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2022 Vol. 37, No. 4

2022, 37(4): 1-2.
Abstract:
Animal Science
Preparation and Efficacy of Inactivated Pseudorabies Vaccine Using Different Adjuvants
HOU Bo, WANG Chenyan, CHEN Qiuyong, WU Xuemin, LIU Yutao, WANG Longbai, ZHOU Lunjiang
2022, 37(4): 423-428. doi: 10.19303/j.issn.1008-0384.2022.004.001
Abstract:
  Objective  Immune efficacy of inactivated pseudorabies vaccine prepared with different adjuvants were compared.   Methods   Using 3 different adjuvants as base, inactivated vaccines against the novel variants of pseudorabies virus (PRV), FJ-2012, were prepared from the gE/gI-deleted virus. After a quality assessment, these water-phase GEL02-, amphoteric ISA 206VG- or white oil adjuvant-based vaccines were injected into sheep. Detection of gB and gE antibodies in the animals were performed using ELISA. The protective efficacy against the disease in 28 d after vaccination was determined by comparing to that of an FJ-2012 challenge test.   Results  The successfully prepared vaccines showed no adverse reactions on the inoculated sheep. The gB antibody was tested positive, but gE negative, in the vaccinated sheep. Out of 5 sheep in the 4 test animal groups, 5 in the challenge control died in 6 d and two perished in the group received ISA 206VG-based vaccine. But all sheep in the group injected with either the experimental GEL02- or the white oil-based vaccine survived.   Conclusion  A perfect protection rate against FJ-2012 was demonstrated on the sheep vaccinated by the GEL02- or the white oil-based vaccine obtained from the FJ-2012ΔgE/gI strain in this study. A new venue to prevent and control the novel variants of PRV in China was made available.
Ovarian Proteomics of Yaks in Pregnancy and Postpartum Anestrus
MA Junyuan, WANG Jine, LI Yang, HU Songming, CHEN Zhou, LI Shuyuan, YANG Yanmei, ZHAXI Yingpai, HUO Shengdong
2022, 37(4): 429-438. doi: 10.19303/j.issn.1008-0384.2022.004.002
Abstract:
  Objective  Differentially expressed proteins (DEPs) in ovaries of yak s in pregnancy and postpartum anestrus were identified.   Method  Ovarian tissues of 3 randomly selected yaks each in pregnancy or postpartum anestrus from a natural grazing herd in Huangyuan County, Qinghai Province were sampled for DEP identification by the TMT method.   Result  Thirty-eight upregulated and 19 downregulated DEPs were found in the yaks. The COG analysis indicated the major functions of the proteins related to the production and transformation of energy, protein turnover, and amino acid transport and metabolism. The Go analysis showed that they were mainly annotated in the biological processes of metabolism and reproduction, associated with the cellular component including organelle cell components, and participated in molecular function including the molecular transport activity. Whereas KEGG revealed their involvements in 27 signaling pathways that included BK and P450scc in the ovarian steroid hormone production, GSH-P1, GSTA2, GST, and AST in the amino acid transport and protein metabolism, and PI3K in the PI3K-Akt apoptosis signaling.   Conclusion  The current study identified specific DEPs in yak ovary, i.e., BK, P450scc, GSH-P1, GSTA2, GST, AST, and PI3K, that were closely related to the onset of anestrus in the animal.
Prediction and Verification of sRNA SdsR Target Genes in Salmonella typhimurium
ZHANG Jiali, LINGHU Yuanfeng, DUAN Shiyu, PAN Yong, YANG Qi
2022, 37(4): 439-444. doi: 10.19303/j.issn.1008-0384.2022.004.003
Abstract:
  Objective   Target genes of Salmonella Typhimurium sRNA SdsR were investigated to further understand the interactions between the sRNA and the target genes as well as the pathogenic mechanism of S. typhimurium.   Method   The TargetRNA2 software was used to predict the target of sRNA SdsR in the pathogen. According to the results obtained in a previous sRNA SdsR knock-out transcriptome sequencing study, the predicted genes were annotated into GO, KEGG, and eggNOG databases for analysis. Those with high hybridization energy were further verified by RT-qPCR.   Result   There were 29 targets predicted by TargetRNA2. Among them, hemA, STM0951, mreC, STM1252, and dcoC showed high hybridization energy with a possibility of having a continuous base to match the sRNA SdsR. They might be associated with the heme synthesis, redox process, oxaloacetate decarboxylase synthesis, and membrane components and cytoplasmic protein synthesis in S. typhimurium. The RT-qPCR showed, after sRNA SdsR knockout, hemA to be downregulated by 0.70 times and mreC 0.39 times, while STM0951, STM1252, and dcoC upregulated by 0.51, 0.35 and 1.86 times, respectively, over the wild strain 3409.   Conclusion   It appeared that the genes identified in this study, including hemA, STM0951, mreC, STM1252 and dcoC, could directly be regulated by the sRNA SdsR and might affect the expressions of some target genes.
Effects of Dietary Rutin on Rumen Microbial Community Diversity and Composition of Hu Sheep
WANG Haibo, ZHAN Jinshun, GU Zhiyong, LIU Yuhang, HUO Junhong, ZHAO Shengguo
2022, 37(4): 445-452. doi: 10.19303/j.issn.1008-0384.2022.004.004
Abstract:
  Objective  Effects of rutin supplementation in forage on the rumen microbial community diversity and composition of Hu sheep were studied.  Method   Thirty-six healthy 3-month-old Hu sheep of similar body weight were randomly divided into 3 groups of 12 animals (half male and female) each for the treatments. The sheep in the control group (CON) were fed a basal diet, while those in two treatment groups on a daily diet supplemented with rutin at a rate of 50 mg (R50) or 100 mg (R100) per kg of animal body weight. The feeding test lasted for 70 d that included 14 d of pre-test and 56 d of actual test.   Result  (1) Of the 446 OTUs collected in the sheep rumens, 396 (constituted 88.79% of total) were commonly shared by the sheep in the 3 groups that annotated into 14 phyla, 18 classes, 21 orders, 34 families, and 99 genera. (2) The ACE, Shannon, and Chao1 indices of the sheep in the R100 group were significantly lower than those of CON (P<0.05), while the alpha diversity not significantly different between CON and R50 groups (P>0.05). (3) The results of the principal co-ordinates analysis (PCoA), the non-metric multi-dimensional scaling analysis (NMDS), the unweighted pair group method with arithmetic mean clustering analysis (UPGMA), and the anosim analysis showed that the microbial community was significantly altered by the R100 treatment (P<0.05). (4) Bacteroidetes and Firmicutes were two dominant phyla. R100 significantly increased the relative abundance of Patescibacteria but decreased that of Elusimicrobia (P<0.05). On the other hand, R50 significantly raised the relative abundance of Elusimicrobia over CON or R100 (P<0.05). (5) At genus level, the dominant microbes were Prevotella_1. The relative abundance of Selenomonas_1 and Succiniclasticum in the sheep fed with R100 were significantly lower than CON (P<0.05) but not significantly different from R50 (P>0.05).   Conclusion   Addition of rutin to forage at a rate of 100 mg·kg−1 of sheep body weight significantly affected the rumen microbial diversity in Hu sheep .
Crop Science
Connection between Tea ZFP2 and Drought Resistance of Tobacco Plants
LI Wanxue, YAO Xinzhuan, ZHANG Baohui, LIU Yang
2022, 37(4): 453-459. doi: 10.19303/j.issn.1008-0384.2022.004.005
Abstract:
  Objective  Expression of tea ZFP2 in tobacco plants in response to drought stress was studied to elucidate the molecular mechanism.   Method   A zinc finger protein (ZFP) was previously found in our laboratory to interact with the promoter region of F3'5'H gene. Using bioinformatics methods, the structure of ZPF2 from Camellia sinensis was predicted and analyzed. Then, CsZFP2 was cloned and transferred into tobacco by an Agrobacterium-mediated method for functional verification under a simulated drought stress.   Result  The domain of the ZFP from C. sinensis XM_028257969.1 was 68.57% homologous to that from Nicotiana tabacum XP_016463943.1. There were 13 introns in CsZFP2 with a length of 1,233a, a molecular weight of 141 204.45, an isoelectric point of pH 5.9, and an isoelectric point Pi<7 indicating high content of acidic amino acids. The gene encoded mainly two proteins with an α-helix primary structure and a random coil 3D structure composed of α-helix and β-turn. The hydrophilic protein was subcellularly located in the nucleus with more than 50% of the amino acids having a sequence less than zero. Under natural drought for 28 d, the old leaves at the bottom of both wild-type and transgenic tobacco plants were turning yellow. However, those leaves on the wild-type plants became basically chlorotic and withered, but those on the transgenic plants wilted only slightly and largely remained green in color.   Conclusion  CsZFP2 affected the response of tobacco plants to drought stress. The transgenic plants with overexpressed CsZFP2 were more resistant to the stress than the wild-type counterparts.
Breeding and Growth Characteristics of High-yield, High-quality, Disease-resistant Peanut Puhua 45
ZHENG Guodong, GONG Shen, HUANG Jintang, HUANG Yanxia, CHEN Hailing
2022, 37(4): 460-466. doi: 10.19303/j.issn.1008-0384.2022.004.006
Abstract:
  Objective   A high-yield, high-quality, disease-resistant peanut variety was bred, and its growth characteristics and cultivation in Fujian studied.   Method   Years of directional selection were carried out by crossing between the high-yield, high-quality peanut Xianghua 120 as female parent and the disease-resistant Quanhua No. 10 as male parent. The final hybrid cultivar obtained was subjected to field trials and the spring peanut regional tests in Fujian.  Results   In the provincial tests from 2015 to 2016, the newly bred Puhua 45 showed a pod yield of 3 787.05 kg·hm−2 and a kernel yield of 2 559.00 kg·hm−2, which were 9.09% and 7.69% higher, respectively, than those of the reference. Nutritionally, it contained 53.08% crude fat, 26.3% protein, 47.8% oleic acid, 31.6% linoleic acid, and with an O/L ratio of 1.51. Compact in plant type and upright on standing, Puhua 45 grew with vigor and was moderately resistant to bacterial wilt, rust, and leaf spot. It had passed the national non-major crop variety registration[GPA(2019)350271] in January 2021. Its outstanding physiological and agronomical characteristics that were superior to the reference included the more concentrated blooming period and pods per plant, and the higher effective flowering rate, leaf area index, net assimilation rate, chlorophyll content, and dry matter accumulation.  Conclusion   In addition to high-yield, high-quality, and disease-resistance, Puhua 45 exhibited many desirable properties and should be promoted for peanut cultivation in Fujian.
Horticultural Science
Screening and Evaluation of Tea Germplasms Containing High-EGCG3″Me
CHEN Xiao-min, JIN Shan, WU Wenxi, SHAO Shuxian, WANG Shuyan, WANG Pengjie, ZHAO Feng, YE Naixing
2022, 37(4): 467-475. doi: 10.19303/j.issn.1008-0384.2022.004.007
Abstract:
  Objective  Catechin composition of tea germplasms in the wild in Fujian was analyzed to aid organizing and utilizing the natural resources containing the highly desirable functional ingredients in tea.  Methods  Forty-three wild tea germplasms in Fujian and 8 common cultivars were collected for chemical analysis by HPLC. Descriptive statistical, orthogonal partial least squares discriminant, and cluster heat map analyses were conducted for evaluating and screening the candidates.  Results  EGCG3″Me was detected in all 43 specimens with the highest content of 33.65 mg·g−1 found in YX06. Aside from EGCG3″Me, EGCG was also characteristically in significantly greater quantities in the wild tea germplasms than the 8 cultivated varieties. The cluster analysis grouped 12 wild germplasms, mostly from Zhao'an and Jiaocheng areas, along with the 8 cultivated varieties that had high contents of EC, EGC, and catechin (C). The remaining 31 wild tea germplasms were clustered into a group that had high contents of EGCG3″Me, ECG, and EGCG. Of all the 43 wild tea germplasms, 8 had high EGCG3″Me content (i.e., greater than 20mg·g−1), 9 high EGCG (i.e., greater than 150 mg·g−1), and 18 high C (i.e., greater than 200 mg·g−1).   Conclusion  The tea germplasms collected in the wild in the province were rich in EGCG3″Me, which could be specific cultivars for target breeding of tea.
4-PHF-based Analysis on Seed Dormancy of 6 Cornus Species
XIONG Xing, LU Qiang, WANG Haowei, YANG Ling, FU Xiangxiang
2022, 37(4): 476-485. doi: 10.19303/j.issn.1008-0384.2022.004.008
Abstract:
  Objectives  Seed dormancy of 6 species of ornamental Cornus was studied using the 4-parameter hill function (4-PHF) method to aid the resource conservation, seed storage, plant development, and landscape planning.   Method   Seeds of C. florida (CF), C. kousa subsp. chinensis (CKC), C. hongkongensis (CH), C. hongdongensis subsp. tonkinensis (CHT), C. hongdongensis subsp. elegans (CHE), and C. elliptica (CE) were soaked in a 500 mg·L−1 GA3 solution for 3 d. Then, at durations of 0, 10, 20, 30, 40, 50, and 60 d, the seeds were stratified at low temperature. The 4-PHF method was used for curve-fitting to describe germinating patterns, as well as calculating estimates on the time at germination onset (lag), time at maximum germination rate (TMGR), and dormancy index (DI) for the 6 species.   Result   The stratification effectively facilitated the break of seed dormancy. However, the holding time required for maximal germination varied among the 6 species. For CKC, 78% germination was achieved in 30 d; for CH and CF, it was 71% and 89%, respectively, in 60 d; and for CHE, CHT, and CE, it was 63%, 69%, and 54%, respectively, in 50 d. The germination curves showed steady declines after break of dormancy on lag and TMGR but increase on DI.   Conclusion   As indicated by the germination parameters, it appeared that the evergreen variety of dogwoods went into a deeper dormancy than the deciduous ones. The DI showed the current treatment could not fully break the seed dormancy on the evergreen dogwoods. The germination curve-fitting and the 4-PHF-estimated lag and TMGR could explain the biological differences on the seed germination among the 6 dogwood species by the stratification treatments. On the other hand, DI could not be used to compare the degree of dormancy.
Cloning and Expression of NnWRKY22 in Lotus
WANG Wanru, LIU Ying, LIU Hongli, HE Dan, LIU Yiping, KONG Dezheng
2022, 37(4): 486-491. doi: 10.19303/j.issn.1008-0384.2022.004.009
Abstract:
  Objective   NnWRKY22 in Nelumbo nucifera was cloned and its expressions in various organs under copper stress analyzed.  Method   RT-PCR was used to clone the gene from cDNA of lotus leaves, and bioinformatics of the sequence obtained using ProtParam. The gene expressions in roots, stems, leaves, and flowers under an imposed copper stress for varied durations were detected by qRT-PCR.  Result  The successfully cloned NnWRKY22 had an ORF of 573 bp and encoded 190 amino acid residues. The unstable hydrophilic protein had a sequence containing a conserved WRKY domain and a molecular weight of 21.33 kDa, an isoelectric point of pH 9.03, an instability index of 71.93, and hydrophilicity of −0.692. The phylogenetic analyses revealed a close genetic relationship of the gene with those of Aquilegia coerulea and Macleaya cordata. The qRT-PCR results showed the organ-specific expressions of the gene in the tissues which were highest in the roots and lowest in the flowers. They were significantly upregulated and peaked in 7 d by the copper treatment.  Conclusion  NnWRKY22 was successfully isolated from lotus and cloned. The gene was most highly expressed in the lotus roots and significantly upregulated by the presence of copper. It presumably played an important role in the response of the lotus plants to copper stress.
Bioinformatics and Expression of Hydroxycinnamyl transferase Gene Family from Dendrobium officinale
LONG Xiaoqin, NIE Cong, HE Jize, TIAN Ye, LI Xinran, PI Xinyao, WANG Wanjun, ZHU Qiankun
2022, 37(4): 492-502. doi: 10.19303/j.issn.1008-0384.2022.004.010
Abstract:
  Objective   Characterization and the expressions of hydroxycinnamyl transferase (HCT) gene family from Dendrobium officinale were studied to reveal the biosynthesis of flavonoids and dendrophenol in the plant.   Method  Relevant gene sequences were obtained from the NCBI online website. Conserved motifs and domains, evolutionary tree, and protein secondary and tertiary structures of each member of DoHCTs were analyzed using bioinformatics methods. Expressions of the genes under stresses and in roots, stems, and leaves were determined using RT-PCR.   Result   The gene family had 8 members, DoHCT1–8. Their conserved domains showed that DoHCT7/8 belonged to the transferase superfamily and DoHCT1–6 to the PLN02481 superfamily. Abiotic stresses could affect the expressions, such as, elevated temperatures downregulated them. Except DoHCT7, the genes were differentially expressed in the roots, stems, and leaves.   Conclusion   The comprehensive bioinformatics and expression analyses on the 8 members of the DoHCT family from D. officinale revealed that SoHCTs were with differental expression under different abiotic stress or tissues, and proved to play regulatory role in abiotic stress.
Plant Protection
Biological Characteristics and Fungicides of Cherry Leaf Spot Disease Pathogen
WANG Lei, ZHI Huanhuan, MA Yongqiang, YAO Qiang, CHEN Hongyu, ZHANG Gang, GUO Qingyun
2022, 37(4): 503-513. doi: 10.19303/j.issn.1008-0384.2022.004.011
Abstract:
  Objective  Biological characteristics of Colletotrichum salicis, the pathogen that causes the leaf spot disease on cherry plants in Qinghai Province, were studied and effective fungicides evaluated for the control.  Methods  C. salicis were examined by the cross and spore counting methods. Its sensitivity to 26 fungicides was determined in the laboratory according to the growth inhibition on culture media.  Results  PDA medium was found to be optimal for the C. salicis mycelial growth and sporulation. Inositol and glucose were the optimal carbon sources for sporulation, while beef extract the nitrogen for colony growth and peptone for spore production. The pathogen could grow between 5 ℃ and 40 ℃ but most rapidly at 25 ℃ and died at 58 ℃ in 10 min; between pH 4 and 12 but optimally at pH 7; and well under a photoperiod cycle of 12 h light/12 h dark. Among the tested antifungal agents, 10% phentermine methiconazole aqueous dispersion or 0.3% eugenol dissolvable solution had the greatest inhibition with EC50 of 0.6 mg·L−1 and 1.151 mg·L−1, respectively, whereas 20% allicin oil emulsion, 80% manganese zinc wettable powder, and 500 g·L−1 isobaric urea suspension the least efficacies with EC50 up to 301.44 mg·L−1, 679.36 mg·L−1, and 1 012.52 mg·L−1, respectively.   Conclusion  The conditions and nutrients for optimal C. salicis culture were determined and the effective fungicides were identified.
Thrip Infestation on Sweet Peppers in Fujian and Pathogenicity of Lecanicillium lecanii against Dominant Species of Thrips
HUANG Peng, ZHANG Jie, CHEN Hanxin, LAN Yanyang, YAO Jinai, YU Deyi
2022, 37(4): 514-519. doi: 10.19303/j.issn.1008-0384.2022.004.012
Abstract:
  Objective   Thrips infestation on sweet peppers in Fujian province was surveyed, and potential of using Lecanicillium lecanii as a means of biological control against the dominant species of thrips was explored.   Methods   Species and numbers of thrips that infested varieties of sweet peppers at vegetable farms in Zhangzhou, Fujian were surveyed. Pathogenicity of L. lecanii LL-01 on the dominant species of thrips was determined in laboratory.   Results   The total thrip populations on Lushuai and Bulanni sweet peppers were similar but significantly higher than that on Teyasi. The thrips found were largely Frankliniella intonsa, Thrips hawaiiensis, and T. palmi, and among them, F. intonsa being the most abundant, accounting for 91.31-94.93%. The LC50 of L. lecanii LL-01 was 3.47×105 conidia·mL−1 on F. intonsa 7 d after an inoculated infection. The cumulative lethality was 78.16-87.36% under treatments of 1×107 to 1×108 conidia·mL−1 to reach an LT50 in 3.73-4.24 d.  Conclusion   Thrips had varied preferred host plants.F. intonsa was the dominant species that infested the sweet pepper varieties in the province. Since L. lecanii LL-01 was found strongly pathogenic to F. intonsa, it could be applied as a biological agent to deter wide-spread infestation.
Morphological and Molecular Identification of Potato Cyst Nematode from Sichuan
GU Jianfeng, SHAO Baolin, FANG Yiwu, MA Xinxin, LI Xingyue, ZHENG Jingwu
2022, 37(4): 520-528. doi: 10.19303/j.issn.1008-0384.2022.004.013
Abstract:
  Objective  To isolate and identify the pathogen causing cyst nematode infection in Yuexi, Sichuan.   Method  Roots of the diseased potato plants as well as soil around them were collected to find nematodes by staining and examining under a microscope, while cysts separated by means of simple floatation. The second stage juveniles (J2s), female adults, and cysts found were photographed, and their morphological measurements recorded. DNA of the cysts and the J2s were extracted and identified by species-specific PCR. DNA sequences of 18S gene and 28s D2~D3 region, as well as the ITS location in ribosomal DNA, were obtained. Sequences of some cyst nematode species were downloaded from GenBank for alignment. MrBayes 3.2.3 software was used to construct the Bayesian phylogenetic tree.   Result  The isolated nematode could infect the host root system. The J2 stylet knobs rounded to flattened anteriorly; the mean stylet length was less than 23 μm; and the cyst Granek’s ratio was higher or equal to 3, which is similar to that for Globodera rostochiensis. The DNA templates of 3 cysts and 4 J2s were amplified by species-specific PCR to obtain a band of approximately 430 bp. Further sequencing determined the length to be precisely 434 bp, same as G. rostochiensis. The cyst nematode was shown to be a species of Globodera by an evolutionary analysis on the rDNA 18S and 28S and confirmed to be G. rostochiensis by another evolutionary analysis on ITS gene.   Conclusion  The isolated nematodes from Yuexi, Sichuan was identified as G. rostochiensis, which is of great concern for the domestic disease control and import quarantine, as it can be highly difficult to eradicate once being introduced and colonized in the country. Consequently, a stringent monitoring system must be implemented as soon as possible. Reinforced quarantine, supervision, and management to curtail the possible invasion are urgently needed. Increased efforts on the basic studies as well as developments of detection methodology and prevention and control technology on G. rostochiensis are recommended.
Resources and Environmental Science
Diversity and Network Structure Analysis of Culturable Bacteria in Sporophore Site Soil of Russula griseocarnosa
WANG Yinghao, MAN Jiayin, ZHANG Taoxiang, LIAN Chunlan
2022, 37(4): 529-537. doi: 10.19303/j.issn.1008-0384.2022.004.014
Abstract:
  Objective   The diversity of culturable bacteria and their inter-species interactions were explored by isolating and culturing sporophore site soil bacteria of R. griseocarnosa. It provides insights into the mycorrhizal helper bacteria which may promote the growth of the mycelium and the formation and differentiation of sporophore of R. griseocarnosa.   Methods   The bacteria in the sporophore site soil of R. griseocarnosa were isolated and purified by traditional methods of separation and culture using LB and ISP2 media, and the species of the isolated strains was preliminarily identified by 16S rRNA gene sequence analysis. Interactions between culturable bacterial genera were analyzed using the Bipartite package in R.   Results   A total of 128 strains of bacteria were isolated from 6 sporophore site soils of R. griseocarnosa, which belonged to 34 OTUs (16 genera of 3 phyla). The three genera with the highest abundance were Bacillus , Burkholderia and Streptomyces. Genus-level-Sample network analysis showed that the distribution of culturable bacteria was randomly nested. Bacillus and Burkholderia are important groups in the community, which have more Effective Partners, Closeness and high Species Strength in the bacterial community.  Conclusion   There are abundant bacterial resources in the sporophore site soil of R. griseocarnosa. Combining the analysis of bacterial abundance and network structure can predict the interaction between bacteria more clearly.
Models for Estimating Morphological Characteristics of Pennisetum giganteum Leaves
BU Jianchao, ZHOU Tonghui, LIN Zhanxi, BAI Nini, XIA Jie, LIN Hui, LIN Dongmei, LIU Fengshan
2022, 37(4): 538-546. doi: 10.19303/j.issn.1008-0384.2022.004.015
Abstract:
  Objective  Mathematic models for estimating the morphological characteristics of Pennisetum giganteum leaves were constructed to facilitate the utilization of the plant material.   Method  Measurements on the length, width, area, and fresh weight of P. giganteum leaves were collected. Specifically, 7 parameters including length, width, (length× width), (length – width), (length + width), (length)2, and (width)2 of the leaves were used to construct fresh weight estimation models using univariate linear regression, binary linear regression, and quadratic trinomial analyses.   Result  The correlations among the various measurements had coefficients ranging from 0.74 to 0.91. The estimation models with the highest R2 = 0.99 was on yA = 0.72xP, where yA = leaf area and xP = (length×width), and R2=0.96 on yF=0.02xP, where yF = fresh weight and xP = (length×width). The verification test on the regression equations between the estimated and actual leaf area showed R2 = 0.99 with an RMSE of 18.67 cm2 for leaf area and an RMSE of 0.67 g for fresh leaf weigh.   Conclusion   The models for estimating the area and fresh weight of P. giganteum leaves had high degree of validity in providing basic information for Juncao research.
Review
Molecular Mechanisms of Nitrogen Absorption, Transport, and Assimilation in Plants
DUAN Yongkang, YANG Haiyan, WU Wenlong, LI Weilin
2022, 37(4): 547-554. doi: 10.19303/j.issn.1008-0384.2022.004.016
Abstract:
Nitrogen is one of the essential elements for plant growth and development. External application of nitrogen promotes plant growth, but excessive fertilization can induce a host of problems on soil and water pollution, ozone layer depletion, and agricultural production cost escalation. In nature, to efficiently utilize the resource, plants have evolved mechanisms that regulate the absorption of the critical nutrient transported from the land. This article reviews such fundamental natural functions, in addition to the processes of NO3N, NH4+-N, and organic nitrogen assimilations as well as the roles of transcription factors and miRNAs in response to nitrogen fertilization. Based on the information, improvements on the nitrogen use efficiency of plants, agriculture productivity, and breeding and cultivation of new crop varieties could be studied and realized.