Since the major important factors limiting plant growth and crop productivity are environmental stresses, of which low temperature is the most serious. It has been well known that many physiological processes are alterant in response to the environmental stress. With regard to the relationship between plant hormones and the regulation of chilling tolerance in rice seedlings, the major physiological roles of plant hormones: abscisic acid, ethylene and polyamines are evaluated and discussed in this paper. Rice seedlings were grown in culture solution to examine the effect of such plant hormones on physiological characters related to chilling tolerance and also to compare the different responses among tested cultivars. Intact seedlings about 14 day-old were chilled at conditions of 5~circC and 80% relative humidity for various period. Cis-(＋)-ABA content was measured by the indirect ELISA technique. Polyamine content and ethylene production in leaves were determined by means of HPLC and GC respectively. Chilling damage of seedlings was evaluated by electrolyte leakage, TTC viability assay or servival test. Our experiment results described here demonstrated the physiological functions of ABA, ethylene, and polyamines related to the regulation of chilling tolerance in rice seedlings. Levels of cis-(＋)-ABA in leaves or xylem sap of rice seedlings increased rapidly in response to 5~circC treatment. The tolerant cultivars had significant higher level of endogenous ABA than the sensitive ones. The (~pm )-ABA pretreatment for 48 h increased the chilling tolerance of the sensitive indica cultivar. One possible function of abscisic acid is the adjustment of plants to avoid chilling-induced water stress. Accumulation of proline and other compatible solutes is assumed to be another factor in the prevention of chilling injuies by abscisic acid. In addition, the expression of ABA-responsive gene is reported in some plants and may be involving in the acclimation to low temperature. Ethylene and its immediate precusor, 1-amincyclopropane-1-carboxylic acid(ACC) increased significantly after 5~circC treatment. The activity of ACC synthase which converts S-adenosylmethionine (SAM) to ACC enhanced earlier than the increase of ethylene and ACC. Low temperature increased ACC synthase activity, whereas prolonged chilling treatment damaged the conversion of ACC to ethylene. It was shown that application of Ethphon was beneficial to recovering from chilling injury in rice seedlings. However, the physiological functions of chilling-induced ethylene are still unclear. Polyamines are thought to be a potential plant hormone and may be involving in the regulation of chilling response. Results indicated that chilling treatment induced a remarkable increase of polyamines, especially putrescine content in rice seedlings. The relative higher putrescine content was found in chilling-tolerant cultivar and the maximal level of enhanced putrescine in shoot of chilling cultivar(TNG. 67) was about 8 folds of controls at two days after chilling. The accumulation of polyamines may protect membrane structure or buffer ionic imbalance from chilling damage. Stress physiology is a rapidly expanding field. Plant growth regulators that improve tolerance to low temperature may affect stress protein production. The molecular or gene approaches will help us to elucidate the functions of plant hormones related to the regulation of chilling tolerance in plants in the near future. Abbreviation : ABA : abscisic acid ACC : 1-aminocyclopropane-1-carboxylic acid ADC : arginine decarboxylase ELISA : enzyme-linked immunosorbent assay ODC : ornithine decarboxylase Put: putrescine SAMDC : S-adenosylmethionine decarboxylase Spd : spermidine Spm : spermine TNG 67 : Tainung 67 TCN 1 : Taichung Native 1 TTC : triphenyl tetrazolium chloride

IAA에 대한 단크론 항체를 생산하고 이를 이용하여 생체중의 내생 IAA를 정량분석하기 위해 ELISA를 개발하고 본법을 사용하여 담배 종자 발아중 내생 IAA함량을 정량분석하였다. 그 결과는 1. IAA에 대한 단크론 항체 생산 세포주 3가지를 선발 작성하였으며 이 세포주로부터 생산되는 항체는 모두 IgG1 타입의 면역 글로블린이었다. 2. 상기 항체를 사용하여 ELISA를 수행하여 표준곡선을 작성하였던 바 검출 한계는 1pmol이었으며 검출 범위는 500pmol이었다 3. 표준곡선으로부터 작성한 Scatchard plot에 의한 친화 상수와 결합상수는 6.7 1010 L/M과 6 1010 L/M이었다. 4. 여러가지 IAA유사물질과 교차반응에 의해서 본 mAb는 특이성이 매우 높고 RIA에 의해서 고역가임을 확인하였다 5. 발아중인 담배종자로부터 면역측정에 의해서 내생 IAA를 정량분석하였다 6. 상기의 결과에 따라서 본 mAb를 이용하여 생체중의 내생 IAA를 간편하게 정밀 분석할 수 있음을 확인하였다.

In spite of the development of highly sophisticated instrument, the precise quantitation of plant hormones still has many difficulties. Due to their high specificity, sensitivity and minimal sample purification steps, immunological assays have been widely applied for plant hormone assay. Enzme-linked immunosorbent assay technique for the determination of plant hormones was developed by Voller in 1978. Immunological assays are accomplished by competition of labeled tracer antigen and unlabeled antigen for a limited number of specific antibodies. The use of enzyme as replacement labels for radioisotopes enabled much of the sensitivity and specificity of radioimmunoassay (RIA) to be retained but without the inherent disadvantage of high capital cost, potential health hazard, and short shelf life of the labeled reactants.

The analytic principles of GC and MS were explained in relation to plant hormone analyses and the characteristics of two instruments were compared. The selection of column, condition of measurement and the method of ionization to get a good spectrum were also briefly described. Finally, the pre-treatment of sample by solvent extraction method to remove the unnecessary part of sample and the synthetic method, especially reagents and reaction condition, for the preparation of ether or ester derivative which can be easily vaporized in GC were explained.

A bioassay is a test system using a living organism (in whole or in part) to determine the presence or relative potency of chemical substances. The development and uses of bioassay are intimately linked to the discovery and characterization of the major classes of plant hormones. An application of this relationship is helpful for understanding the concept of plant hormones as well as the use of bioassay. And plant bioassay have been development and employed not only for the discovery and characterization of the biological activity of plant growth regulators but also have served several important secondary roles. The ideal bioassay should possess the characteristic of high specificity. great sensitivity. short response time, low cost and ease of obtaining plant material. acceptable ease of manipulation, and minimal space and equipment requirements.

식물홀몬을 포함한 각종 식물생장조절물질의 생검법(bioassays or biological assays)을 소개 및 비교검토함과 동시에 일관성 있는 결과를 얻기 위한 몇가지 유의점을 지적코자 옥신류 생검에서는 녹두발근과 귀리제1절간장신장, gibberellin에서는 왜성벼의 제2엽신장과 왜성완두의 상조축신장, 그리고 cytokinin류에서는 무자엽생장, 담배줄기수캘러스생장, 그리고 오이자엽내엽록소형성 등의 방법을 요약하였다. 아울러 일련의 실험을 통해 얻어졌던 각종생장조절물질(특히 최근에 개발되는 각종 왜화제)에 대한 반응을 홀몬별로 요약 및 비교하였다.