Leaf Anthocyanin Content Research Articles

Luminescent Quantum Dot Films Increase the Radiation Capture and Yield of Lettuce and Sweet Basil Compared to a Traditional/Neutral-density Greenhouse Glazing

Utilizing quantum dot (QD) luminescent films as a greenhouse covering material is an innovative method of modifying the greenhouse light spectrum. The QD films convert a portion of high-energy ultraviolet and blue photons to lower-energy photons. Previous research has shown that the application of QD films in greenhouses led to improved crop yields of red lettuce and tomatoes. However, the underlying mechanism of the yield increases has not been fully explored. We quantified the effects of solar spectral shifts attributable to QD films on plant morphology, radiation capture, and, subsequently, crop yield. Green and red leaf lettuces and basil were grown in a greenhouse under four treatments: regular-concentration QD film (reg QD film); high-concentration QD film (high QD film); color-neutral polyethylene (PE) film; and control treatment without any films. Compared to the reg QD film, the high QD film converted a higher fraction of blue photons into longer-wavelength photons, resulting in enhanced leaf expansion, stem elongation, and shoot fresh weight of red lettuce and basil compared with those grown under the PE film without spectral modifications. No significant growth differences were observed between the control and high QD film treatments of red lettuce and basil despite a 23% reduction in the average daily light integral (DLI) under the high QD film treatment. Compared to that grown under the control treatment, green lettuce grown under the high QD film treatment had a similar total leaf area but reduced shoot biomass; this was likely associated with reductions in leaf thickness and chlorophyll content. In contrast, the red lettuce showed more pronounced leaf expansion and reduced leaf anthocyanin content under the high QD film, which likely helped to offset the reduction in DLI. Overall, our results indicated that modifying the solar spectrum with QD films as greenhouse covering material could result in improved crop radiation capture and yield in greenhouse production of lettuce and basil. However, the spectral shifts caused by the QD films may affect crop quality attributes, such as anthocyanin levels and the production of other beneficial secondary metabolites. This effect on crop quality should be carefully considered and requires further study.

Comparison of functional and structural biodiversity using Sentinel-2 and airborne LiDAR data in agroforestry systems

Biodiversity plays a critical role in maintaining the health and stability of ecosystems. Biodiversity monitoring has traditionally been labor-intensive, prompting a shift towards remote sensing techniques for efficient and large-scale approaches. In this research, we explore the use of Sentinel-2 satellite data and airborne LiDAR data to evaluate and compare functional and structural biodiversity in agroforestry areas within two distinct ecoregions, namely the Montane forests ecoregion and the Victoria Basin forest-savanna mosaic ecoregion in Columbia and Tanzania, respectively. The aim of the study is to compare functional diversity and structural diversity across varying spatial scales and land cover types including trees, cropland and grassland, thereby addressing the correlation and divergence between functional and structural diversity in different ecological contexts. Our methodology involves integrating airborne LiDAR data to assess structural diversity and Sentinel-2 data to estimate functional diversity based on the proxies of three key functional traits, leaf chlorophyll content (CHL), leaf anthocyanin content (ANTH), and specific leaf area (SLA). We developed two novel functional diversity indices, ShannonF and GiniF, which are modified versions of the well-established Shannon index and Gini index. These novel indices effectively incorporate both functional richness and evenness into their calculations. Our results indicated a significant correlation between our proposed ShannonF index and Shannon index derived from LiDAR, with stronger correlations at larger spatial scales. This study demonstrated that trees exhibit higher biodiversity than grassland and cropland across both study areas, with particularly high biodiversity in Colombia’s Montane forests ecoregion. These findings underscore the potential of integrating satellite and airborne LiDAR data for comprehensive biodiversity assessment in agroforestry systems, offering valuable insights for global ecosystem management and conservation efforts.

Exploring Leaf Anthocyanin Concentrations and Light Effects on Lettuce Growth

Anthocyanins are secondary metabolites classified as water-soluble, non-photosynthetic pigments with the potential ability to shield chloroplasts from excess light energy. This study investigated the morphological and physiological responses of six lettuce (Lactuca sativa) cultivars with different leaf anthocyanin contents grown in a greenhouse under different supplemental photosynthetic photon flux densities (PPFD). Cultivars ‘Cherokee’, ‘Teodore’, ‘Rex’, and ‘Rouxai’ decreased in specific leaf area with increasing PPFD, respectively. We observed that growth in cultivars with higher leaf anthocyanin content (‘Cherokee’ and ‘Rouxai’) increased with increasing PPFD. Light use efficiency (LUE) is an important physiological parameter affecting biomass accumulation, and cultivars ‘Cherokee’, ‘Rex’, ‘Teodore’, and ‘Rouxai’ had the highest LUE and shoot weight. We found that red lettuce varieties, especially ‘Cherokee’ and ‘Rouxai’, showed increased shoot dry weight as light intensity increased. Interestingly, these varieties also had the highest anthocyanin levels in their leaves. This suggests that higher anthocyanin content might contribute to the increased shoot dry weight under higher light intensity, although this was mainly evident in ‘Cherokee’.

The anthocyanin formation of purple leaf is associated with the activation of LfiHY5 and LfiMYB75 in crape myrtle

Purple-leafed plants not only have a higher resistance to biotic and abiotic stresses, but also have higher ornamental value. Anthocyanins are vital for leaf color formation, growth and development of purple leaves. However, the molecular mechanism underlying purple leaf formation in Lagerstroemia indica remains unclear. Metabolomic and transcriptomic analysis of purple-leafed cultivar ‘Ebony Embers’ and green-leafed cultivar ‘Arapahoe’ showed that the high expression of anthocyanin structure genes induced hyperaccumulation of cyanidin and pelargonidin derivatives, making the leaves purple. LfiHY5, LfiMYB75 and LfibHLH1 were identified using correlation analysis and weighted gene co-expression network analysis. In ‘Arapahoe’ × ‘Ebony Embers’ population, LfiHY5 and LfiMYB75 showed significant positive correlation with leaf anthocyanin content. Transient expression of LfiMYB75 and LfiHY5 in tobacco and purple-leafed crape myrtle indicated that the two genes activated anthocyanin synthesis. Yeast two-hybrid analysis showed that LfiMYB75 and LfibHLH1 could form a complex that enhanced anthocyanin synthesis. Yeast monohybrid and dual-luciferase assays confirmed that LfiHY5 activated the expression of LfiMYB75, to activate the transcription of anthocyanin structural genes LfiCHS and LfiANS. Moreover, there were three alleles of LfiHY5 in crape myrtle, and the different sequences had different activation effects on LfiMYB75. In conclusion, the results showed that LfiHY5 led to upregulate the transcription of LfiMYB75, and LfiMYB75 formed a complex with LfibHLH1, which increased the transcription level of LfiCHS and LfiANS to affect anthocyanin synthesis in crape myrtle.

Development and application of Single Primer Enrichment Technology (SPET) SNP assay for population genomics analysis and candidate gene discovery in lettuce.

Single primer enrichment technology (SPET) is a novel high-throughput genotyping method based on short-read sequencing of specific genomic regions harboring polymorphisms. SPET provides an efficient and reproducible method for genotyping target loci, overcoming the limits associated with other reduced representation library sequencing methods that are based on a random sampling of genomic loci. The possibility to sequence regions surrounding a target SNP allows the discovery of thousands of closely linked, novel SNPs. In this work, we report the design and application of the first SPET panel in lettuce, consisting of 41,547 probes spanning the whole genome and designed to target both coding (~96%) and intergenic (~4%) regions. A total of 81,531 SNPs were surveyed in 160 lettuce accessions originating from a total of 10 countries in Europe, America, and Asia and representing 10 horticultural types. Model ancestry population structure clearly separated the cultivated accessions (Lactuca sativa) from accessions of its presumed wild progenitor (L. serriola), revealing a total of six genetic subgroups that reflected a differentiation based on cultivar typology. Phylogenetic relationships and principal component analysis revealed a clustering of butterhead types and a general differentiation between germplasm originating from Western and Eastern Europe. To determine the potentiality of SPET for gene discovery, we performed genome-wide association analysis for main agricultural traits in L. sativa using six models (GLM naive, MLM, MLMM, CMLM, FarmCPU, and BLINK) to compare their strength and power for association detection. Robust associations were detected for seed color on chromosome 7 at 50 Mbp. Colocalization of association signals was found for outer leaf color and leaf anthocyanin content on chromosome 9 at 152 Mbp and on chromosome 5 at 86 Mbp. The association for bolting time was detected with the GLM, BLINK, and FarmCPU models on chromosome 7 at 164 Mbp. Associations were detected in chromosomal regions previously reported to harbor candidate genes for these traits, thus confirming the effectiveness of SPET for GWAS. Our findings illustrated the strength of SPET for discovering thousands of variable sites toward the dissection of the genomic diversity of germplasm collections, thus allowing a better characterization of lettuce collections.

Biochar immobilized plant growth-promoting rhizobacteria enhanced the physicochemical properties, agronomic characters and microbial communities during lettuce seedling.

Spent mushroom substrate (SMS) is the by-products of mushroom production, which is mainly composed of disintegrated lignocellulosic biomass, mushroom mycelia and some minerals. The huge output and the lack of effective utilization methods make SMS becoming a serious environmental problem. In order to improve the application of SMS and SMS derived biochar (SBC), composted SMS (CSMS), SBC, combined plant growth-promoting rhizobacteria (PGPR, Bacillus subtilis BUABN-01 and Arthrobacter pascens BUAYN-122) and SBC immobilized PGPR (BCP) were applied in the lettuce seedling. Seven substrate treatments were used, including (1) CK, commercial control; (2) T1, CSMS based blank control; (3) T2, T1 with combined PGPR (9:1, v/v); (4) T3, T1 with SBC (19:1, v/v); (5) T4, T1 with SBC (9:1, v/v); (6) T5, T1 with BCP (19:1, v/v); (7) T6, T1 with BCP (9:1, v/v). The physicochemical properties of substrate, agronomic and physicochemical properties of lettuce and rhizospheric bacterial and fungal communities were investigated. The addition of SBC and BCP significantly (p < 0.05) improved the total nitrogen and available potassium content. The 5% (v/v) BCP addiction treatment (T5) represented the highest fresh weight of aboveground and underground, leave number, chlorophyll content and leaf anthocyanin content, and the lowest root malondialdehyde content. Moreover, high throughput sequencing revealed that the biochar immobilization enhanced the adaptability of PGPR. The addition of PGPR, SBC and BCP significantly enriched the unique bacterial biomarkers. The co-occurrence network analysis revealed that 5% BCP greatly increased the network complexity of rhizospheric microorganisms and improved the correlations of the two PGPR with other microorganisms. Furthermore, microbial functional prediction indicated that BCP enhanced the nutrient transport of rhizospheric microorganisms. This study showed the BCP can increase the agronomic properties of lettuce and improve the rhizospheric microbial community.

Monitoring the Degree of Mosaic Disease in Apple Leaves Using Hyperspectral Images

Mosaic of apple leaves is a major disease that reduces the yield and quality of apples, and monitoring for the disease allows for its timely control. However, few studies have investigated the status of apple pests and diseases, especially mosaic diseases, using hyperspectral imaging technology. Here, hyperspectral images of healthy and infected apple leaves were obtained using a near-ground imaging high spectrometer and the anthocyanin content was measured simultaneously. The spectral differences between the healthy and infected leaves were analyzed. The content of anthocyanin in the leaves was estimated by the optimal model to determine the degree of apple mosaic disease. The leaves exhibited stronger reflectance at a range of 500–560 nm as the degree of disease increased. The correlation between the spectral reflectance processed by the Gaussian1 wavelet transform and anthocyanin was significantly improved compared to the corresponding correlation results with the original spectrum. The VPs-XGBoost anthocyanin estimation model performed the best, which was sufficient to monitor the degree of the disease. The findings provide theoretical support for the quantitative estimation of leaf anthocyanin content by remote sensing to monitor the degree of disease; they lay the foundation for large-scale monitoring of the degree of apple mosaic disease by remote sensing.

Anthocyanin synthesis is critical for melatonin-induced chromium stress tolerance in tomato

Chromium (Cr) is a toxic heavy metal for both animals and plants. The multifunctional signaling molecule melatonin can confer plant tolerance to heavy metal stress, but the mechanisms remain largely unknown. Here, we unveiled the critical role of the secondary metabolite anthocyanin in melatonin-induced Cr stress tolerance. Excess Cr caused severe phytotoxicity, which was manifested by leaf yellowing, stunted growth, reduced Fv/Fm, and increased accumulation of reactive oxygen species and malondialdehyde in a dose-dependent manner. Interestingly, leaf anthocyanin content increased under Cr stress and was the highest under 100 µM Cr (7.67-fold), while exogenous melatonin further increased anthocyanin accumulation with the highest being with 100 µM melatonin (by 90.72 %). In addition, exogenous melatonin increased endogenous melatonin content and alleviated Cr stress; however, suppression of melatonin accumulation aggravated Cr phytotoxicity and inhibited anthocyanin accumulation by downregulating the transcript levels of key structural genes. Melatonin also reduced the Cr content in roots and leaves. Crucially, suppression of anthocyanin biosynthesis by silencing an anthocyanin biosynthetic gene ANTHOCYANIDIN SYNTHASE (ANS) significantly compromised melatonin-induced anthocyanin accumulation and alleviation of Cr phytotoxicity, suggesting that anthocyanin potentially acts downstream of melatonin and its accumulation is essential for melatonin-induced Cr stress tolerance in tomato plants.

Spatial Variability of Bt Cotton On-farm Situation: A Survey

The survey was carried out during November 2015 in selected cotton fields of seven villages viz., Kalmala, Jagir Venkatapur and Ijapur of Raichur district and Gogi, Ulalkal, Hothpet and Maddarki villages of Yadgir districts covering part of TBP and UKP irrigation commands, respectively. The villages were selected based on the predominance of cotton area. Farmers plots were visited and location were recorded using GPS and observations were made on management practices, leaf reddening incidence and per cent leaf reddening, NDVI values, chlorophyll content, anthocyanin content and seed cotton yield. The spatial variability maps were generated using “krigging”, and interpolation method under GIS environment using observations on spatial spectral variability in NDVI, SPAD (chlorophyll content), anthocyanin content, leaf reddening index, reddening percentage and seed cotton as influenced by irrigation ecosystem, soil type and foliar spray of 19:19:19, date of sowing and cultivars. The data was further subjected for correlation studies. There is a lot of variation in the seed cotton yields among Bt cotton farmers across the Upper Krishna project and Tunga Bhadra Project irrigation commands of the state. Soils cultivated and cultivars used often remain the same the difference in yield could be due to nutritional management, the occurrence of leaf reddening, other factors, or combination of many of these attributing characteristics. Since leaf health is indicative of plant health and yield in turn, leaf health could be assessed through leaf spectral reflectance viz, NDVI, SPAD, and LRI. Based on this a survey was undertaken in November 2015 at Raichur (in three taluks) and Yadgir (in four taluks) districts falling under TBP and UKP irrigation commands, respectively, taking in all 90 farmers. The spectral observations were made on standing field crops besides leaf samples were collected to estimate leaf anthocyanin in the laboratory and GIS mapping was done using ESRI-made ArcGIS version 10.4 from Sujala-III, Remote Sensing and GIS laboratory, College of Agriculture, Raichur, was used to import GPS data and field data attachment for spatial analysis of leaf reddening incidence in cotton. The results on Spectral observations on NDVI, SPAD, leaf reddening index, reddening percentage in addition to leaf anthocyanin content varied due to locations, irrigation or otherwise, foliar spray, fertilization level, date of sowing, and cultivars.The leaf chlorophyll content is an important biometric character, the content quality, and duration (stability) indicate general crop health and ultimately yield directly if not influenced by the rate and efficiency of translocation to sink (kapas yield in case of cotton), therefore, it is often used to monitor real-timeN fertilization (LCC, SPAD, Green Seeker) as well as to forecast crop condition and yield. Periodic spectral observations on SPAD and NDVI are useful indicators of crop health and performance in commercial crop like cotton which could be extrapolated to field scale for crop management and production forecast.

Construction of Genetic Linkage Map and Mapping QTL Specific to Leaf Anthocyanin Colouration in Mapping Population 'Allahabad Safeda' × 'Purple Guava (Local)' of Guava (Psidium guajava L.).

In the present investigation, F1 hybrids were developed in guava (Psidium guajava L.) by crossing high leaf-anthocyanin reflective-index (ARI1) content cultivars purple guava (local) ‘PG’, ‘CISH G-1’ and low leaf-ARI1 content cultivar Seedless ‘SL’ with Allahabad Safeda ‘AS’. On the basis of phenotypic observations, high ARI1 content was observed in the cross ‘AS’ × ‘PG’ (0.214). Further, an SSR-markers-based genetic linkage map was developed from a mapping population of 238 F1 individuals derived from cross ‘AS’ × ‘PG’. The linkage map comprised 11 linkage groups (LGs), spanning 1601.7 cM with an average marker interval distance of 29.61 cM between adjacent markers. Five anthocyanin-content related gene-specific markers from apple were tested for parental polymorphism in the genotypes ‘AS’ and ‘PG’. Subsequently, a marker, viz., ‘MdMYB10F1′, revealed a strong association with leaf anthocyanin content in the guava mapping population. QTL (qARI-6-1) on LG6 explains much of the variation (PVE = 11.51% with LOD = 4.67) in levels of leaf anthocyanin colouration. This is the first report of amplification/utilization of apple anthocyanin-related genes in guava. The genotypic data generated from the genetic map can be further exploited in future for the enrichment of linkage maps and for identification of complex quantitative trait loci (QTLs) governing economically important fruit quality traits in guava.

Leaf Anthocyanin Content Retrieval with Partial Least Squares and Gaussian Process Regression from Spectral Reflectance Data.

Leaf pigment content retrieval is an essential research field in remote sensing. However, retrieval studies on anthocyanins are quite rare compared to those on chlorophylls and carotenoids. Given the critical physiological significance of anthocyanins, this situation should be improved. In this study, using the reflectance, partial least squares regression (PLSR) and Gaussian process regression (GPR) were sought to retrieve the leaf anthocyanin content. To our knowledge, this is the first time that PLSR and GPR have been employed in such studies. The results showed that, based on the logarithmic transformation of the reflectance (log(1/R)) with 564 and 705 nm, the GPR model performed the best (R2/RMSE (nmol/cm2): 0.93/2.18 in the calibration, and 0.93/2.20 in the validation) of all the investigated methods. The PLSR model involved four wavelengths and achieved relatively low accuracy (R2/RMSE (nmol/cm2): 0.87/2.88 in calibration, and 0.88/2.89 in validation). GPR apparently outperformed PLSR. The reason was likely that the non-linear property made GPR more effective than the linear PLSR in characterizing the relationship for the absorbance vs. content of anthocyanins. For GPR, selected wavelengths around the green peak and red edge region (one from each) were promising to build simple and accurate two-wavelength models with R2 > 0.90.

Incidence of Galls on Sympatric California Oaks: Ecological and Physiological Perspectives

Galls are abnormal outgrowths on the external tissues of plants caused by a restricted group of organisms. In this study, we surveyed the incidence and diversity of galling structures in sympatric oak species of a biological preserve (Jasper Ridge Biological Preserve, NC, USA). We also measured different physiological parameters (SLA-specific leaf area, chlorophyll, nitrogen, flavonol, anthocyanin, and water content) in galled and ungalled leaves on the same individuals of the most abundant oak species (Quercus agrifolia, Q. lobata, and Q. douglasii). Overall, Q. lobata showed the highest gall incidence, with 64.5% of the sampled leaves affected by galls, followed by Q. douglasii, Q. agrifolia, Q. durata, and Q. kelloggii. The proportion of stems with galls was considerably lower than for leaves in all oak species, ranging from 0% incidence in Q. kelloggii to 27.4% in Q. lobata. The highly schlerophyllous Q. agrifolia supported the most diverse galling community at Jasper Ridge, with ten species, mostly belonging to the Cynipidae family. Our results show that leaf galling had no significant impact on the studied ecophysiological variables. The lack of differences between galled and ungalled leaves under controlled conditions (same tree and position in the tree) suggests that the ecophysiological variables measured are not significantly affected by galling agents or that our data collected for fully-developed galls (end of summer) are not sensitive enough to detect differences. However, there were some trends in plant responses to galling. Changes in galled vs. ungalled leaves were greater in flavonols, followed by chlorophyll, nitrogen, anthocyanin, SLA, and water content, indicating a nutrient deficiency in the plant nutrients. Our findings underscore the complexity of the gall-plant interaction and suggest some promising lines of future research.

Impact of salicylic acid on the growth and physiological activities of parsley plants under lead toxicity.

Impact of spraying 50µM salicylic acid (SA), lead nitrate soil treatments [1 and 2mM Pb (NO3)2] and their combinations on parsley leaves (Petroselinum crispum L.) for 3 weeks was studied to evaluate leaf symptoms, photosynthetic pigments, anthocyanin, ultrastructure, malondialdehyde (MDA), soluble proteins, phenolic compounds, and guaiacol peroxidase activity (GPOX). Under Pb effect, parsley leaves showed chlorosis and decline in the content of photosynthetic pigments chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoid (Car) with increasing Pb treatments compared to the control. SA spraying helped to reduce chlorosis and increase photosynthetic pigments of Pb-treated plants compared to that of Pb treatment alone. Leaf anthocyanin content of SA-sprayed plants significantly increased compared to the control. On contrast, the anthocyanin content of Pb-treated plants with or without SA treatment decreased compared to the control. Parsley leaf chloroplasts were characterized by many and large starch grains. Deformations of chloroplast shape, increasing formation of plastoglobules and degeneration of chloroplast grana thylakoids were observed in Pb-treated plants. MDA and total phenolic compound contents increased in Pb-treated plants compared to the control. In contrast, soluble protein content decreased in Pb-treated plants. The decrease in leaf photosynthetic pigments and increase MDA contents was Pb-concentration dependent. The results as indicated by increasing lipid peroxidation confirmed Pb treatments generated reactive oxygen species (ROS) which caused oxidative stress. In contrast, SA application declined the extent of detrimental and harmful influence of Pb toxicity as indicated by the decrease MDA content, and increase in photosynthetic pigments, anthocyanin and phenolic compound contents of parsley leaves.

Comparison of prediction power of three multivariate calibrations for estimation of leaf anthocyanin content with visible spectroscopy in Prunus cerasifera.

The anthocyanin content in leaves can reveal valuable information about a plant’s physiological status and its responses to stress. Therefore, it is of great value to accurately and efficiently determine anthocyanin content in leaves. The selection of calibration method is a major factor which can influence the accuracy of measurement with visible and near infrared (NIR) spectroscopy. Three multivariate calibrations including principal component regression (PCR), partial least squares regression (PLSR), and back-propagation neural network (BPNN) were adopted for the development of determination models of leaf anthocyanin content using reflectance spectra data (450–600 nm) in Prunus cerasifera and then the performance of these models was compared for three multivariate calibrations. Certain principal components (PCs) and latent variables (LVs) were used as input for the back-propagation neural network (BPNN) model. The results showed that the best PCR and PLSR models were obtained by standard normal variate (SNV), and BPNN models outperformed both the PCR and PLSR models. The coefficient of determination (R2), the root mean square error of prediction (RMSEp), and the residual prediction deviation (RPD) values for the validation set were 0.920, 0.274, and 3.439, respectively, for the BPNN-PCs model, and 0.922, 0.270, and 3.489, respectively, for the BPNN-LVs model. Visible spectroscopy combined with BPNN was successfully applied to determine leaf anthocyanin content in P. cerasifera and the performance of the BPNN-LVs model was the best. The use of the BPNN-LVs model and visible spectroscopy showed significant potential for the nondestructive determination of leaf anthocyanin content in plants.

Characterization of Anthocyanins in Sweet Potato Leaves Grown in Various Stages and Conditions

Phytochemical-enriched edible greens, sweet potato leaves (Ipomoea batatas L.), have become popular due to potential health benefits. However, the phytochemical contents in sweet potato leaves and their subsequent change over harvest stages and growth condition are mostly unknown. In this study, the anthocyanin profile and content in leaves of four sweet potato cultivars, i.e., white-skinned and white-fleshed Bonita, red-skinned and orange-fleshed Beauregard, red-skinned and white-fleshed Murasaki and purple-skinned and purple-fleshed P40, were evaluated. Fourteen anthocyanins were isolated and identified by HPLC-MSI/MS. The most abundant was cyanidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, which comprised up to 20% of the total anthocyanins. Of the young leaves (1st and 2nd slip cuttings), Bonita contained the highest anthocyanin content followed by P40. Of the mature leaves (vine stage), Beauregard had the greatest anthocyanin (592.5 ± 86.4 mg/kg DW) and total phenolic (52.2 ± 3 mg GAE/g DW). It should be noted that the lowest anthocyanin and total phenolic content of shoots were found in P40, while tubers of P40 contain the highest content of each. Furthermore, the increase in leaf anthocyanin content over the growth stages that was observed in three of the cultivars but not in P40. No significant difference of anthocyanin content was found in Beauregard leaves grown in the high tunnels when compared with that in the open field. This study demonstrated for the first time that anthocyanin levels were significantly changed in response to various growth stages but not high tunnel condition, indicating that the effect of anthocyanin biosynthesis in sweet potato leaves is highly variable and genotype specific.

The Effect of Phosphorus and Root Zone Temperature on Anthocyanin of Red Romaine Lettuce

In this study, phosphorus (P) strength [(full strength: 1×-P, half strength: 0.5×-P and zero strength: 0×-P)] and root zone temperature (10 and 15 °C RZT) were investigated in red romaine lettuce to determine their effects on anthocyanin content. This experiment was conducted using a deep-flow technique (DFT) hydroponic system in a greenhouse during the winter in Gangwon province in the Korea Republic. The treatments were 1×-P (15 and 10 °C RZT), 0.5×-P (15 and 10 °C RZT) and 0×-P (15 and 10 °C RZT). The results showed that the P (phosphorus), K (potassium) and Ca (calcium) accumulation contents were lower in the 0×-P -treated red romaine lettuce leaves than in the other treatments. The maximum red romaine lettuce yields per plant, leaf number and leaf length were exhibited during the 1×-P at 15 °C RZT treatment. In 0×-P at 10 °C, RZT treatment showed lower leaf color values of L*, b*, chrome, ºh and higher leaf color a* values. Moreover, in the 0×-P treatment at 10 °C RZT, the leaf chlorophyll content (SPAD), chlorophyll a, chlorophyll b and chlorophyll total were the lowest. Anthocyanin content was the highest in the 0×-P treatment, followed by 0.5×-P and 1×-P treatments at both 15 and 10 °C RZT. Regardless of the P intensity treatment, anthocyanin content was higher at 10 °C RZT than at 15 °C RZT. In summary, the 1×-P at 15 °C RZT treatment is the best for red romaine lettuce leaf yield, and the 0×-P at 10 °C RZT treatment is the best for lettuce leaf anthocyanin content.

Characterization of Anthocyanins in Sweetpotato leaves

As phytochemical‐enriched edible greens, sweetpotato (Ipomoea batatas L.) leaves have become popular due to potential health benefits. However, the phytochemical contents in sweetpotato leaves and their subsequent change over harvest stages and growth condition are mostly unknown. In this study we determined the anthocyanin profile and content in leaves of four sweetpotato cultivars (Bonita, Beauregard, Murasaki, and P40). Fourteen anthocyanins, including one newly discovered, were identified by HPLC‐MS/MS. The most abundant was cyanidin 3‐caffeoyl‐p‐hydroxybenzoyl sophoroside‐5‐glucoside, which comprised up to 20% of the total anthocyanins. Of the young leaves (1st and 2nd slip cuttings), Bonita contained the highest anthocyanin content followed by P40. Of the mature leaves (vine stage), Beauregard had the greatest anthocyanin (391 mg/kg DW) and total phenolic (52 GAE/g DW) content. It should be noted that the lowest anthocyanin and total phenolic content of shoots were found in P40, while tubers of P40 contain the highest content of each. Furthermore, the increase in leaf anthocyanin content over the growth stages that was observed in three of the cultivars was absent in P40. No significant difference of anthocyanin content was found in Beauregard leaves grown in the high tunnels or open field.Support or Funding Informationsupported by USDA Cooperative KS511‐1001903

A R2R3-MYB Gene LfMYB113 is Responsible for Autumn Leaf Coloration in Formosan sweet gum (Liquidambar formosana Hance).

The regulation of autumn leaf coloration in deciduous trees has long been an enigma. Due to the fact that different coloration phenotypes may be considered when planting, more understanding of the regulation mechanism is needed. In this study, a R2R3-MYB transcription factor gene LfMYB113 was identified from a subtropical deciduous tree species Formosan sweet gum (Liquidambar formosana Hance). The expression patterns of LfMYB113 in four selected phenotypes were different and were positively correlated with leaf anthocyanin content. In a 35S::LfMYB113 transgenic Nicotiana tabacum plant, both the early and late genes in the anthocyanin biosynthetic pathway were shown to be up-regulated. It was also shown that LfMYB113 can activate the promoter sequence of LfDFR1 and LfDFR2. Transient overexpression of LfMYB113 in Nicotiana benthamiana showed strong anthocyanin accumulation and pre-senescence; the latter was confirmed by up-regulation of senescence-associated genes. In addition, the activation of proLfSGR::YFP by LfMYB113 in transient experiments indicated that LfMYB113 may have a role in regulation of Chl degradation. To our knowledge, this is the first time a R2R3-MYB transcription factor has been functionally identified as one of the key regulators of autumn leaf coloration and autumn leaf senescence.

Early Autumn Senescence in Red Maple (Acer rubrum L.) Is Associated with High Leaf Anthocyanin Content.

Several theories exist about the role of anthocyanins in senescing leaves. To elucidate factors contributing to variation in autumn leaf anthocyanin contents among individual trees, we analysed anthocyanins and other leaf traits in 27 individuals of red maple (Acer rubrum L.) over two growing seasons in the context of timing of leaf senescence. Red maple usually turns bright red in the autumn, but there is considerable variation among the trees. Leaf autumn anthocyanin contents were consistent between the two years of investigation. Autumn anthocyanin content strongly correlated with degree of chlorophyll degradation mid to late September, early senescing leaves having the highest concentrations of anthocyanins. It also correlated positively with leaf summer chlorophyll content and dry matter content, and negatively with specific leaf area. Time of leaf senescence and anthocyanin contents correlated with soil pH and with canopy openness. We conclude that the importance of anthocyanins in protection of leaf processes during senescence depends on the time of senescence. Rather than prolonging the growing season by enabling a delayed senescence, autumn anthocyanins in red maple in Ontario are important when senescence happens early, possibly due to the higher irradiance and greater danger of oxidative damage early in the season.

Positive Relationship between Anthocyanin and Corosolic Acid Contents in Leaves of Lagerstroemia speciosa Pars.

Corosolic acid content and distribution in Lagerstroemia speciosa Pars. were investigated, indicating that the red leaves contained more corosolic acid than the green leaves and other plant parts such as petals, roots and seeds. The leaf redness was derived from cyanidin 3-O-glucoside which was first identified in this species. The contents of corosolic acid and cyanidin 3-O- glucoside were found to be well correlated, supporting the traditional perception of local people of the Philippines that red leaf banaba tea exerts more pronounced medicinal effects.