• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.443-448
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• 2001

This study was carried out to obtain the basic informations on the characteristics of gametophytes formation and microspore germination in Astragalus membranaceus Bunge. Pollen mother cells passed through meiosis when the flower bud length reaches around 3.5 mm, thus creating the tetrad when it is 4.0 mm long. Pollen attains full growth when the bud is about 10.0 mm long and the anther is found to dehisce when the length of tate bud reach around 12.0 mm. Embryo sac develops at a similar speed as pollen did and it attains its full growth when the bud is about 10-12 mm long. After being stored at 4$^{\circ}C$ or -4$^{\circ}C$, the pollen maintained its germination ability to almost full extent by the 30th day after store. However, the germination rate at room temperature (23~28$^{\circ}C$) decreased below 3％ by the 3rd day of storage and so did the germination speed.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.56-59
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• 2014

Apex removal is a common practice in artichoke cultivation to harvest heads of lateral shoots. This experiment was carried out to investigate the effect of apex removal by different planting times on the growth and yield of Artichoke (Cynara scolymus L.) in open field. Two treatments (apex removal and no apex removal) at three different planting times ($1^{st}$: Sep. 27, 2011, $2^{nd}$: March 29, 2012, and $3^{rd}$: Sep. 21, 2012) were tested using 'Green Globe' variety. There was no difference in the head characteristics and the number of harvested head between the treatments. The head weight was heavier in no apex removal of 242.7 g than the apex removal of 170.8 g. The yield also increased in no apex removal by 25% (1,249 kg/10a) compared to the apex removal of 997 kg/10a at the first planting time. At the second planting time, there was no difference in the head weights between the treatments. But the number of the harvested head was higher in no apex removal with 10.8 than 8.2 of the apex removal. The yield of no apex removal was 2,660 kg/10a, which was higher than 1,848 kg/10a of apex removal. At the third planting time, the head weight increased in no apex removal with 253.5 g compared to the apex removal with 218.7 g. The yield of no apex removal was 1,405 kg/10a, which was higher than 1,148 kg/10a of the apex removal. All the tests at 3 different planting times showed that the artichoke yields were higher in no apex removal than in apex removal. Therefore, it is desirable to cultivate artichoke without removing the apex for the higher yield and labor saving in open-field cultivation in Jeju island.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.242-246
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• 2006

This study was showed into the pollen development with in vivo by bud size and genotype. Microspores of buds from 2.0 mm to 2.5 mm of all genotypes were composed of mainly tetrad cells and early uninucleate stage cells. Microspores derived from buds of 2.5-3.0 mm were exposed cells of early uninucleate, middle uninucleate, and late uninucleate. Microspores from buds of 3.0-3.5 mm contained mostly late uninucleate stage cells and showed some early binucleate stage cells. Microspores of buds with 3.5-4.0 mm in length were composed of mainly binucleate stage cells and decreased late uninucleate stage cells. Microspore with more than 4.0 mm were entered into binucleate stage cells of divided generative nucleus and vegetative nucleus. In 'Tamlayuchae', microspores derived from buds of 3.5-4.0 mm were observed cells of late uninucleate stage and early binucleate stage because of late microspore development. In MS-maintainer, the spring type, microspore derived from buds of 2.5-3.0 mm were observed tetrad stage cells.

• Korean Journal of Medicinal Crop Science
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• v.6 no.3
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• pp.193-197
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• 1998

This experiment was carried out to determine the proper time for flower bud removing to improve growth, yield and paeoniflorin content of root in peony(Paeonia lactiflora Pallas). The flower buds removement caused short stem length by $7{\sim}9cm$ compared with control, but number of stem and stem diameter were similar to that of control. The number of root, fresh root weight and paeoniflorin content in peony increased when their flower buds were removed at earlier stages. The root dry weight was highest of 1.647kg/10a, and increased by 27% compared with control when their flower buds were removed at early stage (bud diameter was less than 10mm). The root dry weight increased by 13% and 10%, respectively. when their flower buds were removed prior to flowering and at flowering stage. Paeoniflorin content in leaf was higher than that in stem, and was higher at early stage. Leaf and stem showed higher paeonif1orin content when their flower buds were removed.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.21-25
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• 2004

This experiment was carried out to investigate the effect of apex removal at different leaf ages on the growth and yield of broccoli in pinching cultivation. Apex was pinched when 2, 3 or 4 true leaves were spread during nursery bed, and non-pinching was conventional method. The plant height was not different among treatments but the fresh weight was decreased as the pinching days were delayed. The numbers of leaves and lateral shoots were increased compared to those of non-pinching by pinching. Days to central budding were shortended by 3 days when pinched at 2 true leaves spreading stage than those of non-pinching. Central (1st) head weight was heaviest when pinched at the time of 2 true leaves spreading (157g). Total head weight was heaviest when pinched at the time of 2 true leaves spreading (378g), and lowest at 4 true leaves spreading stage (196g). Marketable yields were increased by 48% when pinched at the time of 2 true leaves spreading (1,754kg) as compared with those of non-pinching (1,184kg) and lowest when pinched at the time of 4 true leaves spreading (820kg). Also, first harvest was shortended by 6 days by pinching at 2 true leaves spreading stage.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.268-269
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• 2000

• Research in Plant Disease
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• v.23 no.2
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• pp.202-205
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• 2017

Pink rot appeared in greenhouse-grown sunflower (Helianthus annuus L.) in Jeonju, Korea. The symptoms appeared as brown discoloration of sunflower head and progressed into stem in advanced stage. In order to investigate the causal organism of this disease, we isolated a fungus from the infected seeds and maintained the isolated fungal culture on potato dextrose agar medium. Conidiophores were simple or branched, 62.5 to $123.1{\mu}m$ long. Conidia were produced in basipetal chains, ellipsoidal to pyriform with oblique and prominent truncate basal scars, two-celled, hyaline and measured $10.2-21.4{\times}7.5-12.6{\mu}m$. The fungus was inoculated to a new sunflower plant and showed the typical blight on the leaves. Study of morphological characters, pathogenicity tests and sequence analysis revealed that the isolated fungus is confirmed to be Trichothecium roseum. To our knowledge, this is the first report of pink rot on sunflower caused by T. roseum in Korea.

• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.189-195
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• 1999

This study was carried out to clarify several factors affecting embryogenesis from anther culture of nine cultivars in Brassica oleracea L. var. italica and to investigate the characteristics of plants derived from anther culture. Androgenesis from anther culture was elevated on the B5 medium supplemented with 0.1mg/L NAA, 0.1mg/L 2.4-D and 10% sucrose. Embryo production in liquid medium was five-fold higher than solid medium. High temperature treatment at 35$^{\circ}C$ for one day before transfer to culture room maintained at $25^{\circ}C$ had effective to induce embryogenesis of cultured anthers but extended treatment at 35$^{\circ}C$ decreased significantly the percent of embryogenesis. Frequency of embryogenesis from cultured anthers exhibited significant difference from 2.8% in 'Green Valiant' to 21% in 'Haisi' as affected by genotypes. Percent of spontaneously dihaploid among regenerated plants from anther culture was ranged from 62 to 74% as affected by the genotypes. Characteristic in relation to plant height, number of leaves and branches, and size of head from anther-derived plants showed differential variation in 'Rokguray' and 'Haisi'. Among these charaters obtained from two cultivars, five lines were selected for early maturity, long plant height and large head. Selected lines were used as breeding meterials for F$_1$ hybrid.

• Korean Journal of Plant Resources
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• v.20 no.4
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• pp.367-374
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• 2007

This study was carried out to establish the micropropagation system of Bupleurum latissimum Nakai that is a Korean native endangered species. Callus were induced from the leaf, petiole and floral bud and the percentage of callus formation was highest in the floral bud on the MS medium containing 2.0 mg ${\cdot}$ $L^{-1}$ 2,4-D. Especially, callus induced from floral bud was formed 77.8% and the percentage of shoot formation was 42.6% on the MS medium containing 2.0 mg ${\cdot}$ $L^{-1}$ 2,4-D plus 1.0 mg ${\cdot}$ $L^{-1}$ TDZ. For simultaneously callus formation and shoot regeneration, 1/2 MS medium was more effective than MS medium. The percentage callus formation, shoot regeneration and rooting were 46.3%, 13.0%, 13.0% in 1/2 MS medium, respectively. Soot regeneration from callus was good in 1/2 MS medium supplemented with 2.0 mg ${\cdot}$ $L^{-1}$ 2,4-D plus 1.0 mg ${\cdot}$ $L^{-1}$ BA where percentage of shoot regeneration was 74.1 %, and the number of shoot per explant was 2.4. The percentage of rooting was lowest (57.8%) in control while it was highest (97.8%) in 1.5 mg ${\cdot}$ $L^{-1}$ NAA. In acclimatization of regenerated plantlets, the percentage of survived plantlets was highest (86.1%), and plant height, root length and fresh weight were good in the soil for horticulture.

• Korean Journal of Agricultural Science
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• v.27 no.2
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• pp.86-94
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• 2000

This study was carried out to determine the effectiveness of uniconazole in ameliorating low and high temperature injury in tomato plants(Lycopersicon esculentum Mill. cvs. Fireball and Patio). Plants were given a soil drench of 0, 0.001, 0.01 or $0.1mg{\cdot}pot^{-1}$ uniconazole, and after 14 days, were treated with 12-h day/12-h night cycles at $25/25^{\circ}C$, $2.5/25^{\circ}C$, $25/2.5^{\circ}C$ or $40/40^{\circ}C$ for 4 days in controlled-environment chamber. Number of damaged leaves per plant, reduction of stem elongation, and overall injury were high at $2.5/25^{\circ}C$, but more reduction of leaf elongation, delay of flowering, and abortion of floral bud were observed in plants at $40/40^{\circ}C$. There was difference in degree of injury between cultivars, thus, 'Fireball' was much affected by unfavorable temperature regimes. All concentrations of uniconazole reduced leaf and stem elongation, increased total chlorophyll concentration, delayed flowering, and significantly provided protection against low and high temperature injury in two cultivars. In general, the application of uniconazole did not inhibit flowering delay and floral bud abortion induced by high and low temperature exposure. Our results support the hypothesis that the role of uniconazole is related to defense system against oxidative stress induced by low temperature stress. Further research is required to clarifu the phytoprotective mechanism of this compound agaist high temperature stress.