동계시설내 보광이 수경재배 착색단고추(Capsicum annum L.)의 생육에 미치는 영향

This study was conducted to examine the effect of supplemental lighting on the growth and yield of hydroponically grown sweet pepper (Capsicum annuum L. cv. sprit) under low levels of natural light in winter. The plants were treated with natural light only (control), 3-hour supplemental lighting before sunrise, after sunrise and after sunset with high pressure sodium (HPS, 400W). As the result of these three treatments, the supplemental lighting promoted photosynthesis in the low light intensity condition and particularly photosynthesis was more active right after sun rise in the morning, 1.5-$3.0{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$ comparing to those of supplemental lighting after sunset, 0.5-$1.5{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$. Transpiration rate and stomatal conductance sharply increased with supplemental lighting after sunrise then they decreased again after turning the lights off. Stomatal size was observed $32.2{\mu}m^2$ after supplemental lighting, whereas the size of the natural light was almost closed at $7.7{\mu}m^2$. The average plant height of sweet papper cv. spirit was 185 cm before sunrise, 188 cm after sunrise and 208 cm after sunset with supplemental lighting for 3hours while the control was 171 cm. With supplemental lighting a better number of fruit set per plant was measured 4.3 before and after sunrise, 3.7 after sunset but 2.6 in the control. Interestingly, there were no significant differences in the sugar content ($^{\circ}Brix$) degree between treatment of supplemental lighting, whereas slight differences between seasons were seen. The marketable fruit yield of sweet pepper (cv. spirit) was $116.0kg{\cdot}ha$ with supplemental lighting, whereas the control (natural light only) was $75.8kg{\cdot}ha$. Despite of spending electricity and depreciation cost, the economic analysis showed net income with supplemental lighting after sunrise was 51% higher than control treatment in cv. spirit. 본 연구는 보광이 착색단고추의 수량과 품질에 미치는 영향을 구명하여 생산성과 품질향상을 위한 착색단고추 재배기술 확립의 기초 자료를 얻고자 수행하였다. 보광시간대별 광합성은 아침 일출 전 보광에서는 1.5-$3.0{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$의 광합성속도를 나타냈으며, 일몰 후 보광은 0.5-$1.5{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$의 광합성속도를 보여 일출 전 보광이 더 효과적인 것으로 나타났다. 보광에 따른 증산율과 기공전도도는 일출 직후 보광과 함께 높게 상승한 후 소등 후 다시 감소하였다. 보광에 따른 기공면적은 $32.2{\mu}m^2$로 나타났으며, 자연일장(무처리)은 $7.7{\mu}m^2$로 현미경상에서 거의 닫힘 상태를 보였다. 보광에 따른 생육특성에서 스피리트 품종의 경우 초장은 일출 전 후 3시간 보광에 비하여 일몰 후 3시간 보광이 크게 나타났으며, 보광처리가 자연일장에 비하여 모두 초장이 높은 것으로 나타났다. 평균 착과수는 일출 전 후 3시