Popular Leafy Vegetables Research Articles

High-voltage electrostatic field combined with light-emitting diode irradiation: A new method for optimizing the quality of modified atmosphere packaged pakchoi

Pakchoi is one of the most popular leafy vegetables for fleet crews. Modified atmosphere packaging (MAP), most commonly used on ships today, can only extend the shelf life of pakchoi by up to 25 days, far short of the requirements for ocean voyages (>50 days). The objective of this study was to use a combination of emerging non-thermal physical fields (high voltage electrostatic field (HVEF), light emitting diode (LED) irradiation) and modified atmosphere packaging, acting on structural changes caused by external energy field and the molecular changes caused by signal molecular transfer, respectively, to produce a superimposed effect on the pakchoi thereby extending it shelf life to a predetermined target. The treatment maintained the chlorophyll content, ascorbic acid content, hardness and membrane system integrity of packaged pakchoi, effectively reducing respiration rate and polyphenol oxidase activity. Electronic nose and low-field NMR analyses also confirmed better flavor and less water migration in pakchoi. Hierarchical cluster analysis (HCA) revealed that pakchoi stored for 25 days could still be classified in the same category as fresh samples. The results showed that the shelf life of the shipboard pakchoi was successfully extended to 50 days, proving that the synergistic preservation treatment has promising applications.

First report of Pectobacterium carotovorum and Pectobacterium brasiliense causing bacterial soft rot of bok choy in Taiwan.

Bok choy (Brassica rapa var. chinensis) is one of the most popular leafy green vegetables in Asia (Wang et al. 2019; Zhang et al. 2014). In May 2022, disease resembling bacterial soft rot was observed in a commercial greenhouse located in Xiluo, Yunlin County, Taiwan. Affected plants exhibited maceration, primarily close to the base of the plants (Fig. S1). Almost all bok choy plants (about 1,800 plants in total) on site were symptomatic. Macerated tissues were collected from six plants. The samples were homogenized in 10 mM MgCl2 and bacteria were isolated on nutrient agar (NA) by streak plating. After 1 day of culturing at 28°C, creamy-white, round colonies were consistently grown on all the plates, and six strains (Br1 to Br6) were obtained; each isolated from a different plant. The strains were able to ferment glucose and induced maceration on potato tuber slices (Schaad et al. 2001) but could not produce indigoidine on NGM medium (NA added with glycerol and MnCl2; Lee and Yu 2006). The DNA samples of these strains were tested with Pectobacterium-specific primers Y1 and Y2 (Darrasse et al. 1994) and all samples produced the expected amplicon. To identify the isolated pathogens, 1,592-bp sequences concatenated from fragments of the leuS (452 bp), dnaX (492 bp), and recA (648 bp) genes (GenBank accession nos. OP360013-OP360021) were obtained for each strain as previously described (Portier et al. 2019). Three genotypes were detected, the sequences of strains Br1, Br2, Br4, and Br5 were identical, while strains Br3 and Br6 each belong to a different genotype. The sequence identity between Br3 and Br6 was 98.2%. The concatenated sequences (dnaX-leuS-recA), along with those of type strains from known Pectobacterium species, were subjected to maximum likelihood analysis. The reconstructed trees showed that strains Br1, Br2, Br4, and Br5 grouped with P. carotovorum CFBP2046T (Fig. S2); the sequence identity between the isolated strains and the type strain was 98.7%. Strains Br3 and Br6 clustered with P. brasiliense CFBP6617T (Fig S2); the sequence identity between CFBP6617T and Br3 and Br6 were 97.5% and 98.4%, respectively. The six strains were inoculated onto 55-day-old bok choy plants using previously described prick inoculation methods (Wei et al. 2019). Autoclaved toothpicks, each carrying 9.3 x 106- 5.6 x 107 cfu of bacteria, were used to inoculate the base of plant leaves. All six strains were tested, and each strain had three replicates. Plants in the control group were stabbed with bacteria-free toothpicks. The plants were enclosed in clear plastic bags during the assay to maintain humidity and kept in a growth chamber (27/25°C day/night; 14-h photoperiod). After 1 d, all inoculated plants produced soft rot symptoms resembling those observed in the sampling site. No noticeable differences were observed among symptoms produced by different strains. The controls were symptomless. One strain was re-isolated from each treatment group and their identity were confirmed by sequencing the dnaX gene. All re-isolated strains shared the same sequences with those of the original strains tested. This is the first report of P. brasiliense and P. carotovorum causing bacterial soft rot of bok choy in Taiwan. Importantly, the findings showed that different Pectobacterium species and genotypes could induce symptoms on a crop in the same facility at the same time, highlighting the potential complexity of interactions among different soft rot bacteria in the environment.

Effect of different sources of organic fertilizers on crop growth and yield of cabbage

Cabbage is (Brassica oleracea var. capitata) a popular leafy vegetable in Nepal, but depleted soil fertility and inefficient production techniques can limit productivity. To address this, we conducted a study in the Jumla district of Karnali Province, Nepal during the 2022 main cropping season. We evaluated the impact of different organic fertilizers on the growth and yield of cabbage using a Randomized Complete Block Design with seven treatments and three replications with the hybrid cultivar 'Green Coronet'. The treatments included Farm Yard Manure, Poultry Manure, FYM + Vermicompost, Vermicompost, Black Wonder, FYM + Poultry Manure, and Sheep Manure. The parameters, including plant height, stem diameter, leaf length and width, head weight, polar and equatorial diameter, head circumference, root and shoot weight, and weight of the head (g) of cabbage were taken for measurement. Our findings showed that organic fertilizers significantly influenced the growth and yield of cabbage, with Vermicompost showing the most potential as a nutrient source for achieving higher growth and yield. The Vermicompost treatment resulted in the largest size of cabbage head (1026 g), while the Farm Yard Manure and Poultry Manure treatments had limited impact. Our results suggest that the use of organic fertilizers such as Vermicompost can lead to higher cabbage production, improved soil fertility, and reduced reliance on chemical fertilizers and pesticides. This has significant implications for promoting sustainable agriculture practices, improving food security, and providing economic benefits for farmers and communities in Nepal and beyond.

Bacteria Associated With the Leafy Salad Vegetables Of Old Dhaka City and Their Multiple Antibiotic Resistance (Mar) Index

The present work aimed to evaluate the bacteria associated with the most popular leafy salad vegetables like Coriander, Mint, and Lettuce and their antibiotic resistance pattern. Samples were collected from Rayshaheb Bazar, Nazira Bazar, and Shyam Bazar during June-August 2019. The maximum bacterial load was found in Coriander and the minimum bacterial load was in Mint. A total of 149 colonies were isolated and 35 isolates were selected for Culture and Sensitivity test against 15 common antibiotics like Amoxicillin (Ax), Cefixime (CFM), Levofloxacin (Lev), Clarithromycin (CLR), Ceftriaxone (CRO), Neomycin (N), Kanamycin (K), Ciprofloxacin (Cip), Erythromycin (E), Doxycycline (Do), Vancomycin (VA), Cefuroxime (CXM), Chloramphenicol (C), Rifampicin (RA), and Gentamycin (CN). Sixteen antibiotic resistant bacterial isolates were selected for their identification and drug resistance pattern. Among these 15 antibiotic resistant bacterial isolates, only 2 were Gram positive and were identified as Enterococcus faecalis and the Gram negative bacteria belonged to the genus Enterobacter (9), Serratia (3), Klebsiella (2).The drug resistance pattern showed that most of the isolated bacteria were resistant against Amoxicillin and susceptible to Chloramphenicol. The (multiple antibiotic resistance (MAR) inedx of the isolated bacteria ranged between 33.33% and 86.67% which is very alarming. Dhaka Univ. J. Biol. Sci. 31(2): 361-369, 2022 (July)

Mapping of the AgWp1 gene for the white petiole in celery (Apium graveolens L.)

Celery (Apium graveolens L.) is one of the most popular leafy vegetables worldwide. The main edible parts of celery are the leaf blade and especially the petiole, which typically has a white, green and red color. To date, there are very few reports about the inheritance and gene cloning of celery petiole color. In this study, bulked segregant analysis-sequencing (BSA-Seq) and fine mapping were conducted to delimit the white petiole (wp1) loci into a 668.5-kb region on Chr04. In this region, AgWp1 is a homolog of a DAG protein in Antirrhinum majus and a MORF9 protein in Arabidopsis, and both proteins are involved in chloroplast development. Sequencing alignment shows that there is a 27-bp insertion in the 3′-utr region in AgWp1 in the white petiole. Gene expression analysis indicated that the expression level of AgWp1 in the green petiole was much higher than that in the white petiole. Further cosegregation revealed that the 27-bp insertion was completely cosegregated with the petiole color in 45 observed celery varieties. Therefore, AgWp1 was considered to be the candidate gene controlling the white petiole in celery. Our results could not only improve the efficiency and accuracy of celery breeding but also help in understanding the mechanism of chlorophyll synthesis and chloroplast development in celery.

Selection and optimisation of extraction technique for the preparation of phenolic- and flavonoid-rich extract of leafy vegetable, Coccinia grandis (Linn.) Voigt

Coccinia grandis (L.) Voigt (family: Cucurbitaceae) is a popular leafy vegetable in Sri Lankan diet. C. grandis is high in phenolics and flavonoids. The present work attempted to determine a suitable extraction technique, and further optimise it to obtain phenolic- and flavonoid-rich extract from C. grandis leaves, with an aim at developing a nutraceutical targeting the dietary management of diabetes mellitus. Acetone extraction (AE), methanol extraction (ME), pre-warmed water extraction (PWE), electric shake extraction (ESE), reflux extraction (RE), ultrasonication with water (UEw), ultrasonication with ethanol (UEe), ultrasonic assisted-reflux extraction (URE), and reflux assisted-ultrasonic extraction (RUE) were chosen as the extraction techniques. URE was selected as a satisfactory extraction technique for further optimisation for the preparation of phenolic- and flavonoid-rich extract based on the contents of phenolics (32.97 ± 0.41 mg of equivalent gallic acid/g of extract) and flavonoids (4.50 ± 0.04 mg equivalent quercetin/g of extract). The highest yield of 32.8% was obtained by the URE technique. The optimal extraction conditions for URE were determined with an ultrasonic time of 19 min, refluxing time of 168 min, and liquid:solid ratio of 16.4 mL/g. This is the first attempt to investigate the selection and optimisation of an extraction technique for obtaining phenolic- and flavonoid-rich extract from C. grandis leaves. The present findings would be useful in the development of a commercially viable nutraceutical using a phenolic- and flavonoid-rich extract of C. grandis.

Analysis of the presence of enteroparasites in Lactuca sativa (LETTUCE) sold at fairs and supermarkets in the municipality of Grajaú-Maranhão

Among the vegetables, lettuce (Lactuca sativa) stands out as one of the most popular leafy vegetables and consumed fresh. Due to the lack of structural and hygiene conditions, the commercialization of raw products in open markets causes greater exposure to contaminating pathogens. Thus, this study aimed to analyze the presence of enteroparasites in lettuce sold in supermarkets and open markets in the municipality of Grajaú-MA. Samples were collected at two fair stands and four supermarket shelves. The lettuces were separated into leaves, washed manually with distilled water and 5 drops of Tween 80 and left to stand for 3 hours. The resulting liquid was stored in conical cups for sedimentation for 24 hours. The sediment was separated and analyzed under an optical microscope. All investigated samples presented some type of enteroparasites. The results obtained indicated that all samples studied contained some parasitic structure, Entamoeba coli and the nematode eggs, for example, were present in all samples. In addition to protozoa, Ascaris and Trichuris eggs, fungi, yeasts, dirt and other types of single-celled life were found on the observed slides. The most common intestinal parasites were protozoa such as Giárdia lamblia (63.3%) nematode egg (27.3%), and Entamoeba coli. (23.8%). As lettuce (L. sativa) is eaten raw, it is necessary to apply a health education program for farmers to start reducing contamination rates. And for consumers there is a need to wash the leaves correctly before consuming them. Using the recommended hygiene standards, they can avoid ingesting enteroparasites.

First Report of Sclerotinia minor on lettuce in Serbia.

Lettuce (Lactuca sativa L.) is the world's most popular leafy salad vegetable. One of the major challenges facing lettuce producers are fungal diseases that could, under favorable conditions, devastate the harvest (Raid, 2004). During February 2021, poor growth, plant stunning and blanching of leaves of lettuce plants, cultivated in unheated plastic tunel in Potočanje (Zlatibor region), Serbia, were observed. The crowns were softened with spreading decaying lesions covered with white mycelium, particulary on the leaves near the soil surface. Approximately 2 to 3 weeks before harvest, diseased plants began to wilt and collapse. Estimated disease incidence was 50-55%. In order to identify the causal agent, symptomatic tissues from diseased plants were cut into small pieces, surface sterilized with 70% ethanol for 1 min, rinsed three times in sterile distilled water and placed on potato dextrose agar (PDA). Five isolates with uniform morphology were derived from infected tissue. The colonies had fast-growing, white, cottony aerial mycelium, producing profuse numbers (184 sclerotia/ Petri plate in average) of small, black, irregularly shaped sclerotia, less than 2 mm in diameter. Based on morfological features, the isolates were identified as Sclerotinia minor Jagger (Kohn, 1979). To confirm the species identity, the internal transcribed spacer region of nuclear rDNA of a representative isolate 15-2 was amplified using the primer pair ITS1/ITS4 (White et al. 1990). Sequence analysis of ITS region revealed 100% nucleotide identity between the isolate 15-2 (GenBank Accession No. OL423632.1) and 14 isolates of S. minor from different parts of the world (e.g., accession Nos. MK356551.1, KY707828.1, JF2798801.1). Pathogenicity tests were conducted by artificial inoculation of 55-day-old lettuce plants cv. 'Majska kraljica', grown on commercial growth substrate in l L pots. The obtained isolates were grown on PDA for 7 days and mycelial plugs, 5 mm in diameter, were cut from the margin of the colony and placed mycelium-side down on undamaged ground-level leaves of lettuce plants. Two plugs per isolate were placed onto five plants each for a total of ten replicates per isolate. Negative control plants (5) were inoculated similarly with sterile PDA plugs. Inoculated plants were covered with transparent plastic bags, sprayed with water (under the plastic) twice a day for 3 to 5 days to maintain high humidity, and kept in a growth chamber at 22°C (13 h light). After 7 to 10 days, all pathogen-inoculated plants developed lettuce drop disease symptoms, whereas the control plants remained symptomless. The pathogen was reisolated from symptomatic leaves and Koch's postulates were completed by confirming the identity of the isolates. To our knowledge, this is the first report of S. minor on lettuce in Serbia. More research is needed to better understand this disease, establish control strategies and minimize the spread of the pathogen to other lettuce-producing areas of the country.

Influence of growth regulators and length of cuttings on the propagation potential of Piper pedicellatum C. DC. – A threatened wild leafy vegetable of North-East India

Piper pedicellatum C. DC. is a wild leafy vegetable belonging to the family Piperaceae and is categorized as threatened species. It is one of the widely used popular leafy vegetable in Arunachal Pradesh, Manipur, and Sikkim, locally known as Rahre, Raro or Rori. The species is rich in vitamin A, Vitamin C, minerals, dietary fibre, antioxidants, protein, and energy and is also used as an ethnomedicinal plant. An experiment was conducted to study the effect of growth regulators IBA and IAA and length of stem cuttings on propagation potential of P. pedicellatum C. DC in the Forestry Nursery of North Eastern Regional Institute of Science and Technology during the years 2018 and 2019. The experiment revealed that the performance of stem cuttings viz., time taken for first sprouting, maximum sprout per cutting, length of sprouted shoot, number of leaves per cutting, and maximum fresh weight of shoot are found better in the treatment of T4 (L1 + IBA 1500 ppm), T7 (L1 + IAA 1500 ppm), T11 (L2 + IBA 1500 ppm) and T14 (L2 + IAA 1500 ppm), respectively. Similarly, the maximum number of roots per cutting, root length, fresh and dry weight of roots were also recorded in the treatment of T4 (L2 + IAA 1500 ppm) at par with T11 (L1 + IBA 1500 ppm) during both the year. The mean maximum survival rate of cuttings with a higher rooting percentage was observed in T11, which is at par with T7, T14, and T4. Although L2 cuttings performed better than L1 cuttings, the difference was not so prominent. Stem cuttings, irrespective of their length, treated with IBA 1500 ppm and IAA 1500 ppm showed significantly superior performance over the cuttings treated with lower concentrations of IBA and IAA. The outcome of the present study indicated that the P. pedicellatum is a promising wild leafy vegetable plant that can be exploited for conservation, domestication, and cultivation through the vegetative propagation technique, with standardization of its production technology for the adoption of commercial cultivation of the threatened species.

Agronomic Productivity and Organic Fertilizer Rates on Growth and Yield Performance of Cabbage (Brassica oleracea var. capitata L.) in Northwestern Ethiopia.

Cabbage (Brassica oleracea var. capitata L.) is a popular leafy vegetable in Ethiopia. However, the production and productivity of the crop are often constrained by several factors, such as deprived soil fertility and poor agronomic practices. Thus, a study was conducted in two locations in the East Gojjam zone of northwestern Ethiopia during the 2021/2022 cropping season to evaluate the effect of bud numbers and farmyard manure fertilizer rates on the growth and yield components of cabbage. Three numbers of cabbage buds (1, 2, and 3) and four levels of farmyard manure (0, 2.5, 5, and 7.5 tons/ha) were laid out in a 3 × 4 factorial arrangement in a randomized complete block design with three replications. Data on yield and quality were recorded and subjected to analysis of variance. The results revealed that growth, yield, and quality components were significantly influenced by the interaction effects of bud number and farmyard manure fertilizer rate. In both locations, the highest marketable (41.8 tons/ha) and total (43.1 tons/ha) yields were attained from the combined effects of 2 buds of cabbage and 5 tons of farmyard manure. The highest medium-sized heads (31.8 tons/ha) of cabbage were also recorded from the combination of 2 buds with 5 tons of farmyard manure. Moreover, the combined effects of 2 buds and 5 tons of farmyard manure showed the highest net benefit (5,679.03 US dollars) over the other treatments at the two locations. Hence, based on the results of the study, the combination of 2 buds and 5 tons of farmyard manure fertilizer can be suggested for the economical production of cabbage in northwestern Ethiopia and similar environments.

Assessment of Promising Diverse Germplasm Accessions for Stability with Respect to Yield and Its Attributing Traits in Vegetable Amaranth

Vegetable amaranth is one of the popular leafy vegetable that occupies a prominent place in India owing to its high nutritive value and fast growing ability. The presence of considerable genetic variability in the amaranth along with very high phenotypic plasticity demands the development of stable genotypes to secure sustainable production. The present research was carried out to quantify the effect of genotype x environment interaction on the performance of 30 identified promising genotypes of vegetable amaranth. The experiment was laid out in the Randomized Complete Block Design with three replications at three locations viz., Arabhavi, Dharwad and Bagalkot during kharif 2018-19. Stability analysis was done as per the linear regression model described by Eberhart and Russell [1] that measures the genotypic response to changing environments. Variance due to environment + (genotype x environment) was significant for four of the studied traits viz., fresh green yield per hectare, fresh green yield per plant, plant height and leaf length which specified the existence of noteworthy interaction between the genotypes and the environmental conditions. The accessions, VA-16, CO-1, IC-553719 and IC-469645 have been identified as the high yielding stable genotypes for fresh green yield. Stable accessions for plant height include IC-536714, IC-541407, Arka amaranth, IC-469579 and IC-553719 and for leaf length were CO-1, IC-550143, IC-551472, IC-536714 and IC-469722. Further, some stable accessions for yield and its attributes were indicated that can be, commercialised or used in future breeding programs.

Physical and chemical characterization of Corchorus olitorius leaves dried by different drying techniques

Molokhia, Corchorus olitorius, is a popular leafy vegetable, known in many world regions as a good source of nutritional and medicinal properties. Due to its short shelf life and the limited harvesting time, processing such as drying techniques permit to preserve and provide it throughout the year. In the present study, it was attempted to reveal the main physical and chemical characteristics of molokhia leaves. Also, three drying techniques, shade drying (SHD), convective drying (COD), and microwave drying (MID), have been applied to study the kinetics and their main physical and chemical effects. The analysis demonstrated that molokhia leaves are a good source of phenolic compounds, flavonoids, and chlorophylls pigments. Those bioactive compounds have provided the leaves with considerable antiradical scavenging and reducing capacities. Drying time decreased from days, in the case of SHD, to some hours when using COD, and less than 20 min when using MID. Increasing drying temperature and power input have increased the drying rate. Modelling of drying kinetics of MID three power inputs (350, 500 and 750 W) and COD at 60 °C exhibited a high fitting for most empirical models (R2 > 0.980). SHD was less deleterious on leaves colour. Also, it preserved the content of phenolics, flavonoids, and thus the antioxidant activity of leaves. On the contrary, COD at 80 °C had a detrimental effect on previous components and their activity. Vega-Gálvez model can be presented as the best-fitted model to describe the rehydration kinetics of dried leaves. Rheological analysis of the aqueous extracts of the leaves demonstrated the effect of time and grinding on the increase of mucilage diffusion. The obtained results could help industrials to choose the convenient drying method and more analysis on the subject are recommended.

BrpNAC895 and BrpABI449 coregulate the transcription of the afflux-type Cd transporter BrpHMA2 in Brassica parachinensis.

Brassica parachinensis is a popular leafy vegetable. It is able to accumulate high concentrations of cadmium (Cd), but the molecular mechanism of Cd accumulation is unknown. This study investigated the function and regulatory mechanism of the Cd-responsive metal ion transporter gene BrpHMA2. BrpHMA2 was induced by Cd stress and specifically expressed in vascular tissues, and the protein was localized in the plasma membrane. Heterologous expression of BrpHMA2 enhanced Cd accumulation and Cd sensitivity in transgenic Arabidopsis and yeast. After Cd stress, the transcription factors BrpNAC895 and BrpABI449, which may recognize the abscisic acid-responsive elements in the BrpHMA2 promoter, were also differentially expressed. The transcriptional regulation of BrpHMA2 was further investigated using the chromatin immunoprecipitation–quantitative PCR (ChIP–qPCR) assay, the electrophoretic mobility shift assay (EMSA), and luciferase (LUC) reporter activity analysis employing the transient expression system of B. parachinensis protoplasts and tobacco leaves and the Escherichia coli expression system. By binding to the promoter, BrpNAC895 induced the transcription of BrpHMA2. BrpABI449 might bind to the BrpHMA2 promoter or interact with BrpNAC895 to interfere with the action of BrpNAC895. The findings suggest that BrpHMA2 is a membrane-based afflux-type Cd transporter involved in Cd2+ uptake and long-distance transport in plants. BrpNAC895 and BrpABI449, which function as the transcription activator and repressor, respectively, coregulate BrpHMA2 expression.

Growth, Quality, and Nitrogen Assimilation in Response to High Ammonium or Nitrate Supply in Cabbage (Brassica campestris L.) and Lettuce (Lactuca sativa L.)

Plants grow better when they are supplied with a combination of ammonium (NH4+) and nitrate (NO3−) than when either one is supplied as the sole N (nitrogen) source. However, the effects of N forms on N metabolism and major N assimilation enzymes in different plants, especially vegetables, are largely neglected. This study was conducted on two plants with distinct NH4+ tolerances to compare the responses of two popular leafy vegetables, Korean cabbage (Brassica campestris L.) ‘Ssamchu’ and lettuce (Lactuca sativa L.) ‘Caesar green’, to the N source. To this end, plant growth and quality, photosynthesis, carbohydrate, N contents (in the forms of NO3−, NO2−, NH4+, total protein), and key N assimilation-related enzyme (NR, NIR, GS, GDH) activities were investigated. When plants were subjected to one of three NH4+:NO3− regimes, 0:100, 50:50, or 100:0, lettuce was relatively more tolerant while cabbage was extremely sensitive to high NH4+. Both plants benefited more from being grown with 50:50 NH4+:NO3−, as evidenced by the best growth performance, ameliorated photosynthesis, and enriched carbohydrate (C) stock content. In addition, as compared to cabbage, the GS and GDH activities were reinforced in lettuce in response to an increasing external NH4+ level, resulting in low NH4+ accumulation. Our findings suggested that boosting or maintaining high GS and GDH activities is an important strategy for the ammonium tolerance in vegetables.

Phytochemical Responses to Salt Stress in Red and Green Baby Leaf Lettuce (Lactuca sativa L.) Varieties Grown in a Floating Hydroponic Module

Lettuce (Lactuca sativa L.) is one of the most popular leafy vegetables, appreciated globally as a low-calorie food with bioactive compounds. The application of a low dose of abiotic stress is considered a sustainable pre-harvest strategy to modify the nutraceutical value of horticultural products. In this work, we explored the response of two differently colored (red or green) baby leaf lettuce varieties to four NaCl concentrations in the nutrient solution (from 1 to 30 mM), using a full factorial design. We focused on leaf morphological parameters and possible phytochemical enhancement of the main polyphenols and anthocyanins, analyzed by LC-MS. The response to low-to-moderate salt stress exposure was affected mainly by salt concentration for leaf traits or by the cultivar for leaf color, with very limited factors’ interactions. Multivariate analysis indicated a predominant role of the genotypic factor in shaping differences in the two weeks growing cycle for baby leaf lettuce. Phytochemically, different dose–response models to sub-optimal saline conditions may be applied to the various compounds. A significant hormetic stimulation was present only for cyanidin-malonyl glucoside, the main anthocyanin present in the red cultivar.

Morphological evaluation of lettuce genotypes grown under hydroponic system

ABSTRACT Crispleaf lettuce, which is a light green leaf lettuce, is the most popular leafy vegetable in Brazil. However, it is relevant to evaluate agronomic traits of lettuce with more intense green color leaves considering the increase in consumer demand. Thus, the aim of this study was to evaluate lettuce genotypes about the different chlorophyll contents and correlate with green mass production in a hydroponic system. Ten lettuce inbred lines and two cultivars (Vanda and Luiza) were evaluated for agronomic traits and chlorophyll contents in leaves. A randomized block design with four replicates was used. The chlorophyll content was variable among the genotypes, ranging from 43.3 (Luiza) to 20.8 (Vanda). The genotypes with the highest chlorophyll content were those who showed the lowest mass production, but no correlations were found between these variables, though.

Antioxidant, Antidiabetic, and Anti-obesity Potential of Ipomoea reptans Poir Leaves

Ipomoea reptans Poir or kangkung is a popular leafy vegetable, a favorite to people in Asian countries. However, limited information is available on their bioactivities. In the present study, the antioxidant, antidiabetic, and anti-obesity potential of I. reptans leaves were investigated. Different fractions (ethanol, ethyl acetate, and hexane) of I. reptans leaves were evaluated for their scavenging activity on DPPH radicals, whereas their reducing potential was investigated by cupric reducing antioxidant capacity (CuPRAC), total antioxidant, and reducing power assays. The antidiabetic potential was investigated by their inhibition effect on a-glucosidase. Total phenolic and flavonoid contents of I. reptans leaves were solvent dependent. Ethyl acetate contained the highest phenolic content, followed by ethanol and hexane fractions. However, for flavonoid content, the order was ethanol > ethyl acetate > hexane. All fractions showed DPPH scavenging activity in a concentration-dependent manner, with activities weaker than standards ascorbic acid and BHT, in the order of ethanol > ethyl acetate > hexane. All fractions showed reducing capacity, but only hexane and ethanol fractions of I. reptans leaves showed inhibition on a-glucosidase, with hexane showed more potent inhibition compared to acarbose. The study also found that fractions of I. reptans inhibit lipase and trypsin, enzymes related to lipid metabolism. Findings in this study offer a prospect for I. reptans leaves as a functional food source for antioxidant, antidiabetic, and anti-obesity purposes.

Optimization of AB-mix Fertilizer on Varieties of Hydroponic Lettuce (Lactuca sativa L.)

Lettuce (Lactuca sativa L.) is a popular leafy vegetable. Most of its varieties are eaten fresh and commonly served as a garnish in fried rice or complementary vegetables in some fast food meals such as burgers and green salads. Nowadays, most lettuce varieties are grown hydroponically, replacing the soil and feeding all nutrients through the water. A hydroponic system is also considered a solution to overcome the shortage of arable lands and good-quality water. This research aims to evaluate the lettuce response towards the application of AB-mix fertilizer in the hydroponic system. This research was designed using Factorial Randomized Block Design (RBD) with two factors (AB mix concentrations and lettuce varieties) and three replications. The results revealed between AB-mix concentrations and lettuce varieties, where the application of AB-mix increased the number of leaves. AB-mix's application gave an effect to all variables observed: plant height, leaf width, leaf number, and leaf chlorophyll but insignificant to root length.

Compost and Black Polyethylene Mulches Improve Spring Production of Romaine Lettuce in Southern New England

Romaine lettuce (Lactuca sativa) is the most popular leafy vegetable in the United States. Organic and synthetic mulch materials are applied by farmers to reduce their weeding expenditures, manage soil temperatures, and increase the yield and quality of their crops. This study examined the impacts of using black polyethylene, compost, and shredded leaves as surface mulches in spring open field romaine lettuce by using data regarding the soil temperature, lettuce growth, and yield parameters. Mulch treatments were compared to determine effects on soil temperature, lettuce growth rates, leaf area index (LAI), yield, and plant size. Experiments were conducted in 2017 and 2019. Soil temperatures were slightly (but significantly) warmer in 2019, the plants grew more rapidly, and LAI, yield, and plant size were all significantly greater than they were in 2017. Mean soil temperatures were 18.0 and 18.9 °C in black polyethylene mulched plots, 17.7 and 18.5 °C in compost, 17.5 and 17.0 °C in bare ground, and 16.9 and 17.3 °C in shredded leaf plots in 2017 and 2019, respectively. Changes in canopy size presented a similar trend over the growing season for all treatments; shredded leaf and bare ground treatments on all measuring dates had the smallest canopy size, and compost and black polyethylene mulches had the largest canopy sizes. Black polyethylene and compost mulches had the highest LAI and yields in both years. In 2017, the bare ground treatment was similar to black polyethylene and compost mulch treatments for both parameters, and all three treatments were significantly greater than the shredded leaf mulch treatment. In 2019, the bare ground treatment was similar to the shredded leaf mulch treatment and significantly lower than the black polyethylene and compost mulch treatments. In 2017, black polyethylene and compost mulches had LAI of 7.67 and 7.37 and yields of 6.38 and 6.68 kg·m−2, respectively. Bare ground had an LAI of 7.16 and yielded 5.94 kg·m−2. Shredded leaf mulch plots had the lowest LAI (5.94) and yield (4.96 kg·m−2). In 2019, the bare ground treatment had an LAI of 7.5 and yielded 7.6 kg·m−2. Black polyethylene and compost mulches increased LAI by 1.7. Yield increased by 2.8 kg·m−2 with black polyethylene mulch and by 2.4 kg·m−2 with compost mulch. Shredded leaf mulch produced LAI and yield similar to but slightly lower than bare ground. Dry weight, plant height, and head diameter in bare ground and shredded leaf mulch treatments were significantly smaller than in black polyethylene and compost mulch treatments. The cultivar rank order was consistent across treatments in both years; ‘Ridgeline’ grew significantly faster than ‘Coastal Star’, and plants were significantly larger at harvest. Black polyethylene suppresses weeds and increases soil temperatures, thereby enhancing yields of spring-to-summer romaine lettuce under southern New England conditions. Compost mulch has similar effects on yields. Shredded leaf mulch is effective at suppressing weeds but decreases soil temperatures and yields.

EFFECT OF PHOTO-SELECTIVE NETTING ON GROWTH DEVELOPMENT OF GREEN AMARANTH (Amaranthus viridis L.)

Green amaranth (Amaranthus viridis L.) is one of the most popular leafy vegetables cultivated in Malaysia. Photo-selective netting is a revolutionary agricultural-technical idea, allowing traditional nets to be improved to a sophisticated level, which can impact microclimate and solar radiation as well as protect crops from pests. This study aims to investigate the growth performance of green amaranth under different three different treatments of photo-selective nets including black, and yellow shade nets and control. The assessed physiological, pre-harvest and post-harvest parameters were air temperature and relative humidity, measurement of absorption of photosynthetically active radiation (PAR), plant height, number of leaves, and dry weight. This study found that the yellow shade net showed the best performance in plant growth with the average difference in plant height (4.11 cm), average leaves number (7 leaves) and average dry weight (18.58 mg) were the highest compared to black shade net and control (without shading). In conclusion, photo-selective yellow shade net was able to enhance the growth development of green amaranth and could be applied in the large scale production to boost the growth and yield of leafy vegetables.