논문 상세보기
pp.69-89
스테비아는 Paraguay 산중에 야생하는 국화과에 속하는 다년생 초본식물로서 그 엽에는 감미성분 Stevioside가 6～12% 함유되어 있다. Stevioside는 배당체로써 감미가 설당과 유사하적, 감미도는 설당의 약 300배가 된다. 우리나라에서는 당원료(사탕무우, 사탕수수)를 전연 생산하지 않으며 또한 합성감미료의 유해성이 논란되어 그 사용이 제한되므로써 새로운 감미료 개발의 필요성이 절실하다. 그리하여 1973년 우리 나라에 도입된 스테비아를 감미자원식물로서 정착시키기 위하여 재배에 관한 시험을 실시하였는데 그 결과를 요약하면 다음과 같다. 1. 정식에서 발뢰기까지 일수는 공시품종 모두 14시간 일장보다 단일조건에서 단축되었으며, 12시간과 14시간 일장간에서 발뢰기의 차이가 가장 크게 나타났다. 77013은 단일에서 발뢰촉진정도가 크며 수원002, 77067은 감광도가 둔한 계통이었다. 2. 12시간 일장을 발뢰기를 결정하는 변곡점(turning point)이었으며 한계일장은 12시간 내외라고 할 수 있다. 단일에서는 조기 발뢰에 따른 생육일수 불1족으로 생육양이 현저하게 낮았다. 3. 삽본묘는 발근전에도 단일에 감응 하는데 40일 양묘에서 단일감응이 예민하여 발뢰까지 일수가 가장 짧은 20일이있으며 양묘일수가 짧으면 단일감응 후발뢰가 지연된다. 4. 실생묘의 출아에서 발뢰까지 일수는 출아후 20일 단일 처리에서 가장 짧았으며 20일보다 단일처리 시기가 빠르거나 늦을수록 발뢰까지 일수는 길어졌다. 5. 삽목기가 3월 20일에서 5월 20일로 늦어질 수록 초장, 분지수 및 건물중이 현저하게 낮아졌으며, 3월 20일 삽목에서는 40～50일, 4월 20일 삽목에서는 30～40일, 5월 20일 삽목에서는 30일 육묘에서 건엽수량이 높았다. 6. 건엽수량과 재식주수와는 Asymptotic relation을 보였으며 10a당 5,000～10,000주까지는 건엽이 급증하였고, 10.000～20,000주는 그 증가가 수만하며 20.000주 이상에서는 증가율이 더욱 둔화되었다. 따라서 20,000주가 적정재식주수라고 할 수 있다. 7. 수원, 청주, 목포, 제주에서 스테비아 활착과 생육은 양호하였으나 생육성기의 한발은 수량감수원인이 되었다. 정식기가 6월 20일로 늦으면 적기보다 건엽수량이 현저하게 감수되었다. 8. 3월 20일 정식의 보온단일구에서 단일감응으로 건엽수량이 낮았으나 보온 장일 및 보온 자연일장은 보온효과가 크게 나타났다. 4월 20일 이후 안식에서는 보온효과는 인정되지 않았다. 9. Stevioside 함량은 상부엽에서 높았으며 지상 20cm 부위는 현저하게 낮았다 건엽과 Stevioside 수량은 대체로 60～120cm에 집중되어 있었으며 그 집중정도는 품종에 따라 큰 차이가 있었다. 10. 발뢰까지는 수확기를 지연시킬 수록 건엽수량은 현저하게 증가되었으며 발뢰 이후에는 수확기를 지연시켜도 수량 차이는 인정되지 않는다. Stevioside 함량은 발뢰기에 가장 높았고 이보다 빠르거나 늦게 수확할 때 감소하는 경향을 보였다. 건엽수량과 Stevioside 함량을 고려한 수확적기는 발뢰시부터 개화전까지이고 수원 지방에서는 9월 10일～9월 15일경이었다. 11. 영양계의 Stevioside와 Rebaudioside 함량범위는 각각 5.4～l4.3%, 1.5～8.3%로 변이폭이 크며 Stevioside와 Rebaudioside 함량간에는 일정한 경향이 없었다.
Stevia (Stevia rebaudiana Bertoni) is a perennial herb widely distributed in the mountainous area of Paraguay. It belongs to the family Compositae and contains 6 to 12 percent stevioside in the leaves. Stevioside is a glucoside having similar sweetening character to surgar and the degree of sweetness is approximately 300 times of sugar. Since Korea does not produce any sugar crops, and the synthetic sweetenings are potentially hazardous for health, it is rather urgent to develop an economical new sweetener. Consequently, the current experiments are conducted to establish cultural practices of stevia, a new sweetening herbs, introduced into Korea in 1973 and the results are summarized as followings: 1. Days from transplanting of cuttings to the flower bud formation of 6 stevia lines were similar among daylengths of 8, 10 and 12 hours, but it was much greater at daylengths of 14 or 24 hour and varietal differences were noticable. All lines were photosensitive, but a line, 77013, was the most sensitive and 77067 and Suweon 2 were less sensitive to daylength. 2. Critical daylength of all lines seemed to be approximately 12 hours. Growth of plants was severely retarded at daylengths less than 12 hours. 3. Cutting were responded to short daylength before rooting. Number of days from transplanting to flower bud formation of 40-day old cuttings in the nursery bed was 20 days and it was delayed as duration of nursery were shorter. 4. Number of days from emergence to flower bud formation was shortest at short day treatment from 20 days after emergence. It was became longer as initiation of short day treatment was earlier or later than 20 days. 5. Plant height, number of branches, and top dry weight of stevia were reduced as cutting date was delayed from March 20 to May 20. The highest yield of dry leaf was obtained at nursery duration of 40-50 days in march 20 cutting, 30-40 days in April 20 cutting, and 30 days in May 20 cutting. 6. An asymptotic relationship was observed between plant population and leaf dry weight. Yield of dry leaf increased rapidly as plant population increased from 5,000 to 10,000 plants/10a with a reduced increasing rate from 10,000 to 20,000 plants/l0a, and levelled off at the plant population higher than 20,000 plants/l0a. 7. Stevia was adaptable in Suweon, Chengju, Mokpo and Jeju and drought was one of the main factors reducing yield of dry leaf. Yield of dry leaf was reduced significantly (approximately 30%) at June 20 transplanting compared to optimum transplanting. 8. Yield of dry leaf was higher in a vinyl house compared to unprotected control at long daylength or natural daylength except at short day treatment at March 20. Higher temperature ill a vinyl house does not have benefital effects at April 20 transplanting. 9. The highest content of stevioside was noted at the upper leaves of the plant but the lowest was measured at the plant parts of 20cm above ground. Leaf dry weight and stevioside yield was mainly contributed by the plant parts of 60 to 120cm above ground but the varietal differences were also significant. 10. Delayed harvest by the time of flower bud formation increased leaf dry weight remarkably. However, there were insignificant changes of yield as harvests were made at any time after flower bud formation. Content of stevioside was highest at the time of flower bud formation and earlier or later harvest than this time was low in its content. The optimum harvesting time determined by leaf dry weight and stevioside content was the periods from flower bud formation to right before flowering that would be the period from September 10 to September 15 in Suweon area. 11. Stevioside and rebaudioside content in the leaves of Stevia varieties were ranged from 5.4% to 14.3% and 1.5% to 8.3% respectively. However, no definit relationships between stevioside and rebaudioside were observed in these particular experiments.
