제초제 약효평가를 위한 잡초의 생체중 기준 고찰

김민지,강광식,임은상,송재은 한국잔디학회 2018 Weed & Turfgrass Science Vol.7 No.1

This study was conducted to establish standard fresh weight data about the minimum amount of occurred weeds at untreated paddy fields, upland fields and orchard fields (including non-cultivated land) in 10 areas. The amount of occurred weeds in each area was compared fresh weight with dry weight. The average percentage for ratio of dry weight to fresh weight in paddy fields was concluded to be 14.8% of Echinochola crus-galli, 12.5% of annual weeds (including Echinochola crus-galli), and 13.9% of perennial weeds. The average percentage for ratio of dry weight to fresh weight in upland fields was concluded to be 20.1% of annual weeds and in orchard fields was concluded to be 18.4% of annual and perennial weeds. According to the research, standard fresh weight about the minimum amount of occurred weeds at untreated paddy fields was proposed to 210 g m-2 of Echinochola crus-galli, 400 g m-2 of annual weeds (including Echinochola crus-galli), and 220 g m-2 of perennial weeds. Standard fresh weight about the minimum amount of occurred weeds at untreated upland fields was proposed to 250 g m-2 of annual weeds and at untreated orchard fields was proposed to 550 g m-2 of annual and perennial weeds. 본 시험은 논, 밭, 과원(비농경지 포함)에서 주로 발생하는 잡초의 생체중과 건물중을 비교하여 무처리 최소 총발생량의 생체중에 대한 기초 자료를 확립하고자 10개 지역에서 시험을 수행하였다. 논 포장의 일년생잡초인 피의건물률 평균은 14.8%, 일년생잡초(피 포함) 건물률 평균은 12.5%, 다년생잡초 건물률 평균은 13.9%로 나타났다. 밭 포장의 일년생잡초의 건물률 평균은 20.1%로 나타났으며, 과원(비농경지 포함)포장 내 일년생 및 다년생잡초총계의 평균은 18.4%로 나타났다. 이에 따라, 생체중에 대한 무처리 최소 총발생량은 논 포장에서는 피 210 g m-2, 일년생잡초(피 포함) 400 g m-2, 다년생잡초 220 g m-2로 제시할 수 있다. 또한, 밭 포장에서는 일년생잡초 250 g m-2, 과원(비농경지 포함) 포장에서는 일년생 및 다년생잡초 총계 550 g m-2으로 제시할 수 있다.

치커리 근경이 치콘 생육에 미치는 영향

서현택(HyunTaek Seo),원재희(JaeHee Won),전신재(ShinJae Jeon),강호민(Ho-Min Kang) (사)한국생물환경조절학회 2011 생물환경조절학회지 Vol.20 No.2

본 연구는 치커리 뿌리의 외적요인과 치콘의 생체중간에 관계를 분석하고, 이중 높은 상관관계를 보인 요인을 치콘 규격 생산에 적합한 종근의 외적 판단기준으로 이용할 수 있는 자료를 만들고자 수행하였다. 종근의 외적요인인 근경(0.726)과 근중(0.508)의 상관관계를 보면 모두 생체중과 정(+)의 상관관계를 보였다. 치콘 생체중에 영향을 주는 종근의 외적요인인 근경과 근중 중 상대적으로 높은 영향인지를 찾기 위하여 다중회귀 분석을 실시한 결과 치커리 근경의 회귀계수 (6.06<SUP>***</SUP>)만이 유의하여 치콘 생체중에 영향을 미치는 것으로 나타났다. 3가지 품종의 치커리를 근경(x) 크기 별로 x≤30㎜, 30<x≤40㎜, 40<x≤50㎜, x>50㎜로 분류하여 치콘을 생산한 결과 거의 모든 품종에서 근경이 증가할수록 치콘 생체중, 치콘 폭, 엽수 등이 증가하였다. 이상의 결과로 보아 치커리 종근의 탄수화물 함량 등 내부요인을 분석하지 않고, 상대적으로 간편한 외적요인인 치커리 근경을 수확 후 측정하여 치콘의 생체중을 미리 판단할 수 있을 것으로 사료되었다. This study was conducted to investigate correlation between external factors of chicory root and chicon fresh weight, whereby, to provide basic information of external yardstick of producing standardized chicon. For correlation between external factors (root diameter, root weight) of chicory root and chicon fresh weight were highly correlated. The relationship between external factors (root diameter, root weight) of chicory root and chicon fresh weight, root diameter was strongly affecting chicon fresh weight due to significant at its regression coefficient (6.06<SUP>***</SUP>). In order to verify this correlation, the root diameter (x) of chicory that were 3 different varieties were based on the 4 different root diameter treatments, such as x≤30 ㎜, 30<x≤40㎜, 40<x≤50㎜ and x>50 ㎜. The chicon production increased as root diameter increased and the chicon fresh weight, chicon width, and the number of leaves increased as well. Therefore, the measure of root diameter of chicory instead of the internal factors (carbohydrate, and so on.) can be used to predict the chicon fresh weight.

Growth and Nutrient Contents of Tomato Plug Seedlings as Influenced byRoot Substrate Composition and Pre-planting Fertilizer Level

최종명,안주원,구자형 한국원예학회 2008 Horticulture, Environment, and Biotechnology Vol.49 No.6

This research was conducted to determine the effect of root substrate formulations and pre-planting fertilizer levels on growth and nutrient contents of tomato ‘Zuiko No. 102’ seedlings grown in 72-cell plug trays. Three root substrates, coir+perlite (8:2, v/v, CP), peatmoss+perlite (8:2, v/v, PP) and coir+peatmoss+perlite (4:4:2, v/v/v, CPP), had three pre-planting fertilizer levels such as 0.5x, 1.0x and 2.0x. Elevated pre-planting fertilizer levels in the three root substrates increased plant height, fresh weight and dry weights. The fresh and dry weights in the 2.0x treatment in CP, PP and CPP substrates at 35 days after sowing were 1.97 g and 180 mg, 2.84 g and 245 mg, and 2.97 g and 235 mg, respectively. In comparison of the three root substrates containing equal amounts of pre-planting fertilizers, crop growth was the greatest in the PP and the least in the CPP. Elevated pre-planting fertilizer levels in each root substrate also increased the fresh and dry weights at 70 days after sowing. The seedlings grown in CPP showed the greatest dry weight followed by those in PP and CP. Elevated pre-planting fertilizer levels resulted in increase of tissue K, Ca and Mg contents and decrease of tissue Fe and Mn contents at 35 days after sowing in all substrates. However, elevated pre-planting levels decreased tissue P content in CP and CPP but increased that in PP. Elevated pre-planting fertilizer levels increased tissue Ca and Mg contents and decreased tissue Fe and Mn contents in all substrates at 70 days after sowing. Elevated pre-planting fertilizer levels did not affect tissue K content in PP at 70 days after sowing.

Growth and Nutrient Contents of Tomato Plug Seedlings as Influenced by Root Substrate Composition and Pre-planting Fertilizer Level

Jong Myung Choi,Joo Won Ahn,Ja Hyeong Ku 한국원예학회 2008 Horticulture, Environment, and Biotechnology Vol.49 No.6

This research was conducted to determine the effect of root substrate formulations and pre-planting fertilizer levels on growth and nutrient contents of tomato ‘Zuiko No. 102’ seedlings grown in 72-cell plug trays. Three root substrates, coir+perlite (8:2, v/v, CP), peatmoss+perlite (8:2, v/v, PP) and coir+peatmoss+perlite (4:4:2, v/v/v, CPP), had three pre-planting fertilizer levels such as 0.5x, 1.0x and 2.0x. Elevated pre-planting fertilizer levels in the three root substrates increased plant height, fresh weight and dry weights. The fresh and dry weights in the 2.0x treatment in CP, PP and CPP substrates at 35 days after sowing were 1.97 g and 180 ㎎, 2.84 g and 245 ㎎, and 2.97 g and 235 ㎎, respectively. In comparison of the three root substrates containing equal amounts of pre-planting fertilizers, crop growth was the greatest in the PP and the least in the CPP. Elevated pre-planting fertilizer levels in each root substrate also increased the fresh and dry weights at 70 days after sowing. The seedlings grown in CPP showed the greatest dry weight followed by those in PP and CP. Elevated pre-planting fertilizer levels resulted in increase of tissue K, Ca and Mg contents and decrease of tissue Fe and Mn contents at 35 days after sowing in all substrates. However, elevated pre-planting levels decreased tissue P content in CP and CPP but increased that in PP. Elevated pre-planting fertilizer levels increased tissue Ca and ㎎ contents and decreased tissue Fe and Mn contents in all substrates at 70 days after sowing. Elevated pre-planting fertilizer levels did not affect tissue K content in PP at 70 days after sowing.

Differences in Productivity among Rape Varieties for Oil Seed and Forage

Kwon, Byung-Sun,Lim, June-Taeg,Shin, Jeong-Sik,Ahn, Gae-Soo,Park, Hee-Jin The Korean Society of Crop Science 2003 한국작물학회지 Vol.48 No.5

In order to examine the possibility that oil seed rape could be used as a forage fodder crop and to select the most suitable variety of forage rape at the southern area of Korea, two varieties of oil seed rape currently grown for oil production and six introduced varieties of forage rape with relatively high yield and high nutritional value were grown at the same condition their and yield components were observed. Forage rape was superior to oil seed rape in terms of yield components, plant fresh weight and plant dry mater weight. Velox was superior to any other variety of forage rape in these characters. When plant dry matter weight of the rape was subdivided into four components such as a main stem, branch stems, main stem leaves and branch leaves, contribution of these components to plant dry matter weight was in the order of branch stems, branch leaves, the main stem and main stem leaves. Dry matter percentage of the rape ranged from 9.32 to 11.08 percent, which was somewhat low value. There was no significant difference between two groups of the rape in terms of dry matter percentage. Velox showed somewhat higher value in dry matter percentage.

전처리제 및 보존용액이 겹도라지의 절화수명에 미치는 영향

허윤선,이희두,이정관,이기열 한국화훼산업육성협회 2015 화훼연구 Vol.23 No.2

본 연구는 자색 겹꽃이 피어 관상가치가 높은 겹도라지(Platycodon grandiflorum var. duplex Makino)의 수확 후 절화 품질 향상을 위하여 몇가지 전처리제 및 보존용액이 겹도라지 절화 수명에 미치는 영향을 구명코자 하였다. 2년생 겹도라지를 2012년 6월 하순에서 7월 상순에 수확한 후 전처리제 및 보존용액 종류별로 처리하여 절화 특성을 조사하였다. 3% sucrose와 살균제인 200mg • L−1 Al2(SO4)3가 혼용 첨가된 전처리 용액에서 절화 수명 연장 및 개화율 향상 효과가 가장 컸고 생체중 및 용액흡수율도 크게 증가한 반면, 200mg • L−1 GA3 와 150mg • L−1 citric acid를 전처리제에 추가로 첨가하였을 때에는 전처리 효과의 차이는 크게 없는 것으로 조사되었다. 또한 보존용액으로 3% sucrose와 150mg • L−1 HQS을 혼용 처리하였을 때 절화 품질이 가장 양호하였으나, AgNO3이 추가로 첨가되었을 때에는 큰 차이가 없었다. NaOCl이 첨가된 용액에 전처리하였을 경우에는 보존용액의 종류와 상관없이 모든 처리구에서 절화 수명이 짧았고 개화율도 가장 낮게 조사되었는데, 본 실험에 사용된 NaOCl의 농도가 높아 약해가 발생하여 절화 품질이 떨어진 것으로 판단되었다. 따라서 겹도라지 절화의 상품가치를 최대로 높일 수 있는 전처리제 및 보존용액으로 각각 3% sucrose + 200mg • L−1 Al2(SO4)3 및 3% sucrose + 150mg • L−1 HQS 을 사용하였을 때 절화 수명은 최대 22일까지 연장되었고, 90% 이상의 개화율을 보였으며, 생체중 및 용액흡수율도 가장 증가되어 절화 품질을 향상시키는 데 효과적이었다. To improve postharvest flower quality and extend vase life of cut balloon flowers (Platycodon grandiflorum var. duplex Makino), the effects of pretreatment and holding solutions on vase life were investigated in this study. Balloon flowers which were cultivated for two years were harvested from end of June to beginning of July in 2012. After harvest, cut balloon flowers were treated with various pretreatment solutions including distilled water, sucrose, Al2(SO4)3, and NaOCl for 1 hour, and continuously put in the holding solutions including distilled water, sucrose, HQS, and AgNO3. The pretreatment solution containing 3% sucrose + 200 mg • L−1 Al2(SO4)3 significantly extended vase life and increased flowering rate, fresh weight and solution uptake, but when 200 mg • L−1 GA3 and 150 mg • L−1 citric acid were added, differences of flower quality were not observed Holding solution with 3% sucrose + 150 mg • L−1 HQS extended vase life and increased flowering rate, fresh weight and solution uptake. But addition of 25 mg • L−1 AgNO3 into holding solution with 3% sucrose + 150 mg • L−1 HQS showed little differences in flower quality. When 80 mg • L−1 NaOCl was pretreated, vase life was shortened and flowering rate decreased, irrespective of holding solution types. It was suggested that the high concentration of NaOCl induce the phytotoxic effect such as decline of vase life or fresh weight. From these results, we could find that the pretreatment solution containing 3% sucrose + 200 mg • L-1 Al2(SO4)3 and preservatives with 3% sucrose + 150 mg • L−1 HQS were very effective in extending vase life and retarding senescence of cut balloon flowers, furthermore, these postharvest treatments were very useful to improve the physiological properties of cut balloon flowers.

전처리제 및 보존용액이 겹도라지의 절화수명에 미치는 영향

허윤선,이희두,이정관,이기열 한국화훼학회 2015 화훼연구 Vol.23 No.2

To improve postharvest flower quality and extend vase life of cut balloon flowers (Platycodon grandiflorum var. duplex Makino), the effects of pretreatment and holding solutions on vase life were investigated in this study. Balloon flowers which were cultivated for two years were harvested from end of June to beginning of July in 2012. After harvest, cut balloon flowers were treated with various pretreatment solutions including distilled water, sucrose, Al2(SO4)3, and NaOCl for 1 hour, and continuously put in the holding solutions including distilled water, sucrose, HQS, and AgNO3. The pretreatment solution containing 3% sucrose + 200 mg • L−1 Al2(SO4)3 significantly extended vase life and increased flowering rate, fresh weight and solution uptake, but when 200 mg • L−1 GA3 and 150 mg • L−1 citric acid were added, differences of flower quality were not observed Holding solution with 3% sucrose + 150 mg • L−1 HQS extended vase life and increased flowering rate, fresh weight and solution uptake. But addition of 25 mg • L−1 AgNO3 into holding solution with 3% sucrose + 150 mg • L−1 HQS showed little differences in flower quality. When 80 mg • L−1 NaOCl was pretreated, vase life was shortened and flowering rate decreased, irrespective of holding solution types. It was suggested that the high concentration of NaOCl induce the phytotoxic effect such as decline of vase life or fresh weight. From these results, we could find that the pretreatment solution containing 3% sucrose + 200 mg • L-1 Al2(SO4)3 and preservatives with 3% sucrose + 150 mg • L−1 HQS were very effective in extending vase life and retarding senescence of cut balloon flowers, furthermore, these postharvest treatments were very useful to improve the physiological properties of cut balloon flowers. 본 연구는 자색 겹꽃이 피어 관상가치가 높은 겹도라지(Platycodon grandiflorum var. duplex Makino)의 수확 후 절화 품질 향상을 위하여 몇가지 전처리제 및 보존용액이 겹도라지 절화 수명에 미치는 영향을 구명코자하였다. 2년생 겹도라지를 2012년 6월 하순에서 7월 상순에 수확한 후 전처리제 및 보존용액 종류별로 처리하여 절화 특성을 조사하였다. 3% sucrose와 살균제인 200mg • L−1 Al2(SO4)3가 혼용 첨가된 전처리 용액에서 절화 수명 연장 및 개화율 향상 효과가 가장 컸고 생체중및 용액흡수율도 크게 증가한 반면, 200mg • L−1 GA3 와150mg • L−1 citric acid를 전처리제에 추가로 첨가하였을때에는 전처리 효과의 차이는 크게 없는 것으로 조사되었다. 또한 보존용액으로 3% sucrose와 150mg • L−1 HQS을 혼용 처리하였을 때 절화 품질이 가장 양호하였으나, AgNO3이 추가로 첨가되었을 때에는 큰 차이가 없었다. NaOCl이 첨가된 용액에 전처리하였을 경우에는 보존용액의 종류와 상관없이 모든 처리구에서 절화 수명이짧았고 개화율도 가장 낮게 조사되었는데, 본 실험에 사용된 NaOCl의 농도가 높아 약해가 발생하여 절화 품질이 떨어진 것으로 판단되었다. 따라서 겹도라지 절화의상품가치를 최대로 높일 수 있는 전처리제 및 보존용액으로 각각 3% sucrose + 200mg • L−1 Al2(SO4)3 및 3% sucrose + 150mg • L−1 HQS 을 사용하였을 때 절화 수명은 최대 22일까지 연장되었고, 90% 이상의 개화율을 보였으며, 생체중 및 용액흡수율도 가장 증가되어 절화 품질을 향상시키는 데 효과적이었다.

Seed development and hydroxy fatty acid biosynthesis in <i>Physaria lindheimeri</i>

Chen, Grace Q.,Riiff, Timothy J.,Johnson, Kumiko,Morales, Eva,Kim, Hyun Uk,Lee, Kyeong-Ryeol,Lin, Jiann-Tsyh ELSEVIER 2017 INDUSTRIAL CROPS AND PRODUCTS Vol. No.

<P><B>Abstract</B></P> <P>Hydroxy fatty acids (HFAs) are valuable industrial raw materials used in many industries. <I>Physaria lindheimeri</I> accumulates over 80% HFA, in the form of lesquerolic acid (20:1OH), in its seed oil. Understanding the seed development of <I>Physaria lindheimeri</I> is an important step to utilizing this unique wild species as a genetic source of HFAs biosynthesis. The changes of seed growth, lipid accumulation and fatty acid composition during seed development of <I>P. lindheimeri</I> were examined from 14days after pollination (DAP) to desiccation (56 DAP). The seed development could be divided into three periods. During the early period (14 and 21 DAP), seed rapidly increased in size and fresh weight. In mid-maturation period (28, 35, and 42 DAP), lipids and dry weights accumulated steadily. When seeds developed to late-maturation/desiccation stages (49 and 56 DAP), fresh weight dropped significantly due to water loss, and the dry weight and lipid accumulation reached their maximums. Seed color remained green up to 42 DAP and turned to orange-brown at 49 and 56 DAP. The major fatty acid 20:1OH started accumulation when seeds developed into mid-maturation stage (28 DAP) and the accumulation continued thereafter up to 56 DAP, eventually reaching up to 77% of the total seed oil. The HFA accumulation indicates embryonic storage tissue formation, thus 28 DAP defines a critical time point for seed development entering reserve synthesis and accumulation. The information and knowledge obtained from this study are essential to the success of HFA production using metabolic pathway engineering approaches in commodity oilseed crops.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Three distinct seed developmental periods of <I>Physaria lindheimeri</I> have been established. </LI> <LI> A starting time point of embryo development of <I>P. lindheimeri</I> has been identified. </LI> <LI> This research provides a framework for future seed developmental studies in <I>P. lindheimeri</I>. </LI> </UL> </P>

NH₄⁺: NO₃⁻ 시비 비율이 금어초 플러그 묘 생장과 상토 화학성 변화에 미치는 영향

이풍옥(Poong Ok Lee),이종석(Jong Suk Lee),최종명(Jong Myung Choi) (사)한국생물환경조절학회 2010 생물환경조절학회지 Vol.19 No.4

금어초 ‘Potomac Red'를 200공 플러그 트레이에서 육묘하면서 NH₄?과 NO₃? 비율을 조절한 액비로 시비한 결과 초장, 생체중 및 건물중 모두 27 : 73(NH₄?:NO₃?)의 비율로 시비된 처리에서 가장 좋은 생장을 나타냈다. 파종 56일 후 식물조직의 질소와 인산함량은 27 : 73로 시비된 처리에서 각각 2.84% 및 0.39%로 가장 높게 분석되었다. 식물체내 K의 함량은 처리간 차이가 뚜렷하지 않았지만, 관비용액의 NH₄? 비율이 높아질수록 식물체의 Ca 및 Mg 함량이 감소하는 경향이었다. 상토의 pH는 파종 3주 후부터 NH₄?과 NO₃?의 시비 비율에 따른 처리간 차이가 발생하여 8주까지 계속적으로 변하였으며, NO₃?의 비율이 증가할수록 중성쪽으로, 그리고 NH₄?의 비율이 증가할수록 산성쪽으로 변하였다. 상토의 EC는 NH₄?의 비율이 증가할수록 높아졌고, 100% NH₄? 처리에서 파종 8주 후 2.2dSㆍm?¹까지 상승하였다. NH₄?:NO₃?의 비율에 따른 상토 중 질소 농도변화는 100 : 0의 비율에서 가장 높은 NH₄?-N 농도를, 0 : 10에서 가장 높은 NO₃?-N 농도를 나타내었고, 상토의 인산농도는 처리간 뚜렷한 차이가 없이 식물이 생장함에 따라 토양의 인산농도는 낮아졌다. 그러나 관비용액의 NH₄? 비율이 높아질수록 상토의 K, Ca 및 Mg 농도가 높아지는 경향이었다. 관비 용액의 NH₄?:NO₃?의 비율에 대한 식물생장 반응을 고려할 때 두 질소 비율로 27 : 73으로 조절하는 것이 플러그 육묘를 위해 바람직하다고 판단하였다. Objective of this research was to investigate the influence of NH₄? and NO₃? ratios in liquid feeding on the growth of snapdragon 'Potomac Red' and changes in medium chemical properties. The seeds were sown into 200 plug trays and fertigated once a week with nutrient solution containing various ratios of NH₄? and NO₃? such as 0 : 100, 27 : 73, 50 : 50, 73 : 27, and 100 : 0. The total N concentrations were adjusted to 50, 100 and 150 ㎎ㆍL?¹ in plug stages of 2, 3, and 4, respectively. Determination of seedling growth and analysis of plant tissue and root medum were conducted at 56 days after sowing. The treatment of 27 : 73 (NH₄?:NO₃?) had the greatest plant height, fresh weight, and dry weight. The N and P contents in 27 : 73 (NH₄?:NO₃?) treatment based on the above ground plant tissues were 2.39 and 0.39%, respectively, which were the greatest among treatments. The elevation of NH₄? ratio in fertigation solution decreased tissue Ca and Mg contents, but that did not influence tissue K content. The variations in NH₄?:NO₃? ratios impacted the soil solution pH and the difference among treatments had been severe since three weeks after sowing. Elevation of NH₄? ratios in fertigation solution increased electrical conductivity and concentrations of K, Ca, and Mg in soil solution of root medum. The NH₄? and NO₃? concentrations in the soil solution were high in weeks 2, 3, and 4, then decreased gradually as the biomass of seedlings increased. Medium P concentration decreased gradually as seedlings grew, but statistical differences were not observed among treatments.

Growth Characteristics, Antixoident Capacity and Total Phenolic Content of Lettuce According to Generation Position of Air Anion in a Closed-type Plant Factory

Jin-Ho Won,Jung Hyun Lee,Byeong Hyo Cho,Chung Su Han,Tae Hwan Kang 한국원예학회 2018 원예과학기술지 Vol.36 No.6

This study investigated the growth characteristics of lettuce (Lactuca sativa L. ‘Jeokchima’) according tothe position of air anion treatment in a closed-type plant factory. The experimental conditions in theplant factory were as follows: fluorescent light with photoperiod of 16/8 h (light/dark), temperature of20 ± 2°C and 50 ± 5% relative humidity. The nutrient solutions had a pH of 6.0 ± 0.5 and 1.8 ± 0.2 dS·m-1electrical conductivity (EC). The plants were transplanted into the factory from a plastic bed andexposed to air anion treatment from three different positions (sideward, upward, and downward) for 4weeks. The growth characteristics of lettuce (leaf length and width, shoot fresh weight and shoot dryweight, leaf area, chlorophyll content, antioxidant capacity, and total phenol content) were measured at3 weeks and 4 weeks. After 4 weeks in the downward anion treatment, lettuce leaves were 14% longerand 21.5% wider than the leaves of the control plants. Furthermore, the shoot fresh weight of lettucegrown in the downward anion treatment was 37.1% greater than that of the control lettuce. Similarresults were observed for shoot dry weight. Out of the 3 positions of anion generation, the downwardposition produced lettuces with the greatest leaf area. The chlorophyll content of lettuce decreased duringall of the anion treatments. The antioxidative activity and total phenol content of lettuce decreased duringthe downward anion treatment. These results imply that the optimum position of anion treatment forincreasing lettuce production in closed-type plant factories is the downward position.