10 May 2017, Volume 31 Issue 5
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 829-836. https://doi.org/10.11869/j.issn.100-8551.2017.05.0829In understand the roles of glycerol-3-phosphate dehydrogenase gene in stress tolerance in rice, a gene encoding glycerol-3-phosphate dehydrogenase, named as OsGPDH1, was cloned from Nipponbare(Oryza sativa L. ssp. Japonica)in this study. OsGPDH1 encodes a protein that has NAD(P)+ binding domain and dehydrogenase domain. And the two domains are highly conserved in plants. The real-time RT-PCR analysis showed that OsGPDH1 was expressed in flag leaf, spikelet, stem, sheath, node of adult plant, which indicates the gene involved in the process of growth and development of rice. After stress treatments, OsGPDH1 could be induced by PEG6000, salt, hydrogen peroxide, methyl jasmonate (m-JA) as well as salicylic acid (SA), and its expression often reached the peak after 12h. However, OsGPDH1 was insensitive to ABA. The overexpressing gene vector was constructed and transferred into rice, and transgenic plants were obtained. The germination rate of overexpressional plants was higher than the wild-type rice under salt treatment, indicating that enhancing OsGPDH1 expression can improve tolerance to salt stress. The survival of over-expression transgenic plants was significantly higher than of the wild-type plants under 20% PEG6000 treatment at seedling stage, indicating that enhancing OsGPDH1 expression can improve the drought-resistance at the seedling stage. This study demonstrated that OsGPDH1 played an important role in salt and osmotic stress, and could be a new transgenic genetic resource for stress resistant breeding in rice.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 837-843. https://doi.org/10.11869/j.issn.100-8551.2017.05.0837In order to detect quantitative trait loci (QTL) of plant height (PH) and ear position (EP) in maize (Zea mays L.), triple testcross (TTC) populations were constructed using 121 intermated B73×Mo17 (IBM) individuals based on to the TTC genetic mating design. The inclusive composite interval mapping was applied for identification of QTLs. One additive QTL was separately found for heteorosis of PH and EP in two regions linked tightly on chromosome 9 with the phenotypic variation being indicated by single QTL being 14.3% and 18.6 respectively, which was considered the same QTL contributing the heterosis of PH and EP simultaneously. In addition, two overdominant QTLs for heterosis of PH were identified on chromosomes 1 and 3, which could explain individually 9.0%-11.4% of total variation and five overdominant QTLs for heterosis of EP were identified on chromosomes 1, 6 and 8, with 6.6%-16.8% of total variation contributed by single QTL. Further analysis revealed two additive×additive epistatic interactions and two dominant×dominant epistatic interactions for heterosis of EP, which taken together could account for 40.7% and 26.8% of total phenotypic variation due to additive×additive epistatic effect and dominant×dominant epistatic effect. These findings suggest additive, dominance and epistasis interactions may play an essential role in determining the heterosis of maize PH and EP. The major QTL mapped in the present study facilitate the selection of PH and EP in maize breeding based on heterosis.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 844-851. https://doi.org/10.11869/j.issn.100-8551.2017.05.0844To elucidate the genetic mechanism of heat tolerant (HT) variety Rejing35, a microsatellite-based linkage map of Rejing35 was designed using 140 SSR markers and a F2 population comprising 226 plants. The F2 population was derived from the crossover between Rejing35 and XieB. The molecular data was used to analyze the genotype segregation and detect QTL underlying HT, respectively. The results indicated that the map has spanned 2 157.7 cM with an average marker distance of 15.4 cM. Altogether 45 markers (28.5%) significantly showed distortion towards biparents or heterozygote (P<0.01). There were 9 clustered distortion regions distributed on the 1st, 3rd, 4th, 6th,7th and 8th chromosomes, respectively. Among them, 4 distortion regions may be caused by gametophyte and zygote. A total of 3 QTLs controlling HT were detected on the 4th, 8th, and 12th chromosomes, respectively. These results will provide valuable insights into the molecular mechanism underlying HT and a novel gene resource for HT rice variety breeding.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 852-861. https://doi.org/10.11869/j.issn.100-8551.2017.05.0852To understand the new type of alpha amylase inhibitor CL-AI protein in Chickpea seeds, its inhibitory activity, biological activity, and three-dimensional structure were studied. A new type of α-amylase inhibitor CL-AI gene and CL-AI-α, CL-AI-β subunit gene were had been cloned from Chickpea seeds in our previous studies. The gene sequence of CL-AI, CL-AI-α, and CL-AI-β were inserted into the prokaryotic expression vector pE-SUMO3, respectively. CL-AI, CL-AI-α soluble fusion protein and CL-AI-β inclusion fusion protein were obtained from induced protein expression. CL-AI-β soluble fusion protein was obtained through the construction of prokaryotic expression vectors containing different tags. Effect of inhibitory activity against human salivary amylase (HSA) showed that CL-AI, CL-AI-α, CL-AI-β could significantly inhibit HSA. The effect of CL-AI on germination of wheat, maize, and rice had significant effects on germination potential, shoot and root length, and the simplified vigor index of three seeds showed a significant decrease. These results on the study of α-amylase inhibitor CL-AI has laid the foundation for further research and application.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 862-867. https://doi.org/10.11869/j.issn.100-8551.2017.05.0862To study the grape precocious mechanism for providing theoretical guidance for its mature regulation, Yinhong and its three Mutants of Vitis vinifera L. were used as test materials. The content of Brassinosteriods (BRs) was determined in different developmental stages and the expression of the key enzyme genes in the biosynthetic pathway of the plant. Results show that brassinosteriods content was observed earlier in Yongzijing and Yongzaohong than in Yinhong. Brassinosteriods content in Yongfeihong was slightly higher than in Yinhong. This may be the important factor affecting the early maturity. The results of correlation analysis show that there was a positive correlation between the content of BRs and the expression of the two regulatory genes during the growth of grape. DET2 gene may be key regulatory enzymes in the process of BRs biosynthesis. CPD plays a secondary role in BRs biosynthesis. The results in this study provide an important guiding significance for understanding the regulation in the grapes ripening and so on.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 868-875. https://doi.org/10.11869/j.issn.100-8551.2017.05.0868To investigate the application of loop-mediated isothermal amplification (LAMP) method for salmon species identification, a set of species-specific LAMP primers was designed based on the CR fragment of the mitochondrial DNA of Salmo salar. The effects of different concentrations of dNTP Mix, Mg2+and Betaine on LAMP results were analyzed by the single factor and orthogonal experiments. The optimal conditions were determined as follows: 0.2 mM of primer SS-CR-F3 and primer SS-CR-B, 1.6 mM of primer SS-CR-FIP and primer SS-CR-BIP, 1.4 mM of dNTP Mix, 6.0 mM of Mg2+, 0.8 M of Betaine, 8 U of Bst DNA polymerase in 25 μL reaction mixture. The LAMP reactions were carried out at 65℃, for 60 minutes. Under these optimized conditions, the LAMP method displayed high degrees of specificity, sensitivity and stability, with the detection limit of 0.01ng·μL-1. This method could detect S. salar either in single or mixed salmon specimen. This study provided an important technical means for rapid identification of S. salar, which could be utilized in routine inspection & quarantine and market supervision of salmon species.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 876-883. https://doi.org/10.11869/j.issn.100-8551.2017.05.0876In this study, the ITS-rDNA sequence analysis was used to identify six strains of mycorrhizal fungi, then co-culture them with orchids, and the trypan blue staining test was used to verify the symbiosis, in order to establish the symbiosis between orchid and mycorrhiza, and also to screen a suitable medium for symbiotic culturing. The results showed that all Tulasnella spp. strains in this study can establish symbiosis with Epidendrum secundum, and 2.5 g·L-1 oatmeal agar medium was the most suitable co-culture medium for them, a strain effectively promoted the seed germination and protocorm differentiation of Epidendrum secundum was Tulasnella calospora (Tco2). The mycorrhizal fungi and co-culture medium screened for promoting the seed germination of Epidendrum secundum provide the fungi and plant symbiotic relationship research a good experimental system model, which will play a foundation for reproducing and it would be of great significance on protection of species resource of Epidendrum secundum.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 884-888. https://doi.org/10.11869/j.issn.100-8551.2017.05.0884n order to identify potentially effective bacteria to degrade tetracyclines, 6 strains were isolated from tetracycline-contaminated soils, and were further identified by the morphological, physiological and biochemical characteristics, and 16S rDNA sequence analysis. The degradation effects of this 6 strains were analyzed by high performance liquid chromatography. The results showed that all the six strains were able to grow in the medium supplemented with tetracycline as their sole carbon source. The degradation effects of strain TJ-2 towards oxytetracycline, tetracycline, and chlortetracycline were 58.33%, 63.90% and 65.50%, respectively. And also strain TJ-2 was higher effect compared to others strains in the study, which was followed by strain TJ6. After morphological, physiological and biochemical characteristics, and 16S rDNA sequence analysis on strain TJ-2, it was identified as Achromobacter xylosoxidans, while strain TJ-6 was identified as Bacillus subtilis. The results of our study provides practical basis for the microbial degradation of pesticide residues in soil.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 889-898. https://doi.org/10.11869/j.issn.100-8551.2017.05.0889To understand the mechanism of hemicellulose degradation by irradiation, xylan was used as a model compound in this study. The characteristic difference of apparent topography, molecular structure and degradation products of xylan after γ-ray irradiation with different doses of 0, 200, 400, 600, 800, 1 000, 1 200 kGy were analyzed by Scanning Electron Microscopy(SEM), Fourier Transform Raman Spectroscopy(FT-Raman), and Gas Chromatography Mass Spectrometry(GC-MS). The results showed that the apparent topography in xylan was damaged and also increase in porosity of xylan. The intensity of Raman Spectra of 3 354 cm-1 decreased with the location of peak showing a red shift, and the intensity of Raman Spectra of 1 122 cm-1 and 1 093 cm-1 decreased with the increasing dose of γ irradiation, which illuminated the hydrogen bonds and glycosidic bonds of xylan being fractured, respectively. Analyzed degradation products from ethyl acetate extract of xylan after irradiation by GC-MS showed 18 kinds of fatty acid compounds, 5 kinds of saccharides and 2 kinds of furan compounds, and the relative contents of these three compounds group reached the maximum level of 16.59%, 1.46% and 1.03%, at the irradiation dose of 1 200 kGy, 800 kGy and 1 200 kGy, respectively. This study provides support on degradation mechanism of lignocellulose and comprehensive utilization of xylan after γ-irradiation pretreatment.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 899-905. https://doi.org/10.11869/j.issn.100-8551.2017.05.0899Absract: To investigate the Aspergillus flavus infection and aflatoxin B1(AFB1) contamination from sowing to storage and reveal the key period and the main influencing factors of AFB1 contamination in peanut kernels, we chose the peanut fields planting two different varieties (Zhanhong2 and Zhanyou75) in this study. The unshelled peanuts were collected not only in the planting stage but also in the storage period of one to four months. During the growing season, soil samples were also gathered. The occurrence of fungi and A. flavus in soil and peanut kernels was monitored and the concentration of AFB1 in peanuts was also detected by High Performance Liquid Chromatography. During planting period, A. flavus infection mainly occurred at the mature stage of peanuts with the contamination rate < 8%. The number of A. flavus in Zhanyou75 field soil was significantly lower than that of Zhanhong2, while the contamination rate of A. flavus in peanuts was higher. The result indicated that Zhanhong2 peanut could be better resistant against the infection of A. flavus. Not until 110 d in Zhanyou75 kernels and 120 d in Zhanhong2 kernels respectively during the planting stage, could AFB1 be separately detected at the concentration of 3.37 μg·kg-1 and 2.08 μg·kg-1. The outcome suggested the significantly positive correlation between the concentration of AFB1 in peanuts and the contamination rate of A. flavus. However, A. flavus and AFB1 could not be detected in peanut kernels during the storage. It might be due to the low water activity (aw < 0.70) of peanut kernels after drying, which was not suitable for A. flavus growth and aflatoxin biosynthesis. Above all, these results demonstrated that peanut kernels were easily infected by A. flavus in soil during planting period, and this resulted in the production of AFB1. It was crucial of importance to remain low aw for the prevention and control of AFB1contamination during storage. This study provides theoretical foundation for taking scientific control measures of AFB1contamination in peanuts from planting to storage.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 906-912. https://doi.org/10.11869/j.issn.100-8551.2017.05.0906In order to reveal the bio-efficacy of Sepia ink polysaccharides (SIP) on B16F10 cell lines in vitro, the separation of SIP from Sepia ink, and the effects of SIP extracts on the proliferation rate of cells, tyrosinase activity and melanin synthesis were investigated. The results showed that the optimum process for SIP extraction was obtained with the material-liquid ratio of 1∶3 at 40℃ for 4 hours thrice. Under the optimum conditions, the yield of SIP was 14.21mg·g-1. The cell morphology of the cells changed due to the treatment of SIP extracts. The proliferation rate of B16F10 cells, the tyrosinase activity and the synthesis of melanin were all suppressed or down-regulated by SIP extracts, and this inhibitory effect had direct correlation with the concentration of SIP extracts. The results suggested that SIP extracts could inhibit the synthesis of melanin, which resulted to white skin. This research provides a scientific basis for the use of sepia.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 913-917. https://doi.org/10.11869/j.issn.100-8551.2017.05.0913To investigate the effect of Q2 value on seeds of T. fortunei in different storage methods, seeds were preserved under three different conditions, which includes room temperature air storage (AS), cold storage (CS) and sand storage (SS). The Q2 value of Increased Metabolism Time (IMT), Oxygen Metabolism Rate (OMR) and Relative Germination Time (RGT) were investigated by the Q2 technology. The results showed that in all the three storage methods a reduction in the seed vigor was observed, but the Q2 value of CS and FS had no significant differences. CS under 4 ℃ held the best vigor of seeds, which had faster OMR, shorter IMT and RGT. It is showed that CS is the best storage method of T. fortunei. In the meantime, the results were consistent with the practical experience, and provide guidance to large-scale seedling and standard formulation of T. fortunei.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 918-926. https://doi.org/10.11869/j.issn.100-8551.2017.05.0918In order to study the characteristics of potassium content of flue-cured tobacco in Qujing and its relationship with the main ecological factors, 3 506 flue-cured tobacco samples were collected and their potassium content was measured, the potassium content of flue-cured tobacco in Qujing and its main influencing factors were studied by decision tree analysis and regression analysis. The results show that mean potassium content of flue-cured tobacco was 1.65%with a amplitude of 0.35 to 3.60%, and potassium content were lower than 2% in 81.86% of tobacco samples’, but there were significant differences between counties. Furthermore, altitude, soil type, soil texture, soil organic matter, soil available potassium, soil available magnesium, and soil available calcium have great influence on the potassium content of flue-cured tobacco. The inflection point of altitude impact on tobacco potassium content were 1 689, 1 814 and 2 023 m, with the increase in altitude, the potassium content decreased, with the increase in soil texture viscosity, potassium content of flue-cured tobacco increased. Potassium content of flue-cured tobacco was significantly different between different soil types, as yellow soil is the highest (2.07%), and purple soil (1.59%) is the lowest. The inflection point effect of soil organic matter on tobacco potassium content were 23.768 and 39.060g·kg-1, and with the increase of soil organic matter, the potassium content of flue-cured tobacco showed a gradually increasing trend. The inflection point effect of soil available potassium of tobacco potassium content were 153.746, 205.000 and 328.169 mg·kg-1, and with the increase of soil available potassium, the potassium content of flue-cured tobacco showed an increasing trend. With the increase of soil available calcium, potassium content of flue-cured tobacco decreased. With the increase of soil available magnesium, potassium content of flue-cured tobacco was increased at first and then decreased, while the content of available magnesium in soil was about 300 mg·kg-1, the potassium content of flue-cured tobacco was up to the peak value, and the potassium content of flue-cured tobacco showed a decreasing trend with the increase of Ca/K an Mg/K of soil.The results provide a practical source in guiding for improving the potassium content of flue-cured tobacco in Qujing tobacco planting areas.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 927-937. https://doi.org/10.11869/j.issn.100-8551.2017.05.0927ACE inhibitory peptides are a class of peptides inhibiting ACE activity to achieve antihypertensive effects. Compared with synthetic counterparts, ACE inhibitory peptides from nature sources are considered to be safe, few side effects and can be long-term taken. A variety of ACE inhibitory peptides derived from terrestrial plant and animal protein were reported. Marine creatures are a new kind of important bio-resources with multiple protein structures, which can produce new ACE inhibitory peptides. In this paper, the research advances on the ACE inhibitory peptides derived from marine resources were reviewed by bioinformatics retrieval method. The ACE inhibitory peptides from marine fish, shrimp, shellfish, algae, and other marine creatures were reviewed, and mainly focused on the material resources, enzyme, amino acid sequence, and IC50 values. In addition, the application prospects of ACE inhibitory peptides from marine resources were discussed as well. This review is benefited for the development and utilization of marine proteins, and important for the research and development of marine bioactive substances.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 938-945. https://doi.org/10.11869/j.issn.100-8551.2017.05.0938In this study, the effect of different amount of manure (30, 60, 90, 120, 150 t·hm-2) with urea (225 kg N·hm-2) on soil organic nitrogen pool, mineral nitrogen content and nitrogen balance was analyzed in brown red soil using laboratory incubation method. The results showed that the soil organic nitrogen content increased by 16.29%~85.64% with mixing manure in comparison with the single application of urea. In the medium and high manure application treatments, soil nitrogen mineralization potential (p<0.05) and transformation intensity of inorganic nitrogen increased significantly. Besides, the amount of soil mineral nitrogen increased by 52.9~246.0 mg·kg-1; soil nitrogen mineralization peak was delayed by 5d and the transformation amount of mineral nitrogen was 2.3~ 8.7 times higher than that in the urea-only treatments. Moreover, mixing with organic fertilizer could also promote the soil ammonification intensity and the conversion rate of NH4+-N. In mixing manure treatments, the peak values of soil N H4+-N content increased by 2.6~42.6 mg·kg-1; the average ammonification rate increased by 7.8 mg·kg-1·d-1, and the conversion rate was 1.4~8.8 times higher than that of the urea-only treatments. Although the manure application at the range of 30 to 120 t·hm-2 could not make significant impact on soil nitrification, the nitrification rate of the high manure application (150 t·hm-2) increased by 4.2 times higher than the urea-only treatment, which also resulted in a lot soil nitrate (NO3--N) accumulation. The apparent nitrogen loss was increased significantly in the medium and high manure application treatments. In combined application of urea and manure (60, 90 and 120 t·hm-2) treatments, the apparent nitrogen loss was 2.2, 2.8 and 3.3 times higher than that of the urea only treatment, which accounted for 27.5%~34.5% of the total input nitrogen content. Additionally, the conversion loss of N H4+--N was the main approach in the apparent nitrogen loss system. This study provided a theoretical basis for effective fertility manner of brown loam.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 946-953. https://doi.org/10.11869/j.issn.100-8551.2017.05.0946In order to study the biological function of endophytic fungi within allelopathic rice strain 6173, with the normal germination and growth of rice and barnyard grass seeding as control, the effects of 12 different fungi fermentation on the growth and physiological characteristics of non-allelopathic rice and barnyard grass were evaluated by measuring the germination rates, stem length, fresh weight and some protective enzymes in vitro. The results showed that 7 of 12 endophytic fungi fermentation production promoted the germination of rice,while 11 kinds of endophytic fungi fermentation production played catalytic role in promoting rice seedling growth, among which A.tubingensis and R.mucilaginosa broth showed a significant effect.Intriguingly, barnyard grass germination was inhibited by 11 endophytic fungi fermentation production, among which the suppression rates of F.avenaceum was impressively splendid.In addition, A.tubingensis and R.mucilaginosa broth inhibited barnyard grass’ growth.F.avenaceum, R.mucilaginosa and A.tubingensis were selected after preliminary screening and they could significantly reduce the lipase activity of barnyard grass.After 24 h of germination, R.mucilaginosa significantly reduced its lipase activity by 82.61% compared to the control, and after 96 h of germination,the relative activity of Fusarium and R.mucilaginosa treated groups was lower than the control group by 30.88% and 36.50% respectively.Besides, Fusarium and A.tubingensis could increase activities of SOD and POD in rice seedlings on different levels, while Fusarium could also decrease the SOD and POD in barnyard grass and A.tubingensis also remarkably decreased its POD activity.These results suggested that endophytic fungi isolated from allelopathic rice 6173 can promote and suppress the growth of rice simultaneously,while it shows a distinctly inhibiting effect on barnyard grass,which may accomplish through inhibiting the lipase and antioxidant enzymes activity. This paper could establish the theortical foundation for etploring the biopesticide and microbial fertilizer in agricultural production.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 954-963. https://doi.org/10.11869/j.issn.100-8551.2017.05.0954Reasonable sulfur rate and nitrogen fertilizer ratio of base and topdressing can adjust the nitrogen absorption and translocation, which can provide the theory basis of nitrogen application. A pot experiment and 15N tracer technique were carried out to study the effect of sulfur rate and nitrogen fertilizer ratio of base and topdressing on nitrogen accumulation and its proportion from different sources at anthesis and maturity, and analyze their difference of absorption and transport of nitrogen, nitrogen fertilizer productive efficiency in Jingdong8 and Jimai20. There were three nitrogen fertilizer ratio of base and topdressing including 3∶7, 5∶5 and 7∶3, which were marked N1, N2 and N3, respectively. And two sulfur rate were designed at 0 and 45 kg·ha-1, which were marked S0 and S1, respectively. The results showed that nitrogen from fertilizer were the main source in two cultivar, and the proportion were 60%~70% for Jingdong8 and 70%~80% for Jimai20. There were differences in nitrogen absorption and transport of two cultivar under different sulfur rate and nitrogen fertilizer ratio of base and topdressing. For Jingdong8, nitrogen accumulation in grain at maturity, nitrogen translation from vegetative organs to grain, grain yield and nitrogen use efficiency were higher in the treatment of N1S0 than other treatments. For Jimai20, nitrogen accumulation in grain at maturity, grain yield and nitrogen use efficiency were higher in the treatment at N3S1, but nitrogen translation from vegetative organs to grain were higher at the treatment N1S0 than other treatments. To sum up, when the nitrogen fertilizer ratio of base and topdressing was 3∶7, the nitrogen translation from vegetative organs to grain, protein content and nitrogen recovery index were the highest, and the grain yield and nitrogen productive efficiency were the highest in 7∶3. The most suitable fertilizer treatment of increasing yield, NPE and NUE for Jingdong8 was N1S0, but N3S1 for Jimai20. These findings provide a theoretical reference for reasonable fertilizer in winter wheat field production management.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 964-971. https://doi.org/10.11869/j.issn.100-8551.2017.05.0964In order to explore the response of sweet maize growth to low sunlight condition after pollination, the effects of weak-light stress (50% light deprivation by shading net from pollination to fresh stage) on the grain filling and leaf senescence of sweet maize were studied using Jingketian183 and Jingketian533 as materials. The results indicated that shading reduced the grain number and fresh grain weight, which resulted in the loss of fresh grain yield loss under both spring and summer sowing conditions. With the grain development, the fresh grain volume and weight, dry grain weight, and leaf malondialdehyde(MDA) content increased, grain moisture content, leaf soluble protein content and SPAD value decreased gradually. Under weak-light stress conditions the grain weight(dry and fresh) and volume decreased significantly, and the grain moisture content at 27d after pollination was lower. In addition, soluble protein content and SPAD reduced, while MDA content was increased, and the activity of catalase, superoxide dismutase and peroxidase were enhanced significantly. Generally, shading accelerated senscence of the leaf and restricted grain filling of sweet maize, result in the decline of grain weight. The results afford a theoretical reference for regulating the grain filling and leaf senescence of sweet maize under low sunlight conditions after pollination.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 972-978. https://doi.org/10.11869/j.issn.100-8551.2017.05.0972The objective of this experiment was to clarify change law of morphology, photosynthetic fluorescence parameters and dry matter distribution in soybean. This study based on two different patterns of maize-soybean intercropping employed soybean monoculture Zhonghuang 39 as the experiment material, and the effect of maize soybean intercropping on growth, photosynthetic fluorescence and grain yield of soybean were studied. The results showed that, compared with monoculture, the plant height of soybean at the fourth trifoliolate stage (V4), beginning pod stage (R3) and full seed stage (R6) increased by 22.47%, 47.33%and 32.72%, respectively. In addition, plant height was significantly higher than that of intercropping, the stem diameter, internode number, the total biomass of stem, leaf, petiole, and the chlorophyll content had no significant differences between monoculture and intercropping at the fourth trifoliolate stage. At the stages of R3 and R6, the biomass of stem and petiole of soybean in intercropping increased significantly but the biomass of leaf, chlorophyll (a) content, total chlorophyll content and net photosynthetic rate (Pn) were found to be significantly lower than those in monoculture. With the succession of the growing stages of the soybean, the chlorophyll fluorescence parameter (NPQ) and Fo of soybean leaves in intercropping increased first, and then decreased, while F'q/F'm, qP and Fm showed a gradual decline. The chlorophyll fluorescence parameter NPQ in intercropping at stages of V4, R3 and R6 were significantly higher than that in monoculture about 12.2%, 5.04% and 7.20%, respectively. There were no significant differences on the parameters F'q/F'm, qP and Fv/Fm between intercropping and monoculture. In terms of yield components, the pod per plant, seeds per plant and hundred-grain weight of soybean at in intercropping were significantly lower than those in monoculture. Consequently, intercropped maize would affect the growth and photosynthetic characteristics of soybean at the late growth stage, which directly decreases the grain yield components of soybean. The results provide a basis for intercropping soybean cultivation and high yield.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 979-986. https://doi.org/10.11869/j.issn.100-8551.2017.05.0979To explore the regulation mechanism of 2, 4-epibrassionolide (EBR) on the growth of cucumber (Cucumis sativa L.) seedlings under suboptimal temperature and low light intensity (18/12 ℃, PFD 80 μmol·m-2·s-1), cucumber Youbo1-5 was used as experimental material and seedlings sprayed with distilled water as the control. The method of spraying the seedling leaves with EBR was employed and the effects of EBR on chlorophyll content, gas exchange parameters, chlorophyll fluorescence parameters, the activities of key enzymes involved in calvin cycle and antioxidant enzymes were measured in cucumber seedlings under suboptimal temperature and low light. The results showed that compared with the control, the photosynthetic rate (Pn) and the relative chlorophyll content (SPAD) of seedlings in suboptimal temperature and low light treatment significantly decreased by 53.61% and 21.73%, respectively. The malondialdehyde content of cucumber seedlings increased by 78.90% and thus eventually led to the reduction of dry matter accumulation. However, the stressed cucumber seedlings pretreated with 0.1 μmol·L-1 EBR maintained a higher value of specific leaf weight, Pn, SPAD, maximal photochemical efficiency of PSⅡ(Fv/Fm), actual photochemical efficiency of PSⅡ(ΦPSⅡ) and photochemical quenching coefficient (qP), but a decreased non-photochemical quenching coefficient (NPQ). Moreover, EBR treatment significantly increased the activities of ribulose 1,5-biphosphate carboxylase/oxygenase(Rubisco), sedoheptulose-1,7-bisphosphatase(SBPase), fructose-1,6-bisphosphate aldolase(FBA)and transketolase(TK), and also promoted the activities of superoxide dismutase(SOD), peroxidase(POD), catalase(CAT), decreased the membrane lipid peroxidation. The results suggested that EBR could improve photosynthesis by increasing chlorophyll content, photochemistry efficiency and the activities of enzymes involved in Calvin cycle, enhance the antioxidant enzyme activities to decrease membrane lipid peroxidation, and thereby, effectively promote the growth of cucumber seedlings under suboptimal temperature and low light. Therefore, the findings provided a theoretical basis to clarify the regulation mechanism of the alleviation role of EBR on growth of cucumber seedlings under suboptimal temperature and low light.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 987-995. https://doi.org/10.11869/j.issn.100-8551.2017.05.0987Faba bean is susceptible to wilt disease under continuous monocropping management. Faba bean and wheat intercropping was effective measure to alleviate faba bean wilt disease in continuous management soil. To investigate the effects of p-hydroxybenzoic acid on faba bean seedling growth and Fusarium wilt occurrence, and to explore the alleviation mechanism of wheat and faba bean intercropping on faba bean autotoxicity, A plot experiment of faba bean and wheat intercropping with p-hydroxybenzoic acid application was conducted in the greenhouse of Yunnan Agricultural University. Four p-hydroxybenzoic acid rates were set, which were [C0 (0.00 mmol·L-1)、C1(0.36 mmol·L-1)、C2 (0.72 mmol·L-1) and C3 (1.45 mmol·L-1)] ,with two planting patterns, faba bean monocropping and faba bean and wheat intercropping. The growth, enzymes activities (peroxidase, POD and catalase, CAT), peroxidation (MDA) content as well as occurrence of faba bean Fusarium wilt were investigated. The results showed that in comparison with C0, the biomass of monocropped faba bean increased first and then decreased with increasing of p-hydroxylbenzoic acid application rates. The activities of POD and CAT in monocropped faba bean roots were increased with C1 and C2 treatment but decreased with C3 treatment, while the amount of Fusarium oxysporum and the occurrence of Fusarium wilt were decreased with C1 and C2 treatment but increased with C3 treatment, which promoted the occurrence of Fusarium wilt. Malondialdehyde (MDA) content in faba bean roots were significantly increased with increasing of p-hydroxybenzoic acid rates. Thus it was concluded that p-hydroxybenzoic acid was one of the main autotoxins in faba bean continuous cropping. Comparison with monocropped faba bean, Peroxidase (POD) and catalase (CAT) activities in intercropped faba bean roots were increased by 4.17% to 22.22% and 0.53% to 11.11%. MDA content and disease index of intercropped faba bean were decreased by 11.20% to 52.80% and 13.33% to 50.00%, the dry weights were increased by 15.73% to 20.63%. In summary, faba bean and wheat intercropping significantly improved the activities of the antioxidant enzymes in faba bean,and decreased the degree of membrane lipid peroxidation, resulting in a increase in the resistance of faba bean to Fusarium oxysporum, faba bean growth was promoted. Thus, Faba bean and wheat intercropping was an effective method to alleviate faba bean autotoxicity caused by p-hydroxybenzoic acid. The results also provided a theoretical basis for intercropping to control soil-borne diseases caused by continuous crop cultivation.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 996-1004. https://doi.org/10.11869/j.issn.100-8551.2017.05.0996In order to solve the problem that increased production after fertilization was not obvious in rain-fed flax, a field experiment was conducted to elucidate effect of nitrogen application combined with phosphorus on dry matter accumulation, seed yield and water use efficiency of flax. Four fertilizer application treatments were set including two nitrogen levels (N1: 75 kg·hm-2and N2: 150 kg·hm-2) and two phosphorus levels (P1: 75 kg·hm-2and P2: 150 kg·hm-2) which were marked as N1P1, N1P2, N2P1, N2P2, and no fertilization(N0P0) was as the control. The results showed that overground dry matter accumulation of oil flax under the level of nitrogen application combined with phosphorus was markedly increased by 11.90% to 59.29% compared with N0P0. Furthermore, the dry matter distribution amount and proportion in seeds at maturity stage were gradually enhanced with the increase of fertilization rate, and reached the maximum under the N2P1 level which were 7.76% to 34.73% and 8.07% to 9.14% higher than other fertilizer treatments. The dry matter accumulation amount after anthesis and its contribution rate of seeds yield were significantly raised by 3.26% to 39.06% and 5.72% to 61.50% compared with the level of N0P0, respectively. In addition, the effect of nitrogen application combined with phosphorus on seed yield of flax was significant, and the seed yield of N1P1, N1P2, N2P1and N2P2were significantly increased by 16.21%~21.69%, 28.47%~36.05%, 44.27%~56.55% and 36.34%~47.10% compared with N0P0level, respectively. Besides, the changes of water use efficiency was fairly consistent with seed yield, and the N2P1 was the largest followed by the N2P2 which were raised by 30.23%~38.54% and 20.50%~36.81% compared the treatment of N0P0, respectively. Therefore, the optimal ratio of nitrogen and phosphorus which was 150 kg·hm-2 (N) and 75 kg·hm-2(P2O5) ensure high yield and high efficiency on the basis of increasing dry matter accumulation amount and improving soil moisture absorption of rain-fed flax, as well as provided a theoretical basis for high yield cultivation techniques of dryland flax.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 1005-1013. https://doi.org/10.11869/j.issn.100-8551.2017.05.1005In order to explore the response of tomato photosynthesis in different cultivation seasons to soil water content, the effect of 50%, 65% and 80% of soil water content on photochemical activity and absorbed light allocation in photosystem Ⅱ of tomato leaves in different seasons was studied with a pot culture experiment. The results showed that, leaf chlorophyll content decreased with decrease of soil water content for tomato cultivated in spring, but electrolyte leakage increased. Optimal photosynthetic efficiency of PSⅡ(Fv/Fm), actual photochemical efficiency(ΦPSⅡ), the electron transport rate (ETR), photochemical quenching (qP) and quotient of absorbed light used in photochemical reaction (P) decreased, while non-photochemical quenching (NPQ), the relative deviation from full balance between two photosystems(β/α-1), quotient of absorbed light used in antenna heat dissipation (D) and non-photochemical quantum yield [Y(NO)] increased. These data indicated that its photochemical activity of PSⅡ was decreased for the energy metabolism pathway shifting from photochemical to non-photochemical activity, and photo-inhibition and photo-damage occurred, which had a significant-positive correlation with water deficit levels. Accordingly, the 80% soil water content was suitable for tomato cultured in spring. Although for the tomato cultivated in winter, the parameters such as Fv/Fm, ΦPSⅡ, ETR, qP and P with 50% treatment were still lower, these parameters with 65% treatment were significantly higher than those of 80% treatment at the middle and late growth stage. Tomato leaf under moderate water stress exhibited a slighter photo-inhibition compared with well-watered tomato leaf. Therefore, leaf photochemical activity maintained a high level with 80% soil water content for spring-cultivated tomato, but 65% water content was suitable for winter-cultivated tomato. This study provides a theoretical basis for rational irrigation of tomato production in different cultivation seasons.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 1014-1021. https://doi.org/10.11869/j.issn.100-8551.2017.05.1014To explore the physiological mechanism of phosphorus element on the physiological metabolism and yield formation in muskmelon, muskmelon (Jin-fei) was used as experimental material by substrate culture to reveal the change laws of fruit transverse diameter, fruit vertical diameter, chlorophyll content, nitrate nitrogen content, nitrate reductase activity, soluble sugar content, catalase activity and superoxide dismutase activity, single fruit weight and yield. The results showed that the dosage of phosphorus element at the range of 0.9 to 1.2 mmol·L-1 can best promote fruit growth of muskmelon through enhancing the leaf physiological active substance content and protective enzyme activity during fruit-bearing stage, which can improve the photosynthesis ability and physiological metabolism level, increase fruit transverse diameter and fruit vertical diameter,and promote the raising of muskmelon yield. Compared with 0.3 mmol·L-1 (T1) phosphorus content, the fruit diameter, the diameter of the fruit and the yield per hectare increased significantly at the range of 0.9 to 1.2 mmol·L-1 about 30d after pollination were 21.38% to 26.00%, 12.62% to 34.09%, 36.62% to 46.72%, respectively. At the same time, compared with 0.3 mmol·L-1 (T1) phosphorus content, chlorophyll content, nitrate nitrogen content, soluble sugar content, nitrate reductase activity, catalase activity and superoxide dismutase activity increased significantly at the range of 0.9 to 1.2 mmol·L-1 during 20 to 25d after pollination, and were 21.23% to 29.99%, 102.55% to 128.59%, 51.10% to 56.51%, 24.91% to 39.92%, 7.46% to 9.26% and 13.23% to 18.62%, respectively. When phosphorus dosage was less than 0.6 mmol·L-1 (T2) or higher than 1.5 mmol·L-1 (T5), all indexes decreased significantly. Therefore, phosphorus element at the range of 0.9 to 1.2 mmol·L-1 can improve physiological active substance content and protective enzyme activity of the melon plants, and can promote the yield formation of muskmelon. However, the physiological characteristics and yield index of muskmelon during the fruit-bearing stage were different under different phosphorus concentrations. The results provided a theoretical basis and practical guidance for the proper application of phosphorus fertilizer in muskmelon production.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 1022-1028. https://doi.org/10.11869/j.issn.100-8551.2017.05.1022In order to investigate the promoting effect of alfalfa using strain combinations containing ACC deaminase activity under saline-alkali stress, co-inoculated plant growth promoting rhizobacteria Y-2(Acinetobacter beijerinckii),BC-3(Serratia marcescens)and CE-1(Enterobacter aerogenes)combinations containing ACC deaminase were selected by antagonistic reaction. The characteristics of salt-alkali tolerance and growth-promoting of single and combinations strains were evaluated, as well as evaluating the effect of promoting on the growth of alfalfa by pot experiment. Results showed that there were no antagonistic reactions between Y-2+CE-1 and BC-3+CE-1 strain combinations, and the two strain combinations could be mixed and grew well under the condition of pH10 and 7% NaCl. Both single stain and combinations could synthesize ACC deaminase, secreat IAA (Indole-3-acetic acid) and solubilize phosphate. The growth-promoting of strain combinations were better than single strain. In addition, inoculation of single and combination strains could promote alfalfa growth in different extent, compared with control, the remarkable effects of plant growth promotion were found in co-inoculated strain combinations Y-2+CE-1 and BC-3+CE-1, the plant height were increased by 20.3% and 20%, respectively, the root length were increased by 51.4% and 45.9% respectively, dry weight of shoot were increased by 47% and 36.4% respectively, the dry weight of root were increased by 68.8% and 52% respectively, and better than alfalfa inoculated with single strain. The data obtained in our study suggest that strain combinations containing ACC deaminase activity can alleviate saline-alkaline stress, and promote the growth of alfalfa significantly. This paper established the theoretical foundation for the development of compound fertilizer, governance and utilization of saline-alkalive soil.
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Journal of Nuclear Agricultural Sciences. 2017, 31(5): 1029-1035. https://doi.org/10.11869/j.issn.100-8551.2017.05.1029The fundamental carbon source is one of the most important ecosystem indice which can influence the biodiversity, pattern and stability of the river ecosystem through inter-specific energy transformation. This paper reviewed the types of fundamental carbon sources, the estimation models of their energy contribution to food webs and carbon source theory model based food webs, which was based on stable isotope techniques. The carbon theory model based on food webs and its interaction were explored, which included Riverine Productivity Model (RPM), River Continuum Concept (RCC) and Flood Pulse Concept (FPC). Meanwhile, we discussed the pros and cons of these models in practical applications and put forward the hypothesis that the riverine ecosystem synthesis adapted to diversified hydrological characteristics can balance the advantages and disadvantages among these models. In conclusion, it is important to establish a long-term river isotope database by stability isotope technology combined with a non-lethal sampling method. This paper further explained the relation of different biological nutrients in river ecosystem and provided a theoretical basis for restoration and protection of river ecosystem.
