10 December 2021, Volume 35 Issue 12
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2681-2687. https://doi.org/10.11869/j.issn.100-8551.2021.12.2681
In order to understand the difference in the response of wild and cultivated lotus seeds to the gamma rays,60Co-γ radiation with various doses were used to treat the seeds of Nelumbo nucifera Weishan Hong and 50 cultivars. It was found that the numbers of spread leaves and roots, survival rate of the seedlings dropped sharply when the seeds were treated at 320 Gy for wild Weishan Hong, the treatment of higher doses at 750 and 1 000 Gy severely inhibited unfolding of the young leaves, and the survival rates of the seedlings were 0.6% and 0, respectively. By analysis with the linear regression, the semi-lethal dose of 60Co-γ for the seeds of wild lotus Weishan Hong and cultivated locus was 192 and 173 Gy, respectively, indicating the higher tolerance of the Weishan Hong seeds to 60Co-γ radiation. From 1 150 irradiated seeds of Weishan Hong, a mutant with narrow tepals was obtained, then a new cultivar chenshan Feiyan was bred. For this cultivar, the mean width/length of the tepals was 0.31, which was significantly lower than 0.44 of the wild type Weishan Hong. Also, the tepal number per flower, flower density and emerging leaf density were significantly reduced. Based on this study, the suggested irradiation dose of seeds from wild and cultivated lotus could be 150 - 200 Gy and 130 - 180 Gy, respectively, for future radiation breeding and mutant induction. This research gives technical references to create new germplasms by large-scale radiation of seeds with γ rays in lotus industry, and also provides a good parent for producing novel cultivars with specific tepal-shapes.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2688-2695. https://doi.org/10.11869/j.issn.100-8551.2021.12.2688
In order to create germplasm resources resistant to stem rot in hybrid Cymbidium, protocorm-like bodies (PLBs) of Cymbidium Yunv were employed to establish the method of screening the mutants resistant to stem rot using heavy ion beam irradiation and crude toxin leachate of Fusarium oxysporum. The results showed that the mortality rates of PLBs irradiated by various irradiation dosage of 12C6+heavy ion beam were significantly different, and the mortality rate was 54.32% when the irradiation dosage was 50 Gy. Crude toxin leachate of Fusarium oxysporum had significant inhibitory effect on survival rate of PLBs in Cym. Yunv, and the survival rate was 41.98% when the concentration of crude toxin leachate was 80%. After the PLBs of Cym. Yunv were irradiated by 12C6+heavy ion beam with 50 Gy, 14 lines resistant to stem rot were obtained by stepwise selection method with the screening rate being 4.67%, and eventually, three lines, Z50Gt1, Z50Gt2 and Z50Gt3, were gained after differentiation, rooting and strong seedling culture, and transplanting in turn. The activity of SOD and POD in PLBs of resistant lines was higher than that of in control, and the peak value of the POD increased by 826.67 U·g-1·h-1compared with the control, while the content of MDA in PLBs of resistant lines was higher within 36 h and lower after that compared to the control. The test-tube seedlings of Z50Gt2 and Z50Gt3 showed the resistance to stem rot by artificial inoculation, and the disease indices of seven-month-old pot plants of the two lines were significantly lower than that of control, and the resistant level reached resistant rank. The results laid a foundation of creating new cultivars with resistance to stem rot by heavy iron beam irradiation breeding in hybrid Cymbidium.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2696-2703. https://doi.org/10.11869/j.issn.100-8551.2021.12.2696
A pale yellow leaf 3(pyl3) mutant was isolated from the 60Co-γ radiation mutagenized population of indica rice restorer Chuanhui907 (R907). To clarify the regulation mechanism of the pale yellow leaf phenotype in pyl3 mutant, phenotype identification, major agronomic traits and gene mapping analysis were performed in this study. The results showed that pyl3 mutant exhibited a pale yellow leaf phenotype from the seedling stage to mature stage. Chlorophyll and carotenoid contents were significantly reduced in pyl3 leaves at seedling stage and most agronomic traits including plant height, panicle length, grain number per panicle and seed setting rate of pyl3 were significantly decreased at mature stage. Genetic analysis indicated that the phenotype of the pyl3 mutant was controlled by a single recessive nuclear gene. The candidate gene was preliminarily mapped to a 3.2 Mb region between InDel markers M4 and M6 on chromosome 3 by using molecular marker linkage analysis. Further Bulked-Segregant Analysis (BSA) based whole genome resequencing and sanger sequencing analysis showed that a point mutation (C1034T) in the CHLI gene, which encoded the Mg-protoporphyrin Ⅸ chelatase Ⅰ subunit, resulted a substitution of Tyr by Cys at the 345thposition of the encoding protein, suggesting that the CHLI pyl3gene in pyl3 mutant is a novel allele of the chl9/chli gene. Additionally, the qRT-PCR analysis showed that the expression levels of chlorophyll synthesis and photosynthesis related genes were altered in pyl3 mutant. This study provides a new genetic material and theoretical basis for further studying the molecular regulation mechanism in rice leaf color.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2704-2715. https://doi.org/10.11869/j.issn.100-8551.2021.12.2704
Natural polyploid has not been found in Eucalyptus yet. Therefore, the establishment of artificially inducing unreduced 2n pollen technology is of great significance for promoting the creation and genetic improvement of polyploid germplasm in Eucalyptus. In this study, Eucalyptus pellita was used as the research material to explore the characteristics of flower bud development and microsporogenesis. Colchicine treatment was applied to the buds at different developmental stages to induce pollen chromosome doubling. Results showed that the proportion of flower buds in the meiosis stages from leptotene to pachytene was the highest when they were at 48 hours after the initiation of meiosis. During this period, the flower branches closed to the inflorescence were cut an incision and infused with 0.5% colchicine solution for 6 hours. In this way, the efficiency of artificially induced 2n pollen was reached up to 31.34%. The morphology of 2n pollen was significantly different from the normal haploid pollen. This study revealed the temporal relationship between flower bud development and microsporogenesis in E. pellita, and established a method to instantly identify the specific meiosis stage of microsporogenesis based on the location and development time of flower buds. The best and optimal timing and treatment conditions for inducing unreduced 2n pollen with colchicine solution were also clarified. This study laid an important foundation for further innovation of polyploid germplasm in Eucalyptus species.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2716-2723. https://doi.org/10.11869/j.issn.100-8551.2021.12.2716
The aim of this study was to investigate the expression and localization of heat shock protein27 (HSP27) gene in yak oocytes and early parthenogenetic activated embryos. In this experiment, real-time fluorescence quantitative PCR (RT-qPCR) and Immunofluorescence staining techniques were used to detect the relative mRNA expression and differential distribution of yak HSP27 gene in immature oocytes, mature oocytes, and parthenogenetic activated early embryos at different stages. The qRT-PCR results indicated that yak HSP27 gene expressed in immature oocytes, mature oocytes, in vitro cultured parthenogenetic activated 2~4 cell stage embryos, 5~8 cell stage embryos, mulberry embryos, and blastocyst stage embryos. The expression of yak HSP27 at the oocyte stage in immature oocytes and mature oocytes was significantly different. The highest expression level was found in the 24 cell stage embryos in vitro, whereas the lowest expression level was detected in blastocyst stage embryos in early parthenogenetic activation stage. The expression of HSP27 decreased gradually with embryo development. In vitro cultured parthenogenetic activated 24 cell stage and blastocyst embryos, expression in parthenogenetic activated blastocyst embryos was significantly different from other experimental groups (P<0.05), but the differences in expression between 5~8 stage embryos and morula stage embryos were not significant (P>0.05). Immunofluorescence staining showed that yak HSP27 protein expressed in cumulus cells and oocytes, and it was mainly found in the nucleus and cytoplasm in parthenogenetic activated 2~4 cell stage, 5~8 cell stage, and mulberry embryos in vitro. During the blastocyst stage, HSP27 protein was expressed was mainly in the cytoplasm and was consistent with the expression of gene. These results show that the expression of HSP27 in yak immature oocytes and mature oocytes was significantly different, with the development of parthenogenetic activated embryos, the expression gradually decreased. It was speculated that HSP27 plays an important role in yak oocyte maturation, embryogenesis, and development. Our study provides theoretical reference for further exploring the role of HSP27 in yak reproductive physiology.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2724-2732. https://doi.org/10.11869/j.issn.100-8551.2021.12.2724
Linalool synthetase (LIS) is a key enzyme in the synthesis of linalool-a plant aroma compound. In order to understand the function of this enzyme in contribution to the formation of fragrance in the scented Rhododendron species-Rhododendron fortunei, we have cloned a gene coded this enzyme and subsequently examined the relationship between the gene expression patterns and the linalool content during development in various tissues. The full length of LIS gene was cloned by RT-PCR (Reverse transcription-polymerase chain reaction)and RACE(Rapid amplification of cDNA ends)techniques, LIS gene expression levels were measured by qRT-PCR (Real-time quantitative reverse transcription PCR) technology and the amount of linalool compounds were assayed with SPME-GC-MS (Solid-phase micro-extraction and gas chromatography-mass spectrometry). The results showed that the ORF of LIS gene amplified from the cDNA templates of flower buds was 1335 bp in length, encode 444 amino acids which shared 40% to 50% homologous to the LIS amino acid sequences from other species. qRT-PCR analysis indicated that the expression level of LIS gene decreased first and then increased in the petals at different stages from buds to blooming and reached the highest in full blooming. It is interesting to note that the expression level in petals was the highest in comparison with that in other tissues, and the expression in stamens was much higher than that in pistils, in new leaves was higher than in old leaves. The linalool contents measured by SPME-GC-MS showed highly positively correlated to the expression level of LIS gene in various tissues and at different flowering stages, implying that the linalool compounds in the flower scent of Rh. fortunei were likely regulated by the LIS gene. This study could have given us insights for the breeding and improvement of fragrant Rhododendron cultivars.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2733-2745. https://doi.org/10.11869/j.issn.100-8551.2021.12.2733
Ethylene responsive factor (ERF) plays an important role in the signal transduction pathways of plant disease resistance through activating or inhibiting enhancement the expression of downstream disease-related protein genes. In order to explore the molecular regulatory mechanism of ERF-B3 subgroup gene GhB301 in cotton resistance to Fusarium wilt, using the obtained GhB301 transgenic cotton lines were used as material in this study. The spore suspension was dipped into the roots to transfect GhB301 transgenic cotton strains (N) and wild-type controls (WT). Results of disease resistance identification showed that GhB301 overexpressing of the transgenic cotton lines enhanced their disease resistance to Fusarium wilt with a disease index of 14.77%,which was significantly lower than that of the WT (the disease index was 37.50%). RNA-seq technology was used to sequence and analyze root tissues of fuse-infected N and WT at 0, 6, 12, 24 and 48h after infection. Totally 273 111170 clean reads were obtained,and their Q30 were all greater than 87.64%. The clean reads were compared to the reference genome tm-1 of upland cotton, and 14021 differentially expressed genes (DEGs) were obtained. Compared with the WT, the transgenic strains could respond more quickly after pathogen infection. GO and KEGG enrichment analysis revealed that a total of 135 DEGs were involved in the REDOX process, 67 DEGs were involved in the defense reaction, and 31 DEGs were involved in phenylpropane biosynsynthesis. We speculated that these DEGs may be closely related to the increased Fusarium wilt resistance in transgenic cotton. The results of this study laid a foundation for elucidating the response of GhB301 gene to cotton Fusarium wilt infection..
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2746-2755. https://doi.org/10.11869/j.issn.100-8551.2021.12.2746
In order to study the genetic diversity of squash and pumpkin (Cucurbita) cultivars and landrace, molecular marker analysis of 35 accessions were investigated with 43 simple sequence repetition (SSR) markers. The agronomic traits were also investigated. The results showed that all the SSR markers can produce polymorphic bands among 35 accessions. A total of 155 alleles were detected with an average of 4.1 alleles for individual marker. The polymorphism information content (PIC) was ranged from 0.130 8 to 0.775 4 with an average value of 0.487 2. The cluster analysis of 35 accessions by the unweighted pair group average method with arithmetic mean (UPGMA) indicated that all the accessions could be divided into three categories, corresponding to the American squash (C. pepo L.), Chinese pumpkin (C. moschato Duch) and Indian squash (C. maxima Duch), of which the Indian squash had a closer genetic relatedness to the American squash. Analysis of the agronomic characters of different accessions indicated that dramatic diversity in the agronomic traits was found not only among different species but also among different cultivars of the same species. This study provided a reference for further study on the genetic structure, fingerprinting construction, and molecular breeding of cucurbita cultivars.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2756-2765. https://doi.org/10.11869/j.issn.100-8551.2021.12.2756
In order to screen superior table grape cultivars that are suitable for cultivation in Weinan area of Shaanxi Province and optimize the planting structure of table grape cultivars, ten table grape cultivars including Xinyu, Flame Seedless, Zicui Seedless, Zaoheibao, Summer Black, Zitian Seedless, Hutai No.8, Jumeigui, Shine Muscat, Gold Finger were introduced for cultivation. Field observation and laboratory detection were used in the introduction experiment. The phenological phase and botany properties of the experimental cultivars were observed and recorded, physical and chemical compositions of berries were measured and sensory quality of berries was evaluated. Finally, the berry quality was evaluated comprehensively and ranked with the method of principal component analysis (PCA). The results showed that there were differences among the cultivars in the phenological phase, the botany properties, the physical and chemical compositions and the sensory scores under the conditions of simple rain shelter in Weinan area. The PCA analysis indicated that Xinyu and Hutai No.8 showed better quality, and the quality of Zaoheibao, Shine Muscat, Zitian Seedless were general, but the other cultivars were poor. Xinyu and Hutai No.8 were suggested to be the prior, and the cultivars of Zaoheibao, Shine Muscat and Zitian Seedless could be scaled up moderately. However, the other cultivars were not recommended to plant in large-scale in this area or the cultivation management for planting them had been improved. The results could provide some references for introduction of superior cultivars and planting structure optimization of table grape cultivars in Weinan area.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2766-2775. https://doi.org/10.11869/j.issn.100-8551.2021.12.2766
In order to enhance the vitamin D2 content in Lentinus edodes, and evaluate the effects of UV-B treatment on nutrient qualities, active oxygen metabolism-related enzyme activities and ultrastructure of L. edodes. fresh L. edodes was exposed to UV-B light at 0.203 mW·cm-2for 0.5, 1, 2, 3 and 4 h, respectively. Compared with control group, the vitamin D2 content of 2 h UV-B treatment was significantly increased from not detectable to 104.87 μg·g-1, however prolonged processing time could not significantly increase the vitamin D2 content. The vitamin C content increased gradually to 46.1 μg·g-1by 2 h of UV-B treatment. Organic acid, soluble sugar, and reactive oxygen species were not sensitive to the UV-B treatment. In comparison, long time UV-B treatment could significantly deepen the surface color, which also caused cell damage, and increase membrane permeability. Compared with the control group, an increase of 20.61% and 63.25% in relative conductivity were found for 2 and 3 h UV-B treatment, respectively. Meanwhile, the nutrient qualities of L. edodes with 2 h UV-B treatment showed good stabilities during the storage. These results indicated that 2 h UV-B treatment could increase vitamin D2 and vitamin C contents, as well as increased the antioxidant system of L. edodes, with no significant negative effects on nutritional qualities observed, which provided references for the commercial value improvement of L. edodes.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2776-2786. https://doi.org/10.11869/j.issn.100-8551.2021.12.2776
To solve the serious loss of nutrients in heat-sterilized kiwifruit juice, the effects of different heat-assisted ultrasonic treatment process parameters on the physicochemical characteristic indexes of kiwifruit juice and its sterilization effect were studied, and the optimal process parameters were obtained. Taking cloudy kiwifruit juice as sample, the physicochemical indexes and antibacterial rate were used as response values to optimize the conditions of ultrasonic power, ultrasonic time and temperature, the models of bactericidal rate and physicochemical characteristics of cloudy kiwifruit juice were established based on the extracted physicochemical characteristic indexes of cloudy kiwifruit juice. The results showed the physicochemical characteristic indexes were preservation rate of chlorophyll, PPO activity, ΔE value, and the ratio of sugar to acid. The optimal parameters for thermalassisted ultrasonic treatment of cloudy kiwifruit juice were as follows: the ultrasonic power was 420 W, the ultrasonic time was 30 min and the temperature was 60℃, and the preservation rate of chlorophyll was 30.99%, PPO activity was 19.48 U·mL-1, ΔE value was 4.43, the ratio of sugar to acid was 6.17, and the antibacterial rate was 95.68%. This study provides a technical guidance for the processing and production of cloudy kiwifruit juice.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2787-2798. https://doi.org/10.11869/j.issn.100-8551.2021.12.2787
In order to identify the polyphenolic compounds in daylily and study the influence of blanching and storage at room temperature on their stability, response surface methodology and orthogonal experiment design, quadrupole time-of-flight liquid mass tandem system and triple quadrupole liquid mass tandem system were employed to optimize the technological parameters for extraction and identification of polyphenols by ultrasound-assisted extraction, and adsorption by HPD-600 macroporous resin, and desorption by ethanol. The content of polyphenols from fresh, blanched and stored daylily at room temperature were analyzed. The results showed that the optimal conditions for ultrasonic-assisted extraction of polyphenols were ethanol concentration 66%, time 22 min, temperature 43℃, material-liquid ratio 1∶12 g·mL-1, and the yield of polyphenols was 2.12%. The optimum conditions for HPD-600 macroporous resin adsorption of polyphenols were temperature 50℃, pH 6, adsorption time 3 h, and polyphenol adsorption rate was 28.76%. The best conditions for desorbing polyphenols by ethanol were temperature 60℃, pH 6, desorption time 3 h, under which polyphenol desorption rate was 78.94%, and the concentration of purified polyphenol solution was 0.61%. LC-MS/MS (HPLC/ESI-QTOF-MS) analysis showed that the main polyphenolic compounds in daylily were rutin, chlorogenic acid and quercetin in descending order. At the same time, the data also demonstrated that polyphenols from daylily were sensitive to temperature. High temperature blanching and storage induced significant loss of polyphenol, resulting in a decline in the nutritional quality of daylily. This study provides references for the isolation and identification of daylily polyphenols, as well as their stability during blanching and storage.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2799-2809. https://doi.org/10.11869/j.issn.100-8551.2021.12.2799
The gardenia yellow liposomes were prepared by ethanol injection method. The reaction parameters of gardenia yellow liposomes were optimized by response surface methodology, in which encapsulation ratio (EE) of gardenia yellow was taken as the index. The structure and morphology were characterized by Zeta potential, particle size, Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). In addition, chitosan was used to modify the surface of gardenia yellow liposomes. The stability of chitosan modified gardenia yellow liposomes was studied by analyzing the changes of Zeta potential, particle size and release rate in the liposomes treated with UV irradiation, heating and in vitro simulated digestion. The results showed that the optimal reaction conditions were as follows: stirring temperature 51.5℃, mass ratio of lecithin/cholesterol 5.2∶1, buffer liquid volume 32.4 mL, and the yield of gardenia yellow liposome EE 78.36%. According to the result of Zeta potential, particle size, FT-IR and TEM analysis, gardenia yellow liposomes were proved to be successfully prepared, and the average particle size increased from 203.77 nm to 282.17 nm. In addition, the results of UV irradiation, heating and in vitro digestion showed that the stability of chitosan modified liposomes was significantly higher than that of unmodified liposomes. The study can provide theoretical basis for the preparation and application of water-soluble carotenoid liposomes.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2810-2820. https://doi.org/10.11869/j.issn.100-8551.2021.12.2810
In order to realize the rapid detection of microcystin-LR (MC-LR), a sensitive, simple and efficient detection method was established by optimizing the concentration of salt solution and the aptamer concentration of MC-LR based on aptamers and gold nanoparticles technologies. According to the reported aptamer sequence specific to MC-LR (Apt-1), its secondary structure was fitted and analyzed by Mfold software. Moreover, a new aptamer sequence (Apt-3) was designed and synthesized by the site-directed mutation, which had a completely different secondary structure from Apt-1. The AuNPs colorimetric detection system was constructed using these two adapters, and the concentration of each component in the reaction mixture were optimized. The results indicated that the visual detection limit of MC-LR was 70 ng·mL-1using the (Apt-1)-AuNPs system, whereas it was 30 ng·mL-1by the (Apt-3)-AuNPs system. When the concentration of NaCl and Apt-3 was 0.05 mol·L-1and 0.06 μmol·L -1, respectively, a good linear calibration relationship was obtained between A673/A520 and concentration of MC-LR within the range of 0120 ng·mL-1. The linear regression equation was y = 0.007x + 0.564 (R 2=0.988 5), and the detection limit was calculated to be 7.08 ng·mL-1. At the same time, the specificity of the AuNPs-Apt system was evaluated. Compared with the Apt-1, Apt-3 has higher specificity and binding affinity to MC-LR. This study would provide a basis for the subsequent optimization of aptamer sequence and structure, and the development of sensitive sensors.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2821-2829. https://doi.org/10.11869/j.issn.100-8551.2021.12.2821
To provide a theoretical basis for the safety evaluation and promotion of genetically modified (GM) soybean, we studied the effects of GM soybean GTS40-3-2 on the organ and reproductive functions of male rats. In this study, female and male rats were randomly divided into two groups and fed diets containing GM or non-GM soybean components for 90 d, respectively. Then by mating within the parental rat groups, the offspring rats were obtained, which fed the corresponding feed after weaning. After 30, 60 and 90 d of feeding, the testes, epididymis, brain, heart, lungs, liver, spleen, kidneys and adrenal glands of the offspring rats were extracted and their organ coefficients were examined; paraffin sections of testes, epididymis, kidneys and lungs were prepared, respectively, to observe the histological changes of each organ; the expression changes of glucose transporter 8 (GLUT8) gene, a restriction protein for androgen synthesis in testes, were examined by real-time PCR and further verified by enzyme-linked immunosorbent assay (ELISA). The results showed that there was no significant difference in the organ coefficients of the nine organs after 30 d and 90 d feeding compared with the control group (P>0.05); after 60 d feeding, only the organ coefficients of lung and epididymis were significantly different (P<0.05), but there was no biological significance; there was no significant structural changes observed in testis, epididymis, kidney and lung by microscopic examination of tissue sections; the transcript level and protein level of GLUT8 gene in testis were not significantly affected (P>0.05). These results revealed that the feed containing GM soybean GTS40-3-2 had no any adverse effects on the vital organs of male offspring rats during the experimental period, and also on male reproductive organs and their physiological functions. This study further expanded the research depth of safety evaluation of GM soybean, which was of great significance to the popularization and application of GM soybean.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2830-2840. https://doi.org/10.11869/j.issn.100-8551.2021.12.2830
The Rhizobacteria plays a crucial role in plant growth, development and health. In this study, rhizosphere soils of seven different crops, including soybean [Glycine max (L.) Merr.], maize (Zea mays), peanut (Arachis hypogaea L.), kidney bean (Phaseolus vulgaris L.), cowpea [Vigna unguiculata (L.) Walp], sweet potato [Ipomoea batatas (L.) Lam.] and cocoyam [Colocasia esculenta (L.) Schoot], were collected in July 2017 to explore the effects of crop taxa on rhizosphere microbiomes. Illumina MiSeq sequencing and phospholipid fatty acid (PLFA) were used to investigate the microbial community structure and diversity of rhizosphere soil. The difference in microbial PLFA biomarker contents among different crops were observable. Compared with the other crops, the total PLFAs and the biomass ratio of fungi and bacteria (F/B) in the rhizosphere soil of peanut were the highest, whereas the biomass ratio of gram positive bacteria and gram negative bacteria (G+/G-) was the lowest. Although the seven groups had similar dominant phyla, such as Proteobacteria, Actinobacteria, Acidobacteria and Firmicutes, their bacterial compositions at the class and order level were obviously different. Alpha diversity analysis showed that the OTU richness (Chao1, P <0.001) and bacterial community diversity (Shannon, P <0.001) in the rhizosphere of soybean was the highest among the seven crops. Non-metric multidimensional scale analysis (NMDS) revealed that the rhizosphere microbial community structure formed significant clustering with different crops under OTU and PLFAs levels. The screening and comparison of sensitive microorganisms in the rhizosphere further showed that crops had distinctive selection of the rhizosphere bacterial community and species-sensitive microorganism. These results indicated that the rhizosphere microbiome was correlated with crop taxa. This study can provide a basis on which to construct a healthy plant rhizosphere microbiome to improve plant breeding.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2841-2849. https://doi.org/10.11869/j.issn.100-8551.2021.12.2841
To clarify the toxic effect of excessive selenium (Se) application on crop growth and provide a basis for rational application of Se fertilizer, the effects of foliar spraying of excessive Se on yields and contents of Se and mineral elements of the waxy maize cultivar Jingkenuo 2000 and the common maize cultivar Zhengdan 958 were investigated under field conditions. The results showed that when the amount of Na2SeO3 sprayed on the leaf surface was ≤ 0.2 g·L-1, the plant biomass and grain yield of the waxy corn Jingkenuo 2000 were equal to the control treatment or slightly increased, and no toxic effect was observed. When the spraying amount of Na2SeO3 on Jingkenuo 2000 and Zhengdan 958 exceed 0.5 g·L-1and 0.1 g·L-1, respectively, the biomass and grain yield decreased significantly. With the increase of the spraying amount of Na2SeO3, the Se concentrations in grains of these two maize cultivars were increased gradually. The yield and Se concentration in grain of Zhengdan 958 were more sensitive to the spraying amount of Na2SeO3 than that of Jingkenuo 2000. Foliar Na2SeO3 spraying could significantly promote the absorption of zinc (Zn) and iron (Fe) by maize grains, but had insignificant effects on the absorption of copper, phosphorus, magnesium and calcium, and inhibited the absorption of boron. In general, excessive foliar Na2SeO3 spraying inhibited maize yields, but improved the nutritional status of Se, Zn and Fe of the two maize cultivars; these results provided meaningful guidance on the regulation of micronutrient nutrition in maize plants.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2850-2859. https://doi.org/10.11869/j.issn.100-8551.2021.12.2850
In order to investigate the effects of nitrogen application rate and planting density on grain yield and nitrogen use efficiency of double cropping rice production system (Oryza sativa L.) under mechanized direct-seeding, two high quality rice varieties such as Qiliangyou 2012 and Meixiangzhan 2 were used in field trials in 2018 and 2019. Four nitrogen application rates such as 0 (N0), 120 (N1), 150 (N2) and 180 (N3) kg·hm-2were for early season rice and 0 (N0), 120 (N1), 165 (N2) and 210 (N3) kg·hm-2were for late season rice. In addition, three mechanized direct-seeding densities i.e. 86 (S1), 143 (S2), 200 (S3) seeds·m-2were for early season rice, and 57 (S1), 114 (S2), 172 (S3) seeds·m-2were for late season rice. The growth and development, grain yield, yield components, characteristics of nitrogen uptake and utilization of double cropping rice population were investigated. The results showed that the increase of nitrogen application and sowing density were beneficial to the increase of double cropping rice yield. The highest yields of early and late rice were obtained under N3 and N2treatments, and increased by 11.41%~12.32% and 8.58%~9.21% compared with N1treatment, respectively. Compared with S1treatment, S2 and S3 treatments increased yield by 8.71%~10.38% and 8.33%~10.89% for early rice, respectively; and yield increased by 6.33%~8.11% and 6.78%~8.56% for late rice, respectively. There was no significant difference in yield between N2S2 and N3S2 treatments for early rice. The possible reasons for the increased yield of mechanized direct-seed double cropping rice may attribute to the higher dry matter accumulation and leaf area index, the higher amount of nitrogen uptake after heading and the advantage of carbon and nitrogen accumulation at tillering stage. The N2S2 treatment showed a higher leaf area index, dry matter mass and nitrogen accumulation, and which also had higher nitrogen agronomic utilization, nitrogen physiological utilization and nitrogen absorption utilization for mechanized direct-seed double cropping rice. Therefore, yield improvement and higher efficiency of mechanized direct-seed double cropping rice be integrated in the combination of 150 kg·hm-2with 143 seeds·m-2for early rice and 165 kg·hm-2with 114 seeds·m-2for late rice. The study provides a theoretical basis for rational dense planting and optimal nitrogen management for mechanized direct-seeding double cropping rice production.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2860-2868. https://doi.org/10.11869/j.issn.100-8551.2021.12.2860
A two-year field experiment was conducted to investigate the responses of dry matter accumulation, yield and nitrogen use efficiency of different non-waxy and waxy broomcorn millet varieties to different nitrogen levels. Non-waxy broomcorn millet Longmi No.13 and waxy broomcorn millet Longmi No.14 were used as experimental materials, and 45 kg·hm-2(N1), 90 kg·hm-2(N2) and 135 kg·hm-2(N2) with no nitrogen as control (CK) were set under field condition. The dry matter accumulation and translocation, agronomic traits and yield of non-waxy and waxy broomcorn millet varieties at the anthesis and maturity stages were studied under three different nitrogen supply levels. The responses of nitrogen accumulation, nitrogen agronomic efficiency, nitrogen partial factor productivity, nitrogen utilization efficiency, nitrogen apparent recovery efficiency were further analyzed. The results showed that the dry weight of aboveground organs of different broomcorn millet showed a single peak curve with the increase of nitrogen application rate. The dry weight of stem, leaf, sheath and panicle were significantly higher than those without nitrogen application (P<0.05) under the treatment of 90 kg·hm-2at the anthesis and maturity stages. The nitrogen partial productivity of different broomcorn millet decreased with the increase of nitrogen application rate, while the nitrogen use efficiency decreased first and then increased. The nitrogen application with 90 kg·hm-2can significantly improve the plant height, stem diameter, panicle length, grain weight per panicle, 1000 grain weight and yield, and elevate nitrogen agronomic efficiency, nitrogen apparent recovery efficiency of different non-waxy and waxy broomcorn millet varieties. The two-year date showed that the agronomic characteristics, yield and nitrogen use efficiency of Longmi 13 treated with 90 kg·hm-2were better than those of Longmi 14. For this study, the recommended amount of nitrogen fertilizer for planting different non-waxy and waxy broomcorn millet varieties in Huining area of Gansu Province was 90 kg·hm-2, which has a guiding significance for planting different non-waxy and waxy broomcorn millet in Northwest China.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2869-2878. https://doi.org/10.11869/j.issn.100-8551.2021.12.2869
In order to explore the response of dry matter accumulation and yield of spring maize(Zea mays L.) to hydrothermal change regulated by sowing date, a four-year sowing date (May 1, 10, 20, 30) experiment was conducted in 2017-2020 with genotypes (“Jingnongke728” and “MC812”)at the experimental station of Hebei Normal University of Science & Technology. Due to the difference in temperature and precipitation at different growth and development stages, there are changes in the dry matter accumulation amount, yield and water use efficiency of spring maize. The results showed that affected by temperature and precipitation, the dry matter accumulation of spring maize decreased with the delay of sowing date in the early and middle growth stages, but the most amount of dry matter accumulation appeared at the treatment of sowed on May 30 from mid-filling stage to maturity stage. The dry matter accumulation dynamics in spring maize was consistent with the Logistic model. The total duration of dry matter accumulation and the duration of the rapid growth period of spring maize sowed on May 30 were the longest. The effective ears number, ear diameter, corn-cob diameter, ear row number and seed rate were not affected by temperature and precipitation, while the value of grain number per ear-corn, 1 000-grain weight, ear length and row kernel number was firstly decreased and then increased with delayed sowing date, and the minimum value appeared at the treatment of sown on May 20. The yield had significant positive correlation with 1 000-grain weight, the yield was the highest in the treatment of sown on May 30. In addition, total water consumption was reduced with the delay of the sowing date, while water use efficiency was increased. Reasonable arrangement of sowing date and paying attention to the influence of rainfall on the growth and yield formation of spring maize are important measures for the high yield of Spring Maize in Eastern Hebei Province. This study provided theoretical basis and technical support for the selection of spring maize sowing date in Eastern Hebei Province.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2879-2892. https://doi.org/10.11869/j.issn.100-8551.2021.12.2879
In order to reveal the physiological mechanism of trehalose and transgenic rice with high expression of maize C4-type PEPC gene during the seed germination under drought stress, C4-PEPC transgenic rice (PC) and wild type rice Kitaake (WT) were used in this study. Under different concentrations of trehalose combined with drought treatment, their seeds viability, soluble sugar and proline content, α-amylase activity and its associated genes, the expression of PEPC-related genes, sugar signal-related genes, and some trehalose genes during germination were measured. The results showed that drought treatment significantly inhibited the germination rate of the two materials, and their growth of shoot as well; the external low concentration trehalose treatment could alleviate the inhibition of rice seed germination under drought treatment. As compared with WT, PC was more sensitive to trehalose. 0.5 mmol·L-1trehalose showed the obvious mitigation effect on PC, which was better than that of WT under 10 mmol·L-1trehalose. External application of 0.5 mmol ·L -1trehalose combined with drought treatment could maintain the higher values of seed vigor, the content of osmotic regulators and the activity of α-amylase in rice seeds, especially being beneficial to PC. External application of 0.5 mmol·L -1trehalose could increase the expression levels of calcium-dependent CBL1-OsSnRK3.1/3.23 in PC, activate OsK1a-OsMYBS1/2-OsAmy3/8 pathway, and induce OsTPP1/7 to synthesize trehalose, increase sucrose and glucose contents, and then accelerate the mobilization of glucose metabolism and maintain seed germination. In addition, trehalose also up-regulated the transcriptional levels of SAPK8/9/10 and C4-PEPC in PC line, which made PC show drought tolerance at bud stage. This study provides new clues for improving the germination rate of rice varieties by direct seeded and the improvement of "C4" rice.
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Journal of Nuclear Agricultural Sciences. 2021, 35(12): 2893-2903. https://doi.org/10.11869/j.issn.100-8551.2021.12.2893
In order to clarify heat tolerance of different genotypes of hybrid rice and to determine the effect of Brassinolide (BR) application on heat tolerance, two Indica Hybrid Rice, two Indicaclinous Hybrid Rice, and two Japonicaclinous Hybrid Rice were used as materials and three treatments (normal temperature, high temperature, and high temperature with 0.15% BR) were designed to determine the yield and yield components, seed setting rate, pollen fertility, and antioxidant capacity. The results indicated that high temperature significantly decreased seed setting rate, yield per plant, and pollen fertility. The heat tolerance coefficient of Indica Hybrid rice was 0.73, which was significantly higher than that of Japanicaclinous Hybrid rice(0.47). BR application under high temperature can signifig cantly increase rice seed setting rate, yield per plant, and pollen vigor. The recovery coefficients of Indica Hybrid Rice, Indicaclinous Hybrid Rice and Japonicaclinous Hybrid Rice were 1.23、1.43 and 2.00, respectively. Mitigation effect of Japonicaclinous Hybrid Rice was the most significant. BR application increased Gly Ⅰ activity and AsA and GSH content, and reduced superoxide content and the expression levels of the antioxidant enzymes genes (OsAPX1, OsCATB, OsGPX3 and OsGLYI8) under high temperature. The yield of Indica Hybrid rice was lower than that of Indica-Japonica Hybrid rice under normal temperature, while it had strong high temperature resistance. BR application can increase Hybrid rice yield under high temperature, at which the yield of Indica Hybrid rice was significantly lower than that of Indica-Japonica Hybrid rice. Although Indica-Japonica Hybrid rice, especially Japonicaclinous Hybrid rice, is sensitive to high temperature, the interaction with BR can effectively increase yield under high temperature, which was the same as under normal temperatures. The results of this study provide a theoretical basis and practical experience for the research on improving hybrid rice yields during flowering period under high temperature.
