• Journal of Bio-Environment Control
• /
• v.18 no.2
• /
• pp.153-159
• /
• 2009

This study was carried out to investigate effect of $GA_{3}$ foliar application on the growth and flowering of Limonium spp. 'Ocean Blue' to develop an effective $GA_{3}$ treatment method for a year round commercial production. Plants were treated with different concentrations of $GA_{3}$ 0, 100, 200, 400, and 800 mg.$L^{-1}$ in summer, and 0, 100,200, and 400 mg.$L^{-1}$ in winter at seven weeks after transplanting. The effects of $GA_{3}$ treatment time (0, 10, 20, 30, 40, and 50 days after planting) and plant age (raising during 3, 5, 7, and 9 weeks) was investigated. The $GA_{3}$ treatment advanced bolting and flowering with little difference between the two seasons. In a summer culture the effective concentration of $GA_{3}$ ranged from 200 to 400 mg. $L^{-1}$, while in winter it was found to be 400 mg. $L^{-1}$. The $GA_{3}$ treatment at 10 days after planting significantly reduced days to flowering. However, the greatest cut flower yield was observed in plants treated at 20 days after planting. The $GA_{3}$ treatment to different age plants did not show a significant effect, except in the oldest (nine weeks old plants). In conclusion, to induce early flowering in Limonium spp. 'Ocean Blue', the proper concentration and time of application of $GA_{3}$ was 400 mg.$L^{-1}$ $GA_{3}$ treated to nine weeks old plants at 20 days after transplanting.

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

• Journal of Apiculture
• /
• v.34 no.3
• /
• pp.197-206
• /
• 2019

Pollination is an important ecosystem service involved in plant breeding and reproduction. This study analyzed the pollination network, which is the interaction between flowering plants and flower-visiting insects in the agricultural landscape. Flower-visiting insects from blossoms of flowering crops and surrounding plants were quantitatively surveyed during summer time. The pollinator species and abundance on each flowering plant were analyzed. A total of 2,381 interactions were indentified with 154 pollinators on 30 species of plants. Species richness of the pollinators was highest in Coleoptera (34%) followed by Hymenoptera (28%), Diptera (28%) and Lepidoptera (10%). Apis mellifera dominated (50%) followed by Calliphora vomitoria (5.3%) and Xylocopa appendiculata among pollinators, and remaining wild pollinators provided complex interaction. Among plants, Platycodon grandiflorum, Perilla frutescen and Fagopyrum esculentum harbored most pollinators and showed highest interaction frequencies. In the modular analysis, Apis mellifera was located as a hub-species which connect the interaction of others, implying most important role in the network. This results provide the basic information on the pollinator species associated with each crop and pollinator habitat in which plant provide the nectar, pollen and habitat resources for wild pollinators.

• Journal of the Korean Society of Tobacco Science
• /
• v.18 no.2
• /
• pp.126-131
• /
• 1996

In this study effects of isolation distance, transplanting time of maternal plants, and bagging of flower head with the gauze-cloth bag on the outcrossing of burley tobacco (Nicotiana tabacum L.) were investigated. Also the effect of fertilizer level and control of the number of capsules per plant on seed production and quality were examined. A male sterile line. produced 0.3 to 3.8 capsules Per plant when it was Planted with normally flowering tobacco with the average outcrossing of 7.2 plants, ranging from 2 to 18 out of 20 plants. With the farther the isolation distance between maternal plants and pollen donor plant, the lower the outcrossing occurred. Outcrossing occurred even at the isolation distance of 312 m. When the maternal plants were transplanted 35 days after transplanting the pollen donor ones, the outcrossed plants were not decreased significantly. The bagging of the flower head with the gauze-cloth bas (#0.9∼ 1.0 mm) decreased the outcrossed plants significantly, but couldn't prevent the outcrossing completely. The seed amount per plant was higher in the highly fertilized cultivation. The number of seed capsules per plant affected significantly on seed yield and quality. When the seed capsules was controlled by 30 or 50 capsules per plant, the weight of 1,000 seeds and germination rate were higher than those with 70 or 90 capsules per plant. Key words : Nicotiana tabacum, outcrossing, bagging.

• Journal of Plant Biotechnology
• /
• v.36 no.4
• /
• pp.366-372
• /
• 2009

This study was conducted to develop new lines expressing the characteristic of early flowering by introducing MdMADS2 gene in chrysanthemum (Dendranthema grandiflorum (Ramat.) Kitamura) ‘Zinba'. Transformation of chrysanthemum was conducted by Agrobacterium tumefaciens LBA4404 harboring the binary vector containing MdMADS2 controlled by double CaMV 35S promoters. Ninety three shoots were regenerated from 1,463 leaf segment explants cultured on the first selection medium (MS basal salts + 1.0 mg/L BA + 0.5 mg/L IAA + 10 mg/L kanamycin + 400 mg/L cefotaxime, pH 5.8) after co-cultivation, and 20 out of the 93 shoots rooted on the second selection medium containing 20 mg/L kanamycin and 400 mg/L cefotaxime. Many escapes (98.6%) were removed on the selection stage for rooting. Nineteen lines were confirmed as transgenic plant with transgene by PCR analysis. Six transgenic plants flowered 2-11 days earlier than non-transgenic plant without big change of phenotype, and especially, 3 (Mo-7, Mo-11, Mo-17) out of 6 transgenic lines showed a significant reduction in days to flowering compared to non-transgenic plant. Introduction and expression of MdMADS2 gene in them were confirmed by Southern and real-time PCR analyses, respectively.

• The Korean Journal of Ecology
• /
• v.26 no.4
• /
• pp.189-197
• /
• 2003

Properties of seed production in Corydalis, spring ephemeral, group were studied during two years at Namhansansung area. Corydalis´ flower was out in the early April and its seed dispersed in the early May. The period of total seed production was 30 days. The decrease rate of sex organs was the highest between deflowering time and early fruiting time. The numbers of flower and seed per plant were in the range of 1∼13 and 0∼76, respectively. And the number of seed per fruit was from zero to twenty. In a plant, seed production was the most (11.8 seeds) in the lowest fruit and conspicuously decreased along the upward fruit. In the same plant, seed production was various by each year. The plants of small tuber size produced more seeds and those of large tuber size produced fewer seeds in the next year than this year. In the early growth season, the flowering plants/total plants rate increased in proportion to plant size (tuber volume), the rate of the smallest size class (<100 ㎣) was in the range of 5.0%(1999)∼5.4%(2000), those over the 600 ㎣ size classes were 100%. The number of flower per plant at the same size class were higher in 2000 than in 1999. Especially, at the size class of 900 ㎣≤, the numbers of flower per plant were 13.2 in 2000 and 6.5 in 1999. In the late growth season, the flowering plants/total plants rates were 13.3%in the smallest size class (<100 ㎣)and 100% over the 500 ㎣ size classes. Therefore, the flowering plants/total plants rates along the size classes were higher in the late growth season than in the early one. The bumer of fruit or seed per plant increased in proportion to the volume and dry weight of tuber, there was not significant and varied along each plant in the same size class. The number of fruit or seed per plant conspicuously increased in proportion to the leaf area. Therefore, it was thought that seed production was related to photosynthetic ability during growth season.

• Plant Biotechnology Reports
• /
• v.3 no.2
• /
• pp.111-126
• /
• 2009

MicroRNAs (miRNAs) are endogenous, non-coding, small RNA molecules consisting of 21-24 nucleotides (nts) that regulate target genes at the posttranscriptional level in plants and animals. In plants, miRNAs negatively regulate target mRNAs containing a highly complementary sequence by either mRNA cleavage or translational repression. MiRNAs are processed from single-stranded precursors containing stem-loop structures by a Dicer-like enzyme and are loaded into silencing complexes, where they act on target mRNAs. Although plant miRNAs were first reported in Arabidopsis 10 years later than animal miRNAs, numerous miRNAs have since been identified from various land plants ranging from mosses to flowering plants, and their roles in diverse aspects of plant developmental processes have been characterized. Furthermore, most of the annotated plant miRNAs are evolutionarily conserved in various plants. In particular, recent functional studies using Arabidopsis mutants have contributed a great deal of information towards establishing a framework for understanding miRNA biogenesis and functional roles. Extensive appraisal of miRNA-directed regulation during a wide array of plant development and plant responses to environmental conditions has confirmed the versatile roles of miRNAs as a key component of plant molecular biology.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.2
• /
• pp.297-305
• /
• 2003

The family of lemnacae colloquially known as duckweed contains the world' smallest species of flowering plants (macrophytes). Aquatic and free-floating, their most striking qualities are a capacity for explosive reproduction and an almost complete lack of fibrous material. They are widely used for reducing chemical loading in facultative sewage lagoons, but their greatest potential lies in their ability to produce large quantities of protein rich biomass, suitable for feeding to a wide range of animals, including fish, poultry and cattle. Despite these qualities there are numerous impediments to these plants being incorporated into western farming systems. Large genetically determined variations in growth in response to nutrients and climate, apparent anti-nutritional factors, concerns about sequestration of heavy metals and possible transference of pathogens raise questions about the safety and usefulness of these plants. A clear understanding of how to address and overcome these impediments needs to be developed before duckweed is widely accepted for nutrient reclamation and as a source of animal feed.

• Journal of Plant Biotechnology
• /
• v.1 no.1
• /
• pp.56-60
• /
• 1999

Sexual reproduction is an essential process in the propagation of flowering plants. Recent advances in plant cell biology and biotechnology have brought new and powerful methodologies to investigate and manipulate the reproductive processes of angiosperms including agronomically important crop plants. Successful cryopreservation of maize, rye and triticale pollen and young embryos of microspore-and zygote-origine contributes to long term preservation of important plant germ-lines in gene banks. Discovering morphogenetic characteristics of the different developmental pathways taking place in wheat and maize androgenesis in vitro helps to influence the procedure to produce genetically and phenotipically stable homozygous doubled haploid plants for breeding purposes. Detailed ultrastructural and cell-biological studies on the developmental sequences of male and female gametophyte development in wheat, experimental protocols developed to isolate and micromanipulate egg cell protoplasts, make it possible to use plant gametes and the sexual route itself to produce genetically improved organisms. Plant gametes can become useful tools for crop improvement in the near future. Recent achievements by our laboratory in this field are reviewed in the present paper

• Journal of Plant Biology
• /
• v.20 no.1
• /
• pp.45-52
• /
• 1977

During the period of 1975-76, a survey was carried out to find out zinc indicators in the natural vegetation in Korea. The symptoms fo chlorosis were observed in flowering plants in the areas of zinc outcrop of Wolgok-A, Seokgok-9, and Sowolgok. Although 28 species were found to be chlorotic, the total quantity of chlorotic foliage observed was small. Reasons for chlorosis in the areas of zinc are deposits is considered as effects of zinc, lead, copper and calcium ions. Sedum sp. and Dianthus sinensis were confined to soil containing more than exchangeable zinc of 30 ppm and to accumulation in the plants contained at least 1,300-14,000 ppm of zinc. Therefore Sedum sp. and Dianthus sinensis might be used as zinc indicators in Korea.