Analysis of the peel structure of different Citrus spp. via light microscopy, SEM and µCT with manual and automatic segmentation.

The peels of lime, lemon, pomelo and citron are investigated at macroscopic and microscopic level. The structural composition of the peels is compared and properties such as peel thickness, proportion of flavedo, density and proportion of intercellular spaces are determined. µCT images are used to visualize vascular bundles and oil glands. SEM images provide information about the appearance of the cellular tissue in the outer flavedo and inner albedo. The proportion of intercellular spaces is quantitatively determined by manual and software-assisted analysis (ilastik). While there are macroscopic differences in the fruits, they differ only slightly in the orientation of the vascular bundles and the arrangement of the oil glands. However, in peel thickness and flavedo thickness, the fruit peels differ significantly from each other. There are no significant differences between the two analysis methods used, although the use of ilastik is preferred due to time reduction of up to 70%. The large amount of intercellular spaces in the albedo but also the denser flavedo both have a mechanical protective function to prevent damage to the fruit. In addition, the entire peel structure is mechanically reinforced by vascular bundles. This combination of penetration protection (flavedo) and energy dissipation (albedo) makes Citrus spp. peels a promising inspiration for technical material systems.

Effects of cell morphology on the textural attributes of fruit cubes in freeze-drying: Apples, strawberries, and mangoes as examples.

The influence of cell morphology on the textural characteristic of freeze-dried apple, strawberry, and mango cubes was evaluated. Corresponding restructured cube samples without intact cell morphology were prepared as controls. Results indicated that the presence of cell morphology strengthened the shrinkage and collapse of samples during freeze-drying, especially in mangoes due to the high content of sugar. Intact cell morphology was found in natural fruit cubes after freeze-drying by scanning electron microscopy (SEM) observation, making them exhibit a more regular microporous structure, further resulting in higher hardness than the restructured cubes. However, the intact cell morphology negatively affected the crispness of freeze-dried cubes since it enhanced structural collapse. The freeze-dried samples without cell morphology would destroy the cellulose structure and form a continuous open-pore structure under the concentration effect of ice crystals during freezing, which accelerates the escape of water molecules, increases the drying rate, and avoid collapse. Sensory experiments found that restructured cubes without intact cell morphology exhibited greater comprehensive acceptance, suggesting the potential application of cell morphology disruption in the future freeze-drying industry.

Zn2+-Dependent Nuclease Is Involved in Nuclear Degradation during the Programmed Cell Death of Secretory Cavity Formation in Citrus grandis 'Tomentosa' Fruits.

Zn2+- and Ca2+-dependent nucleases exhibit activity toward dsDNA in the four classes of cation-dependent nucleases in plants. Programmed cell death (PCD) is involved in the degradation of cells during schizolysigenous secretory cavity formation in Citrus fruits. Recently, the Ca2+-dependent DNase CgCAN was proven to play a key role in nuclear DNA degradation during the PCD of secretory cavity formation in Citrus grandis 'Tomentosa' fruits. However, whether Zn2+-dependent nuclease plays a role in the PCD of secretory cells remains poorly understood. Here, we identified a Zn2+-dependent nuclease gene, CgENDO1, from Citrus grandis 'Tomentosa', the function of which was studied using Zn2+ ions cytochemical localization, DNase activity assays, in situ hybridization, and protein immunolocalization. The full-length cDNA of CgENDO1 contains an open reading frame of 906 bp that encodes a protein 301 amino acids in length with a S1/P1-like functional domain. CgENDO1 degrades linear double-stranded DNA at acidic and neutral pH. CgENDO1 is mainly expressed in the late stage of nuclear degradation of secretory cells. Further spatiotemporal expression patterns of CgENDO1 showed that CgENDO1 is initially located on the endoplasmic reticulum and then moves into intracellular vesicles and nuclei. During the late stage of nuclear degradation, it was concentrated in the area of nuclear degradation involved in nuclear DNA degradation. Our results suggest that the Zn2+-dependent nuclease CgENDO1 plays a direct role in the late degradation stage of the nuclear DNA in the PCD of secretory cavity cells of Citrus grandis 'Tomentosa' fruits.

Genetic diversity and population structure of ridge gourd (Luffa acutangula) accessions in a Thailand collection using SNP markers.

This study explored a germplasm collection consisting of 112 Luffa acutangula (ridge gourd) accessions, mainly from Thailand. A total of 2834 SNPs were used to establish population structure and underlying genetic diversity while exploring the fruit characteristics together with genetic information which would help in the selection of parental lines for a breeding program. The study found that the average polymorphism information content value of 0.288 which indicates a moderate genetic diversity for this L. acutangula germplasm. STRUCTURE analysis (ΔK at K = 6) allowed us to group the accessions into six subpopulations that corresponded well with the unrooted phylogenetic tree and principal coordinate analyses. When plotted, the STRUCTURE bars to the area of collection, we observed an admixed genotype from surrounding accessions and a geneflow confirmed by the value of FST = 0.137. AMOVA based on STRUCTURE clustering showed a low 12.83% variation between subpopulations that correspond well with the negative inbreeding coefficient value (FIS = - 0.092) and low total fixation index (FIT = 0.057). There were distinguishing fruit shapes and length characteristics in specific accessions for each subpopulation. The genetic diversity and different fruit shapes in the L. acutangula germplasm could benefit the ridge gourd breeding programs to meet the demands and needs of consumers, farmers, and vegetable exporters such as increasing the yield of fruit by the fruit width but not by the fruit length to solve the problem of fruit breakage during exportation.

Transcriptome and Metabolome Analyses Provide Insights into the Watercore Disorder on "Akibae" Pear Fruit.

Watercore is a physiological disorder that commonly occurs in sand pear cultivars. The typical symptom of watercore tissue is transparency, and it is often accompanied by browning, breakdown and a bitter taste during fruit ripening. To better understand the molecular mechanisms of watercore affecting fruit quality, this study performed transcriptome and metabolome analyses on watercore pulp from "Akibae" fruit 125 days after flowering. The present study found that the "Akibae" pear watercore pulp contained higher sorbitol and sucrose than healthy fruit. Moreover, the structure of the cell wall was destroyed, and the content of pectin, cellulose and hemicellulose was significantly decreased. In addition, the content of ethanol and acetaldehyde was significantly increased, and the content of polyphenol was significantly decreased. Watercore induced up-regulated expression levels of sorbitol synthesis-related (sorbitol-6-phosphate dehydrogenase, S6PDH) and sucrose synthesis-related genes (sucrose synthesis, SS), whereas it inhibited the expression of sorbitol decomposition-related genes (sorbitol dehydrogenase, SDH) and sorbitol transport genes (sorbitol transporter, SOT). Watercore also strongly induced increased expression levels of cell wall-degrading enzymes (polygalactosidase, PG; ellulase, CX; pectin methylesterase, PME), as well as ethanol synthesis-related (alcohol dehydrogenase, ADH), acetaldehyde synthesis-related (pyruvate decarboxylase, PDC) and polyphenol decomposition-related genes (polyphenol oxidase, PPO). Moreover, the genes that are involved in ethylene (1-aminocyclopropane- 1-carboxylate oxidase, ACO; 1-aminocyclopropane- 1-carboxylate synthase, ACS) and abscisic acid (short-chain alcohol dehydrogenase, SDR; aldehyde oxidase, AAO) synthesis were significantly up-regulated. In addition, the bitter tasting amino acids, alkaloids and polyphenols were significantly increased in watercore tissue. Above all, these findings suggested that the metabolic disorder of sorbitol and sucrose can lead to an increase in plant hormones (abscisic acid and ethylene) and anaerobic respiration, resulting in aggravated fruit rot and the formation of bitter substances.

Archaeobotanical evidence of the use of medicinal cannabis in a secular context unearthed from south China.

ETHNOPHARMACOLOGICAL RELEVANCE: As one of the first plants used by ancient people, cannabis has been used for medicinal purposes for thousands of years. The long history of medicinal cannabis use contrasts with the paucity of archaeobotanical records. Moreover, physical evidence of medicinal cannabis use in a secular context is much rarer than evidence of medicinal cannabis use in religious or ritual activities, which impedes our understanding of the history of medicinal cannabis use. AIM OF THE STUDY: This study aims to provide archaeobotanical evidence of medicinal cannabis use and analyse the specific medicinal usage of cannabis in a secular context in ancient times. MATERIALS AND METHODS: Plant remains were collected from the Laoguanshan Cemetery of the Han Dynasty in Chengdu, South China, with the archaeological flotation process and were identified based on morphological and anatomical characteristics. The examination of the medicinal significance of the remains relied on the investigation of the documentation on unearthed medical bamboo slips, the diseases of the tomb occupants, the cemetery's cultural background and Chinese historical records. RESULTS: The botanical remains were accurately identified as cannabis. More than 120 thousand fruits were found, which represents the largest amount of cannabis fruit remains that have been statistically analysed from any cemetery in the world thus far. The cannabis fruits are suspected to have been used for medical purposes in a secular context and were most likely used to stop severe bleeding of the uterus and treat lumbago and/or arthralgia. CONCLUSIONS: The cannabis fruit remains reported here likely represent the first physical evidence of medicinal cannabis use for the treatment of metrorrhagia, severe lumbago, and/or arthralgia. This study emphasizes the importance of the evidence of the diseases suffered by the occupants of the tomb in determining the medicinal use of cannabis in a secular context and contributes to a comprehensive understanding of the ancient history of medicinal cannabis.

Anatomical Investigation and GC/MS Analysis of 'Coco de Mer', Lodoicea maldivica (Arecaceae).

Lodoicea maldivica (J.F.Gmel.) Pers. (Arecaceae), 'Coco de Mer', is a palm, growing as endemic in the Seychelles islands. Its fruit weighs up to 20 kg and is characterized by a fleshy and fibrous envelope surrounding the nutlike portion. The present work combines a morpho-anatomical and a phytochemical analysis of the fruit exocarp and mesocarp. The exocarp is composed by a layer of palisade cells. The mesocarp is characterized by vascular bundles and by sclereids. In the aerenchyma, the internal zone of the mesocarp, cells aggregates were positive to phenols, while idioblasts were positive to terpenes. We performed a GC/MS analysis with a semi-quantitative relative amount calculation of the recorded compounds. The GC/MS essential oil profile revealed the dominance of acyclic sesquiterpenoids (53.95 %), followed by bicyclic sesquiterpenoids (31.69 %), monoterpenes (11.89 %) and monocyclic sesquiterpenoids (2.44 %). The terpenes detected in higher amounts, ß-caryophyllene and bicyclogermacrene, are known for activity against insect larvae, but have been proposed as antiviral candidates against SARS-CoV-2. The third compound in amount, aromadendrene, is active against bacteria and, again, known to possess insecticidal properties.

Multiscale Localization of Procyanidins in Ripe and Overripe Perry Pears by Light and Transmission Electron Microscopy.

Histochemical staining with 4-dimethylaminocinnamaldehyde (DMACA), light microscopy, and transmission electron microscopy (TEM) were applied to characterize procyanidin localization at ripe and overripe stages in perry pear flesh (cv. 'De Cloche'). Pear flesh contained stone cell clusters surrounded by very large parenchyma cells. DMACA staining showed procyanidins mainly located in parenchyma cells from the fruit mesocarp. Under light microscopy and TEM, procyanidins appeared in the vacuole of parenchyma cells as uniformly stained granules, probably tannosomes. They were differently dispersed in ripe and overripe perry pears, as the granules remained free inside the vacuole in ripe pears and mostly attached to the tonoplast in overripe pears.

Carotenogenesis and chromoplast development during ripening of yellow, orange and red colored Physalis fruit.

MAIN CONCLUSION: Formation of specific ultrastructural chromoplastidal elements during ripening of fruits of three different colored Physalis spp. is closely related to their distinct carotenoid profiles. The accumulation of color-determining carotenoids within the chromoplasts of ripening yellow, orange, and red fruit of Physalis pubescens L., Physalis peruviana L., and Physalis alkekengi L., respectively, was monitored by high-performance liquid chromatography/diode array detector/tandem mass spectrometry (HPLC-DAD-MS/MS) as well as light and transmission electron microscopy. Both yellow and orange fruit gradually accumulated mainly ß-carotene and lutein esters at variable levels, explaining their different colors at full ripeness. Upon commencing ß-carotene biosynthesis, large crystals appeared in their chromoplasts, while large filaments protruding from plastoglobules were characteristic elements of chromoplasts of orange fruit. In contrast to yellow and orange fruit, fully ripe red fruit contained almost no ß-carotene, but esters of both ß-cryptoxanthin and zeaxanthin at very high levels. Tubule bundles and unusual disc-like crystallites were predominant carotenoid-bearing elements in red fruit. Our study supports the earlier hypothesis that the predominant carotenoid type might shape the ultrastructural carotenoid deposition form, which is considered important for color, stability and bioavailability of the contained carotenoids.

Hierarchical levels of organization of the Brazil nut mesocarp.

Aiming to understand Nature´s strategies that inspire new composite materials, the hierarchical levels of organization of the Brazil nut (Bertholletia excelsa) mesocarp were investigated. Optical microscopy, scanning electron microscopy (SEM), microtomography (MicroCT) and small-angle X-ray scattering (SAXS) were used to deeply describe the cellular and fibrillary levels of organization. The mesocarp is the middle layer of the fruit which has developed several strategies to avoid its opening and protect its seed. Fibers have a different orientation in the three layers of the mesocarp, what reduces the anisotropy of the structure. Sclereids cells with thick cell walls fill the spaces between the fibers resembling a foam-filled structural composite. The mesocarp has several tubular channels and fractured surfaces which may work as sites for crack trapping and increase toughness. The thick and lignified cell wall of sclereids and fibers and the weak interface between cells can promote a longer and tortuous intercellular crack path. Additionally, fibers with high strength and stiffness due to microfibrils oriented along the main cell axis (µ = 0° to 17°) were identified in the innermost layer of the mesocarp. Such an understanding of each hierarchical level can inspire the development of new cellular composites with improved mechanical behavior.

Vineyard calcium sprays induce changes in grape berry skin, firmness, cell wall composition and expression of cell wall-related genes.

Having a central role in cell wall pectin cross-linking, calcium has been increasingly used as supplement to promote fruit firmness and extended shelf-life. However, the molecular rearrangements associated to increased fruit robustness are still a matter of debate. In this study, mechanical, histochemical and molecular assays were conducted to understand the mechanisms underlying the effects of Ca in fruit physical properties. In a two-year field trial, grapevines were sprayed with exogenous CaCl2 throughout the fruiting season. Results showed an increase in berry Ca concentration at harvest, associated to increased fruit consistency and skin resistance. Scanning electron microscopy showed that fruits from Ca-treated plants had smoother skin surfaces than control fruits, and that microcracks encircling the lenticels were less prominent. Histochemistry assays suggested higher deposition of pectin-like material in skin cell walls in grapes from Ca-treated vines, but no evident modifications in cellulose content were observed. Accordingly, the expression of cellulose synthase family gene CesA3 was not affected by exogenous Ca, while polygalacturonase-encoding genes PG1 and PG2 were downregulated, together with EXP6 belonging to expansin family, and CER9 and CYP15 involved in cuticle biosynthesis. These results suggested that Ca acts by inhibiting pectin degradation and cell wall loosening, while remodeling cuticle structure.

Physicochemical changes and chilling injury disorders in 'Tango' mandarins stored at low temperatures.

BACKGROUND: The susceptibility to chilling injury and quality changes of 'Tango' mandarins stored at different temperatures was evaluated in fruit grown at two locations in Andalusia (Spain) and grafted on Carrizo Citrange or FA5 rootstock. The peel disorders were also characterized by a microstructural study. RESULTS: Fruit developed chilling injuries, manifested as pitting lesions affecting the equatorial area of the fruit stored at 1 °C or 5 °C; fruit growing on FA5 rootstock showed a slightly lower incidence. The microstructural study revealed that only the upper layers of flavedo were affected in the damaged fruit, the epidermal and hypodermal tissues being dramatically collapsed. Although the fruit was prone to accumulate ethanol, especially after the shelf life that followed the different periods of cold storage, the ethanol did not compromise the overall flavor. CONCLUSIONS: Storage of 'Tango' fruit was limited by chilling injuries when stored at 1 °C or 5 °C for more than 20 days. Moreover, at these temperatures, the fruit was prone to accumulate ethanol and develop off flavors. At 9° C, the fruit could be stored for 30 days without compromising external or internal quality. Growing location and rootstock influenced some quality attributes at harvest but not during storage. © 2020 Society of Chemical Industry.

Using microscopic techniques for taxonomic implications of seed and fruits of Delphinium L. (sensu lato) (Ranunculaceae).

In present research, micromorphological characters of the genus Delphinium L. (sensu lato) Ranunculaceae seeds and fruits were studied using microscopic techniques. A total of 37 species were studied using light (LM) and scanning electron microscopy (SEM) to evaluate seeds and fruits micromorphological characteristics for the taxonomic identification and species relationship in the genus. For each taxon, 33 characters were observed and studied. All characters were analyzed using MVSP software and UPGMA method by using dissimilarity index (average taxonomic distance). Considerable differences were observed in trichomes shape of fruit and seed color features. The results revealed that all studied taxa are separated into three clades. The first clade consists of D. pallidiflorum and D. semibarbatum, which have black seed and two types of glandular and crispate trichomes in fruit. The second clade consists of D. speciosum, D. szowitsianum, D. dasystachyson, D. aquilegifolium, D. ursinum, C. trigonelloides, and C. camptocarpa, which had a brown color seeds, two types of glandular and villous trichomes on fruits also have been observed. The remaining species were classified as third clade having various colors including yellow, black, and brown color seeds, the trichome shapes included one of the following forms strigose, villous, trichomes less, glandular, hooked, and crispate trichomes in fruits. The aim of the present study is to use micromorphological characters of seeds and fruits for the taxonomic identification and species delimitation in the genus Delphinium.

Transcription factor CaNAC1 regulates low-temperature-induced phospholipid degradation in green bell pepper.

Phospholipids constitute the main component of biomembranes. During low-temperature storage and transportation of harvested bell peppers (Capsicum annuum), chilling injury participates in their decay. A primary cause of this chilling injury is phospholipid degradation. In this study, three genes encoding phospholipase D (PLD) were identified from bell peppers and their activities were examined under cold stress. Low temperature (4 °C) induced strong accumulation of the CaPLDα4 transcript, suggesting that it is associated with the phenomenon of phospholipid degradation and destruction of cell membranes. Low temperature also significantly induced increased amounts of NAM-ATAF1/2-CUC2 (NAC) domain transcription factors. CaNAC1 was found to interact with the promoter of CaPLD4 in a yeast one-hybrid screen. Electrophoretic mobility shift and ß-glucuronidase reporter assays demonstrated that CaNAC1 binds to the CTGCAG motif in the CaPLDα4 promoter, thereby activating its transcription and controlling phospholipid degradation. The ubiquitination sites of the CaNAC1 protein were characterized by liquid chromatography-tandem mass spectrometry. We conclude that CaNAC1 is a transcriptional activator of CaPLDα4 and suggested that it participates in the degradation of membrane lipids in bell peppers when they are stored at low temperature.

Calycinal secretory structures in Calolisianthus pedunculatus (Cham. & Schltdl) Gilg (Gentianaceae): anatomy, histochemistry, and functional aspects.

Secretory structures were little studied in Gentianaceae. Glandular areas on the calyx dorsal region are commonly reported for Helieae species, the main tribe of Gentianaceae. So, the elucidation of nature of glandular areas is particularly relevant. Trichomes secreting mucilage, interpreted as colleters, are reported only for the sepals of Gentianinae species. We aimed to anatomically characterize and identify the nature of the calycinal secretory structures in Calolisianthus pedunculatus. Samples from floral buds, flowers, and fruits were collected, fixed, and processed following usual procedures for light and scanning electron microscopies. Histochemical tests were performed to determine the nature of the secretion. Glucose, fructose, and sucrose were measured with an ELISA reader. Colleters occur on the sepal ventral region and are composed of a multicellular secretory head and a stalk. These structures secrete polysaccharides and proteins, and the secretion is probably released through cuticle microchannels. Nectaries, on the other hand, occur on the sepal dorsal region. They are formed by 3-5 cells arranged in rosettes circling a central cell or pore. These structures also secrete polysaccharides (mainly fructose), lipids, and proteins. The identification of the secretory structures in the sepals of Calolisianthus pedunculatus highlights the importance of anatomical studies in this family. The interpretation of the glandular areas on the calyx of the Helieae species as nectaries has been proven, as well as the confirmation of colleters as common structures in the sepals of Gentianaceae. Besides the taxonomic and phylogenetic importance of nectars and colleters, we highlight the importance of the secretion for the protection of floral buds against dehydration.

Visualization of Carotenoid-Storage Structures in Fruits by Transmission Electron Microscopy.

Plastids are cell organelles that, beside other functions, have the capability to store carotenoids in specialized structures, which may vary among the different plant species, tissues or according to the carotenoid complement. Fruits are an important source of carotenoids, and during ripening, chloroplasts differentiate into chromoplasts that are able to accumulate large amounts of carotenoids, rendering then the characteristic fruit coloration. Whereas lycopene or ß-carotene may accumulate as crystal in the chromoplasts of some fruit, other xanthophyll-accumulating fruits differentiate plastoglobuli as a preferred system to enhance carotenoids stability and storage. Visualization of plastid ultrastructure and their transformation during ripening or in fruit of contrasting coloration are fundamental objectives within carotenoids research in fruits. Therefore, in this chapter, we describe a protocol for the visualization and analysis of plastid ultrastructure by transmission electron microscopy (TEM), specially designed and adapted to fruit tissues.

Crack initiation and propagation in sweet cherry skin: A simple chain reaction causes the crack to 'run'.

Rain cracking severely affects the commercial production of many fleshy-fruit species, including of sweet cherries. The objectives were to investigate how the gaping macroscopic cracks (macrocracks) of a rain-cracked fruit can develop from microscopic cracks in the cuticle (microcracks). Incubating fruit in deionized water is well known to cause significant macrocracking. We found that after a lag phase of 2 h, the numbers and lengths of macrocracks increased. Macrocrack number approached an asymptote at 12 h, whereas macrocrack length continued to increase. The rate of macrocrack propagation (extension at the crack tip) was initially 10.8 mm h-1 but then decreased to a near-constant 0.5 mm h-1. Light microscopy revealed three characteristic zones along a developing macrocrack. In zone I (ahead of the crack), the cuticle was intact, the epidermal cells were unbroken and their cell walls were thin. In zone II, the cuticle was fractured, the first epidermal cells died and their cell walls began to thicken (swell). In zone III, most epidermal cells had died, their cell walls were swollen and cell:cell separation began along the middle lamellae. The thickness of the anticlinal epidermal cell walls and the percentage of intact living cells along a crack were closely and negatively related. Cracks were stained by calcofluor white, but there was no binding of monoclonal antibodies (mAbs) specific for hemicelluloses (LM11, LM21, LM25). Strong binding was obtained with the anti-homogalacturonan mAb (LM19), indicating the presence of unesterified homogalacturonans on the crack surface. We conclude that macrocrack propagation is related to cell death and to cell wall swelling. Cell wall swelling weakens the cell:cell adhesion between neighbouring epidermal cells, which separate along their middle lamellae. The skin macrocrack propagates like a 'run' in a fine, knitted fabric.

Cell wall polysaccharides degradation and ultrastructure modification of apricot during storage at a near freezing temperature.

The effects of near freezing temperature (NFT) storage at -1.9 °C on cell wall degradation of 'Shushanggan' apricot was studied comparing to 0 °C and 5 °C storage. Our results indicated that NFT storage strongly inhibited the solubilization of Na2CO3-soluble pectin and cellulose, by the suppression of cell wall modifying enzymes (polygalacturonase, ß-Galactosidase, pectin methyl esterase and cellulase) and related genes expressions. The loss of side chains was the main modification in CDTA (Cyclohexane-diamine-tetraacetic Acid)-soluble pectin during storage and made the main contribution to the softening of apricot, while the loss of side chain was suppressed by NFT storage. Microscopic observation showed that NFT storage delayed the degradation of pectin fraction and protected cell wall structure from loosing. This study proves that NFT storage is an effective technology to suppress the cell wall polysaccharides degradation and ultrastructure modification of apricot.

Water state and sugars in cranberry fruits subjected to combined treatments: Cutting, blanching and sonication.

To ease the mass exchange in fruit tissues, cutting and blanching are traditionally performed. However, recently, unconventional methods such as sonication are becoming more popular, which cause several alterations of physical and chemical properties as well as microstructure changes. The aim of this work was to evaluate the distribution of water inside the cranberry fruits, microstructural changes and sugars content, following traditional and sonication pre-treatments in osmotic solutions. TD-NMR spectroscopy was used to measure the transverse relaxation time (T2) and intensity of proton pools in different cellular compartments. The microstructure of the samples was evaluated by SEM microscopy, sugars content by HPLC and sucrose melting temperature and enthalpy by DSC. Different pre-treatments appeared to promote microstructure alterations and loss of water from vacuole and cytoplasm/extracellular space, more pronounced in cut and blanched samples. Cutting and blanching followed by osmotic dehydration with assisted sonication eased sucrose penetration into the tissue.

Taxonomic significance of caryopsis in subfamily Panicoideae (Poaceae) using scanning electron microscopy and light microscopy.

In recent study, 13 taxa of subfamily Panicoideae were investigated for morphological characterization of caryopsis. Light microscope (LM) and scanning electron microscope (SEM) were utilized to study macro- and micro-morphological caryopsis features respectively. Caryopsis size in studied taxa was recorded as 1.5-10 mm long and 1-4 mm wide. Caryopsis color was brown, green, yellow, and whitish-brown. Caryopsis shape studied was obovate, elliptic, linear oblate, and round shallowly obtriangular. Hilum position is grooved and depressed. Caryopsis compression type was lateral and dorsiventral. Major variations among studied taxa were observed in terms of caryopsis surface pattern and epicuticular projection types. Six types of caryopsis surface pattern were observed viz. scabrate, rugose, striate, reticulate, papillate, and scabridulous. Structures such as silica cells, bulges, spines, prickles, granules, and bicellular microhair were studied as epicuticular projections. Major variations were observed among Cenchrus pennisetiformis and Cenchrus ciliaris as both has entirely two different types of surface patterns and epicuticular projections. Anticlinal wall thickness and pattern as well as periclinal wall texture and level were investigated. The present research work emphasized on caryopsis characterization of subfamily Panicoideae and it is recommended to establish phylogeny within subfamily Panicoideae and with other subfamilies of Poaceae.