Red Leaf Cultivars Research Articles

Stress Response to Climate Change and Postharvest Handling in Two Differently Pigmented Lettuce Genotypes: Impact on Alternaria alternata Invasion and Mycotoxin Production.

Many species of Alternaria are important pathogens that cause plant diseases and postharvest rots. They lead to significant economic losses in agriculture and affect human and animal health due to their capacity to produce mycotoxins. Therefore, it is necessary to study the factors that can result in an increase in A. alternata. In this study, we discuss the mechanism by which phenol content protects from A. alternata, since the red oak leaf cultivar (containing higher phenols) showed lower invasion than the green one, Batavia, and no mycotoxin production. A climate change scenario enhanced fungal growth in the most susceptible cultivar, green lettuce, likely because elevated temperature and CO2 levels decrease plant N content, modifying the C/N ratio. Finally, while the abundance of the fungi was maintained at similar levels after keeping the lettuces for four days at 4 °C, this postharvest handling triggered TeA and TEN mycotoxin synthesis, but only in the green cultivar. Therefore, the results demonstrated that invasion and mycotoxin production are cultivar- and temperature-dependent. Further research should be directed to search for resistant cultivars and effective postharvest strategies to reduce the toxicological risk and economic losses related to this fungus, which are expected to increase in a climate change scenario.

Physiological and Molecular Analysis Reveals the Differences of Photosynthesis between Colored and Green Leaf Poplars.

Leaf coloration changes evoke different photosynthetic responses among different poplar cultivars. The aim of this study is to investigate the photosynthetic difference between a red leaf cultivar (ZHP) and a green leaf (L2025) cultivar of Populus deltoides. In this study, ‘ZHP’ exhibited wide ranges and huge potential for absorption and utilization of light energy and CO2 concentration which were similar to those in ‘L2025’ and even showed a stronger absorption for weak light. However, with the increasing light intensity and CO2 concentration, the photosynthetic capacity in both ‘L2025’ and ‘ZHP’ was gradually restricted, and the net photosynthetic rate (Pn) in ‘ZHP’ was significantly lower than that in ‘L2025’under high light or high CO2 conditions, which was mainly attributed to stomatal regulation and different photosynthetic efficiency (including the light energy utilization efficiency and photosynthetic CO2 assimilation efficiency) in these two poplars. Moreover, the higher anthocyanin content in ‘ZHP’ than that in ‘L2025’ was considered to be closely related to the decreased photosynthetic efficiency in ‘ZHP’. According to the results from the JIP-test, the capture efficiency of the reaction center for light energy in ‘L2025’ was significantly higher than that in ‘ZHP’. Interestingly, the higher levels of light quantum caused relatively higher accumulation of QA- in ‘L2025’, which blocked the electron transport and weakened the photosystem II (PSII) performance as compared with ‘ZHP’; however, the decreased capture of light quantum also could not promote the utilization of light energy, which was the key to the low photosynthetic efficiency in ‘ZHP’. The differential expressions of a series of photosynthesis-related genes further promoted these specific photosynthetic processes between ‘L2025’ and ‘ZHP’.

Elucidation of the core betalain biosynthesis pathway in Amaranthus tricolor

Amaranthus tricolor L., a vegetable Amaranthus species, is an economically important crop containing large amounts of betalains. Betalains are natural antioxidants and can be classified into betacyanins and betaxanthins, with red and yellow colors, respectively. A. tricolor cultivars with varying betalain contents, leading to striking red to green coloration, have been commercially produced. However, the molecular differences underlying betalain biosynthesis in various cultivars of A. tricolor remain largely unknown. In this study, A. tricolor cultivars with different colors were chosen for comparative transcriptome analysis. The elevated expression of AmCYP76AD1 in a red-leaf cultivar of A. tricolor was proposed to play a key role in producing red betalain pigments. The functions of AmCYP76AD1, AmDODAα1, AmDODAα2, and AmcDOPA5GT were also characterized through the heterologous engineering of betalain pigments in Nicotiana benthamiana. Moreover, high and low L-DOPA 4,5-dioxygenase activities of AmDODAα1 and AmDODAα2, respectively, were confirmed through in vitro enzymatic assays. Thus, comparative transcriptome analysis combined with functional and enzymatic studies allowed the construction of a core betalain biosynthesis pathway of A. tricolor. These results not only provide novel insights into betalain biosynthesis and evolution in A. tricolor but also provide a basal framework for examining genes related to betalain biosynthesis among different species of Amaranthaceae.

GhGSTF12, a glutathione S-transferase gene, is essential for anthocyanin accumulation in cotton (Gossypium hirsutum L.)

Anthocyanins are flavonoid pigments providing plants a range of colors from red, pink, orange to blue. Anthocyanins are synthesized in the cytosol but accumulate predominantly in the vacuoles through vacuolar sequestration involving glutathione S-transferases (GSTs) and multidrug and toxic compound extrusion (MATE) and the ATP binding cassette (ABC) transporters. However, little is known about anthocyanin-related GSTs in Upland cotton (Gossypium hirsutum L.). In this study, we performed genome-wide identification of GST genes in Upland cotton and identified GST genes functioning in accumulation of anthocyanins. We demonstrated that GhGSTF12 was able to complement the defective leaf color phenotypes of the Arabidopsis tt19 mutant caused by mutation in a GSTF gene. Virus-induced silencing of GhGSTF12 in the red leaf cultivar turned its red color to green and transient overexpression of GhGSTF12 accelerated anthocyanin accumulation in the red leaf cultivar but not in the green leaf cultivar. Collectively, GhGSTF12 may be involved in transport of anthocyanins from cytosol to vacuoles in cotton. These results also demonstrated a conserved function of plant GSTF genes in anthocyanin accumulation and provide a candidate gene for manipulating pigmentation in cotton tissues.

Influence of fertilizer and salicylic acid treatments on growth, physiological, and antioxidant characteristics in green and red Perilla frutescens varieties

Perilla is herbaceous plant, functional food, and nutraceutical product with antioxidant properties. The objective of this study was to investigate the growth, reflectance indices, and antioxidant properties of P. frutescens species in response to fertilizer and salicylic acid (SA) applications. Two independent experiments were carried out in an environmentally controlled greenhouse: (1) pots of red-leaf and green-leaf cultivars divided into four groups treated with 10-30-20 (10N-13.1P-16.6K), 15-10-30 (15N-4.4P-24.9K), 20-20-20 (20N-8.7P-16.6K), and 30-10-10 (30N-4.4P-8.3K) fertilizers for periods of 10 weeks, and (2) pots of red and green Perilla cultivars divided into five groups treated with 0 (control), 125, 250, 500, and 1,000 µM of SA for periods of 7 weeks. Wide variations occurred in the agronomic performance, soil-plant analysis development (SPAD) value, adjusted normalized difference vegetation index (NDVI), maximal quantum yield of PSII photochemistry (Fv/Fm), and antioxidant activity of the two Perilla varieties. All the measured traits were higher in green than in red Perilla under identical fertilizing, and all agronomic traits in green and red Perilla plants subjected to 125 and 500 μM SA were better than in controls. The SPAD and NDVI values of all plants increased as N% increased, the lowest Fv/Fm values of all plants were observed under 15-10-30 fertilizer treatment, the lowest NDVI values were detected in controls, and the Fv/Fm values of all plants decreased under 1,000 μM SA treatment. These indices can be used as indicators to characterize the physiology of these plants and are suitable for evaluating their growth and development under specific fertilizer and SA treatments. Green Perilla leaf extract (PLE) contained higher rosmarinic acid (RA) concentration in each fertilizer treatment, and higher total phenolic (TP) and RA concentration in each SA treatment. However, red PLE contained higher caffeic acid (CA) concentration than green PLE in each fertilizer and SA treatment, implying that their two genotypes exhibited different abilities and specificities of photosynthetic metabolites, and that different varieties may prepare for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity by up-regulating TP, RA, and CA concentration differently. Thus, Perilla plants can be used as health foods due to high TP, RA, and CA concentration. To produce Perilla efficiently in industrial applications, we undertook to determine the optimum N-P-K fertilizer ratio and SA application for maximizing the growth and accumulation of TP, RA, and CA in Perilla plants.

Using Amaranth as a Model Plant for Evaluating Imperfect Storages: Assessment of Solar-refrigerated and Evaporatively-cooled Structures in India

Some storages have limited control over their internal environment and undergo daily and seasonal fluctuations in both temperature and humidity, which cause variation in the metabolic activity of stored products. As a result, it is difficult to assess and compare the performance of these imperfect storages using measures of environmental control. We propose using measures of plant senescence as a proxy for estimating storage performance of these “imperfect” storages based on the premise that physiological processes integrate changes of temperature and/or humidity in a predictable, mathematically describable manner. We evaluated amaranth (Amaranthus tricolor L.) as a model plant for evaluating imperfect storages using a red-leaf cultivar Pusa lal chaulai and a green-leaf cultivar Pusa kiran. Amaranth is a leafy vegetable grown worldwide and is a highly nutritious and versatile food. Cumulative respiration, a measure of integrated metabolic activity, was regressed against leaf abscission, chlorophyll loss, and leaf yellowing of amaranth stems for four storages having different, variable, temperature profiles. Storages included 1) an evaporatively cooled (EC) structure; 2) a solar-refrigerated and evaporatively cooled (SREC) structure; 3) an uncooled laboratory (UL); and 4) a household refrigerator (REF). We found that the rate of abscission, chlorophyll loss, and leaf yellowing differed markedly for the four storages; however, these measures of senescence were linearly related to estimates of cumulative respiration. The ease of measuring leaf abscission, chlorophyll loss, and leaf yellowing permits data collection even with minimal resources. We propose that amaranth would make an effective model plant for comparing the performance of storages differing dramatically in temperature control. A 10% leaf abscission in amaranth is proposed as a target for comparing storages.

Evaluation of Yield, Marketability, and Nitrate Levels of Lettuce Cultivars Produced in Southern Louisiana

Forty-five cultivars of lettuce (Lactuca sativa) were field-grown using best management practices at the Louisiana State University Agricultural Center (LSU AgCenter) Botanic Gardens in Baton Rouge during the Fall 2011 and Fall 2012 seasons. Recommended cultivars were selected for commercial production in Louisiana based on fresh weight and lettuce size (width and height). Nitrate (NO3–) concentration was analyzed for each cultivar, as lettuces are known to accumulate and concentrate NO3–, and were then compared with the U.S. Environmental Protection Agency’s (EPA) oral reference dose (RfD—the EPA’s maximum acceptable oral dose of a toxic substance) of 1.6 mg NO3-nitrogen (N) per kilogram body weight per day. Recommended butterhead cultivars were Caliente and Harmony (21.6 and 13.9 ppm NO3–, respectively); recommended green-leaf cultivars were Salad Bowl and Tango (10.6 and 4.6 ppm NO3–, respectively); recommended red-leaf cultivars were Red Salad Bowl, Red Sails, and New Red Fire (15.2, 15.4, and 24.0 ppm NO3–, respectively). The only recommended romaine cultivar was Green Towers (11.2 ppm NO3–), and recommended crisphead cultivars included Raider and Ithaca (17.6 and 14.9 ppm NO3–, respectively). Of the highest yielding cultivars, New Red Fire accumulated the greatest NO3– concentration: 24.0 ppm in both years 1 and 2. The NO3– concentration is less than the levels of concern for both men and women 20 to 74 years old, 3.9% of the RfD for men and 4.59% of the RfD for women.

Physiological and Nutraceutical Quality of Green and Red Pigmented Lettuce in Response to NaCl Concentration in Two Successive Harvests

Nutritional eustress such as salinity or nutrient stress applied in soilless systems, is a convenient pre-harvest factor efficient in modulating the phytochemical components of horticultural crops, by triggering defensive mechanisms and accumulating plant secondary metabolites in plants tissues. Nevertheless, genetic material (cultivars with different pigmentation) dictates lettuce metabolites and physiological response to extrinsic eustress, with red leaf cultivars being highly nutrient packed notwithstanding the stress. Product quality can be meliorated equally by applying several cuts, a practice proven to increase bioactive compounds accumulation. In this study, we analyzed the effects of four salinity levels (1, 10, 20 and 30 mM NaCl) on green and red pigmented Salad Bowl lettuce (Lactuca sativa L. var. acephala) in two successive harvests cultivated in a floating raft system. The morphological parameters, mineral composition, leaf gas exchanges, bioactive compounds, and antioxidant activity of both cultivars were assessed. The green cultivar exhibited superior crop productivity but was more prone to salinity effect than the red cultivar. Irrespective of cultivar and cut order, the net photosynthesis decreased with increasing salinity in the nutrient solution. The second cut incurred higher dry biomass, greater accumulation of most minerals and higher photosynthetic activity. In red lettuce, 20 mM NaCl proved adequate eustress to increase phytonutrients and beneficial minerals (K, Ca, and Mg) with minimal loss of yield. Mild salinity and sequential harvest have proven effective pre-harvest tools in positively modulating the quality of lettuce. Eustress interaction with genotype was demonstrated as a promising field for future breeding programs targeting select genotypes for agronomic application of eustress to improve the nutraceutical value of vegetable crops.

Promotion of lettuce growth under an increasing daily light integral depends on the combination of the photosynthetic photon flux density and photoperiod

In indoor farms, electric lighting controls pla growth and quality attributes, but incurs high capital and operating costs. The photon spectrum, photoperiod, and photosynthetic photon flux density (PPFD) can be optimized with other environmental variables to maximize harvestable yield considering production time and lighting costs. Previous studies have determined that increasing the photoperiod or PPFD can increase lettuce (Lactuca sativa) yield. However, it is unclear how, at multiple daily light integrals (DLI), combinations of a wide range of PPFDs and photoperiods affect growth and quality attributes of green- and red-leaf lettuce. We investigated the interaction between these factors on lettuce growth and quality attributes by growing lettuce ‘Rex’ and ‘Rouxai’ under DLIs from 6.9–15.6 mol m−2 d−1 using PPFDs of 120–270 μmol m–2 s–1 and photoperiods of 16–24 h d–1. Increasing the DLI increased shoot fresh and dry mass, leaf width and number, and chlorophyll concentration of both cultivars, regardless of the combination of the PPFD and photoperiod. Furthermore, increasing the DLI increased the red pigmentation of the red-leaf cultivar, ‘Rouxai’. Additionally, at a DLI of 15.6 mol m−2 d−1, lettuce grown under a lower PPFD and a longer photoperiod had greater fresh and dry mass than lettuce grown under a higher PPFD and a shorter photoperiod, while at a lower DLI of 10.4 mol m−2 d−1, this did not occur. We conclude that although increasing the DLI increased lettuce growth and improved quality attributes, the specific PPFD and photoperiod combination can have different effects on plant growth.

Reducing Energy Requirements in Future Bioregenerative Life Support Systems (BLSSs): Performance and Bioactive Composition of Diverse Lettuce Genotypes Grown Under Optimal and Suboptimal Light Conditions.

Space farming for fresh food production is essential for sustaining long-duration space missions and supporting human life in space colonies. However, several obstacles need to be overcome including abnormal light conditions and energy limitations in maintaining Bioregenerative Life Support Systems (BLSSs). The aim of the present study was to evaluate six lettuce cultivars (baby Romaine, green Salanova, Lollo verde, Lollo rossa, red oak leaf and red Salanova) of different types and pigmentations under optimal and suboptimal light intensity and to identify the most promising candidates for BLSSs. Baby Romaine performed better than the rest of the tested cultivars under suboptimal light intensity, demonstrating a more efficient light-harvesting mechanism. Stomatal resistance increased under suboptimal light conditions, especially in the case of Lollo verde and red oak leaf cultivars, indicating stress conditions, whereas intrinsic water-use efficiency was the highest in baby Romaine and red oak leaf cultivars regardless of light regime. Nitrate content increased under suboptimal light intensity, especially in the cultivars green Salanova and Lollo verde, while P and Ca accumulation trends were also observed in baby Romaine and Lollo verde cultivars, respectively. Chicoric acid was the major detected phenolic acid in the hydroxycinnamic derivatives sub-class, followed by chlorogenic, caffeoyl-tartaric and caffeoyl-meso-tartaric acids. Chicoric and total hydroxycinnamic acids were not affected by light intensity, whereas the rest of the detected phenolic compounds showed a varied response to light intensity. Regarding cultivar response, red oak leaf exhibited the highest content in chicoric acid and total hydroxycinnamic acids content under suboptimal light intensity, whereas red Salanova exhibited the highest hydroxycinnamic derivatives profile under optimal light conditions. The main detected carotenoids were β-cryptoxanthin and violaxanthin+neoxanthin, followed by lutein and β-carotene. All the target carotenoids decreased significantly under low light intensity, while red Salanova maintained a distinct carotenoids profile. Overall, cultivation of assorted lettuce cultivars is the optimal scenario for space farming, where baby Romaine could provide adequate amounts of fresh biomass owing to its high light-use efficiency while red oak leaf and red Salanova could contribute to the daily dietary requirements for health-promoting bioactive compounds such as polyphenols and carotenoids.

Light quality shapes morpho-functional traits and pigment content of green and red leaf cultivars of Atriplex hortensis

Recently the value of red-leaf species as food plants is increasing due to their high content in antioxidant compounds, mainly anthocyanins. Most work has been done on the modulation of light quality to maximise the production of antioxidant compounds in reddish leafy vegetables that mostly adjust the amount of foliar anthocyanins as a reaction to several environmental factors, including light. The aim of this study was to compare the effect of light quality on green- and red-leaf cultivars with a focus on the influence that different light wavelengths have on morpho-functional traits and pigment content. We selected as model plant Atriplex hortensis considering that cultivars with either fully-red or fully-green leaves are available. This species is characterized by the presence of betacyanins, an anthocyanin-homologue pigment known for its antioxidant properties. Plants were grown under four lighting treatments: 100% white light (W), 100% red light (R), red/blue light 50/50 % (RB), and red/green/blue light 33/33/33 % (RGB). All treatments provided a daily light integral (DLI) of 10.8 mol·m‒2·day‒1 over a 12-h photoperiod. Results showed that, in both green and red cultivars, light quality determines changes in morpho-functional traits and the combination of red and blue wavelengths enhances productivity and betacyanin content. In red plants, betacyanin content was two order of magnitude larger than in green plants, was significantly modulated by light quality, and increased according to the increasing percentage of blue wavelengths within the light spectrum. In the framework of enhancing antioxidant compounds in plant food through the adjustment of light spectrum, fully red plants should be considered as more promising than green cultivars.

Metabolite profiling of green, green/red, and red lettuce cultivars: Variation in health beneficial compounds and antioxidant potential

Salad vegetables, commonly consumed at baby-leaf stages, are the most appropriate and emerging dietary source of antioxidant compounds. Screening and identification of nutrient-rich cultivars can be potentially useful to obtain a nutrient-dense diet. Thus, in this study, we explored the genetic potential of baby leaves of 23 diverse lettuce cultivars for the health-beneficial metabolites. The results showed that the composition and contents of the studied metabolites in lettuces varied significantly between cultivars and were principally dependent on leaf color. All red-leaf cultivars were rich in carotenoids, cyanidin, polyunsaturated fatty acids (PUFAs, primarily in the form of α-linolenic and linoleic acid,) total phenolic contents (TPC), and antioxidant potential. Among carotenoids, all-E-lutein was found in highest amount, followed by all-E-violaxanthin and all-E-lactucaxanthin, accounting for an average of 30%, 28% and 15% of total carotenoids, respectively. The content of total folate was recorded in the range of 6.51 (cv. Caesar Green) to 9.73μg/g (DW) (cv. Asia Heuk Romaine). The principal component analysis (PCA) showed that the cyanidin and other phenolic compounds are the most potent scavengers of ABTS and DPPH radicals. The overall results suggested that all red-leaf lettuce cultivars have a distinct profile of phytoconstituents, which can be used as a nutrient-dense food.

06-857, a Green Leaf Lettuce Breeding Line with Resistance to Leafminer and Lettuce Mosaic Virus

This paper describes a green leaf lettuce breeding line with combined resistance to leafminers (Liriomyza langei [L. huidobrensis]) and Lettuce mosaic virus (LMV), which is adapted to the major lettuce production areas of the central coast of California, USA. The breeding line 06-857 was derived from a cross between crisphead cultivar 'Salinas 88' that has mo-1e (mo12) alleles, and red leaf cultivar 'Lolla Rossa' that showed low leafminer sting density in previous screening experiments.

Cercospora leaf spot on Impatiens spp. in Argentina

Impatiens balsamina (balsam) and Impatiens × hawkerii (New Guinea impatiens) are cultivated worldwide because of their ornamental value. They are used in bedding, borders and as pot plants. Since 2001, plants growing in gardens and in commercial nurseries of La Plata (Buenos Aires Province) were found to be heavily affected by amphigenous leaf spots. As the disease progressed, the appearance of lesions varied among hosts. Lesions on balsam plants were brown, with circular (up 10 mm diameter) to irregular in shape. In most cases they coalesced and necrotic tissues dropped out of the leaves. On this cultivar, disease occurred during late summer and autumn. New Guinea red leaf cultivars had circular (up to 15 mm) and zonate spots of alternating light brown and dark brown areas with light ochre centres, distributed mainly near the leaf margins. New Guinea green leaf cultivars had circular (up to 7 mm) or irregular greyish spots with defined dark reddish-brown borders, randomly distributed on the leaf. Autumn to late spring were favourable seasons for disease development in these two cultivars. Heavily infected leaves wilted and died. Leaf spots contained scattered black, undistinguishable stromata with conidiophores that were similar on all hosts. Conidiophores were mostly straight, geniculate and unbranched. Conidia were hyaline, straight to slightly curved, with apices rounded and visible scars on the basal cells. Conidia, indistinctly multiseptate, measured 33–115 × 3–3·75 μ m. The pathogen was determined to belong to the genus Cercospora . The fungus was easily recovered on potato dextrose agar either by transferring mature conidia or by routine isolation. The pathogen was identified as Cercospora apii sensu lato (incl. C. fukushiana ) by Dr U. Braun, Martin-Luther University Institute of Geobotany and Botanical Garden Herbarium, Halle (Saale), Germany. The pathogen was previously reported on I. balsamina and Impatiens noli-tangere (Chupp, 1954; Guo & Jiang, 2000). Pathogenicity tests were conducted in the glasshouse by spraying 3-month-old plants of the three different hosts with an aqueous suspension of conidia (1 × 10 4 mL − 1 ). Control plants were treated with distilled water. They were incubated in a moist chamber for 48 h, then maintained at 17–22 ° C. After 40 days, leaf symptoms developed into lesions similar to those produced on naturally infected leaves and the pathogen was again isolated. No symptoms appeared on control plants. This is the first report of C. apii s. lat. ( C. fukushiana ) on I. balsamina in Argentina, and the first record of this fungus on Impatiens × hawkerii in the world.

Variation for Tipburn Resistance in Lettuce

Tipburn (TB) is a physiological disorder that results in necrosis along the margins of lettuce leaves. The disorder is objectionable to consumers and reduces the shelf life of whole and minimally processed lettuce. The objectives were to 1) determine the variation for tipburn resistance in iceberg, romaine, green leaf, and red leaf cultivars; and 2) determine the genotype × location interaction for tipburn resistance. Tipburn incidence was recorded on 10 plants in each of three repetitions in Salinas, Calif., and Yuma, Ariz., trials with 20 iceberg, 21 romaine, 11 green leaf, and six red leaf cultivars. Data were analyzed using analysis of variance type statistics of ranked data. Variation for TB resistance was found in all lettuce types at both locations, although iceberg cultivars (average percentage of TB = 31% Salinas; 77% Yuma) had significantly (P < 0.01) higher levels of resistance at both location than romaine (58% Salinas, 81% Yuma), green leaf (52% Salinas; 88% Yuma), and red leaf (43% Salinas, 89% Yuma). The Yuma, Ariz., trial was more conducive for TB, and had less variation (range of percentage of TB = 33% to 100% Yuma, 0% to 100% Salinas). Four iceberg, one green leaf, and one red leaf genotype with industry acceptable levels of TB (<5%) were identified in the Salinas environment. Genotype × location interaction was present (P < 0.01), and included rank order changes within all lettuce types. The correlation between the locations was low, 0.26, but significant (P = 0.045). A need exists for romaine, green leaf, and red leaf germplasm with improved TB resistance, particularly in the Yuma environment. The presence of variation within each lettuce type and genotype × location indicates that genetic improvement should be possible using within type crosses followed by selection in the Yuma or Salinas target environment.

Anthocyanin and Flavonoid Production from Perilla frutescens: Pilot Plant Scale Processing Including Cross-Flow Microfiltration and Reverse Osmosis

Extraction and concentration at a pilot plant scale of anthocyanins and flavonoids from Perilla frutescens var. frutescens harvested in the Guangzhou area of China were investigated. The study of extraction efficiency using mineral acids and organic acids showed that 0.01 mol/L nitric acid was the most suitable to extract flavonoids from this slightly red leaf cultivar. The red extract contained 12 mg/L (as cyanidin equivalent) anthocyanins and other flavones. The multistep process included cross-flow microfiltration (CFM) with a ceramic type membrane, reverse osmosis (RO), and rotating evaporation (RE). The filtration fluxes were high and constant for CFM (150 L/h/m2 at 0.6 b) and for RO (22 L/h/m2 at 40 b). The red extract was concentrated 9.4 times by RO and then 5.4 times by RE. It contained 422 mg/L anthocyanins, representing 77% of the total extracted anthocyanin. The proportion of flavonoids was found unchanged during processing. The concentrated extract showed a pH of 2.7, and its free acidity was found to be 46% of the acidity added for extraction, because of the buffering capacity of the extract. At the concentration level reached, a crystallized deposit occurred and was identified as tartrate.

Characterisation and variation of antioxidant micronutrients in lettuce (Lactuca sativa folium)

AbstractThe main phenolic compound in six studied lettuce cultivars (five green and one red) was identified as dicaffeoyl tartaric acid. Quantitative but not qualitative differences were found in the phenolic profiles among green cultivars. The red oak leaf cultivar contained twofold more dicaffeoyl tartaric acid and 10‐fold more chlorogenic acid than the green cultivars. Total phenolics ranged from 8.4 to 12.9 mg g−1 dry weight in green varieties and reached 27.8 mg g−1 dry weight in red oak leaf. Carotenoids and vitamins E and C were also quantified. Lutein was the main carotenoid found in all cultivars, together with another xanthophyll. The period of harvesting had only a marginal influence on total phenolic levels, whereas carotenoid and vitamin E levels were higher at the second period of harvesting. Vitamin C levels ranged between 6.1 and 9.9 mg per 100 g fresh weight. We investigated the total antioxidant power in lettuce. Total phenolics accounted for more than 60% of the total antioxidant capacity. Dicaffeoyl tartaric acid accounted for 55%. Copyright © 2004 Society of Chemical Industry

Cold Hardiness Estimates of Acer L. Taxa

Abstract The cold hardiness of eleven Acer taxa was determined by laboratory techniques. The red leaf cultivars of A. platanoides were less cold hardy than the green leaf ‘Emerald Queen.’ ‘Crimson Sentry,’ a branch sport of ‘Crimson King,’ exhibited similar cold hardiness to that of its parent. Among A. saccharum cultivars, ‘Legacy’ was the most cold hardy followed by ‘Green Mountain,’ ‘Commemoration’ and ‘Bonfire.’ ‘Green Column,’ a selection of black maple from a native Iowa population, developed −30°C (−22°F) midwinter cold hardiness but lost all cold hardiness [killed at −3°C (27°F)] by March. All sugar maple cultivars survived at least −9°C (16°F) on the March date. Of the hybrids of Acer platanoides and A. truncatum, Pacific Sunset™ was significantly more cold hardy than Norwegian Sunset™ and should be rated USDA Zone 4 and 5, respectively.

The Inheritance of Red Color of Leaves and Dwarf Character in Peach

This study was started in 1967 to clarify the inheritance of several characters which were consi-dered important to breed new peach cultivar for rootstock use. This paper deals with studies on inheritance of characters of red color of leaves and dwarfness in height. The peach crosses used in this study were grown for two generation. Akame, one of the parent cultivars, is a red leaf cultivar of normal height and the other one Juseito is a green leaf cultivar of dwarfish type.