Immature Green Research Articles

ПОЛУЧЕНИЕ ФУНКЦИОНАЛЬНЫХ НАПИТКОВ С ПРИМЕНЕНИЕМ ЦЕНТРОБЕЖНОГО СМЕСИТЕЛЯ ПИЩЕВЫХ СРЕД

Consumption of whole grains has attracted more consumer attention over the past few years because of their health benefits. Apart from eating the grains in their whole forms, people usually process them to increase the amount and availability of their nutrients. During germination, the endosperm is degraded using specific enzymes, followed by the release and synthesis of bioactive molecules according to the degree of germination. Juices from sprouted grains are rich in nutrients; they contain essential vitamins and minerals that are rarely found in such high concentrations in other foods. Microgreens are immature greens and are considered functional foods because of the presence of chlorophyll, β-carotene, lutein and minerals such as magnesium, potassium, phosphorus and calcium. The choice of the equipment type depends on ingredients to be mixed and the mixing scenario. It is crucial to find the balance between equipment and ingredient properties for obtaining an efficient production capacity in less time and with less energy. The experiment produced six samples of functional beverages. The combination of ingredients in the functional beverages was optimised by organoleptic and sensory evaluation of the beverages with different levels of green juice from barley and oat microgreens and juice from the fruit of small-fruited apple trees.

Effect of postharvest treatments and storage temperature on the physiological, nutritional, and shelf-life of broccoli (Brassica oleracea) microgreens

Microgreens are categorized in the class of ‘super foods’ due to their high content of phytochemical and bioactive compounds. Rapid senescence and short life span are the restrictive parameters for the industrial production and marketing of these immature greens. Hence, there is a need to improve the production and storage conditions of microgreens to magnify postharvest quality, life span, and safety of microgreens, thereby emerging markets. To prolong their shelf life, effect of different postharvest treatments (MAP (modified Atmospheric Packaging) and GRAS chemical treatments) and storage temperature on physiological, nutritional and shelf life of broccoli (Brassica oleracea) microgreens studied. The effect of ascorbic acid + citric acid (0.25 % w/v each) along with MAP conditions (15 % CO2 + 5 % O2 + balanced N2) stored at 5 °C was used for post-harvest quality evaluation of broccoli microgreens. Microgreens treated with an organic acid in high CO2 conditions retained significantly (p < 0.05) higher bioactive compounds in terms of total phenols (1247.68 mg GAE/100 g FW), flavonoids (56.9 mg QE/100 g FW), and chlorophyll (42.12 mg/100 g FW) with better antioxidant activity (44.78 % inhibition). In addition, MAP conditions in the package significantly (p < 0.05) suppressed the weight loss that helped to retain better firmness. The combined effect of organic acids and MAP conditions significantly (p < 0.05) reduced the microbial load with better color quality and higher overall acceptability. The results indicate that post-harvest treatment of ascorbic acid + citric acid along with MAP conditions could be the practical approach to enhance the shelf life of microgreens up to 12 days while maintaining the nutritional quality, to provide avenues for better marketability and commercial gains.

Prospects of microgreens as budding living functional food: Breeding and biofortification through OMICS and other approaches for nutritional security.

Nutrient deficiency has resulted in impaired growth and development of the population globally. Microgreens are considered immature greens (required light for photosynthesis and growing medium) and developed from the seeds of vegetables, legumes, herbs, and cereals. These are considered "living superfood/functional food" due to the presence of chlorophyll, beta carotene, lutein, and minerals like magnesium (Mg), Potassium (K), Phosphorus (P), and Calcium (Ca). Microgreens are rich at the nutritional level and contain several phytoactive compounds (carotenoids, phenols, glucosinolates, polysterols) that are helpful for human health on Earth and in space due to their anti-microbial, anti-inflammatory, antioxidant, and anti-carcinogenic properties. Microgreens can be used as plant-based nutritive vegetarian foods that will be fruitful as a nourishing constituent in the food industryfor garnish purposes, complement flavor, texture, and color to salads, soups, flat-breads, pizzas, and sandwiches (substitute to lettuce in tacos, sandwich, burger). Good handling practices may enhance microgreens'stability, storage, and shelf-life under appropriate conditions, including light, temperature, nutrients, humidity, and substrate. Moreover, the substrate may be a nutritive liquid solution (hydroponic system) or solid medium (coco peat, coconut fiber, coir dust and husks, sand, vermicompost, sugarcane filter cake, etc.) based on a variety of microgreens. However integrated multiomics approaches alongwith nutriomics and foodomics may be explored and utilized to identify and breed most potential microgreen genotypes, biofortify including increasing the nutritional content (macro-elements:K, Ca and Mg; oligo-elements: Fe and Zn and antioxidant activity) and microgreens related other traits viz., fast growth, good nutritional values, high germination percentage, and appropriate shelf-life through the implementation of integrated approaches includes genomics, transcriptomics, sequencing-based approaches, molecular breeding, machine learning, nanoparticles, and seed priming strategiesetc.

Phytochrome-Mediated Light Perception Affects Fruit Development and Ripening Through Epigenetic Mechanisms.

Phytochrome (PHY)-mediated light and temperature perception has been increasingly implicated as important regulator of fruit development, ripening, and nutritional quality. Fruit ripening is also critically regulated by chromatin remodeling via DNA demethylation, though the molecular basis connecting epigenetic modifications in fruits and environmental cues remains largely unknown. Here, to unravel whether the PHY-dependent regulation of fruit development involves epigenetic mechanisms, an integrative analysis of the methylome, transcriptome and sRNAome of tomato fruits from phyA single and phyB1B2 double mutants was performed in immature green (IG) and breaker (BK) stages. The transcriptome analysis showed that PHY-mediated light perception regulates more genes in BK than in the early stages of fruit development (IG) and that PHYB1B2 has a more substantial impact than PHYA in the fruit transcriptome, in both analyzed stages. The global profile of methylated cytosines revealed that both PHYA and PHYB1B2 affect the global methylome, but PHYB1B2 has a greater impact on ripening-associated methylation reprogramming across gene-rich genomic regions in tomato fruits. Remarkably, promoters of master ripening-associated transcription factors (TF) (RIN, NOR, CNR, and AP2a) and key carotenoid biosynthetic genes (PSY1, PDS, ZISO, and ZDS) remained highly methylated in phyB1B2 from the IG to BK stage. The positional distribution and enrichment of TF binding sites were analyzed over the promoter region of the phyB1B2 DEGs, exposing an overrepresentation of binding sites for RIN as well as the PHY-downstream effectors PIFs and HY5/HYH. Moreover, phyA and phyB1B2 mutants showed a positive correlation between the methylation level of sRNA cluster-targeted genome regions in gene bodies and mRNA levels. The experimental evidence indicates that PHYB1B2 signal transduction is mediated by a gene expression network involving chromatin organization factors (DNA methylases/demethylases, histone-modifying enzymes, and remodeling factors) and transcriptional regulators leading to altered mRNA profile of ripening-associated genes. This new level of understanding provides insights into the orchestration of epigenetic mechanisms in response to environmental cues affecting agronomical traits.

Transcriptome Analysis of the Fruit of Two Strawberry Cultivars "Sunnyberry" and "Kingsberry" That Show Different Susceptibility to Botrytis cinerea after Harvest.

Gray mold (Botrytis cinerea) is a fungal plant pathogen causing postharvest decay in strawberry fruit. Here, we conducted a comparative transcriptome analysis to identify differences in gene expression between the immature-green (IG) and mature-red (MR) stages of the “Sunnyberry” (gray mold-resistant) and “Kingsberry” (gray mold susceptible) strawberry cultivars. Most of the genes involved in lignin and alkane-type wax biosynthesis were relatively upregulated in “Sunnyberry”. However, pathogenesis-related proteins encoding R- and antioxidant-related genes were comparatively upregulated in “Kingsberry”. Analysis of gene expression and physiological traits in the presence and absence of B. cinerea inoculation revealed that the defense response patterns significantly differed between IG and MR rather than the cultivars. “Kingsberry” showed higher antioxidant induction at IG and upregulated hemicellulose-strengthening and R genes at MR. Hence, “Sunnyberry” and “Kingsberry” differed mainly in terms of the expression levels of the genes forming cuticle, wax, and lignin and controlling the defense responses. These discrepancies might explain the relative difference between these strawberry cultivars in terms of their postharvest responses to B. cinerea.

Effect of tomato fruit cultivar and ripening stage on Bactrocera tryoni (Froggatt) egg and larval survival

AbstractIn studies of frugivorous tephritids, determining when offspring (i.e. egg and three larval instars) mortality occurs within the fruit can greatly improve the mechanistic understanding of the fly/host interaction. Previous research has demonstrated that the Queensland fruit fly, Bactrocera tryoni, has differential offspring performance in two tomato cultivars Cherry and Roma, but when juvenile mortality was occurring was not determined. We examined B. tryoni egg and larval survival in three different ripening stages (immature‐green (IG), colour‐break (CB) and fully‐ripe (FR)) of Cherry and Roma tomato cultivars through destructive fruit sampling at 72 and 120 hr for eggs, and 48 (1st instar), 96 (2nd instar) and 120 hr (3rd instar) after fruit inoculation with neonates for larvae. Cultivar and ripening stage had no significant effect on egg survival, nor larval survival at 48 hr: the overall percentage of egg survival was at least 80% across all treatments, while 1st‐instar larval was less than 52% across all treatments. In immature‐green tomatoes of both varieties, nearly all mortality occurred during the first and second instars, but at 96 and 120 hr, there were significant interaction effects between cultivar and ripening stage on larval survival. In both colour‐break Cherry and Roma tomatoes, there was significant larval mortality between 96 and 120 hr. However, in fully‐ripe Cherry, no further significant larval mortality happened after 48 hr, while in fully‐ripe Roma significant larval mortality occurred between the first and second larval instars but not thereafter. The difference in timing of larval mortality with ripening stage provides indirect evidence of active fruit defence which is strongest in immature‐green fruit, less in colour‐break fruit and absent in fully‐ripe fruit.

Sensory Attributes and Consumer Acceptability of 12 Microgreens Species

Microgreens are gaining increasing recognition among consumers, acclaimed for their freshness and health promoting properties associated with densely fortified secondary metabolites. These immature greens enhance human diet and enrich it with sharp colors and flavors. While numerous species are being tested for agronomic and nutritional suitability, consumer acceptance of appearance, texture, and flavor is critical for the microgreens’ marketplace success. This study investigates whether sensory attributes and visual appearance affect consumer preference for microgreens and their willingness to consume them. By means of a consumer test, the sensory attributes of 12 microgreens species were evaluated, wherein a partial least squares structural equation model was developed to link sensorial attributes to willingness to eat the product. The results showed that although visual appearance of the microgreens was largely appreciated, consumer acceptance overall was mainly determined by flavor and texture. In particular, the lower the astringency, sourness, and bitterness, the higher the consumer acceptability of microgreens. Among the 12 examined species, mibuna and cress scored the lowest acceptance by consumers, while Swiss chard and coriander were the most appreciated, being therefore good candidates to be introduced in Western country markets. In addition, both Swiss chard and coriander have been identified by previous literature as good dietary source of phenolic antioxidants.

Selenium Biofortification Impacts the Nutritive Value, Polyphenolic Content, and Bioactive Constitution of Variable Microgreens Genotypes.

Selenium (Se) is considered essential for human nutrition as it is involved in the metabolic pathway of selenoproteins and relevant biological functions. Microgreens, defined as tender immature greens, constitute an emerging functional food characterized by overall higher levels of phytonutrients than their mature counterparts. The nutraceutical value of microgreens can be further improved through Se biofortification, delivering Se-enriched foods and potentially an enhanced content of bioactive compounds. The current study defined the effect of sodium selenate applications at three concentrations (0, 8, and 16 μM Se) on the bioactive compounds and mineral content of coriander, green basil, purple basil, and tatsoi microgreens grown in soilless cultivation. Analytical emphasis was dedicated to the identification and quantification of polyphenols by UHPLC-Q-Orbitrap-HRMS, major carotenoids by HPLC-DAD, and macro micro-minerals by ICP-OES. Twenty-seven phenolic compounds were quantified, of which the most abundant were: Chlorogenic acid and rutin in coriander, caffeic acid hexoside and kaempferol-3-O(caffeoyl) sophoroside-7-O-glucoside in tatsoi, and cichoric acid and rosmarinic acid in both green and purple basil. In coriander and tatsoi microgreens, the application of 16 μM Se increased the total phenols content by 21% and 95%, respectively; moreover, it improved the yield by 44% and 18%, respectively. At the same Se dose, the bioactive value of coriander and tatsoi was enhanced by a significant increase in rutin (33%) and kaempferol-3-O(feruloyl)sophoroside-7-O-glucoside (157%), respectively, compared to the control. In green and purple basil microgreens, the 8 μM Se application enhanced the lutein concentration by 7% and 19%, respectively. The same application rate also increased the overall macroelements content by 35% and total polyphenols concentration by 32% but only in the green cultivar. The latter actually had a tripled chicoric acid content compared to the untreated control. All microgreen genotypes exhibited an increase in the Se content in response to the biofortification treatments, thereby satisfying the recommended daily allowance for Se (RDA-Se) from 20% to 133%. The optimal Se dose that guarantees the effectiveness of Se biofortification and improves the content of bioactive compounds was 16 μM in coriander and tatsoi, and 8 μM in green and purple basil.

Production of selenium-biofortified microgreens from selenium-enriched seeds of basil.

Microgreens (i.e. tender immature greens) are a popular alternative to sprouts (i.e. germinating seeds) because of their higher content of vitamins, carotenoids and phenols, as well as their lower content of nitrates. Their nutritional value can be improved by biofortification, which increases micronutrient levels during plant growth. Because selenium (Se) plays a significant role in antioxidant defense, biofortification with Se is a good way of improving the nutritional quality of sprouts and microgreens. The present study investigated the production of Se-fortified microgreens from Se-enriched seeds of sweet basil (Ocimum basilicum L.). These microgreens could be used as new beneficial dietary supplements. Basil plants were grown in a nutrient solution, containing 0 (control), 4 or 8 mg Se L-1 as sodium selenate, to full maturity. Seeds accumulated a high amount of Se and were then used to produce microgreens. The germination index was higher in the seeds from Se-treated plants and the microgreens were enriched in Se. The antioxidant capacity of Se-fortified microgreens was higher compared to the control. The production of microgreens from Se-enriched seeds could comprise a good system for obtaining microgreens with a high nutritional value. Basil plants treated with Se could be used to produce both Se-fortified leaves and microgreens. © 2019 Society of Chemical Industry.

Nutritional and anti-nutritional analysis of some selected microgreens

Microgreens are immature greens of edible vegetables and herbs which may serve as a good nutrient source. The present study was conducted on ten locally available plants, tested as microgreens. The study included evaluation of seed germination and growth pattern for two weeks period and nutritional characterization of selected microgreens. Results showed that the seeds of selected plants had > 80% germination and attained 6–7 cm height within two weeks. Vitamin C was high in all the microgreens tested; while thiamine, riboflavin and niacin were high in microgreens of Amaranthus viridis, Vigna radiata and Allium cepa, respectively. However, vitamin content was higher in sprouts than microgreens and mature edible parts of selected plants even though some exceptions were found. Anti-nutrients analyzed in microgreens were below the toxic levels. Microgreens had low carbohydrates and anti-nutrient contents; but high vitamin contents, so these can be recommended as dietary supplement, especially for those who preferred less carbohydrate-containing food supplements.

Molecular characterization of fruit-specific class III peroxidase genes in tomato (Solanum lycopersicum)

In this study, expression of four peroxidase genes, LePrx09, LePrx17, LePrx35 and LePrxA, was identified in immature tomato fruits, and the function in the regulation of fruit growth was characterized. Analysis of amino acid sequences revealed that these genes code for class III peroxidases, containing B, D and F conserved domains, which bind heme groups, and a buried salt bridge motif. LePrx35 and LePrxA were identified as novel peroxidase genes in Solanum lycopersicum (L.). The temporal expression patterns at various fruit growth stages revealed that LePrx35 and LePrxA were expressed only in immature green (IMG) fruits, whereas LePrx17 and LePrx09 were expressed in both immature and mature green fruits. Tissue-specific expression profiles indicated that only LePrx09 was expressed in the mesocarp but not the inner tissue of immature fruits. The effects of hormone treatments and stresses on the four genes were examined; only the expression levels of LePrx17 and LePrx09 were altered. Transcription of LePrx17 was up-regulated by jasmonic acid (JA) and pathogen infection and expression of LePrx09 was induced by ethephon, salicylic acid (SA) and JA, in particular, as well as wounding, pathogen infection and H2O2 stress. Tomato plants over-expressing LePrx09 displayed enhanced resistance to H2O2 stress, suggesting that LePrx09 may participate in the H2O2 signaling pathway to regulate fruit growth and disease resistance in tomato fruits.

Effect of 1-methylcyclopropene on tomato flavour components, shelf life and decay as influenced by harvest maturity and storage temperature

In Florida, tomatoes are harvested green (GR), which includes mature green (MG) and immature green (IG) fruits, and stored at low temperature (13 °C), resulting in poor flavour. Flavour improvement might be achieved if fruits were harvested with some colour (to eliminate IG fruits) and/or stored at higher temperature with the ripening inhibitor 1-methylcyclopropene (1-MCP). 'Florida 47' tomatoes were harvested at GR (MG + IG), breaker (BR), turning (TR) and pink (PK) stages, treated (+) or not (-) with 1-MCP and stored at 13 and/or 18 °C. 1-MCP treatment resulted in a gain of up to 6 days of shelf life depending on harvest maturity and storage temperature. Storage at 18 °C rather than 13 °C resulted in an increase in internal red colour, soluble solids (SS)/titratable acidity (TA) ratio and levels of many volatiles studied. The shelf life of BR (+) MCP fruits stored at 13 °C was similar to that of MG fruits. IG fruits exhibited lowest levels of SS, TA and ten volatiles compared with BR fruits. Harvesting tomatoes with colour (BR), thereby eliminating IG fruits, and treating with 1-MCP resulted in better quality with adequate shelf life.

한국 연안의 멸종위기 바다거북의 분포 및 좌초 현황

This paper reports the strandings of sea turtles on Korean shores monitored for the first time in 2008. A total of 19 sea turtles, consisting of 12 greens and 7 loggerheads, were recorded as stranded from the east coast to the south including Jeju Island. Reported strandings reached a peak in July and dominant area was Jeju Island. The curved carapace length of loggerhead sea turtles ranged 65-84.2cm and that of green sea turtles ranged 39.2-90cm, indicating most of them were immature to sub-adult. Out of 19 turtles, 11 were found dead with unknown reasons. Possible causes of death may include drawning by fishing gear, swallowing of marine debris, boat collision, and diseases. An immature green sea turtle tagged with a satellite transmitter spent winter near Jeju Island where it was released, suggesting that the Island provide immature greens a feeding ground. Considering thousands of sea turtles crawl on Japanese shores for nesting every year, the number of sea turtles reported in Korean waters was relatively small. Therefore, it is suggested that an appropriate monitoring system be necessary to protect and conserve endangered sea turtle species in Korean waters.

Different responses of goldenberry fruit treated at four maturity stages with the ethylene antagonist 1-methylcyclopropene

Goldenberries ( Physalis peruviana L.) were harvested at four different maturity stages: immature green (IG), mature green (MG), yellow (Y) and orange (OR). Fruit were treated or not with 1-methylcyclopropene (1-MCP) at 25 °C for 20 h and then kept at 20 °C for 8 d. 1-MCP gas concentrations used were 0, 0.5 or 5 μL L −1. Application of 1-MCP delayed the onset of the ethylene climacteric in IG and MG fruit in a dose-dependent fashion, and transiently decreased ethylene production in Y and OR fruit. 1-MCP application transitorily decreased the respiration rate in MG fruit and, to a lesser extent, in IG and Y fruit. In contrast, 1-MCP-treated OR fruit displayed higher respiration rates than control fruit throughout the experimental period. Fruit treated with 5 μL L −1 1-MCP showed for 6 d average CO 2 production levels approximately 41% higher than those of control fruit, with a respiration rate up to 76% higher on day 4. The hue angle was higher in 1-MCP-treated Y goldenberries than in control fruit for 8 d but differences between MG treated and untreated fruit were recorded only at the end of the experiment. In contrast, no differences were detected in IG and OR fruit. 1-MCP-treated fruit were not consistently firmer than untreated fruit during storage. Also, 1-MCP had no effect on soluble solids or ascorbic acid contents. 1-MCP application did not prevent decay in OR fruit but reduced its incidence thus suggesting that it may influence pathogen infection and development in ripe goldenberries.

Developmental expression of stress response genes in Theobroma cacao leaves and their response to Nep1 treatment and a compatible infection by Phytophthora megakarya

Developmental expression of stress response genes in Theobroma cacao leaves and their response to Nep1 and a compatible infection by Phytophthora megakarya were studied. Ten genes were selected to represent genes involved in defense ( TcCaf-1, TcGlu1,3, TcChiB, TcCou-1, and TcPer-1), gene regulation ( TcWRKY-1 and TcORFX-1), cell wall development ( TcCou-1, TcPer-1, and TcGlu-1), or energy production ( TcLhca-1 and TcrbcS). Leaf development was separated into unexpanded (UE), young red (YR), immature green (IG), and mature green (MG). Our data indicates that the constitutive defense mechanisms used by cacao leaves differ between different developmental stages. TcWRKY-1 and TcChiB were highly expressed in MG leaves, and TcPer-1, TcGlu-1, and TcCou-1 were highly expressed in YR leaves. TcGlu1,3 was highly expressed in UE and YR leaves, TcCaf-1 was highly expressed in UE leaves, and TcLhca-1 and TcrbcS were highly expressed in IG and MG leaves. NEP1 encodes the necrosis inducing protein Nep1 produced by Fusarium oxysporum and has orthologs in Phytophthora species. Nep1 caused cellular necrosis on MG leaves and young pods within 24 h of application. Necrosis was observed on YR leaves 10 days after treatment. Expression of TcWRKY-1, TcORFX-1, TcPer-1, and TcGlu-1 was enhanced and TcLhca-1 and TcrbcS were repressed in MG leaves after Nep1 treatment. Expression of TcWRKY-1 and TcORFX-1 was enhanced in YR leaves after Nep1 treatment. Infection of MG leaf disks by P. megakarya zoospores enhanced expression of TcGlu-1, TcWRKY-1, and TcPer-1 and repressed expression of TcChiB, TcLhca-1 and TcrbcS. Five of the six genes that were responsive to Nep1 were responsive to infection by P. megakarya. Susceptibility of T. cacao to P. megakarya includes altered plant gene expression and phytotoxic molecules like Nep1 may contribute to susceptibility.

Immunohistochemical localization of IAA in developing strawberry fruit

SummaryThe immunohistochemical localization of indole-3-acetic acid (IAA) was carried out by using an anti-indole-3-acetic acid (IAA) monoclonal antibody in the achenes and the receptacles of developing field-grown strawberries in May. The distribution of free-IAA in the achenes and the receptacles and their dynamic variations were established.A small IAA signal was detected in the achenes and the receptacles of strawberry at anthesis. In the receptacles, the IAA signal gradually increased at the immature green (IG) stage. From day 7 after bloom to the inception (IC) stage, the IAA signal was localized throughout the vascular bundles of the receptacle tissues, and the signal strengthened at the early phase of the mature green (MG) stage and at the inception (IC) stage. However, at the firm ripe (FR) stage, the signal was hardly detected in the receptacles. In the achenes, the IAA signal gradually increased from the late phase of the immature green (IG) stage to the late phase of the mature green (MG) stage and was mainly localized in developing embryos. Little signal could be detected after inception (IC) stage in the achenes. The results showed that IAA was especially localized in the phloem of the receptacles and was mainly localized in developing embryos in the achenes, which gave apparent evidence for IAA distribution in fleshy fruits. Moreover, in our research, there was still a strong IAA signal in the receptacles of strawberry at the IC stage, which differed significantly from data in some other reports.

The Effects of Fasting and Increased Feeding on Plasma Thyroid Hormones, Glucose, and Total Protein in Sea Turtles

The effects of fasting and increased feeding on plasma thyroid hormones, glucose, and total protein levels were investigated in immature greens (Chelonia mydas) and Kemp's ridley (Lepidochelys kempi) sea turtles. Under constant temperature, nutritional status affected plasma thyroid hormones and glucose level, but not protein level in green and Kemp's ridley turtles. Plasma T4 in green turtles decreased with deprivation of food, but did not do so in Kemp's ridleys. Increased feeding did not affect circulating levels of plasma T4 in either species. Plasma T3, in contrast, tended to decrease during fasting and increase with refeeding or increased feeding. Blood glucose level fell with deprivation of food, but remained constant during increased feeding. Sea turtles may use glycogen or lipid during short-term fasting as in endothermic vertebrates.

Alterations in Structural Polysaccharides during Liquefaction of Tomato Locule Tissue.

The locule tissue of tomato (Lycopersicon esculentum, Mill.) undergoes extensive liquefaction during ripening. In this study, the solubility, molecular mass, and glycosyl composition of locule pectic and alkali-soluble polysaccharides were examined with the aim of identifying features contributing to the unique properties of this tissue. Ethanol-insoluble solids were prepared from de-seeded locule tissue from tomato fruit at the immature green (IMG), mature green, and breaker stages of development. Ethanol-insoluble pectins were extracted sequentially in H2O, 50 mM trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid, 50 mM Na2CO3, and 4 M KOH. At the IMG stage, nearly 85% of the locule pectins were solubilized by water, trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid, and Na2CO3 solutions. Solubility increased only slightly with further locule development. The noncovalently associated polymers were of high molecular mass throughout liquefaction. Polymers extracted in mild alkali were of considerably lower molecular mass. Locule pectins in IMG fruit were heavily glycosylated with galactose, arabinose, and xylose. All pectin classes exhibited similar deglycosylation trends during liquefaction. Locule hemicelluloses were rich in glucose, xylose, and arabinose. These polymers collectively showed molecular mass downshifts with minimal compositional changes during liquefaction. The KOH-soluble material also included xylose-rich acidic polymers not matching the neutral sugar profile of the noncovalently associated pectic polymers.

Surface Topology of Chilling Injury of Tomato Fruit

Chilling-injury symptoms on the surface of eight cultivars or lines of tomato (Lycopersicon esculentum Mill.) fruit were mapped with respect to subtending locules. Mature-green (MG) fruit were chilled at SC for 10 to 25 days and then ripened to red ripe at 20C. Mature-green fruit showed a major portion of injury over subtending locules and on the stem end. The location of injury corresponded with the regions that were the last to ripen. The injuries of immature-green (IG) fruit treated in a similar manner were different from those of MG fruit both in appearance and in distribution.

Tomato Fruit Cell Wall Synthesis during Development and Senescence

The pedicel of tomato fruit (Lycopersicon esculentum Mill., cv ;Rutgers') of different developmental stages from immature-green (IG) to red was injected on the vine with 7 microcuries [(14)C(U)]sucrose and harvested after 18 hours. Cell walls were isolated from outer pericarp and further fractionated yielding ionically associated pectin, covalently bound pectin, hemicellulosic fraction I, hemicellulosic fraction II, and cellulosic fraction II. The dry weight of the total cell wall and of each cell wall fraction per gram fresh weight of pericarp tissue decreased after the mature-green (MG) stage of development. Incorporation of radiolabeled sugars into each fraction decreased from the IG to MG3 (locules jellied but still green) stage. Incorporation in all fractions increased from MG3 to breaker and turning (T) and then decreased from T to red. Data indicate that cell wall synthesis continues throughout ripening and increases transiently from MG4 (locules jellied and yellow to pink in color) to T, corresponding to the peak in respiration and ethylene synthesis during the climacteric. Synthesis continued at a time when total cell wall fraction dry weight decreased indicating the occurrence of cell wall turnover. Synthesis and insertion of a modified polymer with removal of other polymers may produce a less rigid cell wall and allow softening of the tissue integrity during ripening.