Height Suppression of Cucumber and Tomato Plug Seedlings Using of Brushing Stimulus

Abstract

This study aimed to evaluate the effect of height suppression of cucumber and tomato plug seedlings as affected by mechanical stimulus using brushing as environment-friendly method. Cucumber (Cucumis sativus L. 'Joeunbaekdadagi') and tomato (Solanum lycopersicum L. 'Mini Chal') seeds were sown in 40-cell plug trays (54 × 27.5 × 5 cm) filled with growing medium on Oct. 9, 2017. The cultivation environment in a venlo-type glasshouse was maintained as cultivation temperature range of 15-25 o C and the relative humidity of 50 ± 10%. Non-treatment and diniconazole (7.5 mg·L-1) application at 15 days after sowing were used as the control. In addition, brushing treatments in cucumber and tomato were applied interval of 2, 4 or 6 hrs for 15 and 20 days, respectively. Plant height, hypocotyl length, and internode length were inhibited for cucumber and tomato in the diniconazole treatment than in the control. The leaf size was reduced, both cucumber and tomato, while the SPAD increased under the diniconazole treatment. However, stem diameter of cucumber was the thickest in the 2 hrs brushing interval treatment. Fresh weights of shoot and root were the significantly lowest in the diniconazole treatment. Application of brushing improved seedlings quality by promoting dry weights of shoot and root, and compactness of tomato seedlings. The chlorophyll fluorescence of tomato seedlings drastically decreased with 2 hrs treatment, indicating that mechanical stress by brushing treatment. The relative growth rate of tomato seedlings was significantly lower in the diniconazole treatment, but cucumber seedlings were not significantly different in all treatments. As a results, height suppression of cucumber and tomato seedlings was best achievement in the diniconazole treatment by the chemical as growth regulator. In an environment-friendly point of view, however, it is considered that 2 hrs brushing interval treatment can be the applicability for replacing the chemical methods in plug seedling growth of cucumber and tomato. Additional key words : compactness, Cucumis sativus, mechanical stimulus, relative growth rate, Solanum lycopersicum 서 론 플러그 묘(plug seedlings)란 응집성이 있는 소량의 배 지가 담긴 개개의 셀(cell)에서 길러진 묘종을 말한다 (Nelson, 1991). 플러그 묘는 적은 면적에서 균일한 묘의 대량 생산과 관리 및 운반이나 취급의 편의성을 가지고 있으며(Moon 등, 2010), 1990년대 초반 국내에 공정육 묘 산업이 도입되기 시작하며 육묘와 재배의 전문화 및 분업화를 실현하였다(Jeong, 2002). 과채류 공정묘의 생 산에 있어 양질의 묘란 굵은 경경, 짙은 녹색 잎, 그리 고 잘 발달된 뿌리와 같은 형태적 특성을 나타낸다. 줄 기가 도장되고 옅은 녹색 잎과 발달되지 못한 작은 뿌 리를 가진 묘종은 정식 후 환경적 스트레스로 인해 수 확량 감소의 결과를 초래할 수 있는 문제점이 발생한다 (Seiler와 Johnson, 1988; Vu 등, 2015). 하지만 플러그 묘는 작은 셀 내에서 육묘되기 때문에 재식밀도가 높아 육묘기에 도장하기가 쉬우며, 이러한 과채류 작물 육묘 의 도장 현상은 부적절한 수분 및 온도조절, 고온기 및