Effects of Ultrasonic Seed Treatment on Rice Performances under the Seawater Irrigation

Irrigation with desalinated seawater is an effective way to use ocean resources and save freshwater resources. However, seawater irrigation would cause yield loss of rice. In order to explore the effects of ultrasonic seed treatment on rice performances under seawater irrigation, the present study was conducted with three irrigation treatments (fresh water (SW0), ten times diluted seawater (SW1%, 0.34% salinity), and five times diluted seawater (SW2%, 0.68% salinity)) and two seed treatments (ultrasonic treated seeds (UT) and untreated seeds (CK)). Compared with SW0 + CK treatment, SW1 + CK and SW2 + CK treatments significantly decreased grain yield by 56.19% and 66.69%, spikelets per panicle by 30.11% and 55.80%, seed-setting rate by 23.05% and 18.87%, and 1000-grain weight by 4.55% and 14.50%, respectively. Seawater irrigation also significantly increased malonaldehyde (MDA) and proline contents and the activities of superoxide dismutase (SOD) and peroxidase (POD). Ultrasonic seed treatment significantly increased the grain number per panicle, seed-setting rate, and grain yield of rice under seawater irrigation. Compared with CK, UT treatment substantially reduced MDA content, SOD activity, and POD activity in SW1 and SW2 conditions. Furthermore, UT treatment significantly increased proline content and down-regulated proline dehydrogenase activity under seawater irrigation. We deduced that ultrasonic seed treatment enhanced the salinity tolerance of rice by inducing the proline accmulation. Our findings indicated that ultrasonic seed treatment could an effective strategy to promote rice productivity under seawater irrigation.     

Effects of Different Potassium (K) Fertilizer Rates on Yield Formation and Lodging of Rice

As one of the most important nutrients for plants, potassium (K) has substantial effects on growth and development of crops. Present study was conducted in three different sites in South China in late season in 2019 with the objective to study the effects of different applied amounts of K fertilizer on yield formation and lodging of rice. Four K fertilizer treatments, K₀: 0 kg potassium oxide (K₂O) ha⁻¹ (control); K₁: 64.20 kg K₂O ha⁻¹ ; K₂: 128.55 kg K₂O ha⁻¹ and K₃ 153.90 kg K₂O ha⁻¹ were applied in the field experiment. The results showed that K₂ and K₃ treatments significantly increased panicle number per unit area, grain number per panicle, seed-setting rate and the grain yield of rice compared with K₀ treatment. Higher net photosynthetic rates were recorded in K₂ and K₃ treatments than K₀ treatment at tillering stage, heading stage and maturity stage. K fertilizer treatments also increased the chlorophyll content and dry matter accumulation by 6.16–23.52% and 21.32–64.59% compared with K₀ treatment, respectively. Moreover, the total N and K accumulation in the aboveground tissues of rice significantly increased under K₂ and K₃ treatments compared with K₀ treatment. Furthermore, compared with K₀ treatment, K fertilizer treatments significantly enhanced the breaking-resistant strength by 40.94–144.24% and reduced the lodging index of rice by 13.14–36.72%.     

Molybdenum supply increases root system growth of winter wheat by enhancing nitric oxide accumulation and expression of NRT genes

Plant and Soil - Success in agronomic biofortification of maize and wheat is highly variable. This study aimed to elucidate the differences in uptake and translocation of foliar-applied zinc (Zn)...     

Nitric Oxide Synthase-3 Promotes Embryonic Development of Atrioventricular Valves

Nitric oxide synthase-3 (NOS3) has recently been shown to promote endothelial-to-mesenchymal transition (EndMT) in the developing atrioventricular (AV) canal. The present study was aimed to investigate the role of NOS3 in embryonic development of AV valves. We hypothesized that NOS3 promotes embryonic development of AV valves via EndMT. To test this hypothesis, morphological and functional analysis of AV valves were performed in wild-type (WT) and NOS3^−/− mice at postnatal day 0. Our data show that the overall size and length of mitral and tricuspid valves were decreased in NOS3^−/− compared with WT mice. Echocardiographic assessment showed significant regurgitation of mitral and tricuspid valves during systole in NOS3^−/− mice. These phenotypes were all rescued by cardiac specific NOS3 overexpression. To assess EndMT, immunostaining of Snail1 was performed in the embryonic heart. Both total mesenchymal and Snail1⁺ cells in the AV cushion were decreased in NOS3^−/− compared with WT mice at E10.5 and E12.5, which was completely restored by cardiac specific NOS3 overexpression. In cultured embryonic hearts, NOS3 promoted transforming growth factor (TGFβ), bone morphogenetic protein (BMP2) and Snail1expression through cGMP. Furthermore, mesenchymal cell formation and migration from cultured AV cushion explants were decreased in the NOS3^−/− compared with WT mice. We conclude that NOS3 promotes AV valve formation during embryonic heart development and deficiency in NOS3 results in AV valve insufficiency.     

Enhancement of Ultrasonic Seed Treatment on Yield,Grain Quality Characters,and 2-Acetyl-1-Pyrroline Biosynthesis in Different Fragrant Rice Genotypes

Fragrant rice is popular for the good grain quality and special aroma. The present study conducted a field experiment to investigate the effects of ultrasonic seed treatment on grain yield, quality characters, physiological properties and aroma biosynthesis of different fragrant rice genotypes. The seeds of three fragrant rice genotypes were exposed to 1 min of ultrasonic vibration and then cultivated in paddy field. The results of present study showed that ultrasonic seed treatment increased grain yield of all fragrant rice genotypes but the responses of yield formation to ultrasonic were varied with different genotypes. Compared with control, ultrasonic seed treatment increased grain 2-acetyl-1-pyrroline (2-AP, the key component of fragrant rice aroma) content by 13.40%–44.88%. Ultrasonic seed treatment also reduced the crude protein contents in grains. The head rice rate, rice length, chalky rice rate, and chalkiness degree were influenced by ultrasonic for one or two fragrant rice genotypes. The activities of peroxidase and superoxide dismutase were also enhanced due to ultrasonic seed treatment. In conclusion, ultrasonic seed treatment increased grain, regulated grain aroma and quality, and improved stress resistance of fragrant rice varieties.     

Genome analysis and in vivo virulence of porcine extraintestinal pathogenic Escherichia coli strain PCN033

Background

Strains of extraintestinal pathogenic Escherichia coli (ExPEC) can invade and colonize extraintestinal sites and cause a wide range of infections. Genomic analysis of ExPEC has mainly focused on isolates of human and avian origins, with porcine ExPEC isolates yet to be sequenced. To better understand the genomic attributes underlying the pathogenicity of porcine ExPEC, we isolated two E. coli strains PCN033 and PCN061 from pigs, assessed their in vivo virulence, and completed and compared their genomes.

Results

Animal experiments demonstrated that strain PCN033, but not PCN061, was pathogenic in a pig model. The chromosome of PCN033 was 384 kb larger than that of PCN061. Among the PCN033-specific sequences, genes encoding adhesins, unique lipopolysaccharide, unique capsular polysaccharide, iron acquisition and transport systems, and metabolism were identified. Additionally, a large plasmid PCN033p3 harboring many typical ExPEC virulence factors was identified in PCN033. Based on the genetic variation between PCN033 and PCN061, corresponding phenotypic differences in flagellum-dependent swarming motility and metabolism were verified. Furthermore, the comparative genomic analyses showed that the PCN033 genome shared many similarities with genomic sequences of human ExPEC strains. Additionally, comparison of PCN033 genome with other nine characteristic E. coli genomes revealed 425 PCN033-special coding sequences. Genes of this subset included those encoding type I restriction-modification (R-M) system, type VI secretion system (T6SS) and membrane-associated proteins.

Conclusions

The genetic and phenotypic differences between PCN033 and PCN061 could partially explain their differences in virulence, and also provide insight towards the molecular mechanisms of porcine ExPEC infections. Additionally, the similarities between the genomes of PCN033 and human ExPEC strains suggest that some connections between porcine and human ExPEC strains exist. The first completed genomic sequence for porcine ExPEC and the genomic differences identified by comparative analyses provide a baseline understanding of porcine ExPEC genetics and lay the foundation for their further study.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1890-9) contains supplementary material, which is available to authorized users.     

Third-order NLO properties of the DMF solutions of 3-D network and 2-D layered organic-metal polymers with (4, 4) grid units

Reactions of 1,1′-(1,4-butanediyl)bis-1H-benzimidazole (bbbm) with Cd(II), Ni(II), or Co(II) afford three organic-metal polymers: {[Cd(bbbm)(SO₄)(H₂O)₂]CH₃OH}_n (1), {[Ni(bbbm)₂(H₂O)₂](NO₃)₂ · 2CH₃OH · 6H₂O}_n (2) and {[Co(bbbm)₂(H₂O)₂](NO₃)₂ · 2CH₃OH · 6H₂O}_n (3). In 1, bbbm and coordinate to Cd(II) simultaneously leading to a 3-D structure. In 2 and 3, each bridging bbbm ligand links two Ni(II) or Co(II) ions forming the 2-D layered structure with (4, 4) grid units. Each (4, 4) grid unit is a 44-membered ring and constructed by four bbbm ligands acting as four sides and four Ni(II) or Co(II) ions representing four corners. Their third-order nonlinear optical (NLO) properties in DMF solution have been studied by Z-scan technique. The results show that the DMF solution of 2 possesses both the large third-order NLO absorptive and strong refractive behaviors; and 3’s shows large NLO absorptive effect and weak NLO refractive behavior. A reasonably good fit between the experimental data and the theoretical curve suggests that the experimentally obtained NLO effects are effective third-order in nature.     

Novel cup-like helical coordination polymers: synthesis, crystal structures and thermal properties

By the design of ligand 1,1^′-(1,5-pentamethylene)bis-1H-benzimidazole (pbbm), we have synthesized polymers {[Co(NO₃)(pbbm)₂]NO₃ · 1/2H₂O}_n (1), {[CdCl(pbbm)₂]Cl · CH₃OH}_n (2) and {[Cu(Ac)₂(pbbm)] · CH₃OH}_n (3), and characterized their structures by single crystal X-ray diffraction as well as thermoanalysis. In polymers 1 and 2, one of the anions coordinates to the central ion, the other is located in the environment. Two pbbm ligands coordinate simultaneously to two metal centers generating one-dimensional cup-like helical chains. To our best knowledge, this cup-like structure has never been observed in the reported polymers. In polymer 3, each Cu atom is five-coordinate by two nitrogen atoms from two pbbm ligands, and three oxygen atoms from one monodentate acetate anion and one chelating acetate anion leading to one-dimensional wave-like linear chain. In addition, the DTA and TG results of the three polymers are in agreement with the crystal structures.