• 한국환경과학회지
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• 제31권7호
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• pp.569-577
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• 2022

This study aimed to evaluate the growth of Cichorium intybus, Brassica juncea, and Lactuca sativa at varying seed ratios, and to suggest an efficient management plan for sustainable indoor agriculture systems. It was treated with mixed sowing as follows: 30 chicory seeds (chicory alone: CC), 22 chicory seeds + 8 lettuce seeds (C₃L₁), 20 chicory seeds + 10 lettuce seeds (C₂L₁), 15 chicory seeds + 15 lettuce seeds (C₁L₁) as intraspecies, and 30 mustard seeds (mustard alone: MC), 22 mustard seeds + 8 lettuce seeds (M₃L₁), 20 mustard seeds + 10 lettuce seeds (M₂L₁), 15 mustard seeds + 15 lettuce seeds (M₁L₁) as interspecies. The study identified the competitive response in seed germination between Cichorium intybus and Lactuca sativa, and in the C₃L₁ experimental group, Lactuca sativa had the highest leaf length, root length, chlorophyll content, and fresh weight. Therefore, the higher the ratio of Cichorium intybus, the higher the growth and productivity of Lactuca sativa; however, higher the ratio of Lactuca sativa, the lower the growth of Cichorium intybus. Furthermore, the nitrogen and potassium content in the substrate was the highest in the C₃L₁ experimental grorp which had the highest seeding rate of the Cichorium intybus. Comparing the groups Brassica juncea and Lactuca sativa, the higher the seeding ratio of Lactuca sativa, the higher the growth and productivity of Brassica juncea. Therefore, a companion seeding of Brassica juncea and Lactuca sativa is beneficial; this could be effective in having a high seeding ratio of Lactuca sativa.

• Plant Resources
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• 제7권1호
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• pp.69-76
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• 2004

Lettuce (Lactuca sativa L.) is known to contain water-soluble substances that are biologically active. Aqueous or methanol extracts and residues from leaves of lettuce plants were assayed to determine their allelopathic effects, and the causative allelochemicals from fractions were quantified by means of HPLC analysis and bioassayed. Extracts from oven-dried leaf samples were more phytotoxic than those from freeze-dried samples. Leaf extracts of 40 g L$^{-1}$ were completely inhibitory on root growth of alfalfa (Medicago sativa L.), while root growths of barley (Hordeum vulgare L.) and soybean (Glycine max L.) were less sensitive. Early seedling growth of both alfalfa and barnyard grass (Echinochloa crus-galli) was significantly reduced by methanol leaf extracts. The major allelopathic substances analyzed by HPLC were coumarin, trans-cinnamic acid, o-coumaric acid, p-coumaric acid and chlorogenic acid. Of them p-coumaric acid was found as the greatest amount (8.9 mg 100 g$^{-1}$ ) in the EtOAc fraction; only coumarin was found in all the fractions. Hexane and EtOAc fractions of L. sativa reduced alfalfa root growth more than did BuOH and water fractions. These results suggest that lettuce had potent herbicidal activity, and that its activity differed depending on type and amount of causative compounds by fraction.

• The Plant Pathology Journal
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• 제30권1호
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• pp.90-95
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• 2014

This study was conducted to evaluate the resistance of 212 accessions of lettuce germplasm to gray mold disease caused by Botrytis cinerea. The lettuce germplasm were composed of five species: Lactuca sativa (193 accessions), L. sativa var. longifolia (2 accessions), L. sativa var. crispa (2 accessions), L. saligna (2 accessions), and L. serriola (1 accession); majority of these originated from Korea, Netherlands, USA, Russia, and Bulgaria. After 35 days of spray inoculation with conidial suspension ($3{\times}10^7$ conidia/ml) of B. cinerea on the surface of lettuce leaves, tested lettuce germplasm showed severe symptoms of gray mold disease. There were 208 susceptible accessions to B. cinerea counted with 100% of disease incidence and four resistant accessions, IT908801, K000598, K000599, and K021055. Two moderately resistant accessions of L. sativa, K021055 and IT908801, showed 20% of disease incidence of gray mold disease at 45 days after inoculation; and two accessions of L. saligna, K000598 and K000599, which are wild relatives of lettuce germplasm with loose-leaf type, showed complete resistance to B. cinerea. These four accessions are candidates for breeding lettuce cultivars resistant to gray mold disease.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2022년도 추계학술대회
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• pp.73-73
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• 2022

Lettuce (Lactuca sativa L., Family Asteraceae) is highly ranked in production and economic value and is consumed either fresh or in salad mixes because of its important dietary source of bioactive phytochemicals. The world collection of Lactuca spp. leafy crops, maintained in NAC, includes 2,464 accessions from 71 countries around the world, of which 2,411 belong to L. sativa species, nineteen to L. saligna, and fifteen to L. serriolar. We aimed to investigate the lettuce germplasm with morphological and biochemical analyses and provide new material for breeding. The lettuce crop comprises seven main groups of cultivars (including oilseed lettuce) differing phenotypically. Agricultural characteristcs were investigated including time to bolting, time to flowering, seed color, flower color, leaf attitude, leaf color, leaf anthocyanin coloration, type of incision of margin, depth of incisions of margins, and leaf venation. Screening of the health beneficial metabolites like anthocyanin and bitter sesquiterpene lactones (lactucin and lactucopicrin) was also conducted. The range of anthocyanin and SLs were 0~563.78 mg/100g D.W. and 3.74~3311.66 ug/g D.W., respectively. The investigation of the degree of variation regarding phenotypic traits and biochemical revealed adaptive stable and highly variable use of trait collection.

• Plant Resources
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• 제2권1호
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• pp.16-21
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• 1999

An efficient regeneration system was established by using in vitro plantlets of germinated seedlings from different cultivars of lettuce (Lactuca sativa cv. Chongchima, Chongchuckmyun, Jeokchima, Jeokchuckmyun). Shoot formation were observed from all cultivars on MS medium supplemented with 0.1 mg/L NAA and 0.5 mg/L BA. In all cultivars, when cotyledon was cultured, the number of shoot per explant was more greater than that hypocotyl and leaf disc were cultured. Shoot formation rate (91.7%) was high in a cotyledon culture of cultivar, Chongchukmyun. The growth of multiple shoots derived from the cultivar, Chongchukmyun, was most effective on medium containing 0.5 mg/L BA and 1.0 mg/L GA$_3$. When shoots were transferred on MS medium without plant growth regulators, roots were effectively differentiated. Rooted plantlets were acclimated on pots for further propagation.

• 생물환경조절학회지
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• 제6권4호
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• pp.270-276
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• 1997

잎상추의 품질 평가 기준을 도출하기 위하여 청치마 상추를 공시하여 수경재배하고 재배적 조건에 따른 상추의 품질변화를 조사한 결과는 다음과 같다. 수비액온도가 $25^{\circ}C$로 항온인 경우 일정할 경우 주상 생체중이 59.7g으로 수양은 가장 높았으나 외관품질점수는 5.2로 가장 낮았고 온도가 15$^{\circ}C$에서는 수량이 가장 났았으나 외관평유점수은 8.2로 가장 좋았다. 한편 수경액의 온도가 주야간 다를 경우 본 실험에서는 주야간이 각각 20/2$0^{\circ}C$일 경우와 25/2$0^{\circ}C$인 경우가 제일 높았고 그보다 고온이거나 저온일 경우 액양이 낮았는데 잎상추의 외관 품질은 주/야 20/15$^{\circ}C$(평균 17.5$^{\circ}C$)일 경우 제일 우수했고, 잎은 온도가 높을수록 진타익형으로 도장하였고, 외관품질이 현저히 떨어졌다. 하파재배시 60% 차광인 경우 생육이 10% 감소하였고 80% 차광에서는 25% 정도 수량이 감소하였으며 차광정도가 커질수록 엽록소 함량은 감소하고 초장, 근장은 길어지는 경향을 나타내었다.

• 한국토양비료학회지
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• 제43권4호
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• pp.498-505
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• 2010

AMF 접종원 처리가 원예작물의 생육에 미치는 효과를 구명하기 위하여 상추 (Lactuca sativa L.)에 파종단계와 이식단계에서 수단그라스를 기주식물로 증식한 g 당 30개의 포자와 AMF가 감염된 뿌리, 균사 및 토양이 혼합된 접종원을 처리한 후 이식 전후에 걸쳐 작물의 생장반응과 수량성을 비교 검토하였으며, AMF 포자밀도와 감염률 및 감염양상을 조사하였고, 작물의 무기양분의 흡수양태를 분석하였다. 상추의 파종단계에서 AMF 접종원을 처리한 후 생육반응을 조사한 결과, 파종 후 3주가 경과한 초기에서 AMF 접종원 처리구의 상추는 대조구보다 엽수는 9%, 엽의 생체중은 59%, 엽면적은 58% 및 엽장과 엽폭은 21-22%가 증가하였으며 엽록소함량은 2%가 향상되었다. 파종 후 9주가 경과하여서는 파종단계와 이식단계에서의 AMF 접종원 처리구는 대조구에 비해 엽수는 21%와 18%, 엽의 생체중은 51%와 41%, 근체중은 56%와 47%가 각각 증가하였으며 엽록소함량은 18%와 19%가 향상된 것으로 조사되었다. 상추 엽의 P 함량을 분석한 결과 이식단계에서 AMF 접종원 처리구가 대조구보다 217%가 증가된 P 함량을 보임으로서 P의 흡수이용이 증진되었고 상추의 생육에 영향을 미친 것으로 판단된다. 상추 근권토양의 AMF 포자밀도는 상추의 생육초기에 AMF 접종원 처리구가 대조구의 3배를 상회하는 높은 수준으로 나타났고, 9주가 경과하였을 때는 276-295%가 증가된 것으로 조사되었다. AMF 감염률 또한 대조구에 비해 크게 향상된 것으로 조사되었고 생육 후기에는 낭상체와 균사가 치밀하게 발달됨으로서 AMF 의존도가 높음을 확인하였다.

• 식물조직배양학회지
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• 제26권3호
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• pp.219-222
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• 1999

부정아를 유도하기 위하여 발아 7∼10일된 일본 결구상추 2품종과 국내 잎상추 (Lactuca sativa L.)4품종의 하배축 및 자엽절편으로부터 식물체 재분화시스템을 확립하였다. 하배축 및 자엽절편을 BA와 NAA가 조합 처리된 MS 및 SH배지에 치상하여 5주 동안 명배양하였다. 일반적으로 하배축보다는 자엽절편에서, SH 배지보다는 MS 배지에서 배양하였을 때에 부정아 형성률이 높았다. MS배지에 BA는 0.5 ㎎/L, NAA는 0.1∼l ㎎/L로 처리하였을 때에 최고의 부정아 형성률을 보였으며, 품종에 따라 30% ( '만추대청치마')에서 86% 까지의 부정아 형성률을 나타내었다. 형성된 shoot의 95% 이상이 MS 기본배지에서 발근하여 소식물체로 발달하였다.

• 한국환경과학회지
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• 제20권12호
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• pp.1509-1519
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• 2011

The protective effect of nitric oxide (NO) on the antioxidant system under paraquat(PQ) stress was investigated in leaves of 8-week-old lettuce (Lactuca sativa L.) plants. PQ stress caused a decrease of leaf growth including leaf length, width and weight. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated PQ stress induced growth suppression. SNP permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under PQ exposure, suggesting that NO has protective effect on chloroplast membrane in lettuce leaves. Flavonoids and anthocyanin were significantly accumulated in the leaves upon PQ exposure. However, the rapid increase of these compounds was alleviated in the SNP treated leaves. PQ treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in the leaves, while SNP prevented PQ induced increase in malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that SNP serves as an antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, superoxide dismutase (SOD) and catalase (CAT) in lettuce leaves in the presence of NO donor under PQ stress were higher than those under PQ stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, to the lettuce leaves arrested SNP mediated protective effect on leaf growth, photosynthetic pigment and antioxidant systems. However, PTIO had little effect on lettuce leaves under PQ stress compared with that of PQ stress alone. The obtained data suggest that the damage caused by PQ stress is in part due to increased generation of active oxygen by maintaining increased antioxidant enzyme activities and SNP protects plants from oxidative stress. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative damage induced by PQ stress and thus confer PQ tolerance.

• 한국토양비료학회지
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• 제49권5호
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• pp.621-626
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• 2016

The present study evaluated the variations in soil microbial population of controlled horticultural land used for lettuce (Lactuca sativa) cultivation by their fatty acid methyl ester and chemical properties. We utilized four treatment groups, no treatment (NT), culture medium (CM), Bacillus subtilis S37-2 (KACC 91281P) ${\times}10^6CFU\;mL^{-1}$ (BS1), and Bacillus subtilis $S37-2{\times}10^7CFU\;mL^{-1}$ (BS2) and analyzed these variations throughout the before treatment and harvesting stage. The chemical properties such as pH, organic matter, available phosphate, and electrical conductivity in soils before treatment and harvesting stage showed no significant difference among the treatments. Total numbers of bacteria and microbial biomass C in soil treated with BS1 were larger than those of NT, CM, and BS2, whereas total number of fungi at the harvesting stage was significantly lower in the BS1 soil than in the NT and CM soils (P < 0.05). On basis of leaf length, leaf width, leaf number and leaf weight, the growth characteristics lettuce on the soil treated with BS1 and BS2 was faster than those of NT and CM soils. Yield of lettuce with treated BS1 and BS2 were 35% and 29% more than that of NT, respectively.