Four coordination polymers
∞
2
Ni(DMF)(L)Ln(bdc)
1.5
(Ln
=
La (
1
) and Nd (
4
)) and
∞
2
Ni
2
(DMF)
2
(L)
2
Ln
2
(bdc)
3
·CH
3
OH (Ln
=
Ce (
2
) and Pr (
3
)) were derived from a symmetrical ...salamo-based ligand (H
2
L) with Ni(OAc)
2
·4H
2
O, Ln(NO
3
)
3
·6H
2
O (Ln = La, Ce, Pr and Nd), and H
2
bdc (terephthalic acid). Coordination polymers
1
–
4
were synthesized and characterized by elemental analyses, X-ray single crystal diffraction, infrared spectroscopy and ultraviolet–visible absorption spectroscopy. Coordination polymers
1
–
4
have similar structures exhibiting two-dimensional coordination polymers with brick wall in which Ni(DMF)(L)Ln units were linked by exodentate (bdc)
2−
linker. In each unit, Ni(II) atoms adopted a slightly distorted octahedral geometry, the Ln(III) atoms were nine-coordinated, and the coordination polyhedron was a distorted tricapped trigonal prism. The crystal structure and supramolecular features were discussed in detail. At the same time, the fluorescent properties of coordination polymers
1
–
4
were also investigated.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Rhizosphere effect of nanoscale zero‐valent iron (nZVI) is crucial but little reported. Maize seeds were dressed with four nZVI concentrations (0, 1.0, 1.5, 2 g kg−1) and inoculated with arbuscular ...mycorrhizal fungus (AMF) (Funneliformis mosseae). The SEM images illuminated that excessive nZVI particles (2 g kg−1) were agglomerated on the surface of hyphae and spore, causing severe deformation and inactivation of AMF symbionts and thereafter inhibiting water uptake in maize seedlings. This restrained the scavenging effects of enzymatic (superoxide dismutase, peroxidase) and non‐enzymatic compounds (proline & malondialdehyde) on ROS, and leaf photoreduction activity and gas exchange ability (p < 0.05). Interestingly, the inoculation with AMF effectively alleviated above negative effects. In contrast, appropriate dose of nZVI, that is, ≤1.5 g kg−1, can be evenly distributed on the hyphae surface and form the ordered symbionts with AMF. This help massively to enhance hyphae growth and water and nutrient uptake. The enhanced mycorrhizal infection turned to promote rhizosphere symbiont activity and leaf Rubisco and Rubisco activase activity. Light compensation point was massively lowered, which increased photosynthetic carbon supply for AMF symbionts. Particularly, such priming effects were evidently enhanced by drought stress. Our findings provided a novel insight into functional role of nZVI in agriculture and AMF‐led green production.
Summary Statement
Proper dose of nZVI can form orderly rhizosphere symbiont with AMF, improve the Rubisco and Rubisco activity for higher assimilation rate, and promote carbon supply for AMF colonization. Yet, excessive nZVI turned to cause severe structural deformation and inactivation of AMF symbionts.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, a salamo-based copper(
ii
) complex probe
L-Cu
2+
was synthesized, which combined with copper(
ii
) ions to form
L-Cu
2+
for the detection of S
2−
and had a good fluorescence chemical ...response. Through spectral analysis, we found that S
2−
could be identified with high sensitivity and selectivity in the presence of various anions and could be used for the detection of S
2−
by the naked eye. With the addition of S
2−
, the solution color changed from colorless to bright yellow. UV absorption, fluorescence and other characterization methods were carried out, and the mechanism of action was determined. In addition, we performed a visual inspection of H
2
S gas, and the probe
L-Cu
2+
could detect S
2−
in the gas molecules, revealing its potential application value in biology and medicine.
A highly sensitive and selective salamo-based copper(
ii
) complex probe,
L-Cu
2+
, was synthesized; it could be used for the detection of S
2−
by UV and fluorescence spectroscopies. And it also could detect S
2−
in gas molecules.
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IJS, KILJ, NUK, UL, UM, UPUK
Two new asymmetric complexes with the chemical structural formulas {Co
2
(L)(μ
2
-OH)}{Co
2
(L)(OAc)(CH
3
OH)}{Co
2
(L)(μ
2
-OCH
3
)}{Co
2
(L)(μ
2
-OAc)}⋅4CH
3
OH and Ni
2
(L)(μ
2
-OAc)(CH
3
OH)⋅CH
2
...Cl
2
⋅3CH
3
OH have been synthesized from cobalt(II) acetate, nickel(II) acetate, and a bis(salamo)-based tetraoxime ligand derived from 3-bromo-5-chlorosalicylicaldehyde and 4-tert-butyl-2,6-diformylphenol, respectively, and characterized by elemental analyses, IR, UV-vis, fluorescence spectra, and single-crystal X-ray diffraction analyses. The Co(II) complex unit cell contained four crystallographically independent and chemically different heterotrinuclear complexes (molecules A, B, C, and D). The crystal structure included eight Co(II) ions, four completely deprotonated ligand (L)
3−
moieties, one bridging hydroxide, one monodentate acetate, one bridging methoxy, one bidentate chelating acetate, one coordinated methanol, and four crystallization methanol molecules. The Ni(II) complex had a dinuclear structure. The crystal structure of the Ni(II) complex included two Ni(II) ions, one completely deprotonated ligand (L)
3−
, one bidentate bridging acetate, one coordinated methanol, one crystallized dichloromethane, and three crystallized methanol molecules. Hirshfeld surface analyses showed that the complexes are stable. Furthermore, the fluorescence quenching of the Co(II) and Ni(II) complexes with H
3
L further confirmed the above experimental results.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Note: P (phosphorus), W (water), + (positive or increase), – (negative or decrease).
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•Plant facilitation was found in the intercropping system of maize and grass pea.•Facilitation ...shifted from +/+, +/0 to +/- from low to high water and P gradients.•In low P, rhizosphere soil acidification of grass pea fostered P mineralization.•Soil microbial biomass P was improved for higher productivity in +/+ facilitation.•Soil water and phosphorus availability altered interspecific facilitation model.
Plant-plant facilitation is widely studied to increase productivity and resource utilization in cereal-legume intercropping system. However, physiological and ecological mechanisms driving interspecific interaction shift along the environmental gradients is largely unknown. To clarify this issue, we first tested plant-plant facilitation along with four phosphorus (P) gradients in maize-grass pea intercropping system. Results illustrated a progressive transition of seed yield-based facilitation from mutually facilitated (+/+) to maize facilitated but grass pea as facilitator (+/-) along with low to high P gradients. Secondly, above trend was evidently enhanced when combining with drought stress gradients, in which severe drought amplified facilitative effects, whereas the magnitude of facilitation was relatively weak under well-watered condition. Interestingly, biomass-based facilitation transition did not synchronize with seed-based one, in which occurred in a broader threshold range of water and P gradients. Specifically, total yield, biomass, N and P uptake increased by 0.5%, 4.1%, 1.8% and 2.9% under the sufficient P and water availability, whereas these indicators increased by 25.3%, 18.5%, 20.5% and 21.4% in P and water deficient soils. And the total net effect was positive under all the environmental conditions. Rhizosphere interaction plays a crucial role in facilitation judgment, and the driving mechanism was associated with soil acidification and microbial community promotion under P-deficient condition. Under low soil moisture and available P, soil acidification and lower rhizosphere soil pH of intercropped maize were observed. Rhizosphere phosphatase secretion were significantly activated in P-deficient soils and accelerated the mineralization of soil organophosphorus, and the microbial biomass P was improved for stronger facilitation. Taken together, our findings confirmed the P and water driven facilitation shift along with stress gradients and highlighted the roles of rhizosphere interaction in affecting species diversity advantage. In conclusion, our work provided a relatively full picture for plant facilitation evaluation and more accurate management regarding intercropping productivity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two newly designed heteromultinuclear CuII4SmIII2 and CuII2TbIII bis (salamo)‐based complexes, {Cu2(L)Sm (NO3)2(μ2‐NO3)(CH3OH)}2·2CH3OH and Cu2(L)Tb (NO3)2(μ2‐NO3)Cu2(L)Tb (NO3)2(μ2‐NO3)(H2O)·CH3OH, ...were synthesized and characterized by elemental analyses, Fourier transform infrared (FT‐IR) spectra, ultraviolet–visible (UV–vis) absorption spectra, and X‐ray crystallography. The ultraviolet titration experiments exhibited that the coordination ratio of the ligand, rare earth metal, and transition metal is 1:1:2. In the CuII4SmIII2 complex, Cu1 atom has a distorted quadrilateral pyramid geometry, whereas Cu2 atom forms a slightly distorted octahedral geometry. The CuII2TbIII complex unit cell contains two crystallographically independent and chemically different heterotrinuclear complexes (Molecules A and B). In Molecule A, the Cu1 atom bears a four‐coordinated plane quadrilateral geometry, whereas the five‐coordinated Cu2 atom forms a slightly distorted tetragonal cone geometry. In Molecule B, the five‐coordinated Cu3 and Cu4 atoms possess slightly distorted tetragonal cone geometries. Noncovalent interactions like hydrogen bonding and π···π stacking interactions are operative in construction of supramolecular architectures. The CuII2TbIII complex behaves as a catalyst towards oxidative coupling of 2‐AP in MeCN medium. In addition, fluorescence properties of the ligand H4L and its CuII4SmIII2 and CuII2TbIII complexes have also been discussed.
Two newly designed heteromultinuclear CuII4SmIII2 and CuII2TbIII bis (salamo)‐based complexes, {Cu2(L)Sm (NO3)2(μ2‐NO3)(CH3OH)}2·2CH3OH and Cu2(L)Tb (NO3)2(μ2‐NO3)Cu2(L)Tb (NO3)2(μ2‐NO3)(H2O)·CH3OH, were synthesized and characterized structurally. Catalytic oxidase properties and fluorescence properties of the CuII4SmIII2 and CuII2TbIII complexes have also been discussed.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The tradeoff between negative and positive interactions of facilitated species and facilitators may depend on the degree of resource availability in agroecosystems. However, the rhizospheric ...mechanisms driving trade-offs that occur along phosphorus (P) and water availability gradients have not yet been systematically clarified. We established three types of root isolation conditions (no barrier, nylon barrier and solid barrier) at different P and water addition levels to address the above issue in a maize-grass pea intercropping system. The total yield and biomass net effect (NE) and the relative interaction index (RII) were significantly higher than 0 under all environmental conditions, demonstrating that plant-plant interactions generated positive effects in the intercropping system. The maize yield and biomass RII were 0.029-0.095 and 0.018-0.066, respectively, which indicated that maize growth was constantly facilitated. However, the RII for grass pea yield and biomass exhibited a different trend in comparison with maize. It was higher than 0 (as the facilitated species) under low soil P and moisture conditions and transitioned to values lower than 0 (facilitator species) under high P and moisture conditions, which showed that the type and intensity of plant-plant interactions steadily shifted with the applied stressors. Direct interactions decreased the maize rhizospheric soil pH by 1.5% and 1.9% under Low-P conditions. Notably, the rhizospheric soil acid and alkaline phosphatase secretions of maize and grass pea increased by 17.4-27.4% and 15.3-27.7%, respectively, in P-deficient soils. These results show that plant-plant interactions can effectively relieve P stress by mineralizing organophosphorus in P-deficient soils. Furthermore, the above tendency became more pronounced under drought-stressed conditions. The nylon barrier partially restricted the exchange and utilization of available nutrients and decreased the total yield and biomass by 1.8-7.8% and 1.1-7.8%, respectively. The presence of a solid barrier completely restricted interspecific rhizospheric interactions and decreased the total yield and biomass by 2.1-13.8% and 1.6-15.7%, respectively. Phytate and KH.sub.2PO.sub.4 addition intensified asymmetric interspecific competition, and grass pea was consistently subjected to competitive pressures. Briefly, the tradeoff between facilitation and competition was driven by rhizospheric interactions, and the transition in the intensity and type of interaction was highly dependent on resource availability in a biologically diverse system.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Long-term overfertilization not only aggravates environmental costs, but reduces the quality and yield of fruit in dryland apple orchard, and this issue is closely associated with post-germination ...fertilization management. On the basis of multi-year observations, we developed a targeted fertigation strategy of FORD, i.e. formula fertilization (rational fertilizer scheme), on-demand fertilization in the sensitive period, reduced fertilization and delayed fertilization. Two-year field investigations were conducted with conventional furrow application (CK), integrated furrow and injection application (FI) and the optimized injection application under the FORD principle in a semiarid apple orchard. The data indicated that FI and FORD had a similar fruit yield of 57.2 Mg ha-1, significantly greater (by 4.5%) than CK. Yet, fruit quality (nutrition, flavor and appearance) was substantially improved under FORD, relative to FI and CK (P<0.05). Importantly, FORD did not induce secondary salinization (soil electric conductivity (EC) of 100-500 μs cm-1, pH of 7.8), but significantly improved soil microbial biomass carbon and the activities of carbon turnover key enzymes (β-glucosidase and cellobiohydrolase). As a result, FORD induced a better functioning of leaves, and a faster speed of fruit expansion than CK and FI did. Totally, the above parameters were positively associated with the efficient couplings of water and fertilizer, which critically depended on nutrients rational supply in FORD. Notably, relative to CK and FI, FORD reduced the fertilization cost by 27.8% and 8.3% respectively, accordingly harvesting 38.1% and 11.6% higher net economic return (2.94×104 US$ ha-1). In summary, there existed remarkable positive effects of FORD-led fertigation strategy on fruit yield, quality and economic benefits. The FORD can be viewed as a general environment-friendly strategy to guide apple post-germination fertilization management for greater economic benefits.
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•A new fertigation strategy regarding the reduced fertilization for apple post-germination was developed.•The strategy reduced chemical fertilizers use of 24.2%.•The strategy improved fruit nutrition, flavor and appearance.•The strategy increased net economic return of 38.1%.•The strategy improved soil quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Ridge and furrow plastic film mulching (RFM) has improved net primary productivity (NPP) to a high level in semi-arid rainfed agricultural regions. Yet, it is unclear whether there is still a room ...for further improvement on NPP while stabilizing soil organic carbon through returning previous maize stover pieces. To address this issue, maize stubbles were smashed into pieces and in situ ploughed into 30 cm topsoil at a semi-arid site in northwest China from 2016 to 2017. This was done using the Pioneer 335 maize variety with three treatments (CK, ridge and furrow without mulching; RFM, ridge and furrow with plastic mulching; RFML, 3.49 t ha−1 of maize stover returning in RFM; RFMH, 5.24 t ha−1 of returning in RFM). The results indicated that maize stover returning exhibited similar trend as RFM at early cool seedling stage, raising the topsoil temperature. However, in warm and dry silking stage (2017), both stover returning rates reduced soil temperatures by 1.33 and 0.8 ◦C relative to RFM and CK (P < 0.05), respectively. The soil water storage increased significantly in RFMH by 17.3% and RFML by 28.5% relative to that of RFM, in a warm and dry growing season (2017). Critically, stover returning increased (P < 0.05) soil organic carbon and light fraction organic carbon turnover across the two growing seasons. By improving hydrothermal conditions, stover returning in RFM increased biomass accumulation and grain yield (P < 0.05), leading to higher (P < 0.05) net economic benefit, with greater above-ground biomass NPP (74.5–93.2%) and below-ground biomass NPP (88.5–89.4%), compared with CK. In conclusion, maize stover returning of stover pieces into topsoil might be a promising solution to enhance carbon turnover for higher net primary productivity on the basis of plastic film mulching in semiarid rainfed region.
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•Shallow-incorporated stover returning was tested in plastic film mulching maize.•It was found to improve soil water and temperature status in warm & dry season.•Organic matter input was improved for higher soil light fraction C after two seasons.•Net primary productivity was significantly improved in two growing seasons.•Shallow-incorporated stover returning increased economic profitability significantly.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Two multi-nuclear Ni(II)-based complexes have been successfully prepared by the complexation of more flexible salamo-type ligand (H2L) with nickel salts of different anions.•The structure of ...tetra-nuclear complex 2 is particularly unique because the flexibility of the ligand is better, which creates conditions for the intramolecular self-assembly.
Two new tri- and tetra-nuclear Ni(II)-based complexes, {NiL(EtOH)(μ-OAc)}2Ni·4EtOH (1) and Ni4L2(μ3-OMe)4(MeOH)4 (2), supported by a more flexible salamo-type ligand H2L containing coumarin functional groups have been synthesized. Complex 1 is tri-nuclear, including three Ni(II) atoms with hexa-coordinated octahedral geometries. X-ray single-crystal structure analysis revealed that complex 2 is a novel tetra-nuclear structure previously unreported, and the geometry of four Ni(II) atoms with hexa-coordinate can be regarded as octahedron. Interestingly, due to the improvement of the flexibility of salamo-type ligand H2L, complex 2 is obtained by the form of intramolecular self-assembly. Moreover, the fluorescence properties of H2L and its Ni(II)-based complexes were studied. Subsequently, the supramolecular structure, Hirshfeld surfaces analyses and DFT calculations of the two Ni(II)-based complexes have been performed.
Display omitted Two new tri- and tetra-nuclear Ni(II)-based complexes, {NiL(EtOH)(μ-OAc)}2Ni·4EtOH (1) and Ni4L2(μ3-OMe)4(MeOH)4 (2), supported by a more flexible salamo-type ligand H2L containing coumarin functional groups have been synthesized and characterized structurally. Interestingly, complex 2 is a novel tetra-nuclear structure previously unreported. The fluorescence properties, Hirshfeld surfaces analyses and DFT calculations of H2L and its Ni(II)-based complexes were studied.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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