradiation resulted in the delay of seed germination and the inhibition of the early growth both in water-treated and non-treated seeds before the irradiation. In addition, the heavy-ion beam irradiation to the imbibed seeds inhibited seed germination more than that to the non-imbibed seeds. The screening approach of non-imbibed seeds with heavy-ion beam irradiation using in vitro culture system was more useful than the filter-paper germination method in investigating the characteristics of heavy-ion beam-irradiated seed population and the screening of morphological variants at the early stage of the plant growth.

• Plant Resources
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• v.8 no.2
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• pp.81-86
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• 2005

An efficient plant regeneration system of Gentiana scabra through somatic embryogenesis was established. Leaves and roots of seedlings of Gentiana scabra excised after germination were cultured on MS basal medium with 2,4-D, NAA or BA. Embryogenic callus was obtained on MS medium with 0.5 mg/L 2,4-D alone or 0.1 mg/L 2,4-D combimation with 1.0 mg/L BA after 45 days of culture. These embryogenic calli gave rise to somatic embryos, which subsequently developed into plantlets on MS medium without PGRs. Also, shoots were effectively differentiated from embryogenic callus when root segments were cultured on MS medium supplement with 0.1 mg/L 2,4-D and 1.0 mg/L BA. Shoots were effectively rooted on MS medium without PGRs. In vitro flowers were formed from plantlets cultured on MS medium with $5\%$ sucrose after 60 days of culture.

• Journal of Plant Biotechnology
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• v.40 no.3
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• pp.147-155
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• 2013

In this experiment, we report for the first time mass propagation by in vitro mircrotuberization of Codonopsis lanceolata. We first examined the effect of cytokinins on multiple shoot induction. 2.0 $mg{\cdot}L^{-1}$ of kinetin not only gave the highest rate of shoot induction (19.1%) but also the elongation of shoot (17.1 mm). Secondly, we investigated the effect of sugars on in vitro microtuberization from nodal segments. The diameter of tuberous roots was enlarged in the half-strength MS medium supplemented with 145.9 mM sucrose. Histological analysis revealed that the number of parenchymatous cell containing starch grains increased in the tuberous roots. In addition, unlike in non-tuberous root, vascular bundles were scattered inner cortex layer. Thirdly, in order to preserve and stimulate the germination, microtubers were stored at $4^{\circ}C$ refrigerator during 9 months and then transplanted to the artificial soils (vermiculrite : peatmoss = 1:1 v/v), resulting that the rates of survival and germination were 75% and 70%, respectively. These results indicated that mass propagation of C. lanceolata was achieved by in vitro microtuber formation, suggesting that this protocol might be applied for not only the propagation of elite clones but also conservation of C. lanceolata germplasm.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.1
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• pp.17-25
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• 2015

The following experiments were used to evaluate the effect of seeding method and pre-emergence herbicides on weed control and the production of the $sorghum{\times}sudangrass$ [sorghum bicolor (L.) Moench] hybrid under field and in vitro conditions. Under the in vitro condition, we evaluated how different kinds of herbicides affect the rate of seed germination and the growth of early seedlings in the $sorghum{\times}sudangrass$ hybrid treated with herbicides. Simazine, alachlor, and methabenzthiazuron were used, and their concentration levels were 0%, 40%, 70%, and 100%. The germination ratio of the seeds was reduced by the application of simazine, methabenzthiazuron, and alachlor compared with the control (distilled water). The alachlor application severely decreased the sorghum germination ratio. However, seed germination was not greatly influenced by the concentration level of the herbicides. Root and shoot length were increased in the following order: control > simazine > methabenzthiazuron > alachlor. Overall, alachlor significantly reduced root length more than shoot length. The differential tolerance of the $sorghum{\times}sudangrass$ hybrid to pre-emergence herbicides by seeding method was then tested under the field condition. The plants were severely injured by the alachlor application, leading to a great reduction in the number of stems. However, for the simazine and methabenzthiazuron applications the number of stems lost was slightly lower than it was for the alachlor and simazine + alachlor applications. In the seeding method, drilling was more effective in reducing herbicide injury than broadcasting. All of the herbicides effectively controlled weeds. The simazine and methabenzthiazuron applications showed a significantly higher dry matter (DM) yield. However, the alachlor and simazine + alachlor applications severely reduced the DM yield. This result suggests that the alachlor application has a significant effect on plant production. Similarly, the total digestible nutrient (TDN) yield was greatly reduced by the alachlor and simazine + alachlor applications. From the results presented above, we concluded that the yield of DM was the highest for broadcasting with no herbicide. and drilling was the most-effective way to reduce herbicide injury. The simazine application was the most-effective herbicide, showing the highest forage yield and TDN yield.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.16-16
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• 2019

The Cassava (Manihot esculenta Crantz) is a perennial woody shrub cultivated mainly in the tropics for its starchy tuberous roots. It belongs to the family Euphorbiaceae which also includes rubber (Hevea brasiliensis) and castor bean (Ricinus communis). Among tropical crops, rice, sugarcane, maize and cassava are the most important sources of calories for human consumption. Problems in the propagation of cassava are virus diseases and low rates of seed germination. Thus, a study was undertaken to develop an efficient in vitro mass propagation protocol of Manihot esculenta Crantz. Young and actively growing stem segments were excised from adult plants of cassava. Samples were cut into a 3~4 cm nodal segments with single node after sterilization, and cultivated in the different medium supplemented with various plant growth regulators for 4 weeks. For shoot multiplication, single-node stem segments, approximately 1 cm in length, were taken from in vitro derived shoots and subcultured. After 4~6 weeks, the shoot generation rate was 55.6%, the shoot number and its length were 1.0/explant and 2.3 cm in the most favorable medium composition. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• Journal of Plant Biology
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• v.9 no.1_2
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• pp.17-21
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• 1966

The mutual relationships of boron, Ca and sucrose were studied in relation to in vitro pollen growth and pollen bursting, by using conventient pollen from Crinum asiaticum for experiment. Crinum pollen are paticularly sensitive to Ca. Addition of very small amount of boron to cultural media was apparently synergistic to the action of sucrose and Ca in pollen germination and tube elongation. This action was extended to a higher level of boron concentraton. Combined application of boron, Ca and sucrose always gave the better results in pollen growth and protection against pollen bursting much more than when used singly. This indicated that there is a direct relationship between better growth of pollen and increased rigidity of pollen cell wall. A higher level of Ca concentration tended to increase bursting rate of pollen grains and decrease that of pollen tubes, while boron always depressed the rate of bursting. This was considered due to increased failure in pollen germination at high level of Ca that favors pollen tube elongation. The fact that Ca show an antagonistic effect on the suppressive action of high level of boron in pollen growth and shows different effect in response to pollen bursting from boron, suggested mode of Ca and boron action in the presence of sucrose is quiate different, although to increase in rigidity of pollen cell wall by them is in common nature. It was postulated therefore that Ca acts on pectins of pollen cell wall largely as "non-metabolic" and boron as "metabolic" promoter is pollen growth and protecting pollen bursting, since boron and Ca have common nature in strengthening the pollen cell wall but act differently.but act differently.

• Journal of Microbiology
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• v.34 no.4
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• pp.374-378
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• 1996

In the aquatic fungus Allomyces macrogynus the effects of $Ca^{2+}$ and cAMP on the intracellular signal transduction of zoospore germination were studied using in vitro protein phosphorylation assay system. An endogenously phosphorylated protein (p50) having molecular weight of 50 kDa on SDS-PAGE was found in soluble fractions of both zoospore and mycelium. In zoospore extract, the endogenous phosphorylation of p50 was weak without any effectors, but was enhanced by $Ca^{2+}$ and even more by cAMP. Phosphorylation of the same protein in mycelial extract was high only in the absence of cAMP. Irrespective of the presence of $Ca^{2+}$ and cAMP, its phosphorylation was antagonistically suppressed in assay of combined zoospore and mycelial extracts. These results suggest that p50 is interconvertible in phosphorylation/dephosphorylation as a novel protein involved in germination of A. macrogynus. The antagonistic effect of cAMP to the phosphorylation of p50s from different developmental stages may be important in the regulation of cellular differentiation.

• Mycobiology
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• v.39 no.1
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• pp.26-32
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• 2011

Powdery mildew is one of the most devastating diseases in cucurbits. Crop yield can decline as the disease severity increases. In this study, we evaluated the effect of silver nanoparticles against powdery mildew under different cultivation conditions in vitro and in vivo. Silver nanoparticles (WA-CV-WA13B) at various concentrations were applied before and after disease outbreak in plants to determine antifungal activities. In the field tests, the application of 100 ppm silver nanoparticles showed the highest inhibition rate for both before and after the outbreak of disease on cucumbers and pumpkins. Also, the application of 100 ppm silver nanoparticles showed maximum inhibition for the growth of fungal hyphae and conidial germination in in vivo tests. Scanning electron microscope results indicated that the silver nanoparticles caused detrimental effects on both mycelial growth and conidial germination.

• The Korean Journal of Mycology
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• v.16 no.1
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• pp.1-8
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• 1988

Effect of suppression for zoosporangial germination and mycelial growth of Phyto­phthora capsici causing red pepper fruit rot, was carried out in vitro test by using $NH_4OH$ and $KNO_2$, as ammonium/ammonia, nitrite/nitrous acid and $CaCl_2$, as calcium ion. Results of in vitro tests with $NH_4OH$, $KNO_2$, and $CaCl_2$, mol solutions demonstrated that zoosporangial germination of P. capsici was inhibited about 15 to 50% compared with control, according to $NH_3$, HNO as nonionized form and $Ca^{+2}$ ions. Ammonia concentration$(NH_3)$ was proportionally increased by high pH level and mol concentration, whereas low pH and high mol concentration showed rather higher concentration of $HNO_2$. Ammonia were more toxic at pH 8 than at pH 7 under the same concentration, while nitrous acid$(HNO_2)$ was more toxic than at pH 8. The zoosporangial germination inhibition in the ammonium/ammonia and nitrite/nitrous acid solutions demonstrated that $NN_3$, and $HNO_2$, were primarily responsible for the inhibition at lower concentration and mor" toxic by increasing concentration. $Ca^{+2}$ ions showed that zoosporangial germination was inhibitory by high pH level and increasing mol concentration in comparison with buffer conlrol. pH levels affected to mycelial growth of the fungus, and especially, high pH caused rather retardation of mycelial growth. There was no definite inhibitory response of mycelial growth at various degree concentrations of the toxicant solutions.

• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1578-1583
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• 2008

Rhizobacteria are used as inoculants to enhance crop yield and for biological control of fungal pathogens. Fluorescent pseudomonads isolated from the rhizosphere of groundnut showed suppression of the phytopathogen Macrophomina phaseolina that causes charcoal rot of groundnut, an economically important agroproduct. Two strains of fluorescent pseudomonads, designated as PS1 and PS2, were selected as a result of in vitro antifungal activity. After 5 days of incubation at $28{\pm}1^{\circ}C$, both PS1 and PS2 caused clear inhibition zones in dual cultures, restricting the growth of M. phaseolina by 71 % and 74%, respectively. Both the strains were capable of producing siderophores, indole acetic acid, and hydrocyanic acid, and causing phosphate solubilization under normal growth conditions. These strains, when used as inoculants in groundnut, enhanced germination up to 15% and 30% with subsequent increase in grain yield by 66% and 77%, respectively. Conversely, when the pathogen alone was tested 57% decrease in yield was recorded. Thus the studies revealed the potential of the two pseudomonads not only as biocontrol agents against M. phaseolina, but also as a good growth promoter for groundnut.