In plant studies, electrical properties such as the conductivity and resistance are used for measuring the health of a plant or controlling the salinity of a nutrient solution. In recent years, continuous efforts have been undertaken to determine the state of a plant and establish an optimal growth environment by measuring the internal ion concentration of the sap, in plant horticulture. In this paper, we present a needle-shaped measurement sensor for measuring the internal electrical conductivity of a plant. The needle-sensor is targeted at horticultural plants such as cucumber, tomato, and paprika. As horticultural crops have small stem diameters and xylem areas, a minimally invasive measurement approach and measuring electrodes with small form factors are required. The proposed needle sensor has microscale width electrodes and a hundreds-of-microscale-width needle, enabling local measurement with minimal invasion. The interdigitated electrode was optimized to measure higher range of electrical conductivity (12.8 mS/cm) of horticultural plants through frequency sweeping analysis. The laboratory-proven sensors were applied to greenhouse-grown cucumbers and the ionic concentrations were monitored during the day and at night, in real time. Results indicate peculiar periodic pattern of electrical conductivity variation with respect to time occurring in the plant xylem.
Secondary metabolism is regulated by circadian rhythm based on the clock genes expression. Transcriptome analysis is an important tool to understand these mechanisms. However, sufficient genetic information for this analysis is lacking for many crops. In order to analyze the influence of independent clock genes from growth and environmental stimulation, we investigated the gene expression profiles in the roots and leaves of green perilla (Perilla frutescens), which is an important crop used as a herbal medicine. Green perilla was grown under light emitting diode and fluorescent light, after 7, 14, and 35 d. We also compared the coding DNA sequences with those in the other plants. From the transcriptomic data, green perilla was observed to have 74 contigs that did not depend on growth and cultivation condition. Some of these 74 genes might be related to the clock genes through their interactions with other genes. Some 74 genes had TATA box-like motif and a GA motif of the genes that are regulatory targets of timing of CAB expression 1 (TOC1). Thus, 74 genes that did not depend on cultivation condition and growth were considered to be under the control of TOC 1, suggesting the importance of TOC1 in circadian rhythms.
A profit model provides a guideline for facility construction and management of plant factories. Practically, the model depends on plant growth conditions and shipping type in each plant factory and these parameters should be optimized. However, the profit model has not been studied well. In this study, we focused on plant growth dynamics and three shipping types. A mathematical model of growth dynamics describes the time change of average and distribution of fresh weight from nursing to harvesting. The parameters of the profit model were investigated based on experimental data in a commercial plant factory. In the experimental results, the yield was strongly dependent on the growth dynamics of the lettuce population. From the sensitivity analysis of each parameter, it was clarified that the quality of seedling and the cultivation days are mostly effective for profit as high priority parameters. Our results suggest that it is important to regulate the growth dynamics at early stages (young seedling stage) and cultivation days in order to maximize profit in plant factories.
A low-cost spectrometer, featuring a micro electro mechanical systems (MEMS) sensor, was designed and manufactured using digital fabrication techniques. The spectrometer was morphed into a zelkova leaf-shaped case using a three-dimensional printer. The control software, written in the Arduino sketch programing language, measured the flux of photons in the 400―800 nm range, at 1 nm resolution, every 5 min. The obtained data were saved on a micro SD memory card in the comma separated values format. The spectrometer continuously operated for more than 3 d using a type B universal serial bus micro connector and a 10 Ah mobile battery. Four manufactured spectrometers were installed inside and outside of a tomato canopy in the experimental greenhouse of Wakayama prefecture, and continuously measured the spectroscopic flux of photons for nine d. The quantitative changes in the phytochrome photoequilibrium in the tomato leaves were estimated using the data from the continuous spectroscopic analysis. The effect of pruning under leaves on the illumination in the tomato canopy was quantified in terms of the leaf area index. We expect that the proposed low-cost and high-mobility spectrometer will be used in plant production fields.
Lycopene content in tomato fruit after storage was estimated using the multiple regression analysis at different storage temperatures and durations in this study. Tomatoes were grown hydroponically in greenhouse. Tomato fruit samples after harvesting were stored at 10, 15, 20, 25, and 30℃ in cool incubator for 7 d. The tomato fruit color on the surface and lycopene content of the whole tomato fruit were measured for each temperature before storage (0 d) and after storage (2, 4, and 7 d). Tomato fruit color was measured with chroma meter and a*/b* was calculated. Lycopene content after storage was estimated using the multiple regression analysis with the variables of the tomato fruit color before storage, storage temperatures and durations. Our results showed that the color of tomato fruits stored above 10℃ was increased after storage. With storage condition above 20℃, lycopene content of tomato fruit was increased after storage. Tomato fruit color change after storage was estimated with variables of tomato fruit color before storage, storage temperatures and durations by multiple regression (R＝0.76). Our results suggested that estimation model for lycopene content using the multiple regression analysis might be contributed for providing valuable tomato fruits included the high lycopene to customers.
The effect of isoquercitrin (IQC) addition on quercetin (QUE) solubility was investigated. Evaporated particles (EVPs) were prepared by rotary evaporator ®with QUE, α-glucosyl rutin (Rutin-G), and IQC. Differential scanning calorimetry and powder X-ray diffraction analysis revealed the amorphization of QUE and IQC by evaporation with Rutin-G. No diffraction peaks were detected in EVPs even after storage in sealing condition for 8 weeks at 40℃. The amount of dissolved QUE from the physical mixture was enhanced according to the increase of Rutin-G ratio because QUE was solubilized in the aggregated structure of Rutin-G formed in proportion to Rutin-G concentration. In the case of EVPs, the concentration of dissolved QUE increased when IQC was added in QUE/Rutin-G binary formulation. The concentration of dissolved QUE from EVPs of QUE/Rutin-G/IQC (1/7/3, w/w/w) and QUE/Rutin-G/IQC (1/5/5, w/w/w) was much higher than that with QUE/Rutin-G/IQC (1/10/0, w/w/w). These results suggested that IQC inhibit the re-crystallization from an amorphous QUE in dissolution medium, resulted in the enhancement in stability of an amorphous QUE in the supersaturated state. In conclusion, the addition of IQC into QUE/Rutin-G binary system could obviously improve the solubility of QUE.
Mechanical damage due to vibration and/or shock during transport is a primary factor in inducing disorder in appearance of fresh produce. Thus, designing of cushioning packaging for fresh produce is necessary. As cushioning materials, paper-and/or plastic-based materials are usually used for fresh produce. Especially, plastic-based materials possess suitable cushioning properties to reduce the damage due to shock and vibration. However, it is difficult to recycle these materials compared with paper-based ones. Therefore, it might be ideal to reduce the use of plastic based-materials as much as possible. Based on the aforementioned information, for apple fruit, we evaluated the shock-proof performance of a new cushioning system for portable packaging using a two-ply pulp molded tray instead of the conventional foam net. The results of measurements of peak acceleration (PACC) and velocity change (VC) with the drop height of 0.2 m and 0.4 m using a dummy fruit, and shock test using various PAcc and VC with apple fruit suggested that the proposed cushioning system exhibits superior cushioning performance than that of the conventional packaging system using foam net.
The fertility restorer (Rf) genes and their linked DNA marker (the SCAB101900 marker) of the male sterile eggplant systems having the cytoplasm of the three wild species, Solanum aethiopicum L. Aculeatum Group, S. anguivi Lam. and S. grandifolium C. V. Morton were genetically characterized. The backcross 8th generation (BC8), BC7 and BC8 with S. anguivi, S. grandifolium and S. aethiopicum cytoplasm parents, respectively, segregated for male fertile and sterile in a 3 : 1 ratio, which corresponds to two independent dominant Rf gene model. Presence/absence of the SCAB101900 marker for male fertility and sterility was analyzed in the three backcross progenies. The marker appeared in all the male fertile individuals, except one BC7 plant with S. grandifolium cytoplasm parent. These indicate that this SCAB101900 marker is very closely linked to both of the Rf loci. There would be no quantitative effect of the Rf genes on pollen fertility. If there is at least one Rf dominant allele at any of the 2 loci, pollen seems to be fertile. As a result of detecting the SCAB101900 marker on 7 wild species, S. gilo was revealed to have these Rf and the same male sterile cytoplasm.
The efficacy of 1-MCP in modulating the ethylene sensitivity of Japanese persimmon (Diospyros kaki) in terms of thermal and structural properties was investigated at 0℃ and 25℃. X-ray computed tomography was employed to quantify the structural properties. The physicochemical properties were measured destructively and correlated with X-ray image properties. 1-MCP satisfactorily suppressed the ethylene sensitivity in terms of bio-yield stress, L*, and hue angle value at both temperatures. The changes in porosity and thermal conductivity in 1-MCP-treated fruit were smaller than those in control and ethylene-treated fruit. The histogram profile also shifted slightly to a high-density region in 1-MCP-treated fruit. The L* value, hue angle, apparent density, moisture content, bio-yield stress, and TSS were highly correlated with average CT value and standard deviation at both temperatures. Thus, X-ray CT images could be used to quantify the thermal and structural properties, and 1-MCP could suppress the ethylene sensitivity of Japanese persimmon stored at 0℃ and 25℃ for 8 and 1 weeks, respectively.
Plants in natural conditions are often subjected to different stressors simultaneously. Such as in strawberry cultivation, salt stress and Fusarium wilt under saline environment aggravate production. In this study, beneficial soil microorganism arbuscular mycorrhizal fungi mediated cross-protection in strawberry plants under salt stress and Fusarium wilt disease conditions were examined. Mycorrhizal (Gigaspora margarita) and control plants of strawberry (Fragaria×ananassa Duch., cv. Tochiotome) were subjected to 200 mM NaCl and causal pathogen (Fusarium oxysporum f. sp. fragariae, Fof). Mycorrhization enhanced plant growth in without stress, salt, Fof and dual (salt＋Fof) stress conditions compare with control plants. Moreover, mycorrhization reduced Na＋ but increased K＋ levels in plants under salt stress subsequently, disease incidence, index, and pathogen population were also lower in mycorrhizal plants. As for antioxidant activities, mycorrhizal plants had increased activities of superoxide dismutase and ascorbate peroxidise. In addition, higher production of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and ascorbic acid contents found under conditions were observed. These results suggested that mycorrhization enhanced strawberry plant growth by maintaining a higher antioxidant capacity against oxidative stress, resulted in the protection of plants against dual stress conditions.