Mechanism of Peppermint Extract-Induced Delay of 'Packham's Triumph' Pear (Pyrus communis L.) Postharvest Ripening.

Postharvest ripening is correlated to the quality and shelf life of European pear fruit. In this study, the effects of peppermint extract on fruit phenotype, related physiological activities, and aroma components during postharvest ripening of the European pear variety 'Packham's Triumph' were examined. Fruit treated with 2.0 g L-1 peppermint extract for 12 h showed delayed softening by 4 d compared with that of the untreated control group. The peak values of ethylene and respiratory rate in fruit were reduced to a certain extent after peppermint extract treatment; however, the peppermint extract did not delay the occurrence of the respiratory climacteric peak. Peppermint extract treatment also did not significantly increase the content of the characteristic peppermint aroma in pear fruit. Further, widely targeted metabolome analysis revealed 298 significantly different metabolites, with flavonoids (40%) and lipid compounds (15%) accounting for the highest proportion on the first day after treatment. The Kyoto Encyclopedia of Genes and Genomes pathway result showed significant enrichment in the metabolic pathways of biosynthesis of flavonoid, isoflavonoid, flavone and flavonol, linoleic acid, and alpha-linolenic acid metabolism following peppermint extract treatment. The combined analysis of transcriptome and metabolome data showed significant enrichment in linoleic acid metabolism and alpha-linolenic acid metabolism on the first, third, and fifth days after peppermint extract treatment. This study indicates that peppermint extract mainly affects the pear fruit softening process in the early stage after treatment.

Coprecipitation-based synchronous chlorantraniliprole encapsulation with chitosan: carrier-pesticide interactions and release behavior.

BACKGROUND: Controlled-release pesticide formulations have emerged as a promising approach towards sustainable pest control. Herein, an environment-friendly formulation of insecticide chlorantraniliprole (CAP) was fabricated through a simple approach of coprecipitation-based synchronous encapsulation by chitosan (CTS), with carrier-pesticide interaction mechanism and release behavior investigated. RESULTS: The resulting CAP/CTS controlled-release formulation (CCF) showed a good loading content of 28.1% and a high encapsulation efficiency of 75.6%. Instrument determination in combination with molecular dynamics (MD) simulations displayed that the primary interactions between CAP and CTS were physical adsorption and complicated hydrogen (H)-bonds, which formed dominantly between NH in amides [or nitrogen (N) in ring structures] of CAP and hydroxyl (or amino) groups of CTS, as well as oxygen (O) in CAP with hydrogen in CTS or H2 O molecules. The in vitro release tests exhibited obvious pH/temperature sensitivity, with release dynamics following the first-order or Ritger-Peppas model. As the temperature increased, the CAP release process of the Ritger-Peppas model changed from Case-II to anomalous transport, and ultimately to a Fickian diffusion mechanism. The control effect against Plutella xylostella larvae also was evaluated by toxicity tests, where comparable efficacy of CCF to the commercial suspension concentrate was obtained. CONCLUSION: The innovative, easy-to-prepare CCF can be used as a formulation with obvious pH/temperature sensitivity and good efficacy on target pests. This work contributes to the development of efficient and safe pesticide delivery systems, especially using the natural polymer materials as carriers. © 2023 Society of Chemical Industry.

Jasmonic acid negatively regulates branch growth in pear.

The quality of seedlings is an important factor for development of the pear industry. A strong seedling with few branches and suitable internodes is ideal material as a rootstock for grafting and breeding. Several branching mutants of pear rootstocks were identified previously. In the present study, 'QAU-D03' (Pyrus communis L.) and it's mutants were used to explore the mechanism that affects branch formation by conducting phenotypic trait assessment, hormone content analysis, and transcriptome analysis. The mutant plant (MP) showed fewer branches, shorter 1-year-old shoots, and longer petiole length, compared to original plants (OP), i.e., wild type. Endogenous hormone analysis revealed that auxin, cytokinin, and jasmonic acid contents in the stem tips of MP were significantly higher than those of the original plants. In particular, the jasmonic acid content of the MP was 1.8 times higher than that of the original plants. Transcriptome analysis revealed that PcCOI1, which is a transcriptional regulatory gene downstream of the jasmonic acid signaling pathway, was expressed more highly in the MP than in the original plants, whereas the expression levels of PcJAZ and PcMYC were reduced in the MP compared with that of the original plants. In response to treatment with exogenous methyl jasmonate, the original plants phenotype was consistent with that of the MP in developing less branches. These results indicate that jasmonic acid negatively regulates branch growth of pear trees and that jasmonic acid downstream regulatory genes play a crucial role in regulating branching.

Alleviation of iron deficiency in pear by ammonium nitrate and nitric oxide.

BACKGROUND: Iron is essential for the growth and development of trace elements in plants, and iron deficiency can lead to leaf chlorosis. Ammonium and nitrate are the major forms of nitrogen present in soils. Ammonium nitrate alleviates the chlorosis of leaves caused by iron deficiency, but the mechanism is not clear in pear. RESULTS: Ammonium nitrate induced the increase of nitric oxide (NO) under iron deficiency. We further analyzed the effect of NO by exogenous NO treatment. The results showed that ammonium nitrate and NO increased the activity of ferric chelate reductase. NO induced the expression of multiple IRT genes and promoted the transmembrane transport of irons. Ammonium nitrate and NO promoted the activity of nitrogen assimilation-related enzymes and the nitrogen absorption capacity, and they also increased glutamine synthetase activity. Finally, ammonium nitrate and NO increased chlorophyll synthesis, with subsequent increase in the photosynthetic capacity of plants and accumulation of biomass. CONCLUSION: Ammonium nitrate indirectly alleviates the symptoms of plant yellowing by promoting the increase of NO, which increases the response of iron transporters. Both substances increase the nitrogen accumulation in plants. This study demonstrates a new option for minimizing Fe deficiency by regulating the balance between nutrients.

Bagging Strategy and Identification of Coloring Mode of 'Xinqihong' Pear.

'Xinqihong' is a recently selected and well-colored red pear (Pyrus bretschneideri Rehd.) cultivar that is popular in the marketplace owing to the bright red color and high quality of the fruit. The red pigmentation is strongly associated with the light signal. However, its responses to bagging treatment and to light exposure after shading are unknown. In this study, the fruit were treated with three types of fruit bags. 'Xinqihong' fruit colored rapidly in response to light stimulation. A white fruit bag was optimal for bagging of 'Xinqihong' fruit. To ensure satisfactory red pigmentation, the fruit required exposure to 30 days of light after bag removal. A transcriptome analysis was conducted to screen light-signal-related genes and identify their possible functions. PbCRY1 activated the promoter of PbHY5.2 and enhanced its expression. PbHY5.2 activated the promoter activity of PbUFGT and induced anthocyanin synthesis, and also showed self-activation characteristics. Both PbCRY2 and PbPHY1 induced anthocyanin accumulation. Thus, blue-light receptors played an important role in anthocyanin synthesis. This study provides a theoretical basis for the bagging cultivation of new varieties of 'Xinqihong', and lays a foundation for the study of the mechanisms of red pear fruit coloring in response to light signals.

Comparisons of Anatomical Characteristics and Transcriptomic Differences between Heterografts and Homografts in Pyrus L.

Pear (Pyrus L.) is an important temperate fruit worldwide, and grafting is widely used in pear vegetative propagation. However, the mechanisms of graft healing or incompatibility remain poorly understood in Pyrus. To study the differences in graft healing in Pyrus, the homograft "Qingzhen D1/Qingzhen D1" and the heterograft "QAUP-1/Qingzhen D1" as compatibility and incompatibility combinations were compared. Anatomical differences indicated the healing process was faster in homografts than in heterografts. During the healing process, four critical stages in graft union formation were identified in the two types of grafts. The expression of the genes associated with hormone signaling (auxin and cytokinins), and lignin biosynthesis was delayed in the healing process of heterografts. In addition, the PbBglu13 gene, encoded ß-glucosidase, was more highly up-regulated in heterografts than in homografts to promote healing. Meanwhile, the most of DEGs related starch and sucrose metabolism were found to be up-regulated in heterografts; those results indicated that cellulose and sugar signals were also involved in graft healing. The results of this study improved the understanding of the differences in the mechanisms of graft healing between homografts and heterografts.

Genome-Wide Analysis of KNOX Transcription Factors and Expression Pattern of Dwarf-Related KNOX Genes in Pear.

KNOTTED1-like homeobox (KNOX) transcription factors (TFs) belonging to the homeobox TF family play important roles in plant growth, development, and responses to abiotic and biotic stress. However, little information is available on KNOX TF in pear (Pyrus). In this study, 19 PbKNOXs TFs were re-identified in pear (Pyrus bretschneideri Rehd.). Phylogenetic analysis revealed that the TFs were clustered into three groups with 10 conserved motifs, some of which were group- or subgroup-specific, implying that they are important for the functions of the KNOX in these clades. PbKNM1 and PbKNM2 are KNM (encodes a MEINOX domain but not a homeodomain) genes identified in pear for the first time. KNOX genes in Pyrus and Malus were closely related, and a collinear relationship among PbKNOX genes in Pyrus and Malus was observed. Analysis of the expression patterns of PbKNOX genes in different tissues, at various growth stages, and in response to abiotic and biotic stress revealed that PbKNOXs are involved in plant growth and development. Our comparative transcriptional analysis of dwarf mutant varieties revealed that genes belonging to class I are highly expressed compared with genes in other classes. Analysis of the expression of PbKNOX genes in the hybrid offspring of vigorous and dwarf varieties revealed that PbKNOX genes were highly expressed in the vigorous offspring and weakly expressed in the dwarf offspring. These findings provide new insight into the function of KNOX TFs in pear and will aid future studies of dwarf fruit trees.

Variations in Pedicel Structural Properties Among Four Pear Species (Pyrus): Insights Into the Relationship Between the Fruit Characteristics and the Pedicel Structure.

Fruit pedicel is the bridge linking the parent tree and the fruit, which is an important channel for water and nutrients transport to the fruit. The genetic specificity determines the characteristics of the pedicel and the fruit, but the relationship between the pedicel structure and the fruit characteristics is unexplored. Combining the investigation of fruit characteristics, the statistical analysis of the pedicel structural properties, and the 2D and 3D anatomical observation of the pedicel, this study found distinctive contributions of the pedicel elements to the fruit characteristics in four pear species. The European pear (Conference) showed distinct fruit shape index and pedicel structural properties compared with the oriental pears (Akizuki, Yali, and Nanguoli). The fruit size positively correlated with pedicel length, fiber area, pedicel diameter, the area percentage of the cortex, and the area percentage of phloem; however, fruit firmness and soluble solids concentration are showed a stronger positive correlation with xylem area, pith area, the area percentage of xylem, the area percentage of sieve tube, and the area percentage of pith. Pedicel elements, including pith, fiber, and cortex, likely play a certain role in the fruit growth due to the variations of their characteristics demonstrated in the four pear species. The porosity, the ratio of the surface area to the volume, and the spatial arrangement of the vessels showed significant variations across the pear species, indicating the distinction of the hydraulic conductance of the pedicels. Our findings provided direct evidence that pedicel structural elements contributed distinctively to the fruit characteristics among pear species.

Pear xyloglucan endotransglucosylase/hydrolases PcBRU1 promotes stem growth through regulating cell wall elongation.

Brassinosteroids (BRs) play numerous important roles in plant growth and development. Previous studies reported that BRs could promote stem growth by regulating the expression of xyloglucan endotransglucosylase/hydrolases (XTHs). However, the mechanism of XTHs involved in stem growth remains unclear. In this study, PcBRU1, which belonged to the XTH family, was upregulated by exogenous BL treatment in Pyrus communis. The expression of PcBRU1 was highest in stems and lowest in leaves. Subcellular localization analysis indicated that PcBRU1 was located in the plasma membrane. Furthermore, overexpressing PcBRU1 in tobaccos promoted the plant height and internode length. Electron microscopy and anatomical structure analysis showed that the cell wall was significantly thinner and the cells were slenderer in transgenic tobacco lines overexpressing PcBRU1 than in wild-type tobaccos. PcBRU1 promoted stem growth as it loosened the cell wall, leading to the change in cell morphology. In addition, overexpressing PcBRU1 altered the root development and leaf shape of transgenic tobaccos. Taken together, the results could provide a theoretical basis for the XTH family in regulating cell-wall elongation and stem growth.

Nitrendipine-Treatment Increases Cork Spot Disorder Incidence in Pear 'Akituki' (Pyrus pyrifolia Nakai.) by Altering Calcium Distribution Inside the Fruit.

'Akituki' (Pyrus pyrifolia Nakai.) is a very popular and profitable pear cultivar in China. However, its high susceptibility to cork spot disorder has limited its expansion of cultivated area. The mechanisms of cork spot disorder have been discussed extensively, focusing on Ca2+ deficiency, yet no consensus has been made. In this study, we applied nitrendipine (NI) as a Ca2+ uptake inhibitor to explore the role of calcium in cork spot disorder occurrence. Results showed that NI treatment on the fruit remarkably increased the incidence of cork spot disorder; alteration of mineral contents happened at the early developmental stage of the fruit, especially on the outer flesh and the peel of the fruit; and this gap was filled gradually along with the expansion of the fruit. Significant differences in the expression levels of Ca2+ transport-related genes were found in the inner flesh, outer flesh and peel during the fruit growth period. The observation of free Ca2+ localization indicated the intracellular imbalance of Ca2+ in the NI-treated fruit. In conclusion, NI treatment reduced the calcium content in the fruit at an early developmental stage, altered the related expression of genes and influenced the cellular Ca2+ balance in the fruit, which prompted the occurrence of cork spot disorder. Measures for the prevention and control of cork spot disorder should be taken at the early stage of the fruit development in the field.

Genome-Wide Analysis of RAV Transcription Factors and Functional Characterization of Anthocyanin-Biosynthesis-Related RAV Genes in Pear.

Related to ABSCISIC ACID INSENSITIVE3/VIVIPAROUS1 (ABI3/VP1, RAV), transcription factors (TFs) belonging to the APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) TF family play critical roles in plant growth, development, and responses to abiotic and biotic stress. In this study, 11 novel RAV TFs were identified in pear (Pyrus bretschneideri Rehd). A phylogenetic analysis revealed that the TFs clustered into three groups with 10 conserved motifs, some of which were group- or subgroup-specific, implying that they are important for the functions of the RAVs in these clades. RAVs in Pyrus and Malus were closely related, and the former showed a collinear relationship. Analysis of their expression patterns in different tissues and at various growth stages and their responses to abiotic and biotic stress suggested that PbRAV6 and PbRAV7 play important roles in drought stress and salt stress, respectively. We investigated the function of RAVs in pear peel coloration using two red pear varieties with different color patterns and applying data from transcriptome analyses. We found that PbRAV6 participates in the regulation of pericarp color. These findings provide insight into a new TF family in pear and a basis for further studies on the response to drought stress and fruit coloration in this commercially important crop.

Differences in Anthocyanin Accumulation Patterns and Related Gene Expression in Two Varieties of Red Pear.

Red pear is a popular fruit that is appreciated for its attractive and distinctive appearance and mild flavor. In this study, we investigated the mechanism underlying the red coloration of pear skin using the 'Xinqihong' cultivar-which was selected as a spontaneous bud sport mutant of the 'Xinli 7'(Pyrus betulifolia Rehd.) variety and has a stronger red color that is retained in the mature fruit-as an experimental model. We compared the phenotype and gene expression patterns of the two varieties and found no significant differences at the early stage of fruit development. However, although the red color of 'Xinli 7' fruits began to fade 107 days after full bloom, that of 'Xinqihong' fruits persisted until the time of harvest. Transcriptome sequencing identified 639 genes that were differentially expressed between the two varieties, including genes related to light, calcium, and hormone signaling (e.g., PbPIF3, PbGA2ox, and the calmodulin related genes). Moreover, anthocyanin biosynthesis genes were downregulated as the red color of 'Xinli 7' fruits faded. These results provide insight into the molecular basis of color differences in red pears that can be useful for improving its fruit quality and commercial value.

Characterization of the Auxin Efflux Transporter PIN Proteins in Pear.

PIN-FORMED (PIN) encodes a key auxin polar transport family that plays a crucial role in the outward transport of auxin and several growth and development processes, including dwarfing trees. We identified a dwarfing pear rootstock 'OHF51' (Pyrus communis), which limits the growth vigor of the 'Xueqing' (Pyrus bretschneideri × Pyrus pyrifolia) scion, and isolated 14 putative PbPINs from the pear Pyrus bretschneideri. The phylogenic relationships, structure, promoter regions, and expression patterns were analyzed. PbPINs were classified into two main groups based on the protein domain structure and categorized into three major groups using the neighbor-joining algorithm. Promoter analysis demonstrated that PbPINs might be closely related to plant growth and development. Through quantitative real-time PCR (qRT-PCR) analysis, we found that the expression patterns of 14 PbPINs varied upon exposure to different organs in dwarfing and vigorous stocks, 'OHF51' and 'QN101' (Pyrus betulifolia), indicating that they might play varying roles in different tissues and participated in the regulation of growth vigor. These results provide fundamental insights into the characteristics and evolution of the PINs family, as well as the possible relationship between dwarfing ability and auxin polar transport.

Overexpression of PbrNHX2 gene, a Na+/H+ antiporter gene isolated from Pyrus betulaefolia, confers enhanced tolerance to salt stress via modulating ROS levels.

Intracellular Na+/H+ antiporters (NHXs) play important roles in plant tolerance to salt stress. However, plant NHXs functioning in salt tolerance and the underlying physiological mechanisms remain poorly understood. In this report, we report the identification and functional characterization of PbrNHX2 isolated from Pyrus betulaefolia. PbrNHX2 expression levels were induced by salt, and dehydration, but was unaffected by cold. PbrNHX2 was localized in the tonoplast. Overexpression of PbrNHX2 in tobacco and Pyrus ussuriensis conferred enhanced tolerance to salt tolerance, whereas down-regulation of PbrNHX2 in Pyrus betulaefolia by virus-induced gene silencing (VIGS) resulted in elevated salt sensitivity. The transgenic lines contained lower levels of Na+, higher levels of K+, and higher K/Na ratio, whereas they were changed in an opposite way when PbrNHX2 was silenced. In addition, the transgenic plants accumulated lower levels of reactive oxygen species compared with wild type, accompanied by higher activities of three antioxidant enzymes. Taken together, the data demonstrate that PbrNHX2 plays a positive role in salt tolerance and that it holds a great potential for engineering salt tolerance in crops.

Heterogenous expression of Pyrus pyrifolia PpCAD2 and PpEXP2 in tobacco impacts lignin accumulation in transgenic plants.

Lignin, a natural macromolecular compound, plays an important role in the texture and taste of fruit. Hard end is a physiological disorder of pear fruit, in which the level of lignification in fruit tissues is dramatically elevated. Cinnamyl alcohol dehydrogenase and expansin genes (PpCAD2 and PpEXP2, respectively) exhibit higher levels of expression in 'Whangkeumbae' (Pyrus pyrifolia) pear fruit exhibiting this physiological disorder, relative to control fruit without symptoms. These genes were isolated from pear fruit and subsequently expressed in tobacco (Nicotiana tabacum) to investigate their function. Histochemical staining for lignin revealed that the degree of lignification in leaf veins and stem tissues increased in plants transformed with sense constructs and decreased in plants transformed with antisense constructs of PpCAD2. The expression of native NtCADs was also inhibited in the antisense PpCAD2 transgenic tobacco. Sense and antisense PpCAD2 transgenic tobacco exhibited an 86.7% increase and a 60% decrease in CAD activity, respectively, accompanied by a complementary response in lignin content in root tissues. The basal portion of the stem in PpEXP2 transgenic tobacco was bent and highly lignified. Additionally, the level of cellulose also increased in the stem of PpEXP2 transgenic tobacco. Collectively, these results suggested that PpCAD2 and PpEXP2 genes play a significant role in lignin accumulation in transgenic tobacco plants, and it is inferred that these two genes may also participate in the increased lignification observed in hard end pear fruit.

A novel method for automatic identification of motion artifact beats in ECG recordings.

This paper presents a novel method for automatic identification of motion artifact beats in ECG recordings. The proposed method is based on the ECG complexes clustering, fuzzy logic and multi-parameters decision. Firstly, eight simulated datasets with different signal-to-noise ratio (SNR) were built for identification experiments. Results show that the identification sensitivity of our method is sensitive to SNR levels and acts like a low-pass filter that matches the cardiologists' recognition, while the Norm FP rate and PVB FP rate keep significantly low regardless of SNR. Furthermore, a simulated dataset including random durations of motion activities superimposed segments and two clinical datasets acquired from two different commercial recorders were adopted for the evaluation of accuracy and robustness. The overall identification results on these datasets were: sensitivity >94.69%, Norm FP rate <0.60% and PVB FP rate <2.65%. All the results were obtained without any manual threshold adjustment according to the priori information, thus dissolving the drawbacks of previous published methods. Additionally, the total cost time of our method applied to 24 h recordings is less than 1 s, which is extremely suitable in the situation of magnanimity data in long-term ECG recordings.

A wireless implantable sensor network system for in vivo monitoring of physiological signals.

A wireless implantable sensor network system (WISNS) is designed for in vivo monitoring physiological signals of a population of animals. WISNS can simultaneously monitor more than 15 animals, communicating three kinds of analog information among sensor nodes. Analog signals are transmitted to relay node at 800-KHz carrier by AM. Relay nodes digitalize and package them into messages, and then forward to the Wireless sensor network by Nordic RF technology (NWSN). Smaller overall dimensions (<2 cm (3)), lower power regulation, and dedicated packaging make the system suitable and compatible for implantable devices. The implantable sensor node, protocol stack of NWSN, and performance of the system are evaluated and optimized with ECG monitoring test of rats. Compared with those commercially available sensor nodes, our implantable one is leading in the weight and volume miniaturization, and our WISNS solution shows huge potential in achieving the compatibility of different animals.

A novel method for detection of the transition between atrial fibrillation and sinus rhythm.

Automatic detection of atrial fibrillation (AF) for AF diagnosis, especially for AF monitoring, is necessarily desirable for clinical therapy. In this study, we proposed a novel method for detection of the transition between AF and sinus rhythm based on RR intervals. First, we obtained the delta RR interval distribution difference curve from the density histogram of delta RR intervals, and then detected its peaks, which represented the AF events. Once an AF event was detected, four successive steps were used to classify its type, and thus, determine the boundary of AF: 1) histogram analysis; 2) standard deviation analysis; 3) numbering aberrant rhythms recognition; and 4) Kolmogorov-Smirnov (K-S) test. A dataset of 24-h Holter ECG recordings (n = 433) and two MIT-BIH databases (MIT-BIH AF database and MIT-BIH normal sinus rhythm (NSR) database) were used for development and evaluation. Using the receiver operating characteristic curves for determining the threshold of the K-S test, we have achieved the highest performance of sensitivity and specificity (SP) (96.1% and 98.1%, respectively) for the MIT-BIH AF database, compared with other previously published algorithms. The SP was 97.9% for the MIT-BIH NSR database.

Effect of ploidy increase on transgene expression: example from Citrus diploid cybrid and allotetraploid somatic hybrid expressing the EGFP gene.

Polyploidization is an important speciation mechanism for all eukaryotes, and it has profound impacts on biodiversity dynamics and ecosystem functioning. Green fluorescent protein (GFP) has been used as an effective marker to visually screen somatic hybrids at an early stage in protoplast fusion. We have previously reported that the intensity of GFP fluorescence of regenerated embryoids was also an early indicator of ploidy level. However, little is known concerning the effects of ploidy increase on the GFP expression in citrus somatic hybrids at the plant level. Herein, allotetraploid and diploid cybrid plants with enhanced GFP (EGFP) expression were regenerated from the fusion of embryogenic callus protoplasts from 'Murcott' tangor (Citrus reticulata Blanco × Citrus sinensis (L.) Osbeck) and mesophyll protoplasts from transgenic 'Valencia' orange (C. sinensis (L.) Osbeck) expressing the EGFP gene, via electrofusion. Subsequent simple sequence repeat (SSR), chloroplast simple sequence repeat and cleaved amplified polymorphic sequence analysis revealed that the two regenerated tetraploid plants were true allotetraploid somatic hybrids possessing nuclear genomic DNA of both parents and cytoplasmic DNA from the callus parent, while the five regenerated diploid plants were cybrids containing nuclear DNA of the leaf parent and with complex segregation of cytoplasmic DNA. Furthermore, EGFP expression was compared in cells and protoplasts from mature leaves of these diploid cybrids and allotetraploid somatic hybrids. Results showed that the intensity of GFP fluorescence per cell or protoplast in diploid was generally brighter than in allotetraploid. Moreover, same hybridization signal was detected on allotetraploid and diploid plants by Southern blot analysis. By real-time RT-PCR and Western blot analysis, GFP expression level of the diploid cybrid was revealed significantly higher than that of the allotetraploid somatic hybrid. These results suggest that ploidy level conversion can affect transgene expression and citrus diploid cybrid and allotetraploid somatic hybrid represents another example of gene regulation coupled to ploidy.

[Study on a non-invasive wide-range blood oxygen saturation detecting method and its instrument design].

This paper proposes a nonlinear method of detecting the blood oxygen saturation (SpO2) in a wide range on the basis of spectrophotometry, solves the nonlinear problem in detecting SpO2 in a wide range, and improves the applicable range and detection precision. CAN bus communication and DSP fast digital signal processing are utilized in the design of a non-invasive pulse blood oxygen saturation (SpO2) monitor in a wide range, which has a measure error below 3% within a range of 35% approximately 100%, and is applicable for clinical monitoring and detection of cosmonauts' physiological signals. This oximeter's components and their functions are also introduced in detail in the paper.