Abstract
This study was carried out to investigate the effect of seasonal changes on some of the morphological and physiological characteristics, including the photosynthetic abilities and dark respiration, of young ginseng plants due to planting location under shading. The results obtained are as follows: 1. Seedlings and 2-year old plants planted in the back rows appeared to have broader leaf area, and their leaf weight greatly increased in September. Chlorophyll content was significantly reduced in September rather than in June and the plants in the back rows had more chlorophyll content than those in the front rows. 2. There was no difference in the light compensation point between the front and back rows in June, while in September the light compensation point of 2-year old ginseng leaves was much lower for plants in the back rows compared with those in the front rows. A difference in the light saturation point was not noticeable between plants in the front and back rows in June and September. But the light saturation point of 2-year old ginseng leaves at $15^{\circ}C$ was high in June, while it was high at $20^{\circ}C$ high in September. 3. Maximum photosynthetic ability was attained at $15^{\circ}C$ in June and at $20^{\circ}C$ in September. During June no significant difference in photosynthetic ability was found between plants in the front and back rows, but in September the amount of photosynthesis was significantly increased at the leaves of seedlings as well as 2-year old plants planted in the back rows. 4. The optimum temperature for maximum photosynthesis in 2-year old plants ranged from $14.0^{\circ}C$ to $14.5^{\circ}C$ in June and from $19.5^{\circ}C$ to $20.5^{\circ}C$ in September. However, the optimum temperature for maximum photosynthesis in the seedlings was from $21.2^{\circ}C$ to $21.6^{\circ}C$ in September, but a significant difference in the optimum temperature for the maximum photosynthesis in seedlings and 2-year old plants was not noticeable between the front and back rows. 5. The respiration rate was rather high in seedlings compared with 2-year old plants. During September the respiration rate in seedlings was much lower in the back rows than in the front rows. The rate of increase in the respiration of 2-year old plants was higher at September than June. The increase in respiration rate due to temperature was more significant in seedlings than 2-year old plants. 6. In September, the level of $Q_{10}$ in 2-year old plants was much lower than that found in seedlings. During June, 2-year old plants showed lower $Q_{10}$ levels at a temperature difference between $15^{\circ}C$ and $25^{\circ}C$; but in September this occurred at a temperature difference between $20^{\circ}C$ and $30^{\circ}C$.
본 연구는 저연생 고려인삼의 재배위치에 따르는 광합성능력과 암호흡에 관련된 몇 가지 생태 및 생리적 특징의 계절적 변이를 구명하기 위하여 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 묘삼 및 2연근 인삼에서 엽면적은 후열에서 넓은 경향을 보였고, 엽중은 9월에 현저히 증가하였다. 엽록소 함량은 6월에 비해 9월에 현저히 감소하였고, 전열에 비해 후열에서 높은 경향이 뚜렷하였다. 2. 2연근의 경우 광보상점은 6월에는 전후열간 차이가 없었으나 9월에는 초삼 및 2연근에서 후열의 광보상점이 현저히 낮았고, 6월 및 9월에서 광포화점의 열간 및 계절간 차이는 인정되지 않았다. 다만 2연근의 $15^{\circ}C$에서의 광포화점은 6월이, 그리고 $20^{\circ}C$의 광포화점은 9월이 높은 경향이 뚜렷하였다. 3. 2연근에서 6월은 $15^{\circ}C$에서 전후열 모두 최대광합함량이 가장 높았으나 9월에는 $20^{\circ}C$에서 최고를 보였으며, 6월은 전후열간의 차이가 없었는데 반해 9월은 묘삼 및 2연근에서 모두 후열에서 오히려 최대 광합함량의 현저한 증가를 나타내었다. 4. 최대광합성에 적합한 온도는 2연근의 경우 6월은 1$14.0^{\circ}C$~$14.5^{\circ}C$였으나 9월에는, $19.5^{\circ}C$~$20.5^{\circ}C$였고, 묘요에서는 9월의 경우 21.$2^{\circ}C$~21.6$^{\circ}C$로서 전후열간 차이는 거의 없었다. 5. 2연근에 비해 묘삼의 호흡량이 현저히 많았으며, 또한 묘삼은 9월의 경우 전열에 비해 후열에서 호흡량이 적었는데, 2연근에서는 5월에 비해 9월의 호흡량이 증가되었고, 전열에 비해 후열의 호흡량이 약간 많은 경향이었다. 온도 상승에 따르는 호흡량의 증가율은 묘삼이 2연근에 비해 현저히 높았다. 6. 9월에 있어서 묘삼에 비해 2연근의 $Q_{10}$ 현저히 낮았으며, 2연근의 경우 6월에는 $15^{\circ}C$에서 $25^{\circ}C$로 상승시의 $Q_{10}$이, 그리고 9월에는 $20^{\circ}C$에서 $30^{\circ}C$로 상승시의 Q$_{10}$이 각각 현저히 낮았다.
