• Journal of Plant Biotechnology
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• v.48 no.1
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• pp.44-53
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• 2021

The present work aims to study the induction of somatic embryogenesis in cork oak (Quercus suber L.) from immature zygotic embryos and young apical leaves obtained from 2-month-old seedlings through acorn germination on sterilized peat. The immature zygotic embryos were grown for 1 month on the mineral solution of MS in the presence of 4.52 µM 2,4-D and 30 g/L sucrose. They were then transferred to the same mineral solution with no added growth regulators. In the third subculture, yellow somatic embryos, characterized by two voluminous cotyledons, were differentiated from the radicle of the immature zygotic embryos. The induction of somatic embryogenesis in young leaves required a series of transfers on different culture media containing 30 g/L sucrose and 100 mg/L myo-inositol. Secondary or recurrent somatic embryogenesis occurred within the immature somatic embryo radicles after 1 month of culture on growth regulator-free medium containing WPM macronutrients, MS micronutrients, and vitamins.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.141-147
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• 1995

Glyphosate(N-[phosphonomethyl]glycine) applied to the assimilate-exporting leaves or sprayed to the whole plants of tomato(Lycopersicon esculentum Mil var. Moneymaker). Glyphosate induced the rapid accumulation of shikimic acid within 24 h. The accumulation of shikimic acid companied with chlorophyll loss in meristematic leaves, i.e. apical leaves. The chlorosis was acropetal in apical region of young growing leaf. The degradation of chlorophyll seems to be a secondary or tertiary effect of glyphosate. However, the level of shikimic acid accumulated was reduced except for roots and apical leaves from 5 days after treatment. The accumulating levels are considerably differed through the applicated regions. The level of shikimic acid is highest at the apical meristem 4 days after the application to 3rd old leaf.

• Journal of Plant Biology
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• v.11 no.3
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• pp.23-30
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• 1968

Using several varieties of Cymbidium, investigations were carried out to make clear how the protocormic tissue develops from the cultured explant. Explant to be cultured were prepared in several ways: exclusively apical meristem, apical meristem dissected out with the basal part attached, axillary bud primordia in their initial stage of development, or apical or axillary bud dissected out as a whole etc. It was observed that protocorms or protocormic tissues were developed from the explant's meristematic tissues regardless of where these tissues were located. Apical meristem, leaf primordia, leaf axil, or internodal part of young bud turned easily protocormic, while the scaly leaves of axillary bud or stem tissue of mother shoot turned quickly brwonish and died away. Both in axillary and apical bud explant alike, whether they were cultured whole or divided, some took quickly green color while others were slower, and some developed protocorms easily while others remained unchanged for months. Varietal difference as well as environmental factors seemed to be responsible for it. Further details should be clarified by histogenetical investigations.

• Journal of Plant Biology
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• v.14 no.2
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• pp.15-21
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• 1971

The present paper was designed to investigate the effect of nitrogen, phosphorus and potassium on the histological differentiation of the young leaves of soybean (Glycinemax, M.). Observations were made on the numbers of lamina cells and lateral veins, width and thickeness of the lamina and vascularization of the midrib in the 5th leaf, and the differentiation of leaves at 42$\mu$ from the apical tips of the shoot apecis. Samples were taken at the time when the 2nd leaf was completed. The experimental plots were divided into twelve parts. And the results obtained are as follows. 1) Nitrogen stimulated the differentiation of the leaf, the vascuralization of the midrib and increased the numbers of lamina cells and lateral veins. 2) Phosphorus promoted the differentiation of lamina at the first stage of soybean growth. It was more effective in the plots of excessive application than otherwise. It had a small effect on the differentiation of lateral veins. 3) Among the elements, a deficiency of postassium resulted in a reduced differentiation of the lamina potassium had no effect on the thickening growth of the lamina and the differentiation of the midrib. 4) It appeared that phosphorus might compensate for the negative effect of potassium in the potassium and phosphorus plots.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.100-104
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• 2014

This study was conducted to determine the optimal MS medium strength to improve sprouting rate of apical meristem of strawberry 'Seolhyang' in vitro. Strawberry apical meristems at size (0.2 mm to 0.3 mm) with leaf primordials were cultured on the MS media with four strength levels, ($1/4{\times}$, $1/3{\times}$, $1/2{\times}$, and $1{\times}$) and the sprouting rate and growth characteristics were evaluated after eight weeks after cultivation. Shoot rate of 'Daewang' apical meristems was 93.6%whereas 'Seolhyang' apical meristems were sprouted with 31.6% on $1{\times}$ MS medium strength. Different sprouting rates were observed in 'Seolhyang' apical meristem with 31.6% in $1{\times}$ medium, 75.0% in $1/2{\times}$ medium, and 94.4% in $1/3{\times}$ medium. The sprouting rate was improved with the decrease of medium strength, but the shoot rate in $1/4{\times}$ medium decreased up to 54.5%. Shoot length was 0.9 cm in $1{\times}$ medium, 1.2 cm in $1/2{\times}$ medium, 1.6 cm in $1/3{\times}$ medium, and 1.9 cm in $1/4{\times}$ medium. Shoot length was longer as medium strength decreased and numbers of leaves and roots were not significant differences among the medium strengths. As a result, sprouting rate was highest and plant growth was best in $1/3{\times}$ MS medium compared to the others.

• Journal of Plant Biology
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• v.15 no.1
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• pp.28-32
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• 1972

Young haploid leaf derived from the anthers of tobacco plant was cultuerd and plantlets of various ploidies were obtained. When the leaf was put on the medium supplemented with kinetin as growth regulator, plantlets developed directly from the leaf, and the plants coming out in early stage of culture were all haploid. Plants developing in later stage were mostly haploids with some exception of diploid and aneuploid. Leaves were also cultured on the callus-inducing media supplemented with 2,4-D and kinetiion, and the calluses were sub-cultured for six months. Plants developed from these calluses were mostly aneuploids of various chromosome numbers. In view of the fact that the plants directly developed from the leaf were all haploid, the tissue of the original leaf explant was assumed to be uniform as far as chromosome number was concerned. On the other hand, it seemed that the occurrence of various ploidies in the plants derived from the calluses of same origin was the result of the influence of in vitro culture. Apical meristem tissues and various multicellular bodies were formed in the epidermal and inner mesophyll tissues as well as in the sub-epidermal cells.

• The Plant Pathology Journal
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• v.15 no.5
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• pp.308-310
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• 1999

A fungus associated with gray blight on tea plant (Camellia sinensis) was identifed as Pestalotiopsis theae based on the mycological characteristics. Mycelial growth on potato dextrose agar and size and shape of conidia of P. theae were similar to those of P. longiseta, but P. theae was different from P. longiseta in the color of three median cells and the number of apical appendages. Artificial inoculation of conidial suspension or mycelial mats on the wounded leaves and shoots of healthy plants induced the same disease, respectively. The Korean native variety was relatively. The Korean native variety was relatively more resistat to P. theae than a Japanese variety‘Yabukita’which has bee recently introduced and planted in large areas of southern parts of Korea. Here, we report the report the first record of gary blight caused by P. theae on tea plant in Korea.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.2-3
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• 2003

A method for rapid propagation of mature Jack fruit was developed. Four types of explants (mature embryos, apical meristems of young seedlings, apices from mature plants and nodal segments) were used. It has been found 88% of young apical meristems produced shoots in Campbell and Durzan (CD) medium compared to 60% in Murashige and Skoog (MS) medium. Only 1/3 of them produced multiple shoots. Shoot initiation from nodal segments was very rare. Mature apices produced callus. Although removal of the sheathing cover around mature buds enhanced the shoot initiation but success rate was low in growth regulator free medium. Embryos respond to the CD medium but not to the MS medium. Embryos from seeds soaked in water for 24 hours produced shoots after 8 weeks of incubation and the success rate was 70% while embryos from dry seeds only produced roots. There was no significant effect of cold storage (refrigeration) for 7 days on shoot initiation from mature embryos (65%) but the ability for shoot induction declines with storage time (55% after 21 days of cold storage). Mature axillary buds were established in Modified Campbell and Durzan (CD) medium supplemented with 0.5mg/1 and IBA. There was a significant difference in the growth performance of shoots according to the period of the year in which explants were collected. Highest (60%) was observed in November-January period. It was only 30% when the explants were collected in February-April or May-July and decreased to 20% in August-October. The shoots produced in November-January showed a higher vigor than those produced in other months. Since Jak fruit show seasonal changes in fruit bearing and shedding of leaves, it can be suggested that the difference in growth performances of tissues cultured in artificial culture media would have been affected by endogenous rhythms.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10a
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• pp.9-18
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• 2003

A method for rapid propagation of mature Jack fruit was developed. Four types of explants (mature embryos, apical meristems of young seedlings, apices from mature plants and nodal segments) were used. It has been found 88% of young apical meristems produced shoots in Campbell and Durzan (CD) medium compared to 60% in Murashige and Skoog (MS) medium. Only 1/3 of them produced multiple shoots. Shoot idtiation from nodal segments was very rare. Mature apices produced callus. Although removed of the sheathing cover around mature buds enhanced the shoot initiation but success rate was low in growth regulator free medium. Embryos respond to the CD medium but not to the MS medium. Embryos from seeds soaked in water for 24 hours produced shoots after 8 weeks of incubation and the success rate was 70% while embryos from dry seeds only produced roots. There was no significant effect of cold storage (refrigeration) for 7 days on shoot initiation from mature embryos (65%) but the ability for shoot induction declines with storage time (55% after 21 days of cold storage). Mature axillary buds were established in Modified Campbell and Durzan (CD) medium supplemented with 0.5mg/1 and IBA. There was a significant difference in the growth performance of shoots according to the period of the year in which explants were collected. Highest (60%) was observed in November-January period. It was only 30% when the explants were collected in February-April or May-July and decreased to 20% in August-October. The shoots produced in November-January showed a higher vigor than those produced in other months. Since Jak fruit show seasonal changes in fruit bearing and shedding of leaves, it can be suggested that the difference in growth performances of tissues cultured in artificial culture media would have been affected by endogenous rhythms.

• Journal of Ginseng Research
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• v.11 no.2
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• pp.111-117
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• 1987

The phase and times on the development of dormancy bud in seedling, and those of flower organs in 2-year-old ginseng are different to those of over 2-,3-year-old plant, respectively. The growing aspects of dormancy bud in seedling were investigated from rooting stage (April, 8) to Mid-June, and those of flower organs in 2-year-old plant had done once in two days late in April after compound leaves were unfolded. Firstly, the formation of dormancy bud in seedling was begun on Mid-late in March. This is early about one month compare with those of over 2-year-old plant. Fine bud in seedling was formed between cotyledons, at W spot under young shoot. Secondly, development of flower organs in 2-year-old plant was completed from late of April to early of May after compound leaves of transplanted plant were unfolded. In tare, this is very different characteristics because plants of any other ages form the flower organs one year ago. Thirdly, flower organs of ginseng plant, over 3-year-old plant, always develop in the rhizome formed one year ago, but those of 2-year-old plant develop in apical shoot meristem.