Pyrus Pyrifolia Nakai Cv Research Articles

Study on the Mechanism of Exogenous 5-Aminolevulinic Acid (ALA) in Regulating the Photosynthetic Efficiency of Pear Leaves

To provide a theoretical basis for the application of ALA in pear production, the effects of exogenous 5-aminolevulinic acid (ALA) treatment on leaf photosynthetic gas exchange parameters, chlorophyll fast fluorescence properties, and relative expression of the related genes were investigated using pear (Pyrus pyrifolia Nakai cv. ‘Whasan’) as a material in the study. The results show that exogenous ALA treatment improved the photosynthetic gas exchange parameters of pear leaves, upregulated the expression of multiple key genes which are related to ALA biosynthesis, metabolism, and transformation into chlorophylls. GUS staining in tobacco leaves showed that exogenous ALA activated the promoter activity of PypHEMA and PypCHLH genes, implying that the synthesis of endogenous ALA and chlorophylls was promoted by exogenous ALA. Furthermore, ALA promoted the expression of the genes encoding photosystem II (PSII) reaction center proteins, such as core protein D1, inner light-harvesting pigment proteins CP43 and CP47, and cytochrome b559. This led to increased PSII reaction center activity. In addition, ALA alleviated the donor side oxygen-evolving complex inhibition and reduced the closure rate on the receptor side, allowing for increased photochemical electron transfer and reduced heat dissipation while improving the photosynthetic performance index PIabs and PItotal. The findings of this study contribute to a better understanding of ALA’s promotion of plant photosynthetic efficiency, providing valuable insights for further research and potential applications in pear production.

Nondestructive detection of SSC in multiple pear (Pyrus pyrifolia Nakai) cultivars using Vis-NIR spectroscopy coupled with the Grad-CAM method

Vis-NIR spectroscopy coupled with chemometric models is frequently used for pear soluble solid content (SSC) prediction. However, the model robustness is challenged by the variations in pear cultivars. This study explored the feasibility of developing universal models for predicting SSC of multiple pear varieties to improve the model's generalizability. The mature fruits of 6 pear cultivars with green skin (Pyrus pyrifolia Nakai cv. ‘Cuiyu’, ‘Sucui No.1’ and ‘Cuiguan’) and brown skin (Pyrus pyrifolia Nakai cv. ‘Hosui’,’Syusui’ and ‘Wakahikari’) were used to establish single-cultivar models and multi-cultivar universal models using convolutional neural network (CNN), partial least square (PLS), and support vector regression (SVR) approaches. Multi-cultivar universal models were built using full spectra and important variables extracted by gradient-weighted class activation mapping (Grad-CAM), respectively. The universal models based on important variables obtained satisfactory performances with RMSEPs of 0.76, 0.59, 0.80, 1.64, 0.98, and 1.03°Brix on 6 cultivars, respectively.

First Report of Aureobasidium pullulans var. pullulans Causing Spot Blight of Pear (Pyrus pyrifolia) in Zhejiang Province of China.

Asian pear (Pyrus pyrifolia Nakai cv. cuiguan), is widely grown in Zhejiang province of China. In April 2019, symptoms consisting of small black, round leaf spots and blight flower petals were observed on over 30 % of 'Cuiguan' pear trees in an orchard (ca. 0.8 ha) near Cixi city, Zhejiang province, China. Initially, leaf spots were observed on leaf petioles, which, with time, enlarged and coalesced into necrotic streaks (1-2 cm) along the length of the petioles. Irregularly, reddish brown spots developed on flower petals, which hastened their senescence. Additional symptoms included round, black spots on leaves (2-3 mm in diameter) and necrosis of shoot tips. Symptomatic tissues from petals, petioles and leaves were plated onto potato dextrose agar (PDA). After five days of incubation at 26 °C, slimy fungal colonies (48×48 mm) with pinkish to orange-colored mycelia and with regular annulations were isolated from all tissues. After 10 days, cultured were shiny and dark brown in the center. The color of conidia ranged from hyaline to dark brown. Hyaline conidia were blastic, unicellular, ellipsoidal, smooth, with lengths that ranged from 11.03 to 27.14 (avg. 18.38) μm, and widths that ranged from 3.45 to 8.86 (avg. 6.04) μm (n = 50). Dark brown conidia were 1 to 2 celled, 10.89 to 26.03 (avg. 17.41) μm in length and 4.26 to 12.15 (avg. 6.94) μm in width (n = 50), and a slight septal constriction. Conidiogenous cells were clavate, hyaline, eseptate and top smoothly with 3-11 spores. Indistinct scars remained when the conidia dislodge from the conidiogenous cells. Single spore isolation was used to obtain pure cultures. Mycelia and conidia were scraped from cultures and DNA was extracted using Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech). Amplified PCR products from the internal transcribed spacer (ITS) region ITS1F/ITS4 (White et al. 1990), the partial 28S rDNA (LSU) NL1/NL4 (Boekhout et al. 1995), the β-tubulin (TUB) gene Bt2a/Bt2b (Glass & Donaldson 1995) and the partial elongase gene (ELO) ELO2-F/ELO2-R (Zalar et al. 2008) were sequenced (Tsingke Biotechnology Co., Hangzhou, Zhejiang). A blast search (GenBank Accession No. MT107050, OK485685, OK631951, OK631950) showed 99% Aureobasidium pullulans reference isolate CBS584.75 and EXF-150, which was consistent with the morphological data (Cene et al. 2014). Three-yr-old seedlings from 'Cuiguan' pears were spray with conidial suspension (106 conidia/ml) on the both sides of leaves without wounding. In a greenhouse (26 °C, natural light), six inoculated plants and three noninoculated plants (sprayed with sterile distilled water) enclosed in plastic bags to maintain humidity for 72 h. At 5 days after inoculation, shoot tips blackened and began to wilt. At 15 days after inoculation, symptoms similar to those on the original sample developed on inoculated petioles and leaves, whereas the control plants remained healthy. No symptoms were observed on leaves that were mature at the time of inoculation. Aureobasidium pullulans var. pullulans was reisolated from all inoculated plant. Overall, this disease shortened the life of pear flowers and reduced fruit set. To our knowledge, A. pullulans var. pullulans has not previously been reported as a pathogen of P. pyrifolia.

PpybZIP43 contributes to sucrose synthesis in pear fruits by activating PpySPS3 expression and interacts with PpySTOP1.

Sucrose is an important factor affecting sweetness and flavor in pear fruits, but the molecular mechanism of sucrose synthesis regulation is relatively unknown. Here, we characterized a transcription factor gene from pear (Pyrus pyrifolia Nakai cv. "Hosui") fruits, PpybZIP43, and found that the transient overexpression of PpybZIP43 in pear fruits significantly increased the sucrose content and the relative expression level of sucrose phosphate synthase genes (PpySPS3 and PpySPS8). Subcellular localization analysis in tobacco leaves showed that PpybZIP43 was localized in the nucleus. Yeast one-hybrid, electrophoretic mobility shift assay (EMSA), and dual-luciferase reporter assays indicated that PpybZIP43 was able to activate the expression of PpySPS3 by binding specifically to the G-box (CACGTG) element in the promoter. The protein-protein interaction assays using yeast two-hybrid, bimolecular fluorescence complementation (BiFC), firefly luciferase complementation imaging (LCI), and glutathione S-transferase (GST) pull-down demonstrated that PpybZIP43 could directly interact with PpySTOP1 to form a transcription complex. This study is helpful for understanding the molecular basis of sucrose synthesis and accumulation in pear fruits and provides candidate genes for breeding.

Potential of Changchong pear (Pyrus pyrifolia Nakai cv. Changchong) to improve the growth and survival of probiotic lactobacilli strains

The application of most probiotics in the food industry has been hampered by their sensitivity to oxygen. Natural antioxidants have shown a broad prospect in counteracting the oxygen stress and improving the growth of probiotics in the context of oxygen stress.This study reported on a pear cultivar (Pyrus pyrifolia Nakai cv. Changchong), whose fruit is characterized by a lower browning rate compared to its counterparts. A moderate but persistent antioxidant pear juice was obtained and biochemical analysis suggested its potential to counteract the oxygen stress. Its effect on the growth and survival of the probiotic lactobacilli strains was investigated in the context of oxygen stress. The results indicated that Changchong pear juice is efficient in growth improvement as well as survival enhancement for the Lactiplantibacillusplantarum strain ST-III and other probiotic representatives of this species. Additionally, experiments performed with other probiotic lactobacilli strains showed that it is also effective on Lacticaseibacillusrhamnosus GG and Lactobacillusacidophilus NCFM, suggesting its potential in a broader sense. These results highlighted the potential of a moderate but persistent natural antioxidant in the production and preservation of probiotic foods, and offered a new perspective for protecting oxygen-sensitive probiotics from chronic oxygen stress.

5-hydroxymethyl-2-furaldehyde purified from Japanese pear (Pyrus pyrifolia Nakai cv. Nijisseiki) juice concentrate inhibits melanogenesis in B16 mouse melanoma cells

Pear juice concentrate prepared by boiling Japanese pear (Pyrus pyrifolia Nakai cv. Nijisseiki) juice can significantly inhibit the activity of tyrosinase, a key enzyme in melanin synthesis in human skin. Using the ethanol extract of pear juice concentrate, we homogeneously purified an active compound that was identified as 5-hydroxymethyl-2-furaldehyde (5-HMF) through 1H- and 13C-NMR and mass spectroscopy. We observed that 5-HMF inhibited the monophenolase and diphenolase activities of mushroom tyrosinase as a mixed-type inhibitor (K i values of 3.81 and 3.70mmol/L, respectively). In B16 mouse melanoma cells, treatment with 170µmol/L of 5-HMF significantly reduced α-melanocyte-stimulated melanin synthesis by suppressing the cyclic adenosine monophosphate-dependent signaling pathway involved in melanogenesis. The results of our study indicated that 5-HMF can be potentially used as a skin-lightening agent in the cosmetic industry. Abbreviations: AC: adenylate cyclase; CREB: cAMP response element-binding protein; dhFAME: S-(-)-10,11-Dihydroxyfarnesoic acid methyl ester; DMEM: dulbecco's modified eagle medium; l-DOPA: 3-(3,4-Dihydroxyphenyl)- l-alanine; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HEPES: 4-(2-Hydroxyethyl)-1-piperazine ethane sulfonic acid; 5-HMF: 5-Hydroxymethyl-2-furaldehyde; MITF: microphthalmia-associated transcription factor; α-MSH: α-Melanocyte-stimulating hormone; PKA: protein kinase A; PVDF: polyvinylidene difluoride; SDS: sodium dodecyl sulfate; TRP1: tyrosinase-related protein 1; TRP2: tyrosinase-related protein 2.

Isolation of five proanthocyanidins from pear (Pyrus pyrifolia Nakai) fruit peels.

Five proanthocyanidins, two B-type dimers and three A-type trimers, were purified and isolated from the fruit peels of Pyrus pyrifolia Nakai cv. Chuhwangbae. The isolated compounds were identified as (-)-epicatechin gallate-(4β→8)-(-)-epicatechin (Hahashi et al. in Ann Biol Res 3:3200-3207, 2012), (-)-epicatechin-(4β→8)-(-)-epicatechin (procyanidin B2) (Tanrioven and Eksi in Food Chem 93:89-93, 2005), (-)-epicatechin-(4β→8, 2β→O-7)-(-)-epicatechin-(4β→8)-(-)-epicatechin (cinnamtannins B1) (Salta et al. in J. Fun. Food 2: 153-157, 2010), (-)-epicatechin-(4β→8)-(-)-epicatechin-(4β→8, 2β→O-7)-(-)-epicatechin (aesculitannin A) (Challice and Westwood in Phytochemistry 11: 37-44, 1972), and (-)-epicatechin-(4β→6)-(-)-epicatechin-(4β→8, 2β→O→7)-(-)-epicatechin (Es-Safi et al. in J Agric Food Chem 54: 6969-6977, 2006). Their structures were determined by nuclear magnetic resonance and mass spectrometry. The three A-type proanthocyanidin trimers were identified for the first time from pear.

Enzymatic browning inhibition and antioxidant activity of pear juice from a new cultivar of asian pear (Pyrus pyrifolia Nakai cv. Sinhwa) with different concentrations of ascorbic acid.

Different ascorbic acid (AA) concentrations of 0.16, 0.20, and 0.24% (w/v) were added to pear juice from the new cultivar Pyrus pyrifolia Nakai cv. "Sinhwa". Enzymatic browning reduction and antioxidant activity were analyzed after 24 h at 37°C. Juices with 0.20% added AA showed the highest inhibition of 78.8% of polyphenol oxidase (PPO) activity. L* values of juices a with 0.20 and 0.24% added AA decreased more slowly than controls lacking AA addition and juice with 0.16% added AA after storage for 24 h. Browning indices of juices with added AA were lower than for controls. However, indices increased after storage for 24 h. The DPPH radical-scavenging activity, reducing power, and nitrite scavenging activity of all juices with added AA were higher than for controls and decreased after storage for 24 h. Addition of 0.20% AA to pear juice from the new "Sinhwa" cultivar showed the highest browning activity reduction.

표준 시비에 따른 '신고'배 수체 및 재배지 토양의 탄소 및 질소 저장량 변화

IPCC 2006 지침에서 제시한 Tier 3 수준에 맞게 배나무 과수원의 온실가스 저장량을 산정하기 위하여, '신고(Pyrus pyrifolia Nakai cv. Niitaka)' 배 재배지를 대상으로 1년 시비에 따른 과수와 재배지 토양의 총 탄소와 질소 저장량을 평가하였다. 이를 위해 전라남도 나주에 위치한 농촌진흥청 배시험장 재배포장에서 <TEX>$5.0{\times}3.0$</TEX>으로 재식된 Y수형의 16년 생 '신고'배에 질소와 인, 칼륨비료를 각각 <TEX>$200kg\;N{\cdot}ha^{-1}$</TEX>, <TEX>$130kg\;P{\cdot}ha^{-1}$</TEX>, <TEX>$180kg\;K{\cdot}ha^{-1}$</TEX> 시비하였다. 2013년 8월, 배나무 수체와 토양의 총탄소와 질소 함량을 평가하기 위해 샘플을 채취하였다. 과수는 굴취하여 주간, 주지, 측지, 잎, 과일, 뿌리로 분류하여, 총탄소와 질소 함량, 건중량을 조사하였다. 토양은 과수 주간으로부터 약 0.5m 떨어진 지점에서 0.6cm 깊이까지 0.1m 간격으로 토양을 채취하여, 풍건한 뒤 2mm체에 통과시킨 시료를 채취하여 총 탄소와 질소 함량을 분석하였다. 나무 한 그루당 건중량은 주간은 5.6kg, 주지는 12.0kg, 측지는 15.7kg, 잎은 5.7kg, 과일은 9.8kg, 뿌리가 10.5kg 이었다. 나무 한 그루당 총탄소와 질소 함량은 주간에서 2.6C kg, 0.02N kg였고, 주지는 5.5C kg, 0.04N kg, 측지는 7.2C kg, 0.07N kg, 잎은 2.6C kg, 0.11N kg, 과일은 4.0C kg, 0.03N kg, 뿌리에서는 4.8C kg, 0.05N kg이였다. 재식밀도(667trees/ha)를 기준으로 산정하였을 때, 토양에 저장되는 탄소량은 155.7Mg, 질소량은 14.0 Mg이였으며, 수체에 저장되는 탄소량은 <TEX>$17.8Mg{\cdot}ha^{-1}$</TEX>, 질소량은 <TEX>$0.2Mg{\cdot}ha^{-1}$</TEX>이였다. 따라서 배나무 재배지 내에 저장되는 총탄소량은 173.6Mg였으며, 질소량은 14.2Mg이었다. 이를 작년 2012년 결과와 비교하였을 때, 1년 시비 결과 배 과수원의 탄소 저장량은 <TEX>$17.7Mg{\cdot}ha^{-1}$</TEX> 증가하였으나, 질소 저장량은 변화가 거의 없었다(<TEX>$0.66Mg{\cdot}ha^{-1}$</TEX>). We determined the total C and N stocks in trees and soils after 1 year of fertilization in an experimental orchard with 16-year-old 'Niitaka' pear (Pyrus pyrifolia Nakai cv. Niitaka) trees planted at <TEX>$5.0m{\times}3.0m$</TEX> spacing on a Tatura trellis system. Pear trees were fertilized at the rate of 200 kg N, 130 kg P and <TEX>$180kg\;K\;ha^{-1}$</TEX>. At the sampling time (August 2013), trees were uprooted, separated into six fractions [trunk, main branches, lateral branches (including shoots), leaves, fruit, and roots] and analyzed for their total C and N concentrations and dry masses. Soil samples were collected from 0 to 0.6 m in 0.1 m intervals at 0.5 m from the trunk, air-dried, passed through a 2-mm sieve, and analyzed for total C and N concentrations. Undisturbed soil core samples were also taken to determine the bulk density. Dry mass per tree was 5.6 kg for trunk, 12.0 kg f or m ain branches, 15.7 kg for lateral branches, 5.7 kg for leaves, 9.8 kg for fruits, and 10.5 kg for roots. Total amounts of C and N per tree were respectively 2.6 and 0.02 kg for trunk, 5.5 and 0.04 kg for main branches, 7.2 and 0.07 kg for lateral branches, 2.6 and 0.11 kg for leaves, 4.0 and 0.03 kg for fruit, and 4.8 and 0.05 kg for roots. Carbon and N stocks stored in the soil per hectare were 155.7 and 14.0 Mg, respectively, while those contained in pear trees were 17.8 and <TEX>$0.2Mg{\cdot}ha^{-1}$</TEX> based on a tree density of 667 trees/ha. Overall, C and N stocks per hectare stored in the pear orchard were 173.6 and 14.2 Mg, respectively. Compared with results obtained in 2012, the amounts of C stocks have increased by <TEX>$17.7Mg{\cdot}ha^{-1}$</TEX>, while those of N stocks remained virtually unchanged (<TEX>$0.66Mg{\cdot}ha^{-1}$</TEX>).

추황배(Pyrus pyrifolia Nakai cv. Chuhwangbae) 과피로부터 2종의 Flavonoids의 단리·동정

추황배(Pyrus pyrifolia Nakai cv. Chuhwangbae) 과피로부터 2종의 Flavonoids의 단리·동정

Identification of differentially expressed genes using digital gene expression profiles in Pyrus pyrifolia Nakai cv. Hosui bud release following early defoliation

“Returning bloom” is a major problem in the warm pear-producing regions during autumn–winter after the pear harvest and can cause tremendous pear production losses in the following year. The molecular mechanism causing this phenomenon is a mystery. We used high-throughput tag-sequencing (tag-seq) technology to analyze the gene expression profiling of pear (Pyrus pyrifolia Nakai) floral buds at three time points for completely defoliated plants after harvest. A total of 13.2–15.8 million reads were obtained for each of the six libraries, and approximately 61.81–67.11 % were mapped to Pyrus bretschneideri Rehd. genome sequences. A total of 2713 differentially expressed genes, categorized into 35 functional groups, were associated with 251 Kyoto Encyclopedia of Genes and Genomes pathways. Gene Ontology and pathway enrichment analysis showed differentially expressed genes linked to photosynthesis, hormone/signaling, and carbohydrate biosynthesis and metabolism. Six differentially expressed genes were selected for quantitative real-time PCR analysis, and the expression patterns were consistent with the tag-seq results. We concluded that bud release after artificial defoliation required compensatory mechanisms, which induce genes specifically expressed in association with the process of photosynthesis, endogenous hormones, carbohydrate, and reactive oxygen species. The differential expressions of genes found in pear tree defoliated by hand should play important roles in the reversion phase from paradormancy back to growth.

Establishment of a simple method for purification of high purity chlorogenic acid from immature fruit of pear (Pyrus pyrifolia Nakai)

Chlorogenic acid [3-(3,4-dihydroxycinnamoyl)quinic acid, CGA] is one of the main compounds contained in immature pear fruits. In the present study, we established simple purification of CGA in high purity from the immature fruit of pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) which contains CGA in high concentration. The 80 % MeOH extract (1.4 g) of immature pear fruits (20 g fresh wt.) was partitioned with ethyl acetate (EtOAc) under acidic condition (pH 2.65). Then, the EtOAc-soluble acidic layer (110.3 mg) was further purified using Diaion HP-20 column chromatography (H2O/MeOH, step wise). Then, the CGA-contained fractions were finally purified by preparative ODS-HPLC. The isolated CGA (24.3 mg) showed high purity (>99 %) and the total recovery was estimated to be 63.9 %.

Comparison of bioactive compound contents and in vitro and ex vivo antioxidative activities between peel and flesh of pear (Pyrus pyrifolia Nakai)

We compared chemical constituents and antioxidative activities between the flesh and peel of two Asian pears (Pyrus pyrifolia Nakai cv. Niitaka and Chuhwangbae). Total phenolic, flavonoid, and ascorbic acid contents in the peels were higher than those in the flesh. However, total tocopherol content between peels and flesh was not different. The peels exhibited higher free radical scavenging activities in the in vitro models of DPPH, ABTS+, nitrite radicals, and reducing capabilities than those of the flesh. Pear fruit extracts significantly prevented 3T3-L1 cells from undergoing H2O2-induced oxidation and the effect was higher by the peel extract than by the flesh extract. In addition, blood plasma of rats administered the peel extract showed higher antioxidative activity than that of rats administered the flesh extract. These results suggest that consumption of unpeeled Asian pear fruit may effectively increase antioxidant activity in the body.

Anatomical Structure and Fruit Quality According to the Fruit Developmental Stage as Affected by Gibberellins Treatments in Pyrus pyrifolia Nakai cv. Hanareum

본 연구는 조생종 '한아름'의 기본적인 해부학적 과실 구조 및 과실 품질과 GA 처리 시의 변화를 구명하여 '한아름'의 생리적 특징을 이해하고자 수행하였다. '한아름'의 생육기별 과실 발달을 조사한 결과 만개기의 과실 구조는 바깥쪽으로부터 외표피층, 아표피층, 유조직층, 내표피층으로 구성되어 있으며 5종류의 유관속 조직이 관찰되었다. 코르크층은 무처리구에서는 만개 후 70일, GA 처리구에서는 만개 후 60일경에 형성되었다. '한아름' 품종의 세포분열 기간은 만개 후 40일까지이며 이후에는 세포비대에 의해 과실이 발달하였다. GA 처리에 따른 과실 비대와 조직 발달을 관찰한 결과, GA 처리는 '한아름'의 세포분열에는 영향을 미치지 못하였으며 세포비대를 촉진하는 것으로 조사되었다. 또한 과경부는 세포분열 정지기인 만개 후 40일부터 처리구의 유관속 조직이 무처리구에 비하여 큰 것으로 관찰되어 '한아름' 과실은 GA를 처리할 시 유관속 조직의 발달을 촉진하여 상대적으로 과실로의 양분 공급이 증가하는 것으로 생각되었다. 한편 수확기에 무처리구와 처리구의 평균적인 품질을 비교한 결과, 처리구에서 과중이 높았으나 경도는 낮게 조사되어 '한아름' 과실에 GA를 처리할 경우 수확 후 과실의 저장에 영향을 미칠 것으로 생각되었다. This study was carried out to understand the physiological characteristics of early-matured 'Hanareum' (Pyrus pyrifolia Nakai) pears through anatomical structure and fruit characteristics and also the changes according to gibberellin (GA) treatment. The pericarp at full bloom consists of outer epidermis, hypodermis, parenchyma cell, and inner epidermis from the exterior and five types of vascular bundle tissues. Cork cell layer was formed at 70 days after full bloom (DAFB) in non-treated fruits and formed at 60 DAFB in GA treated fruits. Cell division period was from full bloom (FB) to 40 DAFB and then fruit enlargement was accomplished by the cell growth. Comparison of the fruit enlargement and fruit structure development by GA treatment or non-treatment showed that cell division of 'Hanaerum' fruits did not affect the GA treatment but fruit enlargement was affected cell growth. Fruit stalk of GA treatment fruits was larger than non-treated fruits from 40 DAFB which correspond to the period of the stop of cell division and 'Hanareum' was regarded GA treatment expedite of vascular bundle tissue growth and relatively increased nutrient transport to fruit. In addition to, average fruit quality between the non-treatment and GA treatment showed that fruit weight was higher in fruits treated by GA but firmness was lower and probably was effected fruit storing in 'Hanareum' pear.

'신고'배 재배지 내 수체 및 토양의 탄소 및 질소 저장량

IPCC 2006 guideline에서 제시한 Tier 3 수준에 맞게 배나무 과수원의 온실가스 저장량을 산정하기 위하여, 전라남도 나주에 위치한 농촌진흥청 배시험장 재배포장(<TEX>$35^{\circ}01^{\prime}27.70N$</TEX>, <TEX>$126^{\circ}44^{\prime}53.50^{\prime\prime}E$</TEX>, 표고 6m)에 <TEX>$5.0{\times}3.0m$</TEX> 간격으로 재식된 Y자 수형의 15년생 배 '신고(Pyrus pyrifolia Nakai cv. Niitaka)' 재배지를 대상으로 과수와 재배지 토양의 총 탄소 및 질소 저장량을 측정하였다. 이를 위해 2012년 8월, 3반복으로 과수를 굴취하여 주간, 주지, 측지, 잎, 과일, 뿌리로 분류하였고, 과수 주간으로부터 약 0.5m 떨어진 지점에서 0.6m 깊이까지 0.1m 간격으로 토양을 채취하였다. 나무 한그루당 건물중은 주간이 4.7kg, 주지가 13.3kg, 측지가 13.9kg, 잎이 3.7kg, 과일이 6.7kg, 뿌리가 14.1kg이었다. 단위 질량당 총 탄소 및 질소의 함량은 주간에서 각 2.3kg과 0.02kg, 주지에서 6.4kg과 0.07kg, 측지에서 6.4kg과 0.09kg, 뿌리에서 6.5kg과 0.07kg, 잎에서 1.7kg과 0.07kg, 과일에서 3.2kg과 0.03kg 이었다. 재식밀도(667trees/ha)를 기준으로, 탄소와 질소는 재배지 토양에 각각 138.29 및 <TEX>$13.31Mg{\cdot}ha^{-1}$</TEX>가 저장되어 있었고, 과수에 각각 17.66 및 <TEX>$0.23Mg{\cdot}ha^{-1}$</TEX>씩 보유되어 있었다. 이를 종합한 결과 과수 재배지에서 탄소는 <TEX>$155.95Mg{\cdot}ha^{-1}$</TEX>, 질소는 <TEX>$13.54Mg{\cdot}ha^{-1}$</TEX>가 저장되어 있었다. To report country-specific carbon and nitrogen stocks data in a pear orchard by Tier 3 approach of 2006 IPCC guidelines for national greenhouse gas inventories, an experimental pear orchard field of the Pear Research Station, National Institute of Horticultural & Herbal Science, Rural Development Administration, Naju, Korea (<TEX>$35^{\circ}01^{\prime}27.70N$</TEX>, <TEX>$126^{\circ}44^{\prime}53.50^{\prime\prime}E$</TEX>, 6 m altitude), where 15-year-old 'Niitaka' pear (Pyrus pyrifolia Nakai cv. Niitaka) trees were planted at a <TEX>$5.0m{\times}3.0m$</TEX> spacing on a Tatura trellis system, was chosen to assess the total amount of carbon and nitrogen stocks stored in the trees and orchard soil profiles. At the sampling time (August 2012), three trees were uprooted, and separated into six fractions: trunk, main branches, lateral branches (including shoots), leaves, fruits, and roots. Soil samples were collected from 0 to 0.6 m depth at 0.1 m intervals at 0.5 m from the trunk. Dry mass per tree was 4.7 kg for trunk, 13.3 kg for main branches, 13.9 kg for lateral branches, 3.7 kg for leaves, 6.7 kg for fruits, and 14.1 kg for roots. Amounts of C and N per tree were respectively 2.3 and 0.02 kg for trunk, 6.4 and 0.07 kg for main branches, 6.4 and 0.09 kg for lateral branches, 6.5 and 0.07 kg for roots, 1.7 and 0.07 kg for leaves, and 3.2 and 0.03 kg for fruits. Carbon and nitrogen stocks stored between the soil surface and a depth of 60 cm were 138.29 and <TEX>$13.31Mg{\cdot}ha^{-1}$</TEX>, respectively, while those contained in pear trees were 17.66 and <TEX>$0.23Mg{\cdot}ha^{-1}$</TEX> based on a tree density of 667 <TEX>$trees{\cdot}ha^{-1}$</TEX>. Overall, carbon and nitrogen stocks per hectare stored in a pear orchard were 155.95 and 13.54 Mg, respectively.

An ether and three ester derivatives of phenylpropanoid from pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit and their radical-scavenging activity

The ethyl acetate-acidic layer obtained after solvent fractionation of Asian pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit peel methanol extracts was purified by Sephadex LH-20 column chromatography and octadecylsilane-high performance liquid chromatography, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity was evaluated. The four isolated compounds were identified as 2-O-(trans-p-coumaroyl) glyceric acid (1), 2-O-(cis-p-coumaroyl) glyceric acid (2), guaiacylglycerol-β-ferulic acid ether (3), and 2-O-(cis-caffeoyl) malic acid (4), based on the one- and two-dimensional nuclear magnetic resonance spectroscopic data. The isolated compounds 1–4 were identified for the first time from pear. Compound 4 showed higher DPPH radical-scavenging activity than 1–3.

Influence of heat stress on leaf ultrastructure, photosynthetic performance, and ascorbate peroxidase gene expression of two pear cultivars (Pyrus pyrifolia)

Plants encounter a variety of stresses in natural environments. One-year-old pot-grown trees of pear (Pyrus pyrifolia Nakai cv. Cuiguan and Wonhwang) were exposed to two heat stress regimes. Under constant short-term heat stress, chloroplasts and mitochondria were visibly damaged. Relative chlorophyll content and maximum photochemical efficiency of photosystem II were significantly decreased, which indicated that the leaf photosynthetic capability declined. Under chronic heat stress, mesophyll cell ultrastructure was not obviously damaged, but leaf photosynthetic capability was still restrained. As chronic heat stress was a simulation of the natural environment in summer, further study of the responses under this stress regime was undertaken. Ascorbate peroxidase (APX) activity was increased in 'Cuiguan', but not in 'Wonhwang'. Inducible expression of PpAPX genes in the cytoplasm, chloroplasts and peroxisomes was consistent with increased APX activity in 'Cuiguan', whereas only weak induction of PpAPX genes was observed in 'Wonhwang'. The isoenzymes cytosolic APX1 (cAPX1) and stromal APX (sAPX) were confirmed to be localized in the cytoplasm and chloroplasts, respectively.

Isolation and Expression Analysis of Anthocyanin Biosynthesis Genes from the Red Chinese Sand Pear, Pyrus pyrifolia Nakai cv. Mantianhong, in Response to Methyl Jasmonate Treatment and UV-B/VIS Conditions

The effects of UV-B/VIS on the expression of genes involved in anthocyanin biosynthesis in the red Chinese sand pear cultivar ‘Mantianhong’, and the role played by the plant hormone methyl jasmonate (MJ) in this effect, were investigated. Four full-length cDNAs and three partial cDNA fragments of genes involved in anthocyanin biosynthesis were isolated from the cultivar. PpPAL2 and PpCHS2 showed considerable sequence identity to the reported PpPAL1 and PpCHS1 sequences. Other genes showed low pronounced sequence identity to other reported members of the same gene family. Bagged mature pear fruits were harvested and then used for postharvest treatment. Fruits were immersed in distilled water, then irradiated with UV-B/VIS light; or treated with MJ first, and then irradiated with UV-B/VIS light. Fruits immersed in distilled water and kept in darkness were used as controls. During UV-B/VIS irradiation, most anthocyanin biosynthesis genes were upregulated in pears in quantities commensurate with the accumulation of anthocyanin, but PpDFR1, PpDFR2, PpbHLH, and PpWD40 were not. MJ treatment had two effects on the expression of genes related to anthocyanin biosynthesis. It advanced the peak time and increased mRNA levels. Each family member of genes involved in anthocyanin biosynthesis showed a differential expression profile. The expression patterns of two genes regulating MJ-mediated plant responses, PpJAZ1 and PpCOI1, were also analyzed. More obvious downregulation and upregulation of PpJAZ1 and PpCOI1, respectively, were detected at 2 days of irradiation (DI) in fruits that were subjected to MJ treatment, as the expressions of most genes related to anthocyanin biosynthesis peaked at this time. We also showed that the regulation of MJ and UV-B/VIS occurred at the transcriptional level. These findings should improve our understanding of the molecular mechanism(s) underlying anthocyanin biosynthesis, which may in turn facilitate the development of new methods to improve fruit color.

Coumaroyl quinic acid derivatives and flavonoids from immature pear (Pyrus pyrifolia nakai) fruit

Fourteen compounds were isolated from 60% ethanol extracts of immature pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit using Amberlite XAD-2 column HPLC with guided DPPH radical scavenging assay. Based on MS and NMR analysis, the isolated compounds were identified as 5-O-trans-caffeoyl quinic acid methyl ester (1), malaxinic acid (2), 5-O-trans-p-coumaroyl quinic acid methyl ester (3), 5-O-cis-p-coumaroyl quinic acid methyl ester (4), 5-O-trans-p-coumaroyl quinic acid (5), trans-p-coumaric acid (6), methyl cis-p-coumarate (7), methyl trans-p-coumarate (8), 3,5-O-dicaffeoyl quinic acid (9), (-)-epicatechin (10), (S)-(+)-2-cis-abscisic acid (11), isorhamnetin 3-O-β-d-galacto-pyranoside (12), isorhamnetin-3-O-β-d-glucopyranoside (13), and isorhamnetin 3-O-α-l-rhamnopyranosyl (1→6)-O-β-d-glucopyranoside (14). Six compounds (1, 2, 6, 9, 10, and 13) were identified previously, but other compounds (3–5, 7, 8, 11, 12, and 14) were isolated for the first time from pear.

Caffeoyl Triterpenes from Pear (Pyrus pyrifolia Nakai) Fruit Peels and Their Antioxidative Activities against Oxidation of Rat Blood Plasma

Six triterpenes, including three caffeoyl triterpenes, were purified and isolated from pear fruit ( Pyrus pyrifolia Nakai cv. Chuwhangbae) peel extracts using various column chromatography techniques with a guided 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay. The isolated compounds were identified as betulinic aldehyde (1), lupeol (2), betulinic acid (3), 3-O-cis-caffeoylbetulinic acid (4), 3-O-trans-caffeoylbetulinic acid (5), and 3-O-trans-caffeoyloleanolic acid (6) on the basis of nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. Four compounds (1, 4-6) were identified from Asian pear fruit for the first time. In addition, compounds 4-6, containing a caffeic acid moiety, showed higher DPPH radical-scavenging and suppression effects against copper ion-induced oxidation of rat blood plasma than other compounds without a caffeic acid moiety.