본 실험에서는 국화의 재배방법에 따라 즉, 적심재배방법과 정식시기에 따른 국화 '진바'의 생육과 절화의 상품성과 재배기간의 차이에 미치는 영향에 대하여 알아보고자 하였다. 실험 결과 무적심 재배의 경우 화아 분화 돌입에 필요한 충분한 영양생장기간을 확보하는데 비해, 적심재배의 경우는 충분한 영양 생장기간을 확보하지 못하였다. 화아분화 유기 12주 후의 무적심 재배 개화율은 95%를 상회하였으나 적심재배는 95% 이하로 나타났다. 무적심재배구는 정식시기에 관계없이 3등급상품 이상의 절화가 100% 생산되었으나 적심재배는 첫째주 정식구에서 84.7%로 아주 낮았고 둘째주 정식구는 64.3%, 셋째주 정식구는 18.8%, 넷째주 정식구는 2.6%로 적심재배구의 절화 상품성이 아주 좋지 못하였다. 무적심재배구의 절화품질이 제일 좋지 못한 넷째주 정식구와 적심재배구의 절화품질이 제일 좋은 첫째주 정식구를 비교하면 절화의 품질은 무적심재 배 넷째주 정식구가 좋았고 재배기간도 38일을 단축시킬 수 있었다. 이와 같은 절화국화 무적심재배는 적심 재배에 비하여 재배기간 단축과 품질향상이 가능하므로 경영비 절감과 소득향상이 가능한 재배법으로 판단되었다.
본 연구에서는 자동기상관측시스템(AWS)을 이용하여 기상요소의 관측 자료를 수집하고 실시간으로 그 자료를 제공하는 웹 페이지를 개발하였다. 이 시스템은 실시간으로 자료를 제공하면서 동시에 데이터베이스(DB)로 누적하여, 사용자의 요청에 따라 과거의 기상 자료를 파일로 제공하는 기능도 있다. 완성된 페이지를 이용하여 학교 현장에서 지구과학 교과의 기상분야 탐구학습에 성공적으로 활용하였다. 이 연구 결과, 기상 관측 자료를 실시간으로 제공함으로써 기상 분야 탐구학습의 현장감을 높일 수 있게 되었다. 또 누적된 과거 기상 자료를 이용함으로써 시간규모가 너무 길어서 실질적인 탐구학습이 어렵던 지구과학 교과의 제약을 일부 극복하게 되었다.
This study provides experimental results of pH restoration of acidified desulfurization seawater by the addition of the alkalinity enhanced seawater and additives (limestone and fly ash). The conservative seawater desulfurization processes use chemical solutions such as caustic soda (NaOH) or calcium hydroxide(Ca(OH)2). The method proposed in this study was aimed at reducing usage of chemicals. A control test was conducted to simulate the existing process without addition of the alkalinity-enhanced seawater and additives (limestone and fly ash). The pH of desulfurized seawater was increased by pH 5.84 through the conservative restoration process (i.e., adding raw seawater and NaOH solution followed by aeration). The 20%, 50%, and 80% of added raw seawater was replaced by the alkalinity-enhanced seawater. From the experimental result, 0.28, 0.89, and 1.05 m3/hr of 48% NaOH solution could be saved when applying the proposed method of the alkalinity enhanced seawater addition. When desulfurized seawater with pH 3.5 was mixed with raw seawater at a ratio of 1:1, the pH of seawater was increased up to pH 6. Therefore, the seawater restoration goal was set as pH 3.5. Experiments were conducted to increase pH of desulfurized seawater to pH 3.5 using additives (fly ash and limestone). Based on these results, the addition of fly ash and limestone to seawater was proved effective for pH restoration of desulfurized seawater.
Among many types of flue gas desulfurization (FGD) facilities, wet type FGD using lime or limestone is most popular in the world because of its simplicity of operation and availability of lime and limestone. Seawater desulfurization utilizes the alkalinity of seawater, thus requires no addition of lime and limestone. The efficiency of seawater desulfurization depends on the variation of alkalinity of seawater at different locations. This study presents the effect of gas-water ratio and total alkalinity of absorbing solution on the removal efficiency of sulfur dioxide from the flue gas by means of seawater. Also this study provides an alternative way to increase total alkalinity of seawater by utilizing fly ash from coal-fired power plants. The increase of removal efficiency with increase of alkalinity was measured as 0.26 ± 0.01% per ppm of bicarbonate alkalinity from the set of experiments using seawater, underwater, and distilled water, the alkalinity of which were 111 ppm, 38 ppm, and 1 ppm, respectively. Capability to increase total alkalinity of seawater using fly ash was confirmed.
The distribution of benthic macroinvertebrates in Daecheon stream, an urban stream of Busan, was investigated to analyze the community structure of benthic macroinvertebrates. The collection was peformed monthly at five(A~E) sites divided into three parts, upper, middle and lower, of stream from January to November, 2004. In physicochemical analysis of environmental factors, water quality parameters such as BOD, COD, conductivity and ABS were relatively increased in sites B and C. Whereas sites A, D and E showed little variations with good water quality parameters. However, water quality parameters in all surveyed sites showed gradual decrease with time toward improvement of water quality. A total of 8,226 individuals including 4 phyla, 6 classes, 9 orders, 302 families and 44 species were identified from five sites. The most dominant group was insect(class Insecta), and order Ephemeroptera and Diptera among insect was the largest member in species(30.6%) and individuals(75.0%) of benthic macroinvertebrates, respectively. The primary dominant species were Gammarus sp. and Ephemera strigata in site A, whereas Chironomus sp. and Brenchiura sowerbyi were dominated commonly in the other sites. In community analysis of benthic macroinvertebrates of Daecheon stream diversity index showed relatively low values, whereas dominance index was significantly high. Diversity index was the highest in site A, whereas the dominance index was the highest in site B. However, diversity index showed gradual increase with time showing adverse mode in dominance index. From these results, it can be suggested that long-term ecological monitoring of benthic macroinvertebrate fauna is needed for sustainable management of Daecheon stream.
The effects of wounding and jasmonic acid(JA) on polyphenol oxidase(PPO) in tomato(Lycopersicon esculentum Mill.) seedlings were investigated. PPO was strongly induced by wounding or JA, and the response was also shown to be systemically induced by wounding. Mechanical wounding in cotyledon or leaf produced a signal that caused the concentration of PPO to increase in the unwounded cotyledon, in the first leaves but not in the second leaves. Severity of wounding and light intensity also affected wound induced change in PPO activity, JA showed a stimulatory effect on the loss of chlorophyll and the rapid increase in PPO activity. The PPO was clearly more active in the wounded leaves than in controls. The potency and specificity of the JA indicate a close relationship between JA and wound-induced changes in PPO in tomato species. JA and abscisic acid(ABA) acted similarly on both unwounded and wounded leaves, but the amount of PPO in the wounded leaves was always more than the respective controls. The highest increase in PPO activity occurred in woundand JA-induced leaves of seedlings kept under bright lighting. Benzyladenine(BA) completely abolished JA- and ABA-induced PPO activity. The results suggest that JA-induced PPO activity is due to de novo PPO synthesis. Histochemical tests for PPO in stems of wound- and JA-treated tomato plants indicate that PPO was localized primarily in the outer cortex and xylem parenchyma. It is concluded that exogenously applied JA acts as stress agents and PPO may be a component of the inducible anti-hervivore defense response.
The toxic effects of aluminium (Al) on growth, chlorophyll content, δ-aminolevulinic acid dehydratase (ALAD) activity and anatomy of root and shoot were investigated in 7-day-old azuki bean (Vigna angularis) seedlings. Significant depressions in root elongation was observed in the low concentrations of Al (50, 100 ㎛) and increasing Al concentrations caused a sharp decline of root and shoot growth. The degree of inhibition was dependent upon Al supply. Exposure to 50 ㎛ Al or more inhibited root elongation within 1 day. In the 50 ㎛ Al treatments, a recovery of root growth was seen after 7 days exposure. In contrast, lateral root initials was little affected by Al exposure. Al toxicity symptoms and growth responses were more well developed in the roots than in the shoots. Analysis of Al localization in root cells by hematoxylin staining showed that Al entered root apices and accumulated in the epidermal and cortical cells immeadiately below the epidermis. There was a good positive correlation between the level of chlorophyll and ALAD activity. Increasing Al concentrations caused a decrease in total chlorophyll contents, accompanied by proportional changes in ALAD activity, suggesting a coordinated reduction of a photosynthetic machinery. Al exerted specific influence on the morphology of root and shoot. At higher concentrations of Al the roots induced drastic anatomical changes. The epidermal cells were disorganized or destructed while the cortical cells exhibited distortion of cell shape and/or disintegration. The diameter of root and transectional area of cortical cells decreased considerably with Al treatment. In the shoot Al also enhanced reduction of diameter of shoot and cell size. Gross anatomy of leaves treated with Al did not differ significantly from the controls, except for fewer and smaller chloroplast. Our results indicate that toxic effect of Al appear to be manifested primarily in roots and secondarily on shoots, and changes in root morphology are related to changes in the root growth patterns. Results are further discussed in relation to the findings in other plant species, and it is concluded that Al causes morphological, structural and, presumably, functional damage to the roots of the species investigated.
Various light intensity and light quality were treated to oat seedlings to investigate the effect of light on the chlorophyll accumulation and the formation of chlorophyll-protein complexes. The increase of total chlorophyll accumulation and Chl (chlorophyll) a/b ratio was promoted under H (high intensity) white light during oat chloroplast development when compared to L (low intensity) white light. Also H white right was more effective in the formation of chlorophyll-protein complexes associated with PSI, CCI and CCII than L white light. The seedlings grown in various light quality caused little changes in total chlorophyll and Chl a/b ratio when compared to those grown in L white light. The assembly of LHCII trimer was more affected by L white light treatment in the formation of-chlorophyll-protein complexes than red light treatment. The effect of blue light on the relative composition of chlorophyll-protein complexes was similar to that of L white light. Particualrly, blue light was more effective in the synthesis of LHCII monomer than the other hot quality at the early stage of greening. When compared to red light, blue light was more effective in the formation of LHCII monomer. These results suggest that light intensity is more effective in the increase of chlorophyll accumulation and Chl a/b ratio than light quality, and light quality may be an important factor for the regulation of the organization in the chlorophyll-protein complexes during greening.
Developmental changes of chlorophyll-protein complexes (CPs) and plastid membrane proteins in greening mung bean cotyledons and the effect of spermine thereon were examined by SDS-polyacrylamide gel electrophoresis. The changes in the amounts of CPs became larger with the progress of greening and light-harvesting chlorophyll a/b protein (LHCP) was the main CP in the early greening stage up to 48 h. As the greening proceeded, chlorophyll-protein of the photosystem I (CPI) accumulated. Application of spermine were effective in accumulating CPs of the thylakoid membrane in the early phase of greening. In the profiles of the plastid membrane proteins, quantitative and qualitative changes were observed with the onset of greening up to 72 h. 56 kD protein of major intensity was observed in all greened chloroplasts and 24 kD protein increased remarkablly in both control and spermine-treated cotyledons. The thylakoids from spermine-treated cotyledons showed higher amounts of thylakoid proteins as compared to the controls. The results suggest that spermine may play a role in the regulation of plastid development and stabilizes the membrane function during greening.
The effects of plant hormones (NAA, GA3 and BA) and light qualities (white, red, green and blue light) on the changes of reducing sugar contents and invertase isozyme activities in leaves of maize (Zea mays L.) and mung bean (Phaseolus radiatus L.) seedlings were investigated. NAA accelerated the increase of reducing sugar contents and invertase isozyme activities, on the contrary, GA3 had little effect in the accumulation of reducing sugar and in the increase of enzyme activities from the leaves of maize and mung bean seedlings. On the other hand, BA accelerated an increase in the activities of the invertase isozyme from the leaves of mung bean seedlings whereas it had little effect in the increase of the enzyme activities from those of maize seedlings. The accumulation of reducing sugar in leaves of both seedlings was promoted by red light irradiation compared to white light irradiation, while the activities of the enzyme were little affected by various light qualities. In the simultaneous applications of plant hormone and light quality, NAA with white light was very effective in the increase of reducing sugar contents and the enzyme activities from the leaves of mung bean seedlings, whereas NAA application with blue light showed a prominent enhancement in the reducing sugar contents and the enzyme activities from those of maize seedlings. These results suggest that plant hormone, particularly NAA, may be a more important factor than various light qualities in the stimulation of invertase activity.
Effects of polyamines on chlorophyll and protein content, and δ-aminolevulinate dehydratase(ALAD) activity were investigated during the greening of mung bean cotyledons. Polyamines stimulated chlorophyll formation in greening cotyledons, and this effect was enhanced by KCl. The changes in protein content were similar to the changes for chlorophyll content. The excision entailed an increase in ALAD activity. Then a decrease appeared after 48 h incubation on water in the dark. It was more precocious in the light, but was accelerated when the cotyledons were illuminated after a dark preincubation. Putrescine had little effect on ALAD activity in the dark. In the light, putrescine prevented the decrease in ALAD activity and enhanced this activity when a dark preincubation preceded illumination. KCl had a slight stimulating effect in the dark, but was uneffective in the light. The combination putrescine+KCl was devoid of stimulating effect. The results obtained suggest that plastid development of mung bean cotyledons during greening was affected by polyamines and light and that polyamines may play a role in the regulation of plastid development.