Acta Agriculturae Zhejiangensis

Effects of reduced chemical nitrogen and organic manure substitution on potato root morphology and yield

HAN Tiqian, LIU Zhen, LIU Yuhui, ZHANG Xiaojing, WANG Li, ZHANG Junlian

2020, 32(12): 2111-2118. DOI: 10.3969/j.issn.1004-1524.2020.12.01

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Field experiments were conducted to study the effects of reduced chemical nitrogen and organic manure substitution on root growth in different developmental stages and yield of potato in the semi-arid area under film drip irrigation, in order to provide an efficient nitrogen management method in the cultivation of potato. Potato cultivar Qingshu9 was used in the test. The conventional N rate of 225 kg·hm^-2 was used as the control (CK), 70% chemical nitrogen fertilizer (RN) and 50% chemical nitrogen fertilizer (LN) were set up for reduced chemical nitrogen application treatments, and 80% chemical nitrogen fertilizer+20% organic nitrogen manure (LO) and 60% chemical nitrogen fertilizer+40% organic nitrogen manure (HO) were set up for organic manure substitution application treatments. The results showed that compared with CK, the number of tuber per plant, medium tuber rate and small tuber rate did not change significantly under RN treatment, however, the large tuber rate was decreased by 0.32 percent points and the yield were decreased by 10.93%. The number of tuber per plant were increased by 11.77%, the large tuber rate and medium tuber rate were increased by 0.43 and 6.47 percent points under HO treatment, respectively, and the yield was increased by 19.01%. The potato root under HO treatment had longer root length, larger projected root area, root volume, more tips and forks during the tuber initiation stage, and more tips during the tuber bulking stage compared with CK. The yield was significantly (P<0.01) positively related to the root length during the seedling, tuber bulking and starch formation stage, and the root surface area, the root volume, the number of tips and the number of forks during the tuber bulking stage. Therefore, 90 kg·hm^-2 organic nitrogen and 81 kg·hm^-2 chemical nitrogen as base fertilizers, and 54 kg·hm^-2 chemical nitrogen as topdressing in the tuber formation stage could improve the root growth effectively, promote the formation of effective tuber during the early growth stage, increase the number of tuber per plant and the expansion of tubers, and thus produce a higher yield of potato.

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Breeding potential analyses of 13 new inbred lines in maize

ZHAO Xingkai, SHI Haichun, YU Xuejie, YANG Shu, ZHAO Changyun, XIA Wei, KE Yongpei

2020, 32(12): 2119-2127. DOI: 10.3969/j.issn.1004-1524.2020.12.02

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In order to clarify the breeding potential of new inbred lines, genetic diversities of 13 new inbred lines, eight elite inbred lines and five standard inbred lines were studied by agronomic character identification and SSR markers. 210 combinations were obtained according to Griffing method IV, and the combining ability and heterosis of yield were analyzed. The results showed that K351 and K311 were new inbred lines with good agronomic traits per se. By using genetic similarity coefficient of 0.696 as the threshold, 26 inbred lines were divided into eight groups including five common groups and three new groups by unweighted pair-group method with arithmetic means (UPGMA), in which ten new inbred lines such as K115 were divided into three new groups. Six new inbred lines including K61 had significantly (P<0.05) positive general combining ability (GCA) effect of yield, higher than that of the most of elite inbred lines. There were 18 and three combinations with yield increase over CK significantly (P<0.05) in experiment site of Shuangliu, Sichuan and Xuanwei, Yunnan, respectively, in which K61 × K143 and 21-ES ×K61 had significant (P<0.05) yield increase at both sites, with an average increase of 33.16% and 22.81%, respectively. In summary, the new inbred lines K61, K143 and K115 had the highest GCA of yield and good agronomic traits, in which K61 and K115 were novel germplasms, they were ideal parents for high-yield breeding. K311, K962 and K365 had the higher GCA of yield and good agronomic traits, which had the potential for high-yielding breeding, however, the plant height needed to be further improved as they were kind of the higher plants.

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Effects of different LED light colors on estrus synchronization of rabbits and their molecular regulation mechanism through retina-pineal gland pathway

PAN Xiaoqing, WANG Xinglong, YANG Jie, SHAO Le, QIN Feng, LI Jian, ZHANG Xia, ZHAI Pin

2020, 32(12): 2128-2137. DOI: 10.3969/j.issn.1004-1524.2020.12.03

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To elucidate the molecular mechanism of monochromatic light on estrus in rabbits from the perspectives of behavior, vision and endocrine, the behavioral observation experiment was performed in an artificial light control room. A 6 m×6 m square slotted wooden floor platform was surrounded by open-door rabbit cages in a round shape. Six rabbit cages were placed on each side. Conventional nipples were placed in the cage. Drinking fountains and troughs, with LED strips installed 60cm above each side of the rabbit cage, projecting LED red (660 nm), green (540 nm), blue (480 nm), and white (400~760 nm) light down, the light intensity was 100 lx, and the duration was 12 h. The LED strip position was adjusted randomly once a week to ensure that the LED light color became the only variable. The camera recorded the selective stay behavior of female rabbits. In the light color test, 300 reserve female rabbits reared in a single cage under different LED light colors were randomly divided into 5 groups at random, with 3 repetitions in each group and 20 repetitions in each. LED red light (660 nm), LED green light (540 nm), LED blue light (480 nm) and LED white light (400-760 nm) were projected downward 60 cm above the rabbit cage. The control group was incandescent (400-1 050 nm). Female rabbits received supplementary light from Friday to Sunday evening from 18:00 to 06:00 the next day in the formal experiment, the duration was 12 h, with 7 d pre-experiment and 90 d positive trial period. The light intensity was 100 lx. Different LED light colors can affect the choice of the female rabbit’s activity space. The red LED environment was more easily accepted and stayed by the female rabbit. The frequency of stay was 13.1% and 11.6% higher than that of the LED green light and LED blue light, respectively. The concentrations of β-EP and 5-HT in the serum of reserve young female rabbits in LED red light and incandescent lamp groups were significantly higher than those in LED green light group and LED blue light group (P<0.05). Cortisol concentration in LED red light environment was significantly higher than that in LED green light group (P<0.05). Compared with the incandescent control group and the LED white light group, the estrus rate of female rabbits in the LED red light group increased by 20.89% and 10.51%, respectively, with significant differences (P<0.05). The expression of Opn4 gene in the retina of female rabbits in LED red light group was significantly higher than that in incandescent light group and LED green light group (P<0.05). Different LED light colors had an effect on the serum MLT content of female rabbits in a specific period of time (23:00—00:30). Compared with the LED green light group, the female rabbit serum MLT content in the red light group environment was 10.32% lower with a significant difference (P<0.05). Compared with LED white light, LED red light significantly inhibited the expression of Aanat mRNA in pineal cones (P<0.05). The expression of Mel1a mRNA in pineal gland of female rabbits in LED red light group was significantly higher than that in LED green light group and blue light group (P<0.05). During the periodical breeding and production of short-day sunshine in large-scale rabbit farms, three consecutive times per week, between 18:00—06:00, the use of 100 lx LED red light to supplement light can improve female estrus synchronization. LED red light can affect rabbit behavior and estrus synchronization through Opn4-MLT pathway.

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Effects of different LED light colors on estrus synchronization of rabbits and their molecular regulation mechanism through retina-pineal gland pathway

PAN Xiaoqing, WANG Xinglong, YANG Jie, SHAO Le, QIN Feng, LI Jian, ZHANG Xia, ZHAI Pin

2020, 32(12): 2128-2137. DOI: 10.3969/j.issn.1004-1524.2020.12.03

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To elucidate the molecular mechanism of monochromatic light on estrus in rabbits from the perspectives of behavior, vision and endocrine, the behavioral observation experiment was performed in an artificial light control room. A 6 m×6 m square slotted wooden floor platform was surrounded by open-door rabbit cages in a round shape. Six rabbit cages were placed on each side. Conventional nipples were placed in the cage. Drinking fountains and troughs, with LED strips installed 60cm above each side of the rabbit cage, projecting LED red (660 nm), green (540 nm), blue (480 nm), and white (400~760 nm) light down, the light intensity was 100 lx, and the duration was 12 h. The LED strip position was adjusted randomly once a week to ensure that the LED light color became the only variable. The camera recorded the selective stay behavior of female rabbits. In the light color test, 300 reserve female rabbits reared in a single cage under different LED light colors were randomly divided into 5 groups at random, with 3 repetitions in each group and 20 repetitions in each. LED red light (660 nm), LED green light (540 nm), LED blue light (480 nm) and LED white light (400-760 nm) were projected downward 60 cm above the rabbit cage. The control group was incandescent (400-1 050 nm). Female rabbits received supplementary light from Friday to Sunday evening from 18:00 to 06:00 the next day in the formal experiment, the duration was 12 h, with 7 d pre-experiment and 90 d positive trial period. The light intensity was 100 lx. Different LED light colors can affect the choice of the female rabbit’s activity space. The red LED environment was more easily accepted and stayed by the female rabbit. The frequency of stay was 13.1% and 11.6% higher than that of the LED green light and LED blue light, respectively. The concentrations of β-EP and 5-HT in the serum of reserve young female rabbits in LED red light and incandescent lamp groups were significantly higher than those in LED green light group and LED blue light group (P<0.05). Cortisol concentration in LED red light environment was significantly higher than that in LED green light group (P<0.05). Compared with the incandescent control group and the LED white light group, the estrus rate of female rabbits in the LED red light group increased by 20.89% and 10.51%, respectively, with significant differences (P<0.05). The expression of Opn4 gene in the retina of female rabbits in LED red light group was significantly higher than that in incandescent light group and LED green light group (P<0.05). Different LED light colors had an effect on the serum MLT content of female rabbits in a specific period of time (23:00—00:30). Compared with the LED green light group, the female rabbit serum MLT content in the red light group environment was 10.32% lower with a significant difference (P<0.05). Compared with LED white light, LED red light significantly inhibited the expression of Aanat mRNA in pineal cones (P<0.05). The expression of Mel1a mRNA in pineal gland of female rabbits in LED red light group was significantly higher than that in LED green light group and blue light group (P<0.05). During the periodical breeding and production of short-day sunshine in large-scale rabbit farms, three consecutive times per week, between 18:00—06:00, the use of 100 lx LED red light to supplement light can improve female estrus synchronization. LED red light can affect rabbit behavior and estrus synchronization through Opn4-MLT pathway.

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Construction of prokaryotic expression vector of chicken Prnp gene and expression in Escherichia coli

LI Xianchun, LU Yan, MAO Yaofang, YANG Haifeng, YU Haishan, MA Yonghua1, WAN Xuerui

2020, 32(12): 2138-2146. DOI: 10.3969/j.issn.1004-1524.2020.12.04

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In order to construct the prokaryotic expression vector of chicken Prnp gene and express it in Escherichia coli, and to provide materials for the preparation of monoclonal antibodies against chicken prion protein, primers were designed according to chicken Prnp genome sequence reported by GenBank and the polyclonal site of pET-28a plasmid. Using healthy chicken whole blood genomic DNA as material, the Prnp gene of chicken was amplified by PCR. The target gene fragment was connected with pET-28a vector to construct recombinant prokaryotic expression vector. The recombinant bacteria were transformed into E. coli BL21(DE3) competent cells and induced by isopropyl-β-D-thiogalactoside (IPTG). The expressed recombinant protein was identified by SDS-PAGE. The results showed that the expression of recombinant protein was the highest at the final inducer concentration of 0.08 mmol·L ^-1, 16 ℃, 220 r·min^-1 for 7 hours. To sum up, the recombinant expression strain of pET-28a-ChPrnp was successfully constructed in this study, which provides a method for the study of the structure, physiological function and pathogenic mechanism of Prnp prion protein.

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Effect of porcine OLR1 gene on intramuscular preadipocytes differentiation

QIAO Mu, HUANG Cangyu, WU Junjing, WU Huayu, WAN Xuling, ZHOU Jiawei, LIU Guisheng, MEI Shuqi, PENG Xianwen1

2020, 32(12): 2147-2153. DOI: 10.3969/j.issn.1004-1524.2020.12.05

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The aim of this study was to investigate the role of oxidized low density lipoprotein receptor 1 (OLR1) gene in the differentiation of porcine preadipocytes, and to lay a foundation for further study of the function of OLR1 gene in fat deposition. According to the sequence of OLR1 gene in GenBank (GenBank No.: NM_213805), the over expression vector of OLR1-pcDNA3.1 was constructed and OLR1-siRNA was synthesized. Preadipocytes were isolated from the longissimus dorsi muscle of Enshi black pig. OLR1-pcDNA3.1 and OLR1-siRNA were transferred into the preadipocytes respectively. The cells were induced to differentiate to the 6th day. Then, oil red O staining, triglyceride content detection and fluorescence quantitative PCR were used to detect the effect of OLR1 gene on the preadipocyte differentiation. The results showed that the number of lipid droplets in the overexpression group was significantly(P<0.05) higher than that in the control group, the triglyceride content was significantly increased (P<0.05), and the expression levels of PPARγ, C/EBPα and FAS were significantly increased at P<0.01, P<0.05 and P<0.05 level, respectively. In contrast, after knock down OLR1 gene, the intracellular lipid droplets and triglyceride content were significantly decreased (P<0.05), and the expression of adipogenic differentiation marker genes PPARγ, C/EBPα and FAS were significantly decreased at P<0.01, P<0.05 and P<0.05 level, respectively. In conclusion, OLR1 gene could promote the adipogenic differentiation of preadipocyte.

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Analysis on phenotypic traits of red claw crayfish (Cherax quadricarinatus von Martens) in different growth stages

CHEN Honglin, QIN Gaochan, LOU Bao, QIAN Haojie, YAO Zhenhai

2020, 32(12): 2154-2161. DOI: 10.3969/j.issn.1004-1524.2020.12.06

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In order to study the phenotypic characteristics of red claw crayfish (Cherax quadricarinatus von Martens) in different growth stages, nine phenotypic traits including body weight (Y₁), hepatopancreas weight (Y₂), full-length (X₁), cephalothorax length (X₂), cephalothorax width (X₃), total abdominal segment length (X₄), first abdominal segment length (X₅), first abdominal segment width (X₆), propodite length (X₇) in three growth stages of 3 months, 4.5 months and 6 months were measured and analyzed. The differences of the phenotypic traits in the three stages were compared, and the correlations of the phenotypic traits in different growth stages were analyzed. Multiple regression equations of phenotypic traits to body weight of male and female red claw crayfish populations in different growth stages were constructed to measure the relevance of phenotypic traits and body weight. The results showed that the proportion of cephalothorax or abdominal segments to full-length remained the same in juvenile and adult stage, while the width index increased significantly (P<0.05) at 6 months of age. With the growth of red claw crayfish, the correlations among the majority of the traits decreased, and the differences in phenotypic characteristics between male and female populations gradually increased. The regression equation in 3 months of age was Y₁=-31.33+0.73X₂+0.91X₃. The regression equation in 4.5 months of age was Y₁=-65.25+1.29X₃+0.89X₄+1.46X₆ for female and Y₁=-69.67+1.17X₃+0.40X₇+1.77X₆+0.59X₄ for male, respectively. The regression equation in 6 months of age was Y₁=-79.77+1.01X₁-1.89X₆+1.15X₇ for female and Y₁=-98.02+0.72X₁+1.22X₇ for male, respectively. These results could provide theoretical basis for the selective breeding of red claw crayfish.

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Response of leaf water status, photosynthetic and fluorescence parameters to different irrigation lower limits in substrate culture of cucumber

JIN Ning, LYU Jian, YU Jihua, JIN Li, ZHANG Guobin, XIAO Xuemei, HU Linli

2020, 32(12): 2162-2172. DOI: 10.3969/j.issn.1004-1524.2020.12.07

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In order to find out the suitable lower limit of irrigation and realize agricultural water-saving, the cucumber variety Bote 209 was used as material in this experiment, and four irrigation water limit treatments were set in potted medium, 50%, 60%, 70%and 80% of field water holding capacity, which were represented by A, B, C and D, respectively. The upper limit of irrigation was set to 90% of field water holding capacity. TDR350 water velocimeter was used to control the water content of the substrate.The effects of different irrigation lower limit on water status, diurnal variation of photosynthesis and fluorescence parameters of cucumber leaves were studied.The results showed that the relative water content, free water content and free water/bound water of leaves increased gradually with the increase of irrigation lower limit, while the water saturation deficit, leaf cell sap concentration and bound water content showed a reverse trend.The relative water content and free water content of treatment C and D were significantly (P<0.05) higher than those of treatment A and B.The leaf cell sap concentration of treatment A was significantly(P<0.05) higher than those of treatment C and D, and the bound water content of treatment A and B was significantly (P<0.05)higher than treatment C and D. The content of chlorophyll a, chlorophyll b and chlorophyll a+b increased firstly and then decreased with the increase of irrigation lower limit, while the content of carotenoids decreased firstly and then increased. The content of chlorophyll a and chlorophyll a+b in treatment C was significantly(P<0.05)higher than that in treatment A and B.The change trend of C_i in treatment C and D was showed as V-shape, while that in treatment A and B was W-shaped.T_r in treatment A, B, C, D firstly increased and then declined, which showed a trend of gradually declining after 14:00 in treatment B, C, D, and a trend of rapid decline after 12:00 in treatment A. G_s showed a double peak curve of “M” type in treatment B, C, D, and a single peak curve in treatment A. The change trend of P_n in treatment A, B, C, D leaves were similar as G_s. During the whole process of daily change, P_n in treatment C and D were always higher than that in treatment A and B. F_v/F_m, Φ_PSⅡ, qP increased with the increase of irrigation lower limit, while NPQ decreased.It was concluded that the lower limit of irrigation was 70%-80% of the field water capacity. In this range, the water content of cucumber leaves under substrate cultivation was good, the content of photosynthetic pigment was high, and the net photosynthetic rate was high, which was beneficial to the photosynthesis and the growth and development of cucumber.

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Response of leaf water status, photosynthetic and fluorescence parameters to different irrigation lower limits in substrate culture of cucumber

JIN Ning, LYU Jian, YU Jihua, JIN Li, ZHANG Guobin, XIAO Xuemei, HU Linli

2020, 32(12): 2162-2172. DOI: 10.3969/j.issn.1004-1524.2020.12.07

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In order to find out the suitable lower limit of irrigation and realize agricultural water-saving, the cucumber variety Bote 209 was used as material in this experiment, and four irrigation water limit treatments were set in potted medium, 50%, 60%, 70%and 80% of field water holding capacity, which were represented by A, B, C and D, respectively. The upper limit of irrigation was set to 90% of field water holding capacity. TDR350 water velocimeter was used to control the water content of the substrate.The effects of different irrigation lower limit on water status, diurnal variation of photosynthesis and fluorescence parameters of cucumber leaves were studied.The results showed that the relative water content, free water content and free water/bound water of leaves increased gradually with the increase of irrigation lower limit, while the water saturation deficit, leaf cell sap concentration and bound water content showed a reverse trend.The relative water content and free water content of treatment C and D were significantly (P<0.05) higher than those of treatment A and B.The leaf cell sap concentration of treatment A was significantly(P<0.05) higher than those of treatment C and D, and the bound water content of treatment A and B was significantly (P<0.05)higher than treatment C and D. The content of chlorophyll a, chlorophyll b and chlorophyll a+b increased firstly and then decreased with the increase of irrigation lower limit, while the content of carotenoids decreased firstly and then increased. The content of chlorophyll a and chlorophyll a+b in treatment C was significantly(P<0.05)higher than that in treatment A and B.The change trend of C_i in treatment C and D was showed as V-shape, while that in treatment A and B was W-shaped.T_r in treatment A, B, C, D firstly increased and then declined, which showed a trend of gradually declining after 14:00 in treatment B, C, D, and a trend of rapid decline after 12:00 in treatment A. G_s showed a double peak curve of “M” type in treatment B, C, D, and a single peak curve in treatment A. The change trend of P_n in treatment A, B, C, D leaves were similar as G_s. During the whole process of daily change, P_n in treatment C and D were always higher than that in treatment A and B. F_v/F_m, Φ_PSⅡ, qP increased with the increase of irrigation lower limit, while NPQ decreased.It was concluded that the lower limit of irrigation was 70%-80% of the field water capacity. In this range, the water content of cucumber leaves under substrate cultivation was good, the content of photosynthetic pigment was high, and the net photosynthetic rate was high, which was beneficial to the photosynthesis and the growth and development of cucumber.

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Identification and expression analysis of grape MPT gene family

YANG Mingxia, LIAN Hongjuan, WANG Xiaofang, DU Yiyang, DONG Zhigang, JI Wei

2020, 32(12): 2173-2185. DOI: 10.3969/j.issn.1004-1524.2020.12.08

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The mitochondrial phosphate transporter (MPT) gene family is an important functional protein located on the innner membrane of the nitochondria, transferring important metabolic substrate inorganic phosphate from the cytoplasm to the mitochondrial matrix through mitochondrial inner membrane and playing a key physiological role in maintaining the normal function of cells. Using bioinformatics tools, the phylogenetic evolution, structure, protein physicochemical properties and conserved motifs of grape MPT gene family members were systematically analyzed, as well as the tissue-specific expression and association of homologous gene. The results showed that sixty-four possible MPT family genes were identified in the whole genome of grapes, which could be divided into 7 groups according to the phylogenetic tree, distributed on 19 chromosomes, and two pairs of genes had a tandem replication phenomenon. Conservative motif analysis showed that all MPT family members contained the conserved domain of Mito_carr. Tissue-specific expression showed that VvMPT gene was highly expressed in peels, flowers and leaves. Homologous gene analysis showed that the VvMPT gene family of grapes might play an important role in the development of floral organs and maintenance of ion concentration.

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Optimization of strawberry gynoecium protein extraction method for mass spectrum-based proteomic study

QIU Jieren, CHAI Weiguo, TONG Jianxin, ZHOU Liping, WANG Shuzhen

2020, 32(12): 2186-2191. DOI: 10.3969/j.issn.1004-1524.2020.12.09

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In order to screen a strawberry gynoecium protein extraction method for mass spectrum (MS)-based proteomics studies, a new method named as phenol-chloroform extraction was established by adding a chloroform extraction step to the traditional phenol extraction method, and the application on extracting strawberry gynoecium proteins of the three methods: trichloroacetic acid/acetone precipitation (method Ⅰ), phenol extraction(method Ⅱ) and phenol-chloroform extraction (method Ⅲ) were evaluated. The analysis results of the total protein yield, sum of protein identification, subcellular location and hydrophilic-hydrophobic distribution of non-shared proteins showed that, the phenol-chloroform method was the most efficient and comprehensive for protein extraction. The protein yields of method Ⅰ, method Ⅱ and method Ⅲ were 0.20%, 0.12% and 0.27%, respectively; and the sum of protein identified were 5 170, 5 345, and 5 697, respectively. The Venn diagram analysis showed that method Ⅲ intersected most of the non-shared proteins of method Ⅰ and method Ⅱ. Subcellular location analysis showed that non-shared proteins of method Ⅰ and method Ⅲ were mainly distributed in the nucleus, whereas those of method Ⅱ were mainly distributed in the cytoplasm, indicating that the three methods had different subcellular preferences. Hydrophilic-hydrophobic analysis showed that method Ⅰ had the highest proportion of hydrophilic protein but insufficient hydrophobic protein extraction, while method Ⅱ had insufficient extraction of hydrophilic protein, and method Ⅲ took into account the extraction of both hydrophilic and hydrophobic proteins. According to the results, method Ⅲ should be the optimal protein extraction method for strawberry gynoecium.

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Diversities of microbial communities in midgut of 3 planthoppers species by MiSeq

ZHANG Juefeng, YU Yefei, LI Fang, ZHONG Haiying, CHEN Jianming

2020, 32(12): 2192-2200. DOI: 10.3969/j.issn.1004-1524.2020.12.10

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In this study, we successfully demonstrated that MiSeq was a powerful approach for investigating the bacterial communities in midgut of brown planthopper (BPH) Nilaparvata lugens St?l, white-backed planthopper (WBPH) Sogatella furcifera Horvath and small brown planthopper(SBPH)Laodelphax striatellus(Fallen). For all three planthoppers, 3.44×10 ⁵ effective sequences were selected and utilized for the bacterial diversity and abundance analysis. In total, 76, 103, and 61 operational taxonomic units were obtained at 3% distance cutoff, 49, 68 and 42 at 6% distance cutoff in the BPH, SBPH and WBPH, respectively. Nearly 90% of the sequences in the SBPH were assigned into F-proteobacteria-unclassified. In the other two samples, Arsenophonus was the dominant genus in BPH, accounting for about about 70% sequences, while in WBPH, Halomonas, Candidatus_Cardinium and Arsenophonus were 3 dominant bacterias, accounting for about 35%, 20% and 15%, respectively. Though they were evolved from the common ancestor, the microbial community diversity, richness, dominant bacteria function of endosymbiont in three planthoppers were different.

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Study on ecological service benefits of urban greenway based on i-Tree model

ZHOU Beining, LU Jianguo, HUA Zhuangzhuang

2020, 32(12): 2201-2210. DOI: 10.3969/j.issn.1004-1524.2020.12.11

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In order to quantitatively analyze the value of various ecological services of trees in urban greenways, and provide reference for tree species selection and planting planning in the future. By taking the greenway tree species in “The River Junction Area” of Ningbo City as the research object, the composition of tree community structure, diameter at breast height (DBH) distribution, tree height structure, and growth type were analyzed. The ecological benefits were evaluated by using i-Tree model, and energy-saving benefit, carbon sequestration benefit, air quality improvement benefit, rainwater interception benefit and aesthetic benefit were quantified as economic values. The results showed that there were abundant tree species in the greenway (71 species, 54 genera and 37 families), and the growth types were mostly broad-leaved deciduous trees. The DBH and height of greenway trees were mostly between 15.2-30.5 cm and 5.0-10.0 m, which were in stable growth stage, with abundant seasonal changes and strong landscape effect. According to i-Tree model, the annual total ecological benefit of greenway in “The River Junction Area” is 4 287 024.54 yuan, including aesthetic benefit (64.62%)>carbon sequestration benefit (17.25%)>rainwater interception benefit (9.79%)>energy saving benefit (8.32%)>air quality improvement benefit (0.02%). There was a strong correlation between the dominance of tree species and the total ecological benefit contribution rate of greenway. The contribution rate of Cinnamomum camphora, Ginkgo biloba, Salix babylonica and Acer palmatum were the highest, but there were no strong correlation with the annual ecological benefit of individual tree; Paulownia fortune(2 494.70 yuan per tree) , Platanus acerifolia(1 994.49 yuan per tree), Pterocarya stenoptera(1 824.93 yuan per tree) and Camptotheca acuminata(1 542.23 yuan per tree) had higher ecological benefits per plant, but the numbers of them were not dominant in the greenway. It was suggested that plant volatile organic compounds (BVOC) should be included in the evaluation system of air quality improvement, and tree species with higher ecological benefit value should be applied to greenway.

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Study on ecological service benefits of urban greenway based on i-Tree model

ZHOU Beining, LU Jianguo, HUA Zhuangzhuang

2020, 32(12): 2201-2210. DOI: 10.3969/j.issn.1004-1524.2020.12.11

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In order to quantitatively analyze the value of various ecological services of trees in urban greenways, and provide reference for tree species selection and planting planning in the future. By taking the greenway tree species in “The River Junction Area” of Ningbo City as the research object, the composition of tree community structure, diameter at breast height (DBH) distribution, tree height structure, and growth type were analyzed. The ecological benefits were evaluated by using i-Tree model, and energy-saving benefit, carbon sequestration benefit, air quality improvement benefit, rainwater interception benefit and aesthetic benefit were quantified as economic values. The results showed that there were abundant tree species in the greenway (71 species, 54 genera and 37 families), and the growth types were mostly broad-leaved deciduous trees. The DBH and height of greenway trees were mostly between 15.2-30.5 cm and 5.0-10.0 m, which were in stable growth stage, with abundant seasonal changes and strong landscape effect. According to i-Tree model, the annual total ecological benefit of greenway in “The River Junction Area” is 4 287 024.54 yuan, including aesthetic benefit (64.62%)>carbon sequestration benefit (17.25%)>rainwater interception benefit (9.79%)>energy saving benefit (8.32%)>air quality improvement benefit (0.02%). There was a strong correlation between the dominance of tree species and the total ecological benefit contribution rate of greenway. The contribution rate of Cinnamomum camphora, Ginkgo biloba, Salix babylonica and Acer palmatum were the highest, but there were no strong correlation with the annual ecological benefit of individual tree; Paulownia fortune(2 494.70 yuan per tree) , Platanus acerifolia(1 994.49 yuan per tree), Pterocarya stenoptera(1 824.93 yuan per tree) and Camptotheca acuminata(1 542.23 yuan per tree) had higher ecological benefits per plant, but the numbers of them were not dominant in the greenway. It was suggested that plant volatile organic compounds (BVOC) should be included in the evaluation system of air quality improvement, and tree species with higher ecological benefit value should be applied to greenway.

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Deposition and residue of acetamiprid under protected celery cultivation

YU Xinru, HE Hongmei, WANG Xiangyun, LI Yanjie, XU Lingying, ZHAO Xueping, ZHANG Changpeng

2020, 32(12): 2211-2217. DOI: 10.3969/j.issn.1004-1524.2020.12.12

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Based on the field experiments and laboratory tests, the deposition and residue characteristics of acetamiprid in celery under protected cultivation were studied, and a detection method was also established. The acetamiprid in soil and plant samples was extracted by using acetonitrile, purified by QuEChERs and detected by liquid chromagraphy-mass spectrometry. The average recoveries of acetamiprid in celery leaf, stem, root and soil were 100.2%-102.5%, 83.9%-93.5%, 97.0%-100.1% and 90.8%-94.4%, respectively. The amount of acetamiprid deposition decreased as celery leaf>soil>celery stem>celery root. The degradation curve of acetamiprid in celery leaf was in accordance with the first-order kinetic equation, and the degradation half-life of acetamiprid was 4.2-19.4 d. Seven days after application of acetamiprid with dosage of 18, 27 g·hm^-2, the residues of acetamiprid in celery leaf and stem were 0.330 0-2.570 0, 0.004 7-0.030 0 mg·kg^-1, respectively, which were below the maximum residue limit (3 mg·kg^-1) of the Chinese national standard GB 2763—2019. The results could provide scientific reference for the rational use of acetamiprid on celery under protected cultivation.

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Antimicrobial resistance in Salmonella and Campylobacter isolated from Zhejiang and Fujian Province in 2019

TANG Biao, CHEN Lingyun, LUO Yi, SHI Xingfen, HU Ji, CHEN Yifei, QIAN Mingrong, YANG Hua

2020, 32(12): 2218-2225. DOI: 10.3969/j.issn.1004-1524.2020.12.13

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To understand the epidemicity and antimicrobial resistance of Salmonella and Campylobacter in Zhejiang and Fujian in 2019, 1 480 fecal and anal swab samples were randomly collected in 10 cities of Zhejiang Province and Fujian Province in 2019. Salmonella and Campylobacter strains were isolated by the method of national standards of China, and matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was used for identification. The minimal inhibitory concentration (MIC) of Salmonella and Campylobacter strains against 16 and 9 antibiotics, respectively, was determined by microdilution broth method. A total of 100 Salmonella strains and 100 Campylobacter strains were isolated in the present study. Among them, 11 serotypes were identified in 94 Salmonella strains. The dominant serotypes were Tsevie (20.2%), Kentucky (15.9%), Weltevreden (15.9%), Typhimurium (14.9%) and Enteritidis (14.9%). The results of drug sensitivity test showed that the resistance rates of the isolated Salmonella strains to tetracycline was the highest (76%), which was followed by ampicillin (70%) and sulfamethoxazole (65%). While, the drug resistance rate of Salmonella strains to amoxicillin/clavulanate was low (6%), and all the isolated Salmonella strains were sensitive to meropenem. In addition, the isolated Campylobacter strains had the highest resistance rate to ciprofloxacin (99%), nalidixic acid (88%) and tetracycline (87%), while the resistance rate to gentamicin was the lowest (23%). All in all, the antimicrobial resistance level of pathogenic bacteria from animals was high in Zhejiang Province and Fujian Province, which would affect the quality and safety of animal products and threaten the public health safety.

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Preparation and storage stability of docosahexaenoic acid enriched egg yolk powder

CHEN Yifan, LI Huanhuan, TANG Honggang, ZHANG Jin, ZHANG Yingping, TONG Haowen, ZHU Dongrong, CHEN Lihong

2020, 32(12): 2226-2231. DOI: 10.3969/j.issn.1004-1524.2020.12.14

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In the present study, docosahexaenoic acid (DHA) enriched egg yolk powder was made from DHA enriched eggs. In order to investigate the effects of accelerated oxidation oven test for 25 d and different storage conditions including temperature (4, 25, 37℃), light (light/dark) and oxygen (unsealed/sealed)) on the storage stability of DHA enriched egg yolk powder, the indicators of pH value, color difference, DHA content and peroxide value were measured. It was shown that freeze-drying process could maintain DHA in the DHA enriched egg yolk powder with a content of 17.1 g·kg^-1. High temperature oxidation reduced the pH and brightness value of DHA enriched egg yolk powder, and increased the redness value. The preservation rate of DHA was 93.1% after storage at 37 ℃ for 7 weeks in the DHA enriched egg yolk powder. When stored at 25 ℃ for 60 d, the DHA preservation rate in the DHA enriched egg yolk powder was 95.2%, 93.6%, 94.2%, 91.7%, in sealed and dark conditions, unsealed and dark condition, sealed and light condition, and unsealed and light condition, respectively. The peroxidation value of the DHA enriched egg yolk powder was 3.7 times under unsealed and light condition as that under unsealed and dark condition. In conclusion, temperature had a leading effect on the preservation rate of DHA in the DHA enriched egg yolk powder, while oxygen and light could promote the oxidative process. The storage of DHA enriched egg yolk powder should give priority to low temperature, and sealed and dark condition.

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Study on estimation model of total nitrogen content in rice leaves based on image characteristics

YANG Hongyun, LUO Jianjun, SUN Aizhen, WAN Ying, YI Wenlong

2020, 32(12): 2232-2243. DOI: 10.3969/j.issn.1004-1524.2020.12.15

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In order to explore the quantitative description of the relationship between the external color, geometric shape characteristics of rice leaf growth and its total nitrogen content, it can quickly and accurately diagnose the nitrogen nutrition status of rice. In this study, the sensitive leaf positions for total nitrogen content estimation were screened out, and the models based on multiple linear regression and machine learning methods for total nitrogen content estimation of rice sensitive leaf positions were compared, which provided ideas and methods for establishing high-performance quantitative diagnosis model of nitrogen nutrition. The field experiment of rice was carried out in Chengxin farm, Nanchang City, Jiangxi Province from 2017 to 2018. The tested rice variety was LYP9. Four nitrogen application levels (0, 210, 300 and 390 kg·hm^-2 from low to high) were set. At the panicle differentiation stage and full heading stage of rice, 4 800 images of the first fully expanded leaf (1st leaf), the second fully expanded leaf (2nd leaf) and the third fully expanded leaf (3rd leaf) at the top of rice were obtained by scanning. Twenty-five scanning leaf color and geometric shape characteristics of rice were acquired by image processing technology, and the sensitive leaf positions in two periods were screened by multiple linear regression, and the total nitrogen content estimation model of rice sensitive leaf positions was established by machine learning method. The average relative errors of the length and width of rice leaves obtained by image processing method were 0.328% and 3.404% respectively, compared with the manual measurement; the 3rd leaf at the panicle differentiation stage and the 2nd leaf at the full heading stage were more sensitive than other leaf positions at the same period, and the 3rd leaf at the panicle differentiation stage was the most sensitive; the model of estimating the total nitrogen content in sensitive leaves of rice based on machine learning was slightly better than the multiple linear regression, and BP neural network was the best, RMSE_v=0.089, MRE_v=0.034, $R^{2}_{v}$ =0.887 in the 3rd leaf at the panicle differentiation stage; RMSE_v=0.132, MRE_v=0.046, $R^{2}_{v}$ =0.820 in the top 2nd leaf at the full heading stage. The 3rd leaf of the panicle differentiation stage and the 2nd leaf of the full heading stage were the most representative and more feasible to estimate the total nitrogen content, which can be used as an effective leaf position for nitrogen nutrition diagnosis of rice.

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Estimation method of wheat yield based on convolution neural network

BAO Lie, WANG Mantao, LIU Jiangchuan, WEN Bo, MING Yue

2020, 32(12): 2244-2252. DOI: 10.3969/j.issn.1004-1524.2020.12.16

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Wheat yield is one of the important indices to evaluate agricultural productivity. In order to solve the problem of wheat yield prediction, convolution neural network was applied. It could provide reference for the estimation of agricultural productivity and guide the decision-making of agricultural production management. We constructed the wheat dataset from the images which were collected by unmanned aerial vehicle in Xinxiang and Luohe of Henan Province, and divided them into positive samples (wheat) and negative samples (leaf and background). The convolutional neural network recognition model was designed for normal physiological morphology and growth environment of wheat, and the image pyramid was used to construct multi-scale sliding windows. Finally, Non-maximum suppression (NMS) was used to remove the object frame with high overlap rate to realize counting of wheat ears per unit area. We randomly assigned 100 different wheat images to test. Compared with manual counting result, the accuracy rate reached 97.30%, the missed detection rate was 0.34%, the wrong detection rate was 2.36%, and the error rate was 2.70%. The experimental results showed that this method could overcome many kinds of noise interference in the environment, and could count wheat ear and estimate the yield of wheat accurately.

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Structural characteristics and development gap of regional agricultural economy in China from 1978 to 2017

HU Chenpei, LI Huishang, GUO Xinzhu

2020, 32(12): 2253-2260. DOI: 10.3969/j.issn.1004-1524.2020.12.17

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Since the reform and opening up, China’s agriculture has achieved rapid growth, but the problem of uncoordinated agricultural development among regions is still outstanding. Based on the panel data of labor input and economic output of the first industry in 31 provinces (autonomous region, municipality) from 1978 to 2017, the Theil index was introduced to measure the regional development gap of agricultural economy and its structural characteristics. It was shown that, from the perspective of regional development gaps, the development gap in agricultural economy between the north and south of China has been shrinking since the reform and opening up. The development gap within the east, central and west is the main source of the development gap in China’s agricultural economy currently. The inter-provincial development gap in agricultural economy in the south is larger than that in the north, and the development gap within the west region is larger than that within the central and east regions.

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Impact of rural-household differentiation on cultivated land protection behavior based on intermediary effect

CHEN Yinrong, WANG Xiaomei

2020, 32(12): 2261-2270. DOI: 10.3969/j.issn.1004-1524.2020.12.18

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Clarifying the behavior logic of farmers participating in cultivated land protection is of great significance to improving the quality of cultivated land and increasing the area of effective cultivated land. Based on 483 questionnaires in Wuhan urban circle, by taking cultivated land value cognition as an intermediary variable, the mediating effect model was used to explore the specific mechanism of rural-household differentiation on cultivated land protection behavior. The results showed that the impact of rural-household differentiation on cultivated land protection behavior could be achieved by acting on the intermediary variable of cultivated land value cognition. At a higher level of cultivated land value cognition, the negative effect of rural household differentiation on cultivated land protection behavior would be weakened. The increase in income from non-farm employment would increase the possibility of labor force being replaced by capital, so the negative effect of rural-household differentiation on labor-biased protection behavior was greater than that on capital-biased protection behavior. Therefore, it was necessary to vigorously promote capital-biased cultivated land protection measures and increase the propaganda of the multi-functional value of cultivated land.

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Influencing factors of consumer satisfaction evaluation on quality and safety of agricultural products: an illustration from Zhejiang Province

KE Fuyan, XU Zhiyuan, ZHAN Jinrong

2020, 32(12): 2271-2281. DOI: 10.3969/j.issn.1004-1524.2020.12.19

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Since the melamine incident in 2008, improving consumer satisfaction evaluation has become one of the important objectives of government in the administration of quality and safety of agricultural products. This paper established consumer satisfaction evaluation indicators for agricultural products’ quality and safety. Based on 1 910 interception questionnaires in 13 counties in Zhejiang Province of 2019, the main influencing factors were analyzed and compared through four measurement models. The results showed that: the consumer satisfaction evaluation of quality and safety of agricultural products in Zhejiang Province was at a relatively high level, county-level territorial management effectiveness had played a central role in improving consumer satisfaction evaluation of quality and safety of agricultural products, consumers’ own cognitive level and awareness also had a positive impact on the evaluation. Consumer satisfaction ratings from farmers’ markets were higher than those from supermarkets, and the longer the residence time of consumers, the higher the satisfaction rating of consumers. Consumers with higher age and higher education level were more cautious about their satisfaction evaluation. Therefore, the Chinese government should seize the opportunity of improving public opinion and further promote the local management of quality and safety of agricultural products, improve the level of consumer awareness, and focus on strengthening publicity for the elderly and foreign population.

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Impact of media negative coverage of honey consumption expectations

LI Menglu, ZHANG Shemei

2020, 32(12): 2282-2290. DOI: 10.3969/j.issn.1004-1524.2020.12.20

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The media negative coverage, especially on the quality and safety of agricultural products, had a great impact on the agricultural product market, which not only brings psychological panic to consumers, but also seriously affects consumers’ purchase decisions. In the end of 2018, a famous hospital questioned the effect of honey on their wechat official account had aroused heated debate. To explore the impact of negative coverage on the consumption of honey, the paper adopted the method of questionnaire and statistical analysis. Based on the data of 1 222 questionnaires in 6 cities in the country, the Ologit model was used to study the coverage and subsequent disputes on consumers. At the same time, the propensity score matching (PSM) and TSLS were used to deal with the selective bias. The results showed that impact of media negative coverage, last purchase behavior and consumer confidence were the important factors influencing the change of consumption expectation, and the negative coverage had a significant impact on consumption expectation. Therefore, this paper suggested that the establishment of authoritative institutions should establish speech appraisal and control system, and strengthen the crisis management of negative coverage to guide rational consumer behavior.

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Research status of Kombucha in the world

LI Ruyi, YIN Junfeng, ZOU Chun

2020, 32(12): 2291-2302. DOI: 10.3969/j.issn.1004-1524.2020.12.21

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Kombucha is a functional tea beverage obtained by the fermentation of sugared tea with microorganism. In recent years, with the improvement of people’s living standards and health awareness, Kombucha with various health-care effects has attracted extensive attention from researchers in the world, and its global sales volume is also increasing exponentially. This paper reviewed the composition and symbiotic relationship of microorganism in the Kombucha, generalized the effects of raw materials, culture conditions and strain composition on the fermentation of Kombucha, and summarized the health-care function research of Kombucha in antioxidation, antibacterial activity, hepatoprotective effect, immunity enhancement and anti-cancer effects. Furthermore, in order to provide reference for the industrial production of Kombucha, the lack of in-depth research on the identification and formation mechanism of active macromolecules, probiotic effect of different kinds of strains, precise control of fermentation tank level, and improvement of product stability were proposed, the application prospect of Kombucha in many fields was also prospected.

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Progress on cysteine-rich receptor-like kinase family in plants

GENG Yanfei, LYU Mingfang

2020, 32(12): 2303-2312. DOI: 10.3969/j.issn.1004-1524.2020.12.22

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Cysteine-rich receptor-like kinases (CRKs), as a kind of upstream signaling molecules, are important for sensing stress signals and triggering immune responses to various biotic and abiotic stresses during plant growth and development. CRKs are mainly composed of signal peptide, DUF26 (PF01657), transmembrane domain and intracellular kinase domain, in which both DUF26 and kinase domains are highly conserved in different species. Bioinformatic analysis has shown that there are 37-170 members of CRK family from monocots and dicots, and most of them have been suggested to play different roles in plant growth and stress response. This paper reviewed the current advances on cysteine-rich receptor-like kinase family in plants, such as gene structures and functions in plant growth, development, and stress responses,and may be of great significance for improving the ability of crops to resist stress.

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