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Toyoki Kozai - One of the best experts on this subject based on the ideXlab platform.
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commercial application of a photoautotrophic micropropagation system using large vessels with forced ventilation Plantlet growth and production cost
2004Co-Authors: Yulan Xiao, Toyoki KozaiAbstract:A photoautotrophic or sugar-free medium micropropagation system (PAM) using fi ve large culture vessels (volume = 120 L each) with a forced ventilation unit for supply- ing CO 2 -enriched air was developed and applied to commercial production of calla lily (Zantedeschia elliottiana) and china fi r (Cunninghamia lanceolata) Plantlets. The culture period of calla lily Plantlets in the PAM was reduced by 50%, compared with that in a conventional, photomixotrophic micropropagation system (PMM) using small vessels each containing a sugar-containing medium. Percent survival ex vitro of calla lily Plantlets from the PAM was 95%, while that from the PMM was 60%. The production cost of calla lily in the PAM was reduced by about 40%, compared with that in the PMM, and the initial investment per Plantlet for the PAM was ≈10% lower than that for the PMM. The sales price of ex vitro acclimatized calla lily Plantlet was increased by 25% due to its higher quality, compared with Plantlets produced in the PMM.
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photoautotrophic culture of coffea arabusta somatic embryos development of a bioreactor for large scale Plantlet conversion from cotyledonary embryos
2002Co-Authors: F Afreen, S M A Zobayed, Toyoki KozaiAbstract:Somatic embryos were developed from in vitro-grown leaf discs of Coffea arabusta in modified Murashige and Skoog medium under 30 micromol m(-2) s(-1) photosynthetic photon flux (PPF). Cotyledonary stage embryos were selected from the 14-week-old cultures and were placed under a high (100 micromol m(-2) s(-1) PPF for 14 d. These pretreated embryos were grown photoautotrophically in three different types of culture systems: Magenta vessel; RITA-bioreactor (modified to improve air exchange); and a specially designed temporary root zone immersion bioreactor system (TRI-bioreactor) with forced ventilation. The aims of the study were to achieve large-scale embryo-to-Plantlet conversion, and to optimize growth of Plantlets under photoautotrophic conditions. The Plantlet conversion percentage was highest (84 %) in the TRI-bioreactor and lowest in the modified RITA-bioreactor (20 %). Growth and survival of converted Plantlets following 45 d of photoautotrophic culture in each of the three culture systems were studied. Fresh and dry masses of leaves and roots of Plantlets developed in the TRI-bioreactor were significantly greater than those of Plantlets developed in the modified RITA-bioreactor or Magenta vessel. The net photosynthetic rate, chlorophyll fluorescence and chlorophyll contents were also highest in Plantlets grown in the TRI-bioreactor. Normal stomata were observed in leaves of Plantlets grown in the TRI-bioreactor, whereas they could be abnormal in Plantlets from the modified RITA-bioreactor. Survival of the plants after transfer from culture followed a similar pattern and was highest in the group grown in the TRI-bioreactor, followed by plants grown in the modified RITA-bioreactor and Magenta vessel. In addition, ex vitro growth of plants transferred from the TRI-bioreactor was faster than that of plants from the other culture systems.
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number of air exchanges sucrose concentration photosynthetic photon flux and differences in photoperiod and dark period temperatures affect growth of rehmannia glutinosa Plantlets in vitro
2000Co-Authors: Eunjoo Hahn, Toyoki Kozai, Kee-yoeup PaekAbstract:Rehmannia glutinosa Plantlets were cultured for 4 weeks under different culture conditions to determine the optimum environment for in vitro growth and ex vitro survival. Plantlet growth increased with an increasing number of air exchanges of the culture vessel, exhibiting greatest shoot weight, total fresh weight, leaf area, and chlorophyll content at 4.4 h−1 of air exchanges. High sucrose concentration (30 g l−1) increased root weight but reduced shoot growth. Net photosynthetic rates of the Plantlets were greatest when sucrose was not added to the medium. On the other hand, ex vitro survival of the Plantlets was not influenced by sucrose concentration. In the experiment on difference in photoperiod and dark period temperatures (DIF) and photosynthetic photon flux (PPF), Plantlet growth increased as DIF and PPF levels increased. Particularly, increasing PPF level had a more distinctive effect on Plantlet growth than increasing DIF level. The interaction of DIF × PPF was also significant, showing the greatest Plantlet growth in positive DIF (+8 DIF) and a high PPF (210 μmol m−2 s−1). In conclusion, the results of this experiment suggest that increased number of air exchanges of the culture vessel, decreased sucrose concentration, and positive DIF in combination with high PPF level enhanced growth and acclimatization of Rehmannia glutinosa Plantlets.
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effect of the difference between photoperiod and dark period temperatures and photosynthetic photon flux density on the shoot length and growth of potato Plantlets in vitro
1992Co-Authors: Toyoki Kozai, Sunao Kushihashi, Chieri Kubota, Kazuhiro FujiwaraAbstract:Potato Plantlets (Solanum tuberosum L. cv. Benimaru) under CO2 enriched and photoauto-trophic culture conditions were subjected to three different photo-/dark period temperature combinations (25°/15°C, 20°/20°C and 15°/25°C) and two levels of photosynthetic photon flux densities (74 and 147 μmol-m -2.sec-1). The shoot length of the Plantlets under the same photosytnthetic photon flux density (PPF) was reduced with decreasing the difference between photoperiod and dark period temperatures (it is named DIF, photoperiod temperature minus dark period temperature). No marked differences in the fresh and dry weights per Plantlet were observed among the three DIF treatments in each PPF treatment. The higher PPF led to a decrease in the shoot length, an increase in the fresh weight, dry weight and leaf area per Plantlet in each DIF treatment. It is suggested that shoot length of Plantlets in vitro under CO2 enriched and photoautotrophic culture conditions can be controlled without reducing the weight increments and leaf area per Plantlet by regulating the difference between photoperiod and dark period temperatures.
Kee-yoeup Paek - One of the best experts on this subject based on the ideXlab platform.
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mass production of eleutherococcus koreanum Plantlets via somatic embryogenesis from root cultures and accumulation of eleutherosides in regenerants
2005Co-Authors: Soyoung Park, Hosakatte Niranjana Murthy, Jinkwon Ahn, Wiyoung Lee, Kee-yoeup PaekAbstract:Abstract Eleutherococcus koreanum ( E. koreanum ) is an endangered medicinal plant, which has been used for the treatments of rheumatism, diabetes and hepatitis. An in vitro methodology has been developed for mass propagation of E. koreanum by using adventitious root explants in liquid cultures. Among the various strengths of Murashige and Skoog media sucrose and growth regulators tested, 1/3 strength hormone-free medium supplemented with 60 g l −1 sucrose was found suitable for embryo induction and development from the root segments. Embryos which were developed on the root segments were able to mature and germinate in the same 1/3 MS hormone-free medium. Bioreactor cultures were established for large-scale cultivation of Plantlets. Adventitious roots, embryos and Plantlets could be simultaneously harvested after 12 weeks cultivation of adventitious roots in 1/3 strength MS medium supplemented with 60 g l −1 sucrose. HPLC analysis revealed that biomass harvested (somatic embryos, Plantlets and adventitious roots) contained eleutheroside B and E in considerable amount, and this could be used for the extraction of these phytochemicals. The present system for Plantlet production from root explants would provide an efficient means to produce both Plantlets and phytochemicals from E. koreanum .
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number of air exchanges sucrose concentration photosynthetic photon flux and differences in photoperiod and dark period temperatures affect growth of rehmannia glutinosa Plantlets in vitro
2000Co-Authors: Eunjoo Hahn, Toyoki Kozai, Kee-yoeup PaekAbstract:Rehmannia glutinosa Plantlets were cultured for 4 weeks under different culture conditions to determine the optimum environment for in vitro growth and ex vitro survival. Plantlet growth increased with an increasing number of air exchanges of the culture vessel, exhibiting greatest shoot weight, total fresh weight, leaf area, and chlorophyll content at 4.4 h−1 of air exchanges. High sucrose concentration (30 g l−1) increased root weight but reduced shoot growth. Net photosynthetic rates of the Plantlets were greatest when sucrose was not added to the medium. On the other hand, ex vitro survival of the Plantlets was not influenced by sucrose concentration. In the experiment on difference in photoperiod and dark period temperatures (DIF) and photosynthetic photon flux (PPF), Plantlet growth increased as DIF and PPF levels increased. Particularly, increasing PPF level had a more distinctive effect on Plantlet growth than increasing DIF level. The interaction of DIF × PPF was also significant, showing the greatest Plantlet growth in positive DIF (+8 DIF) and a high PPF (210 μmol m−2 s−1). In conclusion, the results of this experiment suggest that increased number of air exchanges of the culture vessel, decreased sucrose concentration, and positive DIF in combination with high PPF level enhanced growth and acclimatization of Rehmannia glutinosa Plantlets.
Richard G Kulka - One of the best experts on this subject based on the ideXlab platform.
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hormonal control of root development on epiphyllous Plantlets of bryophyllum kalanchoe marnierianum role of auxin and ethylene
2008Co-Authors: Richard G KulkaAbstract:Epiphyllous Plantlets develop on leaves of Bryophyllum marnierianum when they are excised from the plant. Shortly after leaf excision, Plantlet shoots develop from primordia located near the leaf margin. After the shoots have enlarged for several days, roots appear at their base. In this investigation, factors regulating Plantlet root development were studied. The auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) abolished root formation without markedly affecting shoot growth. This suggested that auxin transport from the Plantlet shoot induces root development. Excision of Plantlet apical buds inhibits root development. Application of indole-3-acetic acid (IAA) in lanolin at the site of the apical buds restores root outgrowth. Naphthalene acetic acid (NAA), a synthetic auxin, reverses TIBA inhibition of Plantlet root emergence on leaf explants. Both of these observations support the hypothesis that auxin, produced by the Plantlet, induces root development. Exogenous ethylene causes precocious root development several days before that of a control without hormone. Ethylene treatment cannot bypass the TIBA block of root formation. Therefore, ethylene does not act downstream of auxin in root induction. However, ethylene amplifies the effects of low concentrations of NAA, which in the absence of ethylene do not induce roots. Ag2S2O3, an ethylene blocker, and CoCl2, an ethylene synthesis inhibitor, do not abolish Plantlet root development. It is therefore unlikely that ethylene is essential for root formation. Taken together, the experiments suggest that roots develop when auxin transport from the shoot reaches a certain threshold. Ethylene may augment this effect by lowering the threshold and may come into play when the parent leaf senesces.
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cytokinins inhibit epiphyllous Plantlet development on leaves of bryophyllum kalanchoe marnierianum
2006Co-Authors: Richard G KulkaAbstract:When leaves of Bryophyllum marnierianum are detached from the plant, Plantlets develop from primordia located at their margins. Leaves excised with a piece of stem attached do not produce Plantlets. Severing the major leaf veins overcomes the inhibitory effect of the attached stem, indicating that the control agent is transmitted through the vascular system. A possible mechanism is that an inhibitory substance, possibly a known plant hormone, transported from the stem to the leaf, suppresses Plantlet development. A number of hormones were tested for their ability to inhibit Plantlet primordium development in whole isolated leaves. Auxins had no effect, indicating that apical dominance is not involved. The cytokinins zeatin, kinetin, and benzylaminopurine (BAP) strongly inhibited Plantlet development, suggesting that they may be the or a factor involved in maintenance of Plantlet primordium dormancy when the leaf is attached to the plant. This hypothesis was strongly supported by the finding that treatment of leaves attached to stems with a cytokinin antagonist (purine riboside) released the primordia from inhibition. In contrast to whole leaves, Plantlet primordium development on leaf explants incubated on Murashige Skoog medium containing 3% sucrose was strongly stimulated by cytokinins. A possible explanation of these observations is that in whole leaves the cytokinin signal is transduced into an inhibitory signal whereas in the isolated primordium cytokinin has a direct stimulatory effect. The inhibitory cytokinin pathway must be dominant as long as the leaf is attached to the plant. A model is proposed which could explain these findings. This study points to a novel role of cytokinins in the maintenance of foliar Plantlet primordium dormancy.
Huafang Wang - One of the best experts on this subject based on the ideXlab platform.
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over expression of kdsoc1 gene affected Plantlet morphogenesis in kalanchoe daigremontiana
2017Co-Authors: Chen Zhu, Li Wang, Jinhua Chen, Chenglan Liu, Huiming Zeng, Huafang WangAbstract:Kalanchoe daigremontiana reproduces asexually by producing Plantlets along the leaf margin. The aim of this study was to identify the function of the SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 gene in Kalanchoe daigremontiana (KdSOC1) during Plantlet morphogenesis. In this study, KdSOC1 gene expression was detected at stem cell niche during in vitro somatic embryogenesis and Plantlet morphogenesis. Disrupting endogenous auxin transportation suppressed the KdSOC1 gene response. Knockdown of the KdSOC1 gene caused a defect in cotyledon formation during the early heart stage of somatic embryogenesis. Over-expression (OE) of the KdSOC1 gene resulted in asymmetric Plantlet distribution, a reduced number of Plantlets, thicker leaves, and thicker vascular fibers. Higher KdPIN1 gene expression and auxin content were found in OE plant compared to those of wild-type plant leaves, which indicated possible KdSOC1 gene role in affecting auxin distribution and accumulation. KdSOC1 gene OE in DR5-GUS Arabidopsis reporting lines resulted in an abnormal auxin response pattern during different stages of somatic embryogenesis. In summary, the KdSOC1 gene OE might alter auxin distribution and accumulation along leaf margin to initiate Plantlet formation and distribution, which is crucial for plasticity during Plantlet formation under various environmental conditions.
Chen Zhu - One of the best experts on this subject based on the ideXlab platform.
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over expression of kdsoc1 gene affected Plantlet morphogenesis in kalanchoe daigremontiana
2017Co-Authors: Chen Zhu, Li Wang, Jinhua Chen, Chenglan Liu, Huiming Zeng, Huafang WangAbstract:Kalanchoe daigremontiana reproduces asexually by producing Plantlets along the leaf margin. The aim of this study was to identify the function of the SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 gene in Kalanchoe daigremontiana (KdSOC1) during Plantlet morphogenesis. In this study, KdSOC1 gene expression was detected at stem cell niche during in vitro somatic embryogenesis and Plantlet morphogenesis. Disrupting endogenous auxin transportation suppressed the KdSOC1 gene response. Knockdown of the KdSOC1 gene caused a defect in cotyledon formation during the early heart stage of somatic embryogenesis. Over-expression (OE) of the KdSOC1 gene resulted in asymmetric Plantlet distribution, a reduced number of Plantlets, thicker leaves, and thicker vascular fibers. Higher KdPIN1 gene expression and auxin content were found in OE plant compared to those of wild-type plant leaves, which indicated possible KdSOC1 gene role in affecting auxin distribution and accumulation. KdSOC1 gene OE in DR5-GUS Arabidopsis reporting lines resulted in an abnormal auxin response pattern during different stages of somatic embryogenesis. In summary, the KdSOC1 gene OE might alter auxin distribution and accumulation along leaf margin to initiate Plantlet formation and distribution, which is crucial for plasticity during Plantlet formation under various environmental conditions.
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key kdsoc1 gene expression profiles during Plantlet morphogenesis under hormone photoperiod and drought treatments
2016Co-Authors: Chenglan Liu, Chen Zhu, Huiming ZengAbstract:Kalanchoe daigremontiana utilizes Plantlet formation between its zigzag leaf margins as its method of asexual reproduction. In this study, K. daigremontiana SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (KdSOC1), a key intermediate in the transition from vegetative to asexual growth, was cloned. Furthermore, its expression profiles during Plantlet formation under different environmental and hormone induction conditions were analyzed. The full-KdSOC1 cDNA sequence length was 1410 bp with 70% shared homology with Carya cathayensis SOC1. The conserved domain search of KdSOC1 showed the absence of I and C domains, which might indicate novel biological functions in K. daigremontiana. The full-KdSOC1 promoter sequence was 1401 bp long and contained multiple-hormone-responsive cis-acting elements. Hormone induction assays showed that gibberellins and salicylic acid mainly regulated KdSOC1 expression. The swift change from low to high KdSOC1 expression levels during long-day induction was accompanied by the rapid emergence of Plantlets. Drought stress stimulated KdSOC1 expression in leaves both with and without Plantlet formation. Together, the results suggested that KdSOC1 was closely involved in environmental stimulation signal perception and the transduction of K. daigremontiana Plantlet formation. Therefore, future identification of KdSOC1 functions might reveal key information that will help elucidate the transition network between embryogenesis and organogenesis during Plantlet formation.