Abstract
Objective of this research was to investigate the effect of nitrogen concentrations in the fertilizer solution on growth and development of nutrient deficiency in leaf perilla (Perilla frutesens). The nutrient concentrations in above-ground plant tissue, petiole sap and soil solution of root media were also determined. Nitrogen deficiency resulted in dwarfed growth, small leaves, and bright yellow color of older leaves. The leaves of deficient plants became uniform yellowing in color and finally necrosis occurred on the deficient leaves. Elevation of N concentrations in the fertigation solution from 0 to 20 mM increased the crop growth in leaf length and width as well as fresh and dry weights of above ground plant tissue. That also resulted in the increase of chlorophyll contents. However, light toxicity symptoms such as abnormal leaf surface appeared on crops grown in 20 mM N fertilization. The plant growth was commercially acceptable in the treatments of 10 and 15 mM N. The plants with acceptable growth had 0.9 to 1.25% in N contents of above-ground plant tissue, 800 to $3,300mg{\cdot}kg^{-1}$ in the $NO_3-N$ concentrations of petiole sap, and 28.7 to $47.3mg{\cdot}kg^{-1}$ in the $NO_3-N$ concentrations of soil solution (1:2 extract) at 75 days after transplanting.
본 연구는 질소의 시비농도를 인위적으로 조절하여 잎들깨를 관비재배 하면서 질소의 시비수준이 생장과 결핍증상 발현에 미치는 영향을 구명하고, 생육을 우수하게 유지할 수 있는 식물체 및 토양의 한계농도를 밝히기 위하여 수행하였다. 질소 무시비구에서 지상부 식물생육의 심한 억제 현상과 노엽의 엽신 전체가 황화된 후 점차 괴사하는 결핍증상이 나타났다. 질소 시비농도가 높아질수록 정식 75일 후의 생체중과 건물중이 무거워졌고, 엽병 추출액의 $NO_3-N$ 농도와 토양 $NO_3-N$ 농도가 높아졌으나, 20mM 시비구에서는 질소과잉증상이 나타났다. $10{\sim}15mM$ 시비구에서 가장 바람직한 생장을 보였으며, 이때의 질소 함량은 건물중 기준으로 $0.9{\sim}1.25%$, 엽병추출액 및 1:2 추출법으로 분석한 토양의 $NO_3-N$ 농도가 각각 $800{\sim}3,300mg{\cdot}kg^{-1}$ 및 $28.7{\sim}47.3mg{\cdot}L^{-1}$ 범위에 포함되었다.
