Acta Agriculturae Zhejiangensis

Argonaute2 mutants in Arabidopsis created by CRISPR_Cas9 technology

LI Hongying, GAO Yanwu, YU Ru’en, WANG Zhengbo, LI Xueping, LIU Longchang

2021, 33(11): 2001-2008. DOI: 10.3969/j.issn.1004-1524.2021.11.01

Abstract ( 1789 )

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Argonaute2 (AGO2) plays an important role in plant resistance and development. In order to create Arabidopsis ago2 nucleotides insertion/deletion mutant materials, structure of AtAGO2 gene was analysed firstly, and then the CRISPR_Cas9 based gene editing expression vector which contains three target sites of AtAGO2 was constructed, and transferred into Arabidopsis by Agrobacterium mediated floral-dip. 62 anti-hygromycin resistant seedlings were obtained by screening the seeds of T₀ generation plants on the medium containing hygromycin antibiotic. And 53 definitively transgenic positive seedlings were further confirmed by PCR amplification using hygromycin B gene specific primers. The fragments of AtAGO2 containing the target sites of 10 random selected transgenic progenies were sequenced, and the results showed that six transgenic lines were successfully edited around the T₁ site, all the 10 lines were edited around the T₂ site, and the third target site was not edited. Varied forms of mutation happened in the nearby area of the target sites, and the most frequent ones were deleting or adding one base before PAM. There were also more than 10 bases deletion forms, and the longest one was 106 bases deletion. This study provided abundant useful genetic materials for further study of the function of AGO2 in Arabidopsis.

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Identification and expression analysis of cytochrome P450 family genes from Physalis angulata L.

JIANG Zhifang, HAN Yidie, LOU Panpan, GUO Hong, FENG Shangguo, SHEN Chenjia, WANG Huizhong1

2021, 33(11): 2009-2016. DOI: 10.3969/j.issn.1004-1524.2021.11.02

Abstract ( 1417 )

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Cytochrome P450 enzymes are widely involved in plant secondary metabolism. Based on the transcriptome data of Physalis angulata, several P450 family members had been identified. 795 possible sequence fragments of P450 gene had been identified, and they were clustered into 25 different clusters, including 12 clustering with tissue-specific expression. By bioinformatics splicing, full-length sequence of 30 Physalis angulata P450 gene family, which was highly homologous with other P450 species genes, were obtained. Phylogenetic analysis showed that 30 P450 genes could be classified into nine P450 subfamilies. By qRT-PCR method, expression of 30 P450 genes under different developmental stages of fruits was analyzed. The expression of nine P450 genes increased with fruit maturation, while expression of other nine P450 genes decreased gradually. The expression of P450 family genes under ethylene (ACC) and ethylene inhibitor (1-methylcyclopropene, 1-MCP) treatments were also analyzed. Part of the P450 family genes showed the opposite expression pattern under ACC and 1-MCP treatments, suggesting P450 family genes might be involved in ethylene-mediated fruit ripening process. Further, three fruit-specific expressed P450 family genes (comp164210, comp131532, comp152181) had been cloned, and they were mainly located in the cytoplasm and cell membrane. This study provided valuable genetic information for the genetic improvement of medicinal characters of P. angulata.

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Protective effect of vitamin C in piglet intestinal epithelial cells inflammatory injury induced by β-conglycinin

XIA Jiangying, YANG Ju, SONG Tianhao, PANG Lianfeng, YE Ting, REN Zhihua, DENG Junliang

2021, 33(11): 2017-2025. DOI: 10.3969/j.issn.1004-1524.2021.11.03

Abstract ( 1410 )

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To investigate protective effects of different concentrations of vitamin C (V_C) on inflammatory injury of piglet intestinal epithelial cells (IPEC-J2) induced by β-conglycinin (7S). IPEC-J2 in logarithmic growth phase were used for test. The cells were randomly divided into control group, 7S model group (5 mg·mL^-1 7S), and V_C(25, 50, 100, 200, 400, 600, 800, 1 000 μmol·L^-1)protected groups.After cells were cultured for 24 h, cell viability was assessed by CCK-8 assay and morphological changes of cells were observed by an inverted microscope. Contents of LDH, ALP, DAO, IFABP1, IL-1β, IL-6, TNF-α, IL-4 and IL-10 in the cell supernatant were detected by ELISA assay. The relative expression of IL-1β, IL-6, TNF-α,IL-4 and IL-10 mRNA were detected by qRT-PCR. The results showed that 7S significantly (P<0.01) reduced the viability of IPEC-J2 and destroyed the integrity of cell membranes. 7S also elevated pro-inflammatory and decreased anti-inflammatory factors in cells.Compared with 7S model group, cell viability in the test group added with 7S and V_C at the same time was significantly increased, and contents of LDH, ALP, DAO, IFABP1 in cell supernatant were significantly (P<0.01) reduced. Compared with 7S model group, V_C protection groups reduced the secretion levels of cell pro-inflammatory factors IL-1β, IL-6 and TNF-α, and increased the secretion levels of anti-inflammatory factors IL-4 and IL-10. Therefore, various doses of V_C protected against intestinal epithelial cell injury in piglets induced by 7S, and 100 μmol·L^-1 V_C had the best repair and protection effect on 7S injured IPEC-J2.

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Effect of vitamin A on barrier function damage of piglet intestinal epithelial cells induced by soybean 7S globulin

YANG Ju, DENG Junliang, XIA Jiangying, SONG Tianhao, PANG Lianfeng, REN Zhihua

2021, 33(11): 2026-2033. DOI: 10.3969/j.issn.1004-1524.2021.11.04

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To explore effect of vitamin A (V_A) on barrier function damage of piglet intestinal epithelial cells (IPEC-J2) induced by soybean 7S globulin, took IPEC-J2 as the research object and soybean 7S globulin as the inducing factor, cell viability, trans-epithelial electrical resistance (TEER), permeability of sodium fluorescein, cell membrane integrity related indicators and tight junction protein mRNA expression were assessed. The results showed that 5 mg·mL^-1 soybean 7S globulin caused IPEC-J2 viability, TEER, ZO-1, Claudin-1 and Occludin mRNA expression significantly reduced (P<0.01), and permeability of fluorescein sodium, content of alkaline phosphatase (ALP), lactate dehydrogenase (LDH), diamine oxidase (DAO) and intestinal fatty acid binding protein 1 (IFABP1) in the cell culture fluid significantly increased (P<0.01). 0.1 and 1 μmol·L ^-1 V_A could significantly protect cell viability (P<0.01), 0.1-10 μmol·L^-1 V_A could significantly (P<0.05) alleviate the changes of TEER, fluorescein sodium permeability, cell membrane integrity related indicators and tight junction protein mRNA expression caused by 7S globulin; 10 000 μmol·L^-1 V_A exacerbated these effects. The results indicated that 0.1-10 μmol·L^-1 V_A could protect the cell barrier function of IPEC-J2 caused by soybean 7S globulin through protecting cell viability and cell integrity, and affecting expression of tight junction protein mRNA. However, 10 000 μmol·L^-1 V_A aggravated this damage.

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Isolation, identification and control of rabbit epidemic abdominal distension

JI Quan’an, LIU Yan, XIAO Chenwen, HUANG Ye’e, LI Ke, WEI Qiang, BAO Guolian

2021, 33(11): 2034-2040. DOI: 10.3969/j.issn.1004-1524.2021.11.05

Abstract ( 1357 )

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In order to effectively control the spread of epidemic abdominal distension in rabbits, epidemiological investigation and laboratory differential diagnosis technology were applied in the present study. Pathogen detection was carried out on 112 cases of 40-90-d-old diseased rabbits. Among them, Escherichia coli and Clostridium welchii were isolated and identified from 78 and 69 diseased rabbits, respectively. The pathogenic characteristics test showed that these two species were the main pathogens of epidemic abdominal distension in rabbits. The clinical control trials of lysozyme were carried out in 3 rabbit farms suffering from epidemic abdominal distension. It was shown that either the incidence rate in the prevention trial or the mortality rate in the control trial was lowered by 50 percentage points in the treatment group than that in the control group. The results indicated that lysozyme could prevent and treat the disease, hence effectively curb the spread of the disease. Therefore, it could be used as the substitution of antibiotics. These findings provided scientific basis for the prevention and treatment of rabbit epidemic abdominal distension.

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Screening and expression of cyclins gene in Hyriopsis cumingii

FENG Shangle, LI Xuenan, CHEN Yige, LIU Ruiqi, BAI Zhiyi, LI Wenjuan

2021, 33(11): 2041-2050. DOI: 10.3969/j.issn.1004-1524.2021.11.06

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Cyclins plays an important role in cell cycle entry and progression, they can modulate the catalytic activities of cyclin-dependent kinases (CDKs), cyclins can binding the catalytic subunits of CDKs to regulate cell cycle.To select cyclin genes in Hyriopsis cumingii, explore the function of cyclins, total RNA from mixed sample of mantle, gonad, visceral mass and hemolymph were isolated and sequenced by Illumina HiSeq 2000.Based on the sequencing results, select the cyclin A, cyclin D2, cyclin E genes, through cloning their conserved sequence to verify cyclins genes in H. cumingii. Amino acid sequence similarity analysis showed that cyclin A, cyclin D2 and cyclin E of H. cumingii have high sequence identity with Crassostrea virginica and Crassostrea gigas. At the transcriptional level, quantitative real-time PCR (qRT-PCR) was used to detect expression of cyclin genes in different tissues. The result revealed that all cyclin genes were expressed in tested tissues (adductor, foot, visceral mass, gill, heart, mantle, gonad, blood) with variable levels, expression levels of cyclin A and cyclin E genes in gonad were significantly (P<0.05) higher than those in other tissues, expression level of cyclin D2 gene in gills was significantly(P<0.05) higher than those in other tissues.Between different genders in the same tissue, there were significant(P<0.05) gender differences in the relative expression of cyclin A gene in gonad, adductor, heart and blood.In gonads and heart,there were significant(P<0.05) gender differences in cyclin D2 and cyclin E expression.Cyclin A and cyclin E genes were significantly(P<0.05)higher expressed in female hearts and gonads than those in males,indicated that cyclin A and cyclin E genes play an important role in gonad development.The high expression of cyclin D2 in gill suggested that it might be associated with gill damage repair. In this study, cyclin A, cyclin D2 and cyclin E genes and their functions were preliminarily studied, which laid a molecular basis for further regulation of the cell growth in vitro.

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Cloning and expression analysis of amLDH gene in Apis mellifera

OUYANG Xiahui, ZHENG Tianyu, XU Wenkai, ZHENG Xiangxiang

2021, 33(11): 2051-2058. DOI: 10.3969/j.issn.1004-1524.2021.11.07

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Lactate dehydrogenase (LDH) plays an important role in glycolysis and gluconeogenesis of protease. To explore the molecular characteristics and expression patterns of amLDH gene, in this study, the amLDH genes was cloned by RT-PCR, and its expression patterns of various caste, as well as at different developmental stages of Apis mellifera were analyzed. Moreover, its sequence characteristics were determined by bioinformatics methods. Sequence analysis indicated that the amLDH gene of A. mellifera contained an opening reading frame of 1 008 bp, encoding 335 amino acids, the sequence of amLDH was highly homologous to that of Apis cerana(96.4%). The amLDH had 13 phosphorylation sites and 2 functional domains of lactate dehydrogenase, which was a stable hydrophobic protein. The results of qRT-PCR indicated that the expression level of amLDH gene was of significant difference in various castes and at different developmental stages of A. mellifera(P<0.05). Expression in workers was the highest at 3 days of age in the egg stage. The highest expression in drones and queen was in 3 day-old egg and 4 day-old larvae, respectively. Expression of queen bees and drones was higher than that of worker bees from prepupa to red-eye pupa stage. The results suggested that the amLDH gene played an important role in the growth and glycolysis. This study provided a theoretical basis for exploring the function of amLDH gene in reproductive development in A. mellifera.

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Effect of different light-emitting diode (LED) light treatments on postharvest quality of chili pepper (Capsicum annum L.)

MAO Qi, YANG Youxin, FAN Feijun, WAN Hongjian, ZHOU Guozhi, YAO Zhuping, RUAN Meiying, WANG Rongqing, YE Qingjing, LI Zhimiao, CHEN Shuangchen, CHENG Yuan

2021, 33(11): 2059-2067. DOI: 10.3969/j.issn.1004-1524.2021.11.08

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In order to explore the effect of different light-emitting diode(LED) treatments on the quality of pepper fruit, white LED, red LED and blue LED were introduced in the treatment of the postharvest fruits of chili pepper P1833 (Capsicum annum L.). The results showed that white LED light treatment significantly reduced the capsaicinoid content and increased the content of chlorophyll (P<0.05) compared with the control; There was no significant difference in fruit weight and hardness between red LED light treatment and the control (darkness treatment), but protein and vitamin C content of pepper fruits were significantly higher than the control under red LED light treatment(P<0.05). Capsaicinoid content of pepper treated with blue LED light was significantly lower compared with the control, but higher than that in white LED and red LED light treatment, and vitamin C content was sharply higher than that of the control (P<0.05). In addition,the contents of total amino acids, essential amino acids for human body, essential amino acids for children and umami taste amino acids of pepper treated with blue LED light were about twice as much as those of the control group, and the nutritional value of human essential amino acids was significantly higher than the control and the other light treatments. Given the above, white LED, red LED and blue LED lights play important roles in delaying the fruit chlorosis, maintaining the marketability and increasing the nutritional value of amino acids during postharvest storage, respectively. The results of this study provided a novel idea of maintaining the quality of pepper during storage.

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Variation of acceptor splicing site of BrSPS1Fb of Chinese cabbage and its effect on splicing

TAO Peng, YUE Zhichen, ZHAO Yanting, LEI Juanli, LI Biyuan

2021, 33(11): 2068-2074. DOI: 10.3969/j.issn.1004-1524.2021.11.09

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To investigate the effect of variation of acceptor splicing site on splicing pattern and efficiency, the inbred line “He2” of Chinese cabbage was re-sequenced, and the result indicated that acceptor splicing site of the sixth intron (I6) of BrSPS1Fb-He2 was changed from AG to AC. Through analysis of BrSPS1Fb-He2 read data from transcriptome sequencing library of petals of the “He2” inbred line, it was found that alternative splicing occurred during pre-mRNA processing of BrSPS1Fb-He2. Three sites (A1, A2 and A3) of BrSPS1Fb-He2 could be selected as splicing acceptor during pre-mRNA splicing, resulting correspondingly in the three spliced isoforms (S1, S2 and S3), or the entire I6 was retained to form S4 spliced isoform. Partial I6 was retained in mature mRNA of S1 and S2, the whole I6 in S4, partial E7 was deleted in S3. This study indicated that single nucleotide polymorphisms (SNP) variation of acceptor splicing site had a significant impact on post transcriptional splicing of BrSPS1Fb.

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Effects of arbuscular mycorrhizal fungi on antioxidant enzymes activities and photosynthetic characteristics of Solanum lycopersicum L. under salt stress

ZHAO Hua, REN Qingwen, WANG Xiyu, LI Zhenni, TANG Xiumei, JIANG Lihui, LIU Peng, XING Chenghua

2021, 33(11): 2075-2084. DOI: 10.3969/j.issn.1004-1524.2021.11.10

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To explore the effects of different arbuscular mycorrhizal fungi on Solanum lycopersicum L. under salt stress, and to provide scientific basis for the establishment of the optimal symbiotic coupling system of tomato and its application to the improvement of Solanum lycopersicum L. secondary salinization planting soil, the widely planted Zhongshu No.4 tomatoes were used as experimental materials. Among the four AMFs, Diversispora versiformis (D.v) and Clariodeoglous etunicatum (C.e) with better promotion efficiency were screened as the inoculants for soil culture experiments. The effects of two kinds of arbuscular mycorrhizal fungi on antioxidant enzyme activity, malondialdehyde content, proline content, chlorophyll fluorescence parameters, photosynthetic parameters, nitrogen and phosphorus absorption of tomato were measured. The mitigation effects of two fungal agents on the salt damage of tomato were investigated in order to screen out the fungus with the best effect. The two dominant AMF fungicides had high infection rate and density, which can reduce the damage of salt stress to Solanum lycopersicum L. The results of the salt damage index showed that the salt damage index of the plants in the non-inoculated group was significantly higher than that of the inoculated group, and the salt damage index of the D.v group was the lowest, only 35.63%. With the extension of stress time, the increase of MDA content slowed down and proline (Pro) content in leaves decreased significantly, with a maximum decrease of 60.66%. The inoculation treatment could significantly improve the photosynthetic capacity of plants. After inoculation of D.v and C.e under salt treatment, F_o decreased by 18.29% and 8.94%, and the highest growth rate of F_v/F_m was 7.48%, 5.58%, and the maximum increase of P_n and G_s reached 49.12%, 35.44%. Vaccination with AMF significantly enhanced the salt resistance of the host plant. The activities of SOD, POD and CAT reached the maximum growth rate of 37.09%, 95.60% and 32.71% after D.v treatment. The results of the analysis of nitrogen and phosphorus nutrition status of each part of tomato plants showed that the promotion effect of D.v was more significant, and the total nitrogen and phosphorus contents increased by 18.79% and 14.81% compared with that of the uninocled group, and the contents of C.e were 5.49% and 8.11%, respectively. The trend of underground part was the same as that of the aboveground part. D.v and C.e obtained from the preliminary screening of four kinds of AMF could improve the adaptability of Solanum lycopersicum L. to salt stress and alleviate salt damage effect to a certain extent. Among them, D.v was the best growth-promoting strain and suitable for the large-scale production of Solanum lycopersicum L.

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Study on resistance of different tomato germplasm materials to yellow leaf curl virus disease

WANG Xian, LIU Fang, WEI Xiaohong, ZHU Xiaolin, WANG Baoqiang

2021, 33(11): 2085-2097. DOI: 10.3969/j.issn.1004-1524.2021.11.11

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Different tomato materials were inoculated with tomato yellow leaf curl virus (TYLCV) by Agrobacterium tumefaciens infiltration. Real-time quantitative PCR and physiological and biochemical methods were used to evaluate the resistance to TYLCV. The phenotypic characteristics, virus carrying rate, antioxidant enzyme activity, secondary metabolite content and resistance gene expression of tomato materials with different resistance were analyzed. The results showed that the virus infection rates of tomato materials were 100%; the tested variety 853 had no symptoms, while 802 and 803 were the most susceptible; the varieties 867, 857 and 853 had higher antioxidant enzyme activity, contents of total phenols and flavonoids, and higher resistance gene expression, followed by 817 and 842, the lowest was 803. SOD activity, CAT activity, APX activity, total phenol content, flavonoid content, Ty-1 gene, Ty-2 and Ty-3 gene expression levels were significantly positively correlated with each other (total phenol and Ty-1 showed significantly positive correlation, P<0.01). Compared with other disease resistance genes, the expression of Ty-1 was delayed after tomato plants were infected with TYLCV. The resistance genes, antioxidant enzymes, total phenols and flavonoids in plants were significantly positively correlated, which jointly improved the resistance of tomato plants to TYLCV.

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Potential distribution of Sminthurus viridis in China analyzed by BIOCLIM model

HUANG Fang, ZHANG Wenjun, ZHANG Jiancheng, ZHANG Hongying

2021, 33(11): 2098-2103. DOI: 10.3969/j.issn.1004-1524.2021.11.12

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DIVA-GIS software combined with BIOCLIM ecological niche model was used to predict the habitat of Sminthurus viridis in China. The potential distribution of S. viridis in China was mapped by establishing a dataset of distributed points, screening for major influences and BIOCLIM model prediction. The results showed that S. viridis could colonize the entire North China Plain, the southern part of the Northeast Plain, the Yunnan-Guizhou-Sichuan region in the southwest, and the northern part of South China. The highly habituated areas were in the middle and lower reaches of the Yangtze River and the Yellow River, involving six provinces, i.e. Sichuan, Gansu, Ningxia, Shaanxi, Hubei and Anhui. In view of the high risk of invasion of S. viridis, the inspection and quarantine of this pest should be strengthened, especially vigilant against its entry into China with imported grain.

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Effects of solid-digestate biochar application on soil nitrogen leaching and cabbage yield with liquid-digestate irrigation in karst-mountainous region of southwest China

JIANG Tao, WANG Liguo, SUN Fangfang, CHENG Jianbo, HE Tengbing, QIN Song, FAN Chengwu, YIN Wenfang

2021, 33(11): 2104-2115. DOI: 10.3969/j.issn.1004-1524.2021.11.13

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In order to explore the effects of solid-digestate (SD) biochar application on soil nitrogen (N) leaching and cabbage yield with liquid-digestate irrigation in the karst-mountainous region of southwest China, a pot experiment was performed in a greenhouse to simulate liquid-digestate irrigation, and SD biochar was incorporated into either yellow soil or calcareous soil at the rates (mass fraction) of 0 (CK), 1% (BC1), 2% (BC2), 4% (BC4), and 6% (BC6), respectively.It was shown that no significant effects of biochar application on N leaching and cabbage N uptake were measured in yellow soil. However, in calcareous soil, the leaching of total nitrogen, $NH 4 +$ -N, $NO 3 -$ -N, and $NO 2 -$ -N were lowered by 12.06 kg·hm^-2 (equivalent to 35.89%), 11.82 kg·hm^-2 (equivalent to 52.99%), 1.14 kg·hm^-2 (equivalent to 25.53%), 0.103 kg·hm^-2 (equivalent to 23.25%), respectively, under BC6 treatment as compared with CK. The N uptake of cabbage was increased by 9.25-19.13 kg·hm^-2 with SD biochar application, and the highest N uptake was found in the BC6 treatment, which was 60.15 kg·hm^-2. The yield of cabbage was increased by 29.82%-68.78%, 23.58%-79.07% in the yellow soil and calcareous soil, respectively, and the highest yield in the yellow soil and calcareous soil was recorded under BC4 and BC6 treatment, respectively, which was 13.81, 9.01 t·hm^-2, respectively.

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Phenological period identification of oilseed rape based on time-series PolSAR image and decision tree model

LI Shitao, ZHANG Wangfei, ZHAO Lixian, WANG Xiyuan

2021, 33(11): 2116-2127. DOI: 10.3969/j.issn.1004-1524.2021.11.14

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Crop phenological period identification plays an important role in agricultural condition monitoring. Timely and accurate crop phenological period identification is of great significance for evaluating crop growth trend and improving the agricultural information management level effectively.In this study, we selected oilseed rape as an example and proposed a crop phenological period identification method through polarimetric synthetic aperture radar (PolSAR) data and decision tree algorithms. First, polarimetric SAR parameters were extracted through three popular polarimetric decomposition methods. Their dynamic responses to oilseed rape phenological periods were also analyzed. Then, the parameters extracted by the three polarimetric decomposition methods were used to train and validate the decision tree models, five oilseed rape phenological periods were identified. Finally, confusion matrices were used to verify feasibility of the constructed decision models.The results showed that polarimetric SAR decomposition parameters, including scattering angle(Alpha), eigenvalue(L2, L3), pseudo-entropy(P2) and target azimuth (Beta1) parameters from H/A/alpha decomposition method; ground scattering (Ground) and odd scattering (Odd) parameters from Freeman-Durden decomposition method; odd scattering (Odd_Y) and helix scattering (Helix) parameters from Yamaguchi decomposition method showed great sensitivity to changes of oilseed rape phenological period.The decision tree models were more accurate to classify the phenology of rapeseed. Among the results, primitive decision tree model established based on the combination of extracted parameters from three polarimetric decomposition methods had the highest classification accuracy, the overall classification accuracy was 94%. The results also showed the sensitivity of PolSAR parameters to phenological changes of oilseed rape and the effectiveness of decision tree model in identification of oilseed rape phenological period.

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Optimization of “terpenoids removing and aroma enhancing” process for grapefruit essential oil

YANG Ying, SHI Yingchun, XING Jianrong, LIU Zhe, ZHENG Meiyu, LU Shengmin

2021, 33(11): 2128-2136. DOI: 10.3969/j.issn.1004-1524.2021.11.15

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Limonene, the main component of grapefruit essential oil, is easy to be oxidized and presents a peculiar smell, which will affect the shelf life and aroma profile. In this study, molecular distillation technology was adopted to partially remove the limonene from raw oil and prepare highly concentrated essential oil. Molecular distillation process was optimized using central composite design with temperature and pressure as variables. Limonene contents in distillated fraction (Y₁), limonene contents in residual concentrated fractions (Y₂), linalool (Y₃) and decanal (Y₄) in residual concentrated fractions were set as response values. The concentrations of limonene, linalool, and decanal were determined by GC. The results of response surface analysis indicated that Y₂, Y₃ and Y₄ were significantly affected by temperature and pressure, the optimized conditions were 44.89 ℃ for temperature and 500 Pa for pressure, under which the predicted values of Y₁, Y₂, Y₃ and Y₄ were 94.84%, 49.75%, 1.63% and 2.39%, respectively. Further verification experiments confirmed the validity of the predicted model (Y₁, Y₂, Y₃ and Y₄ values were 94.89%, 49.72%, 1.59% and 2.34%, respectively). The color of concentrated oil was dark brown and its odor was much more mellow, richer and softer than that of raw oil. Total content of oxygenated compounds increased from 3.41% to 29.31%, which indicated that 8.6 folds concentrated grapefruit essential oil was obtained through molecular distillation. This study can provide a reference for the concentration of other citrus essential oils.

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Development of dietary fiber pork floss for children

LU Wenjing, CHEN Di, YE Qin, CHEN Yidan, ZHAO Wensheng, XIAO Chaogeng

2021, 33(11): 2137-2144. DOI: 10.3969/j.issn.1004-1524.2021.11.16

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In the present study, pork ham, citrus fiber and carrot powder were used as raw materials to develop dietary fiber pork floss for children. With the sensory score as the indicator, the effects of cooking pressure, cooking time, frying time on the quality of pork floss were examined. The process formula was also optimized via the orthogonal optimization test. Based on this, the addition amount of citrus fiber and carrot powder was determined by comprehensive evaluation of fat content, dietary fiber content and sensory score. It was shown that the optimized process formula was as follows: cooking pressure of 40 kPa, cooking time of 40 min, frying time of 50 min. After frying, 4 g citrus fiber and 10 g carrot powder could be added into the 100 g products to produce dietary fiber pork floss for children. Under this condition, the produced pork floss was golden yellow, flocculent, soft and easy to chew, moderately salty and sweet, with fat content of 13.1% and dietary fiber content of 3.54%.

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Optimization of ultrasonic extraction technology of Shisandra lignans and its anti-oxidant and anti-fungi potentials

LI Qisi, WANG Yaling, DENG Yuhua, LIAO Jianmeng, YE Lin, WU Lili, ZHENG Jiachun, LUO Xingyan, DENG Qi, SUN Lijun

2021, 33(11): 2145-2154. DOI: 10.3969/j.issn.1004-1524.2021.11.17

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To explore the suitable ultrasonic extraction technology of Schisandra lignans and its inhibitory effect against oxidant and dominant fungi in dried aquatic products, a synchronous detection methods for 5 kinds of lignans was established via LC-MS/MS (liquid chromatography-tandem mass spectrometry). On the basis, four single-factor tests, and the central composite response surface test were adopted to optimize the ultrasonic extraction parameters of Schisandra lignans, and the anti-oxidant and anti-fungi activities of Schisandra lignans were analyzed. It was shown that the suitable extraction parameters included ethanol volume fraction of 70%, liquid to material ratio of 12 mL·g ^-1, extraction times of twice, and ultrasound time of 10 min per time. Under this condition, the extraction amount of lignans was (9.45±0.11) mg·g^-1. The total reducing power, and DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS [2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)] free radical scavenging ability of Schisandra lignans were 2/5, 1/2 and 1/3 of vitamin C (V_C), respectively. The minimum inhibitory concentration (MIC) of Schisandra lignans against Aspergillus flavus, Aspergillus niger, Penicillium citrinum, Fusarium oxysporium, Fusarium chlamydosporum was about 1.17 mg·mL ^-1, and the MIC of Schisandra lignans against Trichoderma harzianum, Penicillium expansum, Fusarium solani was about 2.34 mg·mL ^-1, which indicated that the extracted Schisandra lignans had strong inhibitory effect against oxidant and dominant fungi in dried aquatic products.

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Preliminary study on measuring rice seed respiration based on TDLAS technology

ZHENG Wen, JIA Liangquan, QI Hengnian, WANG Ruiqin, ZHAO Guangwu, YUAN Jun

2021, 33(11): 2155-2163. DOI: 10.3969/j.issn.1004-1524.2021.11.18

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To explore the correlation between rice seed respiration intensity and various vitality indicators, and to provide experimental basis for non-destructive testing of seed vitality through respiratory intensity measurement, a self-designed seed respiration detection system based on tunable diode laser absorption spectroscopy (TDLAS) was used, real-time changes in the concentration of CO₂ produced by seed respiration were detected. The rice seeds of Mengliangyou huanglizhan at different harvest periods were selected as the materials. The seeds in each harvest period were divided into two parts. One part was subjected to a germination test to obtain seed vigor index, and the other part was sterilized and soaked before pretreatment. The respiration intensity test was carried out in a closed environment in the seed respiration container. Each continuous test was about 10 hours, and each group of samples was repeated three times to get the average value. Rice seeds were soaked for 0, 12, 24, 36, 48 h, and it was found that the respiration intensity of the seeds increased with the soaking time within a certain soaking time. After 10 hours of continuous testing, the immersion time period with the highest respiratory intensity was 36 h, and the CO₂ concentration reached 10 151 mg·m^-3. The unsoaked dry seeds had the weakest respiratory intensity, with a CO₂ concentration of 388 mg·m^-3. Rice seed respiration intensity had a certain correlation with germination rate, germination vigor, germination index, three-day flooding germination rate, and field emergence rate. The highest correlation index could reach 0.97, 0.96, 0.97, 0.77 and 0.65. Studies showed that Mengliangyou huanglizhan rice seeds could reach a high respiration intensity after soaking for about 36 hours, and the respiration intensity increased first and then slowed down with the increase of respiration time. The respiration intensity of seeds had a high positive correlation with each vitality index.

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Hyperspectral retrieval for chlorophyll contents of Syringa oblata leaves based on RF-VR

XIAO Zhiyun, WANG Yining

2021, 33(11): 2164-2173. DOI: 10.3969/j.issn.1004-1524.2021.11.19

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Accurate estimation of the chlorophyll content of plant leaves by using hyperspectral technology is of great significance to monitor and manage plant growth trends and nutritional status. Taking Syringa oblata as the research object, aiming at the phenomenon that the large number of bands and strong correlation between bands lead to the increase of redundant information in the data, the spectral data were processed by convolution smoothing and second-order differentiation (SG-SD), the random leapfrog (RF) algorithm was used to screen the characteristic bands, and finally combined with partial least squares (PLSR) and voting regression (VR). The inversion model of chlorophyll content in plant leaves was established and compared with full band spectroscopy and five classical variable extraction methods. The results showed that compared with the original spectral data, SG-SD was an effective spectral pretreatment method to improve modeling accuracy; compared with full-band spectrum and 5 classical variable selection methods, the sensitive bands selected by the RF algorithm had the best modeling accuracy; compared with PLSR model, the prediction accuracy and stability of the VR model were better. In the present paper, after the SG-SD pretreatment of the original spectral data, a VR model was established for the sensitive bands selected by the RF algorithm, the variable number reduced from 204 to 35, the determination coefficients of modeling set and validation set were 0.944 2 and 0.951 4 respectively. Finally, using RF-VR model and pseudo color map technology, the inversion map of chlorophyll distribution of Syringa oblata leaves was obtained, which provided more intuitive information expression for nutrient distribution of Syringa oblata leaves. It was concluded that this method could provide technical support for the diagnosis and growth monitoring of the nutrient content of Syringa oblata leaves.

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Optimum design of precise root cutting mechanism based on characteristics of garlic root disk

CHEN Jianneng, ZHOU Yun, JIA Jiangming, CHEN Tianlong, CAI Shuanglei, YU Chennan

2021, 33(11): 2174-2184. DOI: 10.3969/j.issn.1004-1524.2021.11.20

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To achieve the precise root cutting of the garlic after cutting fiber to reduce the waste, a garlic precise root cutting mechanism was proposed. The design of this mechanism was based on the ideal root cutting locus, which was got from analysis of the root disk characteristics of garlic with a diameter range of 42 mm to 56 mm. The precise root cutting mechanism was designed, kinematics analysis model of the mechanism was established, root cutting mechanism analysis software was written, and influence of several key parameters on the root cutting effect was analyzed. Characteristics of the ideal root disk was taken as the goal, the optimization objective function of the root cutting mechanism parameters was established, and the optimal mechanism parameters that meet the requirements of the root cutting locus were got. Structure design of the root cutting mechanism and the whole root cutting machine was completed according to the best parameters, and development and test of the whole garlic root cutting machine were also accomplished. The test result was basically consistent with the ideal root cutting locus, which verified the rationality of garlic root cutting mechanism and correctness of the optimal design. The test showed that when conveyor line speed was 0.15 m·s^-1 and root cutting motor speed was 65 r·min^-1, success rate of garlic root cutting reached 86%, and garlic loss rate was 8.01%. Efficiency of root cutting machine could reach 100 heads per minute, which met the garlic processing requirements on the market.

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Analysis of agricultural intermediate input greenhouse gas emissions and emission reduction potential in China

ZHEN Wei, ZHUANG Hongyuan, MI Songhua

2021, 33(11): 2185-2194. DOI: 10.3969/j.issn.1004-1524.2021.11.21

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By using the multi-regional input-output analysis, the agricultural intermediate input greenhouse gas (GHG) emissions in 30 provincial regions of China (Hong Kong, Macao, Taiwan and Tibet excluded ) in 2007 and 2017 were measured. The crucial source sectors and crucial intermediate sectors for agricultural intermediate input GHG emissions were identified and their reduction potentials were further revealed. It was shown that the agricultural intermediate input GHG emission accounted for 73.9%-89.5% of agricultural embodied GHG emissions in 2007-2017. Thirteen crucial source sectors and 13 crucial intermediate sectors for agricultural intermediate input GHG emissions were identified in 2007 and 2017, respectively. The distribution of these identified sectors exhibited decentralization trend. Based on the data of 2017, the 13 crucial source sectors had greater emission reduction potential than that of the 13 crucial intermediate sectors.

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Yield-increasing effect of grain total factor productivity in China from 2008 to 2018 based on dynamic space Durbin model

LUO Haiping, HE Zhiwen, LI Zhuoya

2021, 33(11): 2195-2204. DOI: 10.3969/j.issn.1004-1524.2021.11.22

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In the present study, the yield-increasing effect of grain total factor productivity at provincial level in China (Hong Kong, Macao, Taiwan excluded) from 2008 to 2018 was empirically measured based on the dynamic spatial Durbin model. It was shown that the grain total factor productivity increased steadily from 1.024 in 2008 to 1.156 in 2018 in China, and the number of high-efficiency production regions increased from 0 in 2008 to 11 in 2018, but the “Matthew effect” emerged in the process of improvement. The rise in grain total factor productivity could significantly contribute to the increase of grain yield, and its effect was second to the sown area of grains. At the national level, the increase in grain total factor productivity in the neighboring region brought a significant positive spillover effect to the local region. From the spatial structure, the spillover effect of grain total factor productivity showed significant spatial heterogeneity, with a significant negative spillover effect in the central China, a positive spillover effect in west China, and no significant spillover effect in east China.

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Progress of wheat blast and blast resistance gene in wheat

WANG Shizhen, WANG Jiaoyu, WANG Yanli, SUN Guocang

2021, 33(11): 2205-2212. DOI: 10.3969/j.issn.1004-1524.2021.11.23

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Wheat blast, caused by Pyricularia oryzae (syn.Magnaporthe oryzae), had an outbreak in Brazil in 1985 and spreaded to neighboring countries soon. In 2016 and 2017, a severe outbreak happened in Bangladesh and India, respectively, whcih has caused severe impacts on local wheat yield and economics. There is no effective controlling measure at present, thus breeding for resistance is an alternative, environmentally friendly method to control blast disease. And we found the MoO pathotype of P.oryzae could infect wheat via lab inoculation. In this paper, we deem that wheat blast did not been found in China yet, but China is at increased risk for the overwhelming wheat blast since global warming continues. Thus we still need to pay great attention to it, and we should strengthen cooperation and communication with international wheat blast researchers. In addition, we also introduce inoculated methods to identify resistance genes in both seedling and heading stages, which will contribute to identification of resistance genes in wheat accessions of China, providing a reference for resistance breeding and further researches.

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