• Journal of Plant Biology
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• v.15 no.2
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• pp.1-6
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• 1972

Cultivar Yeollow Special A, the most leading Korean economic leaf tobacco in Korea, were field-cultivated in four different localities of Korea for the period of two years (1970 and 1971) and sprayed at varied levels of 2-chloroethyl phosphonic acid (CEPA) for foliar application few days after topping. While no striking difference in leaf yield by weight was obtained among the treatments when compared with control, leaf quality as expressed for shipment price in won tended when compared with control, leaf quality as expressed for shipment price in won tended to improve. The treated leaves with 300 to 900 ppm of CEPA (approximately 140 1/acre of 500 ppm) not only showed yellowing and accelerated maturity to pick 4 to 5 days with practicable optimal level earlier than control, but also speeded up to take nearly with practicable optimal level earlier than control, but also speeded up to take nearly last half of the total time required for the five stages of flue-curing. It is therefore considered that CEPA is as effective maturity-accelerating agent and useful as known for other solanaceous plants showing climacteric stage respiration, and discussions were made about physiological actions of ethylene gas released from CEPA at plant tissues sprayed.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.116-125
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• 2000

This study was conducted to investigate the effects of CEPA(2-chloroethyl phosphonic acid) on bark physiology and anatomy of lactree(Rhus verniciflua Stokes). Sample trees of similar size and growth rate were selected from 7-year-old lactree plantation located in Hyengsung-kun, Kangwon-do. Lanolin pastes containing 0.1, 1, or 10% CEPA were put into the bark-removed hole made by corer(${\phi}1cm$) on the main stem at 1.2m above the ground on June 16, 1995. Five weeks after application of CEPA, bark thickness was markedly increased as a result of the increase in the amount of phloem and intercellular spaces, and correlated with the increased production of urushiol. By the application of 10% CEPA, bark thickness was increased approximately 2.5 times, and the urushiol content within bark was increased 2.8 times compared to that of untreated trees because CEPA stimulated the accumulation of urushiol within bark. Treatment of 10% CEPA also increased the size and the total number of secretory canals, and induced an increase in ray width. The phloem parenchyma cells of CEPA-treated trees were well-developed and closely packed with little intercellular space.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.208-215
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• 2000

In order to improve 'Salso' method (conventional tapping method) which was very inefficient in the aspects of collection time and labor, this study was carried out to investigate the effect of the application date and the distance from treatment point in the lactree(Rhus verniciflua) treated with 10% CEPA and to decide the possibility of application of the technique in the field. Bark thickness was significantly increased to the part 40cm above and below the treatment point, but urushiol content was increased to the part 20cm above and 10cm below the zone treated with 10% CEPA. The urushiol content of the bark was highest at 5cm above the treated zone and decreased in the order of 10, 20, and 40cm. And the urushiol contents of the bark of the upper part were higher than that of the low part. The effects of CEPA on bark thickness were similar to urushiol contents. Urushiol production of lactree is highly dependent on climatic conditions and particularly on the precipitation, and duration of sunshine. Ten percent of CEPA-lanolin pastes which was treated on June 16 affected bark anatomy and urushiol contents, while the treatment on August 24 did not affect. In the Rhus verniciflua treated with 10% CEPA, the urushiol contents was initially increased from 7 days after treatment, continued for the 4 weeks, and then slight decrease occurred at 5 weeks after the treatment. We measured a total sap yield by Salso method in lactree treated with 10% CEPA. By applying 10% CEPA, the sap yield was increased 3-4 times compared to that of untreated trees in the first tapping. But the relative ratio was gradually decreased from the second tapping to sixth, and after seventh tapping, the untreated trees secreted more sap than the treated trees. We discussed about the causes.