• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.53-62
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• 1985

A radioimmunoassay technique has been developed for the determination of abscisic acid (ABA) in crude extracts from germinating rice (Oryza sativa L.). By this method, the changes in ABA level of rice during germination was investigated. The ABA content in rice seeds was found to be 76.5ng/g dry weight in Dong-jin variety and 91.1ng/g dry weight in Sam-gang variety. A rapid decrease in ABA content of rice occurred during germination within 24 hours after seed imbition. The decreasing rate of ABA content during germination showed a significant direct proportion to the imbibition temperature and water-absorbing rate of rice. The decrease in ABA content during germination was found to be caused partly by an elution of ABA from the tissue to the imbibing fluid, and partly by a metabolic conversion of ABA to another compounds. The germination process of rice occurred only when the tissue ABA level decreased below a certain level, and the decreasing rate of ABA level during germination correlated with the ability for germination at low temperature of rice.

• Korean Journal of Environment and Ecology
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• v.17 no.2
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• pp.105-111
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• 2003

To develope reforestation methods for enviromentally sound and ecological forest management, Fraxinus rhynchophylla stand structure and radial growth of the trees were invstigated and compared by study sites. Plantation forest studied on Fraxinus rhynchophylla, was located at Jawoon-ni Nae-myeun, Hongcheon-gun and natural forest studied on Fraxinus rhynchophylla, was located at Jangjeon-ni Jinbu-myeun, Pyeungchang-gun. In 7,8 years after planting, differences of annual diameter increment among three stand origins were significant. The highest mean annual diameter increments of F. rhynchophylla, 4.60 mm/year was measured in sprouting trees, and followed by natural seedlings 4.59 mm/year. The lowest values, 4.18mm/year did in planting trees. Early radial growth of planting F. rhynchophylla was measured lower than that of sprouting or natural seedlings. These facts mean that planting F. rhynchophylla is not proper regeneration methods. Other regeneration methods of F. rhynchophylla forest, by sproutings, direct seeding and natural seeding, might be researched and recommended.