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【Objective】The research was performed to investigate the effects of planting year (Y) and tillage mode (T) on soil improvement and maize yield in thin-layer black soil in the southern part of the Songliao Plain.【Method】Three tillage modes namely strip-tillage (ST), conventional ridge planting (CT) and no-tillage (NT) were conducted to analyze the changes in soil physical properties and yield traits through field location experiment.【Result】The results showed no significant differences were found in the thickness of soil layers (TSL) and soil water holding capacity (SWHC) of the tillage layer under treatments of ST, NT and CT in 2-year cultivation field, while the results were opposite in 4-year cultivation field, with TSL and SWHC increasing by 15.46% and 30.28% under ST compared with that of CT, whereas no difference was observed between ST and NT. For 0-20 cm depth soil, the soil penetration resistance (PR) under ST treatment increased by 57.57% and 42.86% in the 2-year and 4-year cultivation fields, compared with that under CT treatment, while decreased by 5.22% and 19.22% compared with that under NT treatment. And no significant differences were observed in soil bulk density (BD) and soil porosity (SP) between the 2-year and 4-year cultivation fields under the three treatments. For the 20-40 cm depth soil, only BD under ST treatment in 4-year cultivation field was 11.56% lower than that of CT, whereas no difference was found between ST and NT. The PR under ST in 2-year and 4-year cultivation fields were 5.22% and 19.22% lower than that of CT, respectively, while SP increased by 11.8% and 15.92%, correspondingly. Compared with treatments of CT and NT, maize yield under ST in 2-year cultivation field increased by 3.62% and 3.52%, respectively, and that in 4-year cultivation field increased by 16.08% and 9.29%, respectively. From the results of yield components, the increase in effective ear number per unit area was the main factor for the increase of maize yield under ST treatment. The analysis of the random forest model further demonstrated that the TSL and PR in plough layer were the most important factors affecting maize yield with 2-year and 4-year cultivation.【Conclusion】In conclusion, ST is beneficial for the formation of better plough layer and enhancement of maize yield in thin-layer black soil farmland.

【Objective】The study aims to investigate the impact of ginseng cultivation on soil quality improvement and plant growth and development of subsequent maize planting.【Method】Field experiments were conducted at four experimental sites of Beigang, Dafang, Choushui and Jingyu in Fusong County of Baishan City, Jilin Province. The13 physicochemical properties of the topsoil layer, dry matter accumulation of maize plants, as well as nitrogen uptake and utilization were investigated under two different farmland utilization methods, namely normal farmland (NF, as control) and improved farmland by ginseng planting (IFGP).【Result】The soil bulk density under soil depth layer of 10-20 cm and 20-30 cm under treatment of IFGP was ranged from 1.25 to 1.43 g/cm3, which was significantly lower than that of the control(NF). The averaged thickness topsoil layer in the position of the ridge and furrow was 31.4 cm and 16.94 cm, which were 89.6%-93.55% and 39.59%-56.52% higher than the NF, respectively. For the nutrients content in the topsoil, the organic matter, total nitrogen, alkali hydrolyzable nitrogen, and available potassium content in the four experimental sites were increased by 6.18%-38.99%, 2.68%-12.64%, 6.62%-42.90%, and 6.39%-40.54% under treatment of IFGP, respectively, compared to NF. In addition, the range of soil pH in the treatment of IFGP was 4.8-6.82, which significantly improved the trend of soil acidification compared to NF. Compared with NF, except for the result of Jingyu, the dry matter accumulation of maize plants in the other three experimental sites were increased by 14.70%, 11.19%, and 10.32%, respectively. The increase in maize grain yield was ranged from 8.56% to 14.08%, and the increase mainly due to the increase in effective ears per unit area. The nitrogen (N) content in organs such as leaves and grains in maize plants at harvesting stage under treatment of IFGP was significantly higher than that of NF, resulting in 13.60%-26.08% increase of total N absorption of whole maize in IFGP as compared to the NF. Correlation and regression analysis showed that the dry matter accumulation in maize plants was positively correlated with soil available nitrogen and organic matter content, and a significant linear relationship between soil total nitrogen content and grain N concentration were also observed.【Conclusion】IFGP treatment can significantly improve the nutrient status, increase the thickness of the topsoil layer, reduce the soil compaction, which is benefit to the growth and development of post maize. In addition, the increase in N levels in farmland after ginseng cultivation is conducive to the increase in maize yield and soil N absorption and utilization

【Objective】This study aimed to investigate the effects of varies sowing dates on the traits of commodity quality and edible quality of fresh waxy maize and to improve the processing capacity of fresh waxy maize in Jilin Province.【Method】A field experiment with four sowing date were set up on May 12 (SD1), May 26 (SD2), June 9 (SD3)and June 22 (SD4) and the mainly popularized waxy maize variety 'Wannuo2000' was used. The main commodity qualities, such as ear length, bald tip length, ear diameter, grain number per row, grain number per ear, as well as the edible quality (seed coat thickness, residue rate, physical quality) were measured with each treatment.【Result】Sowing date could significantly affect the traits of fresh weight of single ear, ear length, ear diameter, grain number per ear, residue rate, hardness, cohesiveness and gumminess of fresh waxy maize, whereas had no significant effect on seed yield, bald tip length, grain number per row and seed coat thickness. With the delay of sowing date, the fresh weight of single ear, ear length, ear diameter and grain number per ear increased first and then decreased, all of which reached the maximum under SD3 treatment, which were 1.23, 1.09, 1.08 and 1.13 times of those higher than those of early sowing (SD1), and 13.10 %, 5.94 %, 3.53 % and 8.06 % higher than those of late sowing (SD4). The edible quality such as residue rate, hardness and gumminess showed decreased first and then increased. The seed coat thickness increased gradually with the delaying sowing date, although the difference between treatments was not significant. Correlation analysis showed there was a positive correlation between the residue rate of fresh corn and grain elasticity, while showed a negative correlation between seed coat thickness and grain cohesion.【Conclusion】More attention should be paid to these changes of commercial and edible qualities with different sowing dates in fresh waxy maize production. Optimum sowing date (SD3) is beneficial to coordinating the commercial and edible qualities of fresh waxy corn, while sowing (SD1) or late sowing (SD4) is adverse to the improvement of commercial and edible qualities in fresh waxy maize production.

Abstract Lodging resistance is a critical trait in modern maize breeding. This study aimed to examine maize stalk lodging and its related characteristics in response to increasing planting densities in modern hybrids. A two-year field trial was conducted from 2018 to 2019 with two widely grown commercial hybrids (‘Xy335’ and ‘Fm985’) and three planting density treatments of 4.5 × 104 (low density, LD), 6.5 × 104 (medium density, MD), and 8.5 × 104 plants/ha (high density, HD). New hybrid Fm985 had a significantly higher grain yield and lower lodging rate at HD, while there was no significance at LD and MD. Compared to Fm985, old hybrid Xy335 had a significantly high plant height, ear and gravity height, and culm length (CL) across the three planting densities, while opposite stalk bending strength (SBS), dry weight per unit length (DWPU), cross-sectional area, and the cellulose and lignin content in the basal internode were low. Correlation and path analysis revealed that kernel number per ear and lodging rate directly contributed to maize grain yield, while lodging-related traits of SBS, stem lignin, and DWPU had an indirect effect on maize grain yield, suggesting that modern hybrid maize yield enhancement is associated with greater stalk lodging resistance at a high planting density in northeast China.

Abstract Plant growth environment plays an important role in shaping soil microbial communities. To understand the response of soil rhizosphere microbial communities in Oplopanax elatus Nakai plant to a changed growth conditions from natural habitation to cultivation after transplant. Here, a comparative study of soil chemical properties and microbial community using high-throughput sequencing was conducted under cultivated conditions (CT) and natural conditions (WT), in Changbai Mountain, Northeast of China. The results showed that rhizosphere soil in CT had higher pH and lower content of soil organic matter (SOM) and available nitrogen compared to WT. These changes influenced rhizosphere soil microbial communities, resulting in higher soil bacterial and fungi richness and diversity in CT soil, and increased the relative abundance of bacterial phyla Acidobacteria, Chloroflexi, Gemmatimonadetes, Firmicutes and Patescibacteria, and the fungi phyla Mortierellomycota and Zoopagomycota, while decreased bacterial phyla Actinobacteria, WPS-2, Gemmatimonadetes, and Verrucomicrobia, and the fungi phyla Ascomycota, and Basidiomycota. Redundancy analysis analysis indicated soil pH and SOM were the primarily environmental drivers in shaping the rhizosphere soil microbial community in O. elatus under varied growth conditions. Therefore, more attention on soil nutrition management especially organic fertilizer inputs should be paid in O. elatus cultivation.

Global rising atmospheric CO2 concentration ([CO2]) and drought stress exert profound influences on crop growth and yield. The objective of the present study was to investigate the responses of leaf gas exchange and plant water use efficiency (WUE) of wheat (C3) and maize (C4) plants to progressive drought stress under ambient (a[CO2], 400 ppm) and elevated (e[CO2], 800 ppm) atmospheric CO2 concentrations. The fraction of transpirable soil water (FTSW) was used to evaluate soil water status in the pots. Under non-drought stress, e[CO2] increased the net photosynthetic rate (An) solely in wheat, and dry matter accumulation (DMA), whereas it decreased stomatal conductance (gs) and water consumption (WC), resulting in enhanced WUE by 27.82% for maize and 49.86% for wheat. After onset of progressive soil drying, maize plants in e[CO2] showed lower FTSW thresholds than wheat, at which e.g. gs (0.31 vs 0.40) and leaf relative water content (0.21 vs 0.43) starts to decrease, indicating e[CO2] conferred a greater drought resistance in maize. Under the combination of e[CO2] and drought stress, enhanced WUE was solely found in wheat, which is mainly associated with increased DMA and unaffected WC. These varied responses of leaf gas exchange and WUE between the two species to combined drought and e[CO2] suggest that specific water management strategies should be developed to optimize crop WUE for different species in a future drier and CO2-enriched environment.

Glomalin-related soil protein (GRSP), soil nutrients, and soil enzyme activities are closely related to soil fertility and land productivity, which play an important role in indicating soil quality. Little is known about the spatial variation in GRSP and its relationship with edaphic factors. Here, the spatial distribution of GRSP, soil chemical properties, and the soil enzyme activities of 0–20 cm depth farmland soil in the black soil region of northeast China were investigated, and the relationships among edaphic factors were analyzed collected from 41 sampling sites. The results indicate that GRSP, soil organic matter, total nitrogen, and acid phosphatase activities showed significant patterns of spatial variation, generally decreasing from north to south along a latitudinal gradient. Principal component analysis revealed that total GRSP (by 80.19%) and soil organic matter content (by 80.15%) were the greatest contributing factors accounting for the variations. Edaphic factors such as soil organic matter, total nitrogen, total phosphorus, and acid phosphatase were significantly positively correlated with GRSP, while urease was negatively correlated with GRSP. Mantel tests also showed that soil organic matter, total nitrogen, urease, and acid phosphatase were positively correlated with GRSP. The results reflect the soil fertility characteristics of the black soil region of northeast China and reveal the relationship among edaphic factors. These findings could be used to inform agricultural production and provide new insight into the role of GRSP in soil quality.

Stomata play a critical role in the regulation of gas exchange between the interior of the leaf and the exterior environment and are affected by environmental and endogenous stimuli. This study aimed to evaluate the effect of the arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis, on the stomatal behavior of wheat (Triticum aestivum L.) plants under combination with elevated CO2 and NaCl stress. Wheat seedlings were exposed to ambient (400 ppm) or elevated (700 ppm) CO2 concentrations and 0, 1, and 2 g kg−1 dry soil NaCl treatments for 10 weeks. AM symbiosis increased the leaf area and stomatal density (SD) of the abaxial surface. Stomatal size and the aperture of adaxial and abaxial leaf surfaces were higher in the AM than non-AM plants under elevated CO2 and salinity stress. AM plants showed higher stomatal conductance (gs) and maximum rate of gs to water vapor (gsmax) compared with non-AM plants. Moreover, leaf water potential (Ψ) was increased and carbon isotope discrimination (Δ13C) was decreased by AM colonization, and both were significantly associated with stomatal conductance. The results suggest that AM symbiosis alters stomatal morphology by changing SD and the size of the guard cells and stomatal pores, thereby improving the stomatal conductance and water relations of wheat leaves under combined elevated CO2 and salinity stress.

Rosmarinic acid (RA), a polyphenolic phytochemical, is a natural prolyl oligopeptidase inhibitor. In the present study, we found that RA exerted potent anti-inflammatory effects in in vivo models of acute lung injury (ALI) induced by lipopolysaccharide (LPS). Mice were pretreated with RA one hour before challenge with a dose of 0.5 mg/kg LPS. Twenty-four hours after LPS was given, bronchoalveolar lavage fluid (BALF) was obtained to measure pro-inflammatory mediator and total cell counts. RA significantly decreased the production of LPS-induced TNF-a, IL-6, and IL-1β compare with the LPS group. When pretreated with RA (5, 10, or 20 mg/kg) the lung wet-to-dry weight (W/D) ratio of the lung tissue and the number of total cells, neutrophils and macrophages in the BALF were decreased significantly. Furthermore, RA may enhance oxidase dimutase (SOD) activity during the inflammatory response to LPS-induced ALI. And we further demonstrated that RA exerts anti-inflammation effect in vivo models of ALI through suppresses ERK/MAPK signaling in a dose dependent manner. These studies have important implications for RA administration as a potential treatment for ALI.

Ginkgolide B is an anti-inflammatory extract of Ginkgo biloba and has been used therapeutically. It is a known inhibitor of platelet activating factor (PAF), which is important in the pathogenesis of asthma. Here, a non-infectious mouse model of asthma is used to evaluate the anti-inflammatory capacity of ginkgolide B (GKB) and characterize the interaction of GKB with the mitogen activated protein kinase (MAPK) pathway. BALB/c mice that were sensitized and challenged to ovalbumin (OVA) were treated with GKB (40 mg/kg) one hour before they were challenged with OVA. Our study demonstrated that GKB may effectively inhibit the increase of T-helper 2 cytokines, such as interleukin (IL)-5 and IL-13 in bronchoalveolar lavage fluid (BALF). Furthermore, the eosinophil count in BALF significantly decreased after treatment of GKB when compared with the OVA-challenged group. Histological studies demonstrated that GKB substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. These results suggest that ginkgolide B may be useful for the treatment of asthma and its efficacy is related to suppression of extracellular regulating kinase/MAPK pathway.

Global rising atmospheric CO2 concentration ([CO2]) and drought stress exert profound influences on crop growth and yield. The objective of the present study was to investigate the responses of leaf gas exchange and plant water use efficiency (WUE) of wheat (C3) and maize (C4) plants to progressive drought stress under ambient (a[CO2], 400 ppm) and elevated (e[CO2], 800 ppm) atmospheric CO2 concentrations. The fraction of transpirable soil water (FTSW) was used to evaluate soil water status in the pots. Under nondrought stress, e[CO2] increased the net photosynthetic rate (An) solely in wheat, and dry matter accumulation (DMA), whereas it decreased stomatal conductance (gs) and water consumption (WC), resulting in enhanced WUE by 27.82% for maize and 49.86% for wheat. After onset of progressive soil drying, maize plants in e[CO2] showed lower FTSW thresholds than wheat, at which e.g. gs (0.31 vs 0.40) and leaf relative water content (0.21 vs 0.43) starts to decrease, indicating e[CO2] conferred a greater drought resistance in maize. Under the combination of e[CO2] and drought stress, enhanced WUE was solely found in wheat, which is mainly associated with increased DMA and unaffected WC. These varied responses of leaf gas exchange and WUE between the two species to combined drought and e[CO2] suggest that specific water management strategies should be developed to optimize crop WUE for different species in a future drier and CO2-enriched environment. [ABSTRACT FROM AUTHOR]

This study aims to investigate the responses of carbon assimilation, grain yield, leaf stay-green rate, nitrogen uptake and distribution to soil compaction in the hard plow pan caused by repeated use of tractor-driven cultivator in Northeast China. The typical hybrid maize variety "Zhengdan 958" was exposed to two treatments of simulated plow pan (SP) and simulated subsoiling (SS, control) in pot experiments from 2012 to 2014. Compared with SS, SP significantly reduced net photosynthetic rate (Pn) during growth stage, leading to a decrease in dry matter accumulation (DMA) and grain yield (GY) in three consecutive experimental years. Leaf stay-green degrees (LSD), which showed a fast descending trend from 20 days after silking (DAS), significantly decreased in the later filling stage under SP treatment. The translocation efficiency of the stored N (TEN) in stalk and leaf to the grain during pre-silking was enhanced, whereas leaf and grain N concentration (LNC/GNC), together with N accumulation amounts at maturity were significantly reduced under SP treatment. Also, plough pan reduced the N distribution to the organs of stalk, leaf and grain. In conclusion, subsoiling is a possible way to delay leaf senescence and achieve higher DMA and GY, and increased grain N in the corn belt of Northeast China. [ABSTRACT FROM AUTHOR]

Lodging is one of the major factors that constrain grain yield stability and quality worldwide. Stalk lodging often reduce maize (Zea mays L.) grain yield and also causes difficulties in harvest operations. Plant growth regulators (PGRs) are often used widely to control lodging in modern high input cereal management. Two years field experiments were conducted with commercial PGRs of Yuhuangjin (YHJ) to determine their effects on spring maize growth, agronomic characteristics, grain yield and stalk lodging under high planting density in Jilin province, Northeast China. The results showed that, in all experiments, maize lodging-related characters of plant height (PH), ear height (EH), gravity height (GH), dry matter accumulation (DMA), internode 2 to 7 length (IL) were consistently reduced, and stalk bending strength(BS) of node 2 to7 were consistently enhanced by application of YHJ in both years. It is much more significant about above-mentioned character to apply with two (Sprayed twice, before elongation stage and V8 stage, respectively) or three (Sprayed three times, before elongation stage, V8 stage and before tasseling stage, respectively) times YHJ treatment. Maize grain yield, lodging score and HI were significantly influence by PGRs (T), Hybrids (H), and Year (Y). Grain yield increased and lodging score deceased significantly under YHJ treatment in high lodging year, but had little influence on grain yield in low lodging years. Application of YHJ could increase maize harvest index (HI) in all experimental years by reducing maize DMA significantly. Based upon these results, we concluded that PGRs could enhance stem lodging resistance during growth period, provided that they are used in right quantity and time. This is the optimal agronomic management in maize crops cultivated under high planting density in Northeast China. [ABSTRACT FROM AUTHOR]