Intact Fruit Research Articles

Host Status of Persian Lime (Citrus latifolia Tan.) to Oriental Fruit Fly and Mediterranean Fruit Fly (Diptera: Tephritidae) in Hawai'i.

We investigated the host status of harvest-ready green Persian lime, Citrus x latifolia Tan. (Rutaceae), to Oriental fruit fly (Bactrocera dorsalis [Hendel]) and Mediterranean fruit fly (Ceratitis capitata [Wiedemann]) (Diptera: Tephritidae) using laboratory and field studies. In forced-infestation small cage exposures (using 25 × 25 × 25 cm screened cages with 50 gravid females) and large olfactometer cage tests (using 2.9 × 2.9 × 2.5 m walk-in screened cages with 100 gravid females), punctured limes were infested by Oriental fruit fly and Mediterranean fruit fly at low rates compared to papaya controls, whereas undamaged intact fruit was not infested. Field collection and packing of 45,958 commercial export-grade fruit and subsequent incubation to look for natural infestation resulted in no emergence of fruit flies. Forced infestation studies in the field using sleeve cages to enclose fruit with a high density of fruit flies (50 gravid females) on the tree also showed no infestation. Commercial export-grade Persian lime fruit should be considered a conditional nonhost for Oriental fruit fly and Mediterranean fruit fly.

After-Ripening and Stratification Improve the Germination of the Cakile maritima Scop. (Brassicaceae) from the Apulia Region, Italy

Understanding seed germination is crucial for refining the propagation techniques of Cakile maritima, a wild halophyte species with significant potential for biosaline agriculture. However, research on seed germination within intact fruits of this species is limited. Four trials were conducted to study the seed germination of a population from the Apulia region. The focus was on seeds that had undergone after-ripening for 3 years (20AR3) or 2 years (20AR2) (both collected in 2020), or 1 year (22AR1) (collected in 2022), and freshly harvested seeds in 2022 (22AR0) and 2023 (23AR0). The seeds were either incubated as naked or moist-stratified within intact fruits. A portion of 2022 AR0 siliques was submerged in saline water before stratification. The naked seeds collected in 2022 and 2020 (22AR0 and 20AR2) did not germinate, whereas a portion of the 23AR0 (67%), 20AR3, and 22AR1 (45%, irrespective of after-ripening) lots quickly (T50 = 3.5 days) germinated, underlining a lower dormancy level for seeds harvested or dry stored in 2023. Seed germination in the intact fruits was lower than the naked seeds, confirming the role of the pericarp in inducing seed dormancy. Stratification of the shelled seeds was much more effective in improving the germination time (140 days) and levels in the 23AR0 (81%), 20AR3, and 22AR1 (66%, irrespective of after-ripening) lots than in the 22AR0 (34%) and 20AR2 (61%) ones, which required 240 days to germinate. The saline solution imbibition of fruit seems only to delay the occurrence of the maximum emergence. The physiological seed dormancy of this C. maritima population has been proven, which may be variable in depth according to the year of fruit collection, ranging from intermediate to non-deep.

Postharvest Characterization and Storage of Fresh Katmon Fruit (Dillenia philippinensis)

Katmon fruit has great economic potential but little is known about its postharvest behavior. This study characterized the katmon fruit after harvest so that appropriate handling may be recommended to extend its shelf life during storage or market display. Physicochemical characteristics, particularly firmness, pH, total soluble solids (TSS), titratable acids (TA), and TSS:TA ratio were evaluated during storage under room condition (22°C) and at low temperature (15°C). These characteristics were almost constant under 22°C or at 15°C for two weeks, with pH at 2.8, TSS at about 3.40°Brix, TA at 1.1 – 1.5%, and TSS:TA ratio at 3.1 – 2.04. Only moisture loss significantly increased, reaching 29% after the first week, which reduced the fruit’s shelf life and quality. Fruit in small quantities (1.5 kg) favorably responded to modified atmosphere packaging (MAP) using sealed polyethylene bags (PEB, 0.02 mm). About 15% O2 and 0.45% CO2 were maintained in PEB, which extended the fruit’s fresh quality up to two weeks under 22°C. MAP was also able to maintain the firmness of intact fruits for two weeks when stored at 22°C. In contrast, control fruits reached their limit of marketability after one week. Those without peel may also be kept for about two weeks when packed in PEB (300g per pack), especially if stored at 15°C.

Analysis of the Pomelo Peel Essential Oils at Different Storage Durations Using a Visible and Near-Infrared Spectroscopic on Intact Fruit.

Pomelo fruit pulp mainly is consumed fresh and with very little processing, and its peels are discarded as biological waste, which can cause the environmental problems. The peels contain several bioactive chemical compounds, especially essential oils (EOs). The content of a specific EO is important for the extraction process in industry and in research units such as breeding research. The explanation of the biosynthesis pathway for EO generation and change was included. The chemical bond vibration affected the prediction of EO constituents was comprehensively explained by regression coefficient plots and x-loading plots. Visible and near-infrared spectroscopy (VIS/NIRS) is a prominent rapid technique used for fruit quality assessment. This research work was focused on evaluating the use of VIS/NIRS to predict the composition of EOs found in the peel of the pomelo fruit (Citrus maxima (J. Burm.) Merr. cv Kao Nam Pueng) following storage. The composition of the peel oil was analyzed by gas chromatography-mass spectrometry (GC-MS) at storage durations of 0, 15, 30, 45, 60, 75, 90, 105 and 120 days (at 10 °C and 70% relative humidity). The relationship between the NIR spectral data and the major EO components found in the peel, including nootkatone, geranial, β-phellandrene and limonene, were established using the raw spectral data in conjunction with partial least squares (PLS) regression. Preprocessing of the raw spectra was performed using multiplicative scatter correction (MSC) or second derivative preprocessing. The PLS model of nootkatone with full MSC had the highest correlation coefficient between the predicted and reference values (r = 0.82), with a standard error of prediction (SEP) of 0.11% and bias of 0.01%, while the models of geranial, β-phellandrene and limonene provided too low r values of 0.75, 0.75 and 0.67, respectively. The nootkatone model is only appropriate for use in screening and some other approximate calibrations, though this is the first report of the use of NIR spectroscopy on intact fruit measurement for its peel EO constituents during cold storage.

Intact fruit intake is nonlinear inversely associated with visceral adipose tissue area in U.S. adults: a cross-sectional study

Excess visceral adipose tissue (VAT) plays a crucial role in leading to obesity-related diseases. However, the association between fruit intake (excluding fruit juice) and VAT is not well-known. We aim to further explore this association in a large population. We hypothesized that higher intact fruit intake would be inversely associated with VAT. A total of 9582 adult participants from the National Health and Nutrition Examination Survey and the Food Patterns Equivalents Database 2011-2018 were included. Weighted linear regression models were utilized to evaluate the association between intact fruit intake (from two 24-hour dietary recalls) and VAT area (measured by dual-energy X-ray absorptiometry). Subgroup analysis was conducted to test the robustness of the results. Restricted cubic spline analysis was performed to find the nonlinear association. The median of intact fruit intake was 0.32 cup-equivalent (eq)/d, and the mean of VAT was 104.87 ± 1.23 cm2. Intact fruit intake (increased by 1 cup-eq/d) demonstrated an inverse association with VAT area across three adjusted models, with β(95% confidence interval) values of –7(–8.49, –5.51), –6(–7.50, –4.51), and –3.02(–4.11, –1.94) in model 1, model 2, and model 3, respectively. Subgroup analysis revealed no interactions were found among age, sex, ethnicity, body mass index, and physical activity subgroups. Restricted cubic spline revealed the inverse association was more significant when intact fruit intake was less than 1.7 cups-eq/d. These findings suggest that increasing intact fruit consumption could be an effective public health strategy to mitigate VAT accumulation and associated health risks, advancing our understanding of dietary impacts on adiposity.

Tracing metabolic route of thymoquinone biosynthesis in diverse Nigella sativa L. cultivars using RP-HPLC technique

Although the therapeutic role of Nigella sativa has been known for a long time, for optimal utilization of plant parts, the developmental profiling of bioactive constituents and their dependence on germplasm diversity need to be assessed.Different cultivars of Nigella sativa(covering 3 samples from northern states of India and 3 reference samples) were taken to explore the relative accumulation of thymol (Thy) and thymoquinone (TQ) in different plant parts, i.e., stem, leaf, bud, flower, fruit, and seeds. Amongst all N. sativa cultivars, the maximum TQ content was found in the seed (45.3885 ± 0.3616 mg/g fresh weight) of the RS cultivar. Seeds of the AN1 cultivar showed the maximum Thy content (2.7853± 0.3535 mg/g fresh weight). The minimum Thy content was found in leaves of Haryana (0.0009 ± 0 mg/g fresh weight) and leaves from RS showed the minimum TQ content (0.0029 ± 0.0001 mg/g fresh weight). There are indications that mature seeds are the best source for both Thy and TQ, followed by fresh seeds collected from the intact fruit of N. sativa. In addition, Thy (precursor) and TQ (product)contentin many plant parts are inversely related to each other, especially in the buds. This indicatedthe interdependence of these two bioactive constituents, but not necessarily in all plant parts. It appears that there might be another functional precursor (in addition to Thy)leading to TQ biosynthesis (speculated to be Carvacrol) in Nigella. Such relative dominance of bioactive compounds and their precursors may be used for designing formulations and setting biotransformation experiments for further value addition.

Efficient estimation of gas exchange and respiration kinetics in apple using pathlength-resolved GASMAS

Optimization of controlled atmosphere (CA) storage of pome fruit crucially depends on understanding of respiratory gas exchange. Different fruit properties are involved in describing gas transfer and respiration kinetics, which can vary between cultivars, fruit batches and individual fruit. Determination of these properties currently requires a combination of different time-consuming techniques and data analysis procedures. This study introduces a more efficient single method for O2 gas exchange characterization of fruit based on the non-destructive pathlength-resolved GASMAS (gas in scattering media absorption spectroscopy) technique. GASMAS was used to measure the absolute intercellular O2 concentration in fruit of different apple cultivars (Malus x domestica Borkh.) with distinct porosity including 'Jonagold', 'Braeburn', and 'Nicoter'. To resolve the ambiguity between variation in pathlength and O2 concentration inherent to GASMAS, the pathlength travelled through pores cavities was quantified through a second GASMAS measurement at the absorption line of H2O vapour. Dynamic experiments were then performed in which the fruit was subjected to varying external O2 concentrations while measuring the internal O2 response. The observed dynamic profiles of external and internal O2 concentration were fitted with a lumped -respiration model to estimate the effective mass transfer coefficient, maximum respiration rate and Michaelis Menten constant of intact fruit. The model showed a good fit (R2>0.95) with the measured data and reliable estimates for the model parameters. The proposed method provides a novel and more efficient way to estimate the gas exchange properties of fruit that are essential for optimizing CA storage conditions. Future challenges for the proposed method are with applications to other gasses such as CO2 and ethylene.

Fus3 is a pathogenicity factor of Botryosphaeria dothidea on kiwifruit

AbstractThe ascomycete fungus Botryosphaeria dothidea is the causal agent of postharvest rot in kiwifruit. Production and spreading of conidia, differentiation of infection hyphae and invasion of intact fruit surfaces are required to cause fruit rot disease. In several pathogenic fungi, the homologue of the Saccharomyces cerevisiae mitogen activated protein kinase (MAPK) gene Fus3 has been identified as a pathogenicity factor. To investigate the role of the Fus3 homologue in B. dothidea, the gene was deleted and the resulting ∆fus3 mutants were characterized. On artificial media, strong growth defects of ∆fus3 strains were observed, mycelia were non‐pigmented, and mutants were unable to conidiate. Scanning electron microscopy showed that the wild‐type strain differentiated thick hyphae on the surface of kiwifruits, and nose‐down growth of hyphae indicated tight attachment to the fruit. In contrast, hyphae of ∆fus3 strains mutants were thinner and did not firmly attach to the fruit surface. Importantly, pathogenicity test revealed that ∆fus3 strains were unable to cause disease symptoms on intact kiwifruits. These results shown here identify Fus3 of B. dothidea as a novel pathogenicity factor of the ripe rot pathogen on kiwifruit.

Machine learning driven portable Vis-SWNIR spectrophotometer for non-destructive classification of raw tomatoes based on lycopene content

Most of the research on intact fruit spectroscopy is derivative in nature as it primarily showcase application of existing spectroscopy devices which are often proprietary in nature. The regression models developed by researchers to predict physicochemical attributes using spectra remain theoretical due to lack of mechanism to integrate the developed models back into proprietary devices. This poses challenge for commercial adaptation of this technology in commercial food quality supply chain. The present study addresses this research gap by presenting first of its kind innovative approach to classify tomatoes based on lycopene content using chemometrics-machine learning framework driven portable short-wave near infra-red (SWNIR) spectrophotometer developed by integration of open-source hardware (AS7265x multispectral chipset having wavelength range 410–940 nanometre (nm), Arduino Uno microcontroller) and software (R platform), housed in ergonomically designed and 3-dimension printed cabinet ensuring noise-free spectra acquisition. The lycopene content was observed to have strong negative correlation with wavelengths (nm) 485, 560 and 585 at ρ = – 0.65, – 0.70, – 0.70, whereas strong positive correlation with 760 nm at ρ = +0.64. Similar associations were qualitatively observed using principal component analysis. Atypical of literature, feature selection was performed based on analysis of variance and 14 wavelengths which exhibited statistically significant difference with respect to 15-days storage study (p ≤ 0.05) were selected for model development. Chemometrics-machine learning framework was used for development of optimised probabilistic and non-probabilistic models including logistic regression, Linear Discriminant Analysis (LDA), Random Forest (RF), Artificial Neural Networks (ANN) and Support Vector Machine (SVM) models using 10-fold cross validation subjected to 80–20% train-test split of the dataset. In agreement with literature, 500–750 nm wavelength range dominated the classification of lycopene content. Notably, specific wavelengths for logistic regression (560 nm), LDA (730 nm, 645 nm, 560 nm, 535 nm), RF (760 nm, 585 nm, 560 nm, 645 nm), and ANN (585 nm, 560 nm) significantly influenced outcome instances across classifiers. Accuracy obtained from confusion matrix on test dataset was used as performance metric to compare different models. Logistic regression and RF showcased accuracy of 80%, LDA and SVM at 90% while ANN outperformed all models with accuracy of 95%. This study successfully augmented technological advancement in field of spectroscopy for non-invasive quality assessment of fruit. It is recommended to conduct similar studies on other climacteric fruits for wider adoption of this technology.

Effects of Different Irrigation Regimes, Nitrogen Levels and Storage Conditions on Volatiles of 'Gala' Apple.

With a characteristic flavour and aroma, "Maçã de Alcobaça" are apples produced in the western region of the mainland of Portugal. Given the known influence of pre-harvest cultural techniques and post-harvest conservation methods on fruit quality, this work evaluated the effect of cultural factors and conservation methods on the volatile profile of 'Gala' apples. Tests were carried out during four seasons (2018 to 2021) in two 'Gala' apple orchards (F and S) maintained with different irrigation rates and nitrogen fertilisation [normal irrigation and normal nitrogen (Control, NINN), normal irrigation and excess nitrogen (NIEN), excess irrigation and normal nitrogen (EINN), excess irrigation and excess nitrogen (EIEN)], and under three storage conditions [Controlled Atmosphere + 1-methylcyclopropene (CA+1-MCP), Dynamic Controlled Atmosphere (DCA) and DCA+1-MCP]. The intact fruit volatiles were isolated by headspace solid-phase microextraction (HS-SPME) and analysed by Gas Chromatography with Flame Ionisation Detection and Gas Chromatography-Mass Spectrometry at harvest (T0) and after 8 months of storage (T8). HS-SPME volatiles from 'Gala' apples, obtained at T0 in control conditions, were characterised by trans,trans-α-farnesene dominance (36-69%), followed by hexyl acetate (5-23%) and hexyl hexanoate (3-9%). The four irrigation and nitrogen treatments did not evidence main changes in the apple volatile profile. Instead, storage conditions changed the ratio between compounds; previously undetected compounds attained high percentages and decreased the intensity of the dominant compounds in the control conditions. Although all storage conditions tested changed the volatile profile and emanation intensity, the effect was more accentuated in storage for 8 months with DCA+1-MCP.

Directed vertebrate‐mediated seed dispersal of a fleshy‐fruited amaryllid in a heterogenous habitat

AbstractMost plants with fleshy fruits have seeds that are ingested by animals, but a less well‐understood mode of seed dispersal involves fleshy fruits containing seeds that are discarded by frugivorous animals because they are too large or toxic to be ingested. We studied the seed dispersal biology of Haemanthus deformis, an amaryllid lily species found in a mosaic of bush clumps in a grassland matrix in South Africa. We asked whether seed dispersal is directed in and among bush clumps and whether germination and survival are greater for seeds dispersed to bush clumps than for those dispersed into grassland. Using camera trapping, we found that fruits are consumed mainly by birds and rodents. The pulp was removed from the seeds which were then discarded without ingestion. While many seeds were dispersed close to the parent plant, most (c. 78.5%) were dispersed further than 1 m away from the parent plant. Longer distance dispersal resulted mainly from birds flying off with fruits in their bill or from rodents engaging in scatter‐hoarding behavior. Seedling survival was most successful within bush clumps as compared to grasslands and shade was identified as a primary requirement for seedling survival. Seeds from which the fruit pulp had been removed germinated faster than those in intact fruits. Haemanthus deformis deploys a system of directed seed dispersal, whereby both birds and rodents contribute to the dispersal of seeds within patchy bush clumps that are favorable for seedling survival.

In Situ Compositional Analysis of Tomato Plants and Cell Wall Using Fiber Optic Fourier-Transform Near-Infrared Spectroscopy

This research was intended to define and interpret cell wall attributes and other chemical composition of eight different varieties of tomato plants by utilizing fiber optic Fourier-transform near-infrared spectroscopy (FT-NIR) to acquire in situ chemical signatures of leaf, flower, fruit, and stem of tomato plant and cell wall at different developmental stages. Chemical spectral signatures of the tomato’s leaf, flower, fruit, and stem were only acquired during its session and in live mode such as green, yellow, and red in cell wall color. The spectral signature analysis of each tomato plant was performed to see substantial differences in chemical compositions using chemometric data modeling of FT-NIR spectra. In addition, principal component analysis (PCA) was performed to discriminate leaf, flower, fruit, and stem from the same variety. PCA was also performed to differentiate eight different varieties of tomato plants. The study showed how in situ FT-NIR could distinguish eight types of tomato leaf, flower, fruit, and stem chemical composition at different developmental stages related to cell wall and other attributes. This study has also demonstrated how in situ FT-NIR can discriminate between rusty vs. healthy leaf and intact fruit vs. off-the-plant fruit. The main objective of this study is to present the chemical signature differences in the live and developing tomato plants to improve crucial factors of tomatoes that would benefit plant breeding, tomato cell wall study, and ultimately human health.

Determining the critical recruitment needs for the declining population of Olea europaea subsp. africana (Mill.) P.S. Green in Free State, South Africa.

Olea europaea subsp. africana (Mill.) P.S. Green (medium-sized tree species known as "African wild olive"), provides important ecological goods and services for sustaining frugivores in the grassland biome in South Africa. We speculate that O. europaea subsp. africana's population has been declining due to habitat loss and exploitation for domestic benefits suggesting an unrecognized conservation threat. Therefore, the study aimed to investigate the anthropogenic conservation threats for O. europaea subsp. africana in the Free State, South Africa and to determine the potential importance of seed dispersal effectiveness in the restoration of the species in the study area. Overall, the results showed that 39% of the natural habitat range has been transformed by human-mediated activities. Agricultural activities accounted for 27%, while mining activities and human settlement accounted for 12%, of natural habitat loss. In support of the study predictions, seeds of O. europaea subsp. africana had significantly higher germination and germinated faster after passing through the mammal gut (i.e., 28% and 1.49 per week), compared to other seed treatments (i.e., over 39 weeks). However, there were no statistically significant differences between seed germination of the bird-ingested seeds, with intact fruits as the experimental control, although both were significantly greater than the de-pulped seeds. Potential seed dispersal distances by birds were relatively larger, ranging from 9.4 km to 53 km, than those of mammals (1.5 km-4.5 km). We propose that the O. europaea subsp. africana's habitat range may have been declining, and since it is a keystone plant species, we recommend that the complementary seed dispersal services by birds and mammals could be important for its recruitment and restoration in the degraded habitat.

Pomegranate Fruit Cracking during Maturation: From Waste to Valuable Fruits.

The pomegranate is an emerging functional food which is nowadays becoming more and more commercially attractive. Each part of this fruit (peels, arils and seeds) has a specific phytocomplex, rich in anti-oxidant and anti-radical compounds. Among these, punicalagin and ellagic acid continue to be widely studied for their numerous beneficial effects on human health (anti-inflammatory effects, anti-diabetes activity, cardio-protection, cancer prevention). Despite their exceptionally valuable composition and high adaptability to different climatic conditions, pomegranate fruits are highly susceptible to splitting during different stages of ripening, so much so that an estimated 65% of the production may be lost. A "zero-kilometer" approach should therefore be adopted to utilize such a valuable product otherwise destined to be downgraded or even incinerated, with a very high environmental impact. The aim of this work is to highlight and compare the compositional differences between whole and split pomegranates belonging to the cultivar Dente di Cavallo, grown in Apulia (Italy), to assess a valuable role for this split fruit usually considered as waste. The arils and peels are subjected to extraction procedures and the extracts analyzed by CIEL*a*b*, HPLC-DAD and HS-SPME/GC-MS. Moreover, an assessment of the inhibitory activity against α-glucosidase, acetylcholinesterase and tyrosinase enzymes has also been applied. The data show a better chemical profile in split fruits (namely 60% more anthocyanin content than intact fruit) with very interesting results in terms of α-glucosidase inhibition. The juices obtained by squeezing are also compared to commercial juices ("Salus Melagrana" and "La Marianna") processed from the same cultivar and subjected to the same protocol analysis.

Beans with bugs: Covert carnivory and infested seed selection by the red‐nosed cuxiú monkey

AbstractMembers of the Neotropical primate genus Chiropotes eat large volumes of immature seeds. However, such items are often low in available proteins, and digestion of seeds is further inhibited by tannins. This suggests that overall plant‐derived protein intake is relatively low. We examined the presence of insect larvae in partially eaten fruits, compared with intact fruit on trees, and examined fecal pellets for the presence of larvae. We found that red‐nosed cuxiú (Chiropotes albinasus) individuals may supplement their limited seed‐derived protein intake by ingesting seed‐inhabiting insects. Comparison of fruits partially eaten for their seeds with those sampled directly from trees showed that fruits with insect‐containing seeds were positively selected in 20 of the 41 C. albinasus diet items tested, suggesting that fruits with infested seeds are actively selected by foraging animals. We found no differences in accessibility to seeds, that is, no differences in husk penetrability between fruits with infested and uninfested seeds excluding the likelihood that insect‐infestation results in easier access to the seeds in such fruits. Additionally, none of the C. albinasus fecal samples showed any evidence of living pupae or larvae, indicating that infesting larvae are digested. Our findings raise the possibility that these seed‐predating primates might provide net benefits to the plant species they feed on, since they feed from many species of plants and their actions may reduce the populations of seed‐infesting insects.Abstract in Portuguese is available with online material.

Identification of volatile compounds from fruits aroma and citrus essential oils and their effect on oviposition of Ceratitis capitata (Diptera: Tephritidae).

Ceratitis capitata (Wiedemann), also known as the Mediterranean fruit fly, is one of the most serious pests for several fresh fruit commodities causing extensive fruit losses worldwide. The response of C. capitata adults to fruit and nonfruit volatiles has been extensively studied. However, the linkage between fruit volatiles and the female ovipositional choice has not been fully elucidated. The present study focused on identifying the volatile organic compounds emitted by detached intact fresh fruits (oranges, lemons, bergamots, and apples) and citrus essential oils and evaluate their effect on Mediterranean fruit fly oviposition. There were more than 130 and 45 volatiles compounds detected in fruits odors and citrus essential oils, respectively. The volatile profile of fruits was dominated either from terpenes and terpenoids or from esters of butanoic, hexanoic, and octanoic acids while limonene was by far the most abundant compound in all citrus essential oils. Oviposition of C. capitata was strongly affected by volatiles emanated from both intact fruit and the citrus essential oils. Regarding the volatiles of the intact fruits, the odor of sweet orange elicited strong oviposition responses to females, while bergamot had the least stimulatory effect on oviposition. Bergamot oil also elicited the least oviposition stimulation compared to sweet orange and lemon essential oils. Our discussion elaborates on the role of fruit volatiles on host finding behavior and fruit susceptibility to C. capitata infestation and includes possible practical implication of the above findings.

Characterization of bulk optical properties of pear tissues in the 500 to 1000 nm range as input for simulation-based optimization of laser spectroscopy in diffuse transmittance mode

Insight in the transmission of light through intact fruit is important to optimize and interpret the signals acquired with spectroscopy methods such as tunable diode laser absorption spectroscopy (TDLAS). To this end, we quantified the bulk optical properties (BOP) of skin, outer cortex, inner cortex, and core tissue of three pear ( Pyrus communis ) cultivars ( Thimo , Cepuna , and Conference ) using double integrating spheres measurements in combination with the inverse adding doubling method. Similar trends and values were observed for the bulk optical properties of the three cultivars. A clear chlorophyll-a absorption feature was present in the bulk absorption coefficient ( μ a ) at 690 nm for the skin samples. At 761 nm, the bulk scattering coefficient ( μ s ) decreased from the skin towards the core region, for example from 256 ± 34 cm −1 to 146 ± 22 cm −1 for Conference pears. The observed anisotropy factor ( g ) of the skin was lower than these of the other tissue layers (0.87 ± 0.026 vs. 0.94 ± 0.08 for Conference ). Next, Monte Carlo voxelized media (MCVM) simulations were performed based on these BOP values and validated against measurements with a TDLAS setup for gas in scattering media absorption spectroscopy (GASMAS) at 761 nm. In these experiments, the sample thickness was reduced by sequentially slicing the pear from the skin towards the center. Light transmittance through an intact pear at the height of the core region was found to be very low (1.9 × 10 −4 ± 8.5 × 10 −5 %) and exponentially increased around 100-fold when the sample thickness decreased from 64 mm to 24 mm. The simulated transmittance profiles based on the measured BOP values at 761 nm followed the same trend as the measured GASMAS transmittance as a function of the fruit thickness. This shows that simulations based on these measured BOP values can be used to optimize the measurement configuration for O 2 monitoring in intact pear fruit with GASMAS. • The bulk optical properties of pear tissue layers: skin, outer cortex, inner cortex, and core. • 3D Monte Carlo simulation of diffuse transmittance through an intact pear. • Comparison of simulated and measured diffuse transmittance vs pear sample thicknesses. • Simulations provided a valuable tool for optimizing the amplification of GASMAS detectors in diffuse transmittance mode.

Sugary solutions

Sugary solutions

Extraction of phytochemicals from the pomegranate (Punica granatum L., Punicaceae) by reverse iontophoresis.

Plant metabolic profiling can provide a wealth of information regarding the biochemical status of the organism, but sample acquisition typically requires an invasive and/or destructive extraction process. Reverse iontophoresis (RI) imposes a small electric field across a biological membrane to substantially enhance the transport of charged and polar compounds and has been employed, in particular, to extract biomarkers of interest across human skin. The objective of this work was to examine the capability of RI to sample phytochemicals in a minimally invasive fashion in fructo (i.e., from the intact fruit). RI was principally used to extract a model, bioactive compound - specifically, ellagic acid - from the fruit peel of Punica granatum L. The RI sampling protocol was refined using isolated peel, and a number of experimental factors were examined and optimised, including preparation of the peel samples, the current intensity applied and the pH of the medium into which samples were collected. The most favourable conditions (3 mA current for a period of 1 hour, into a buffer at pH 7.4) were then applied to the successful RI extraction of ellagic acid from intact pomegranates. Multiple additional phytochemicals were also extracted and identified by liquid chromatography with tandem mass spectrometry (LC-MS/MS). A successful proof-of-concept has been achieved, demonstrating the capability to non-destructively extract phytochemicals of interest from intact fruit.

Sexual and asexual propagation of Syzygium maire, a critically endangered Myrtaceae species of New Zealand

ABSTRACT Syzygium maire (swamp maire) is an endemic New Zealand Myrtaceae tree species. Current threats to this species include habitat destruction, myrtle rust, declining remnant populations and low capacity for natural regeneration. Large-scale replanting for conservation/restoration initiatives would mitigate against these threats. However, there is limited information available on propagation of this species. In this study, we looked at sexual propagation using seed germination and asexual propagation using softwood cuttings. For seed germination, we examined the effect of seed pretreatments (intact fruit or de-pulped seed) and temperature settings (15/25°C or 20/30°C) to optimise germination. For softwood cutting propagation, we investigated the diameter of the cuttings (1–2 mm or 3–5 mm) and application of exogenous indole-3-butyric acid (IBA) (0, 1.5, 3.0, or 4.5 g L−1) on their efficacy of producing adventitious rooting. The most critical factor for seed germination was the removal of seed pulp. De-pulping the seeds shortened the mean time to germination and positively affected the germination percentage, regardless of the incubation temperature. Germination percentage of ≥94.5% was achieved in seeds sown without pulp. Propagation by softwood cutting of 1–2 mm in diameter was possible without IBA treatment (63.3% of cuttings rooted), but the application of 1.5 g L−1 IBA increased the rooting percentage (to 75%), thereby inducing the production of a higher number of roots. Seed germination and softwood cutting were effective strategies to propagate S. maire. The findings of this research contribute to the knowledge of propagation and restoration of S. maire populations.