Optimized sand tube irrigation combined with nitrogen application improves jujube yield as well as water and nitrogen use efficiencies in an arid desert region of Northwest China.

Efficient water-saving irrigation techniques and appropriate nitrogen (N) application are keys to solving the problems of water scarcity and irrational fertilization in jujube cultivation. In this study, first, the effects of sand tube irrigation (STI) on surface and subsurface wetted characteristics were investigated using in-situ infiltration tests in a jujube garden. Compared with surface drip irrigation (SD), STI reduced surface wetted area by 57.4% and wetted perimeter of the surface wetted circle by 37.1% and increased subsurface maximum infiltration distance of wetting front by 64.9%. At the optimal sand tube depth of 20 cm, surface wetted area of the surface wetted circle decreased by 65.4% and maximum infiltration distance of the wetting front increased by 70.9%, compared with SD. Two-year field experiments then investigated the effects of STI and SD on soil water storage, jujube leaf chlorophyll, net photosynthetic rate, actual water consumption, fruit yield, and water (WUE) and N (NUE) use efficiencies at four levels of N (pure nitrogen: N1, 0; N2, 286 kg ha-1; N3, 381 kg ha-1; N4, 476 kg ha-1) at the same irrigation amount (45 mm irrigation-1, total of 8). Compared with SD, STI increased soil water storage 18.0% (2021) and 15.6% (2022) during the entire growth period and also chlorophyll content, nitrogen balance index, and net photosynthetic rate, with both increasing and then decreasing with increasing N. Compared with SD, STI increased yields by 39.1% and 36.5% and WUE by 44.3% and 39.7% in 2021 and 2022, respectively. Nitrogen use efficiency was 2.5 (2021) and 1.6 (2022) times higher with STI than with SD. STI combined with N3 had the highest yield, WUE, NUE, and net income and is thus recommended as the optimal water-N combination. In conclusion, STI combined with appropriate N application can be an effective water-saving irrigation technology alternative to SD in jujube cultivation in arid areas.

Optimizing the Mulching Pattern and Nitrogen Application Rate to Improve Maize Photosynthetic Capacity, Yield, and Nitrogen Fertilizer Utilization Efficiency.

Residual film pollution and excessive nitrogen fertilizer have become limiting factors for agricultural development. To investigate the feasibility of replacing conventional plastic film with biodegradable plastic film in cold and arid environments under nitrogen application conditions, field experiments were conducted from 2021 to 2022 with plastic film covering (including degradable plastic film (D) and ordinary plastic film (P)) combined with nitrogen fertilizer 0 (N0), 160 (N1), 320 (N2), and 480 (N3) kg·ha-1. The results showed no significant difference (p > 0.05) in dry matter accumulation, photosynthetic gas exchange parameters, soil enzyme activity, or yield of spring maize under degradable plastic film cover compared to ordinary plastic film cover. Nitrogen fertilizer is the main factor limiting the growth of spring maize. The above-ground and root biomass showed a trend of increasing and then decreasing with the increase in nitrogen application level. Increasing nitrogen fertilizer can also improve the photosynthetic gas exchange parameters of leaves, maintain soil enzyme activity, and reduce soil pH. Under the nitrogen application level of N2, the yield of degradable plastic film and ordinary plastic film coverage increased by 3.74~42.50% and 2.05~40.02%, respectively. At the same time, it can also improve water use efficiency and irrigation water use efficiency, but it will reduce nitrogen fertilizer partial productivity and nitrogen fertilizer agronomic use efficiency. Using multiple indicators to evaluate the effect of plastic film mulching combined with nitrogen fertilizer on the comprehensive growth of spring maize, it was found that the DN2 treatment had the best complete growth of maize, which was the best model for achieving stable yield and income increase and green development of spring maize in cold and cool irrigation areas.

Photosynthetic characteristics, yield and quality of sunflower response to deficit irrigation in a cold and arid environment.

In arid regions, deficit irrigation stands as an efficacious strategy for augmenting agricultural water conservation and fostering sustainable crop production. The Hexi Oasis, an irrigation zone situated in Northwest China, serves as a pivotal area to produce grain and cash crops. Nonetheless, due to the predominant conditions of low rainfall and high evaporation, the scarcity of irrigation water has emerged as a critical constraint affecting crop growth and yield in the area. In order to evaluate the effects of deficit irrigation on photosynthetic characteristics, yield, quality, and water use efficiency of sunflower, a two-year field experiment with under-mulched drip irrigation was conducted in the cold and arid environment of the Hexi Oasis region. Water deficits were implemented at sunflower seedling and maturity and consisted of three deficit levels: mild deficit (65-75% field capacity, FC), moderate deficit (55-65% FC), and severe deficit (45-55% FC). A total of six combined water deficit treatments were applied, using full irrigation (75-85% FC) throughout the entire crop-growing season as the control (CK). The results illustrated that water deficit engendered a decrease in leaf net photosynthetic rate, transpiration rate, and stomatal conductance of sunflower compared to CK, with the decrease becoming significant with the water deficit increasing. A mild water deficit, both at the seedling and maturity phases, precipitated a significant enhancement (p< 0.05) in leaf water use efficiency. Under mild water deficit, stomatal limitation emerged as the predominant factor inducing a reduction in the photosynthetic capacity of sunflower leaves, while as the water deficit escalated, non-stomatal limitation progressively assumed dominance. Moreover, a mild/moderate water deficit at seedling and a mild water deficit at maturity (WD1 and WD3) significantly improved sunflower seed quality under consistent yield conditions and significantly increased irrigation water use efficiency, with an average increase of 15.3% and 18.5% over the two years, respectively. Evaluations utilizing principal component analysis and membership function methods revealed that WD1 attained the highest comprehensive score. Consequently, a mild water deficit at both seedling and maturity (WD1) is advocated as the optimal deficit irrigation strategy for sunflower production within the cold and arid environment of Northwest China.

Optimizing water and nitrogen management strategies to improve their use efficiency, eggplant yield and fruit quality.

With improvement in living standards, consumer preferences for vegetables are changing from quantity- to quality-oriented. Water and nitrogen supply, as two major determinants of vegetable crop yield and quality, can be optimally managed to improve the yield and quality. To evaluate the response in yield, fruit quality, and water and nitrogen utilization of eggplant to different water and nitrogen management strategies, a 2-year (2021 and 2022) field trial under mulched drip irrigation was conducted. The growth period was divided into seedling, flowering and fruit set, fruit development, and fruit ripening stages. Three irrigation levels were applied during the flowering and fruit set stage: W0, adequate water supply (70%-80% of field water capacity, FC); W1, mild water deficit (60%-70% FC); and W2, moderate water deficit (50%-60% FC). In addition, three nitrogen application rates were applied: N1, low nitrogen level (215 kg ha-1); N2, medium nitrogen level (270 kg ha-1); and N3, high nitrogen level (325 kg ha-1). The irrigation and nitrogen rates were applied in all combinations (i.e., nine treatments in total). Adequate water supply throughout the reproductive period in combination with no nitrogen application served as the control (CK). The yield of the W1N2 treatment was significantly increased by 32.62% and 35.06% in 2021 and 2022, respectively, compared with that of the CK. Fruit soluble protein, soluble solids, and vitamin C contents were significantly higher under W1 than W2. Fruit quality was significantly higher under the N2 rate compared with the other nitrogen rates. The W1N2 treatment showed the highest water productivity, with a significant increase of 11.27%-37.84% (2021) and 14.71%-42.48% (2022) compared with that under the other treatments. Based on the average water-deficit degree and nitrogen application rate, W0 and N1 had the highest partial factor productivity of nitrogen. Assessment of the results using the TOPSIS (technique for order preference by similarity to an ideal solution) method indicated that mild water deficit in combination with the medium nitrogen application rate (W1N2) was the optimal water and nitrogen management strategy for cultivated eggplant. The present findings contribute novel insights into the sustainable cultivation of eggplant in an oasis arid environment.

Natural Alkaloid Waltherione F-Derived Hydrazide Compounds Evaluated in an Agricultural Fungicidal Field.

In this project, quinoline and quinolone-containing hydrazide compounds were designed and synthesized by introducing a bioactive hydrazide group into the skeleton of waltherione F. The fungicidal activity revealed that some hydrazide compounds exhibited excellent and broad-spectrum fungicidal activity; especially, compounds E8, E12, and E16 showed more than 90% or even 100% inhibition rates against most pathogens at 50 µg·mL-1. The fungicidal mechanism indicated that compound E8 may affect the normal function of the plasma membrane, further generating changes in the morphology and subcellular structure of mycelia. Simultaneously, Fusarium graminearum may resist the E8-treated stress through the metabolic pathways related to l-glutamate, l-glutamine, and glutathione. Finally, the effect of compound E8 on wheat seedling's growth and the toxicity to zebrafish were accomplished. These results will provide important guidance to discover novel fungicidal lead compounds and explore new targets, which are effective ways to alleviate the increasingly severe drug resistance.

Crop coefficient determination and evapotranspiration estimation of watermelon under water deficit in a cold and arid environment.

To investigate the evapotranspiration and crop coefficient of oasis watermelon under water deficit (WD), mild (60%-70% field capacity, FC)and moderate (50%-60% FC) WD levels were set up at the various growth stages of watermelon, including seedling stage (SS), vine stage (VS), flowering and fruiting stage (FS), expansion stage (ES), and maturity stage (MS), with adequate water supply (70%-80% FC) during the growing season as a control. A two-year (2020-2021) field trial was carried out in the Hexi oasis area of China to explore the effect of WD on watermelon evapotranspiration characteristics and crop coefficient under sub-membrane drip irrigation. The results indicated that the daily reference crop evapotranspiration showed a sawtooth fluctuation which was extremely significantly and positively correlated with temperature, sunshine hours, and wind speed. The water consumption during the entire growing season of watermelon varied from 281-323 mm (2020) and 290-334 mm (2021), among which the phasic evapotranspiration valued the maximum during ES, accounting for 37.85% (2020) and 38.94% (2021) in total, followed in the order of VS, SS, MS, and FS. The evapotranspiration intensity of watermelon increased rapidly from SS to VS, reaching the maximum with 5.82 mm·d-1 at ES, after which it gradually decreased. The crop coefficient at SS, VS, FS, ES, and MS varied from 0.400 to 0.477, from 0.550 to 0.771, from 0.824 to 1.168, from 0.910 to 1.247, and from 0.541 to 0.803, respectively. Any period of WD reduced the crop coefficient and evapotranspiration intensity of watermelon at that stage. And then the relationship between LAI and crop coefficient can be characterized better by an exponential regression, thereby establishing a model for estimating the evapotranspiration of watermelon with a Nash efficiency coefficient of 0.9 or more. Hence, the water demand characteristics of oasis watermelon differ significantly during different growth stages, and reasonable irrigation and water control management measures need to be conducted in conjunction with the water requirements features of each growth stage. Also, this work aims to provide a theoretical basis for the irrigation management of watermelon under sub-membrane drip irrigation in desert oases of cold and arid environments.

Spatiotemporal heterogeneity correction in land ecosystem services and its value assessment: a case study of the Loess Plateau of China.

The considerable variation in structures and functions of different ecosystems leads to highly variable ecosystem service values (ESVs). Consequently, the accurate quantification of ESVs can better assess and reflect impacts of land use and cover changes (LUCC) on ecosystem services. In the land use simulations of this study, a CA-Markov model was chosen and nine factors affecting land use change were evaluated, followed by the construction of a multi-criteria evaluation method to simulate land use scenarios between 2025 and 2030 on the Loess Plateau. Six key ecological indicators (economy, water production, net primary plant productivity, habitat quality, accessibility, and soil conservation) were used to correct for spatiotemporal heterogeneity within the terrestrial ESV equivalent weight table for China to obtain an ESV equivalent weight factor table that is applicable to the Loess Plateau. Using the newly corrected table, ESVs for the Loess Plateau region were estimated between 1995 and 2030, and the impacts of LUCC on ESVs were analyzed. The Kappa values for the 2015 land use simulation results were 0.80 and 0.83, which were greater than 0.75, indicating that the CA-Markov model simulations were accurate. Throughout the study period, the largest increases in land use type area were for built-up areas and forest lands, with built-up areas primarily derived from conversions of cultivated lands and grasslands, and forest land increases primarily coming from conversion of grasslands. ESVs increased overall by 933.97 × 108 yuan and 312.86 × 108 yuan from 1995 to 2018 and 2018 to 2030, respectively. The three largest contributors to ecosystem services among land use types were moderate grasses, shrublands, and dense grasslands. In conclusion, ESVs for the Loess Plateau steadily increased year by year from 1995 to 2030, indicating that ecological restoration projects played major roles in improving the stability and sustainability of the region's ecosystems.

Analysis of Land Use Change Drivers and Simulation of Different Future Scenarios: Taking Shanxi Province of China as an Example.

This study analyzed change and spatial patterns of land use in Shanxi from 2000 to 2020. The drivers of land use and cover change (LUCC) in cultivated lands, forest lands, grasslands, and rural construction areas were explored from four dimensions, including population, natural environment, location traffic, and economic development. The CA-Markov model was used to simulate the scenarios of natural growth (NG), ecological protection (EP), economic development (ED), food security (FS), ecological protection-economic development (EP-ED), and ecological protection-food security (EP-FS) in 2030. The results indicated that: (1) The conversion to built-up areas primarily dominated the LUCC processes, and their expansion was mainly to the detriment of the cultivated lands and grasslands during 2000-2020. (2) From 2000 to 2020, population, economy, and land productivity were the main factors of LUCC; the interaction of drivers for the increase of cultivated lands, forest lands, grasslands, and rural construction areas showed enhancement. (3) Under the NG, ED, and EP-ED scenarios, the rural construction areas would have increased significantly, while under the FS and EP-FS scenarios, the cultivated lands would only just have increased. These future land use scenarios can inform decision-makers to make sound decisions that balance socio-economic, ecological, and food security benefits.

Deficit mulched drip irrigation improved yield and quality while reduced water consumption of isatis indigotica in a cold and arid environment.

Deficit irrigation is an effective alternative to traditional irrigation, as it improves crop productivity and conserves water. However, crops may be sensitive to deficit irrigation-induced water stress at different periods. To access the effect of deficit irrigation on the growth, water consumption characteristics, yield, and quality of Isatis indigotica (woad), we performed a three-year (2017-2019) mulched drip irrigation field experiment. Woad plants were provided adequate water supply at the seedling stage but were subjected to mild (65-75% field water capacity FC), moderate (55-65% FC), and severe (45-55% FC) water deficit at the vegetative growth, fleshy root growth and fleshy root maturity stages, respectively; plants supplied with adequate water throughout the growth period served as a control (CK, 75-85% FC). The water consumption characteristics, agronomic traits, dry matter content and distribution, yield, and quality of these plants were measured at various growth stages. The results showed that the total water consumption in water deficit was significantly less than that in CK by 4.44-10.21% (P< 0.05). The dry matter content of plants treated with moderate (WT2 and WT5) and severe (WT3) water deficit was reduced by 12.83-28.75%. The economic yield of mild water deficit-treated plants was higher during vegetative growth (WT1) and fleshy root growth (WT4), while the water use efficiency of these plants was significantly increased by 7.84% and 6.92% at the two growth stages, respectively. Continuous mild water deficit (WT4) enhanced the contents of indigo, indirubin, (R,S)-goitrin, polysaccharides, and soluble proteins during vegetative growth and fleshy root growth, while moderate and severe water deficit were detrimental to the quality of woad plants. Thus, continuous mild water deficit during vegetative and fleshy root growth periods (WT4) is optimal for the cultivation of woad in the cold and cool irrigation district of the Hexi Oasis region.

TXNIP Participated in NLRP3-Mediated Inflammation in a Rat Model of Cervical Spondylotic Myelopathy.

Background: Cervical spondylotic myelopathy (CSM) is a spinal cord disease caused by cervical disc degeneration and related pathological changes. Cervical spondylotic myelopathy may result from inflammation responses and neuronal damage. Thioredoxin-interacting protein (TXNIP)/NOD-like receptor protein 3 (NLRP3) signaling promotes inflammation. However, the effects of TXNIP/NLRP3 on the pathogenesis of CSM have not been reported. Methods: A rat model of chronic cervical cord compression was established to observe changes in the levels of of TNXIP/NeuN and NLRP3/NeuN expression in the damaged anterior horn of the spinal cord following progression of CSM. Rats were injected with TXNIP small interfering RNA (siRNA) and scrambled control to determine the effects of TXNIP inhibition on NLRP3-mediated inflammation in rats with CSM. Behaviors effects and the expression of NLRP3 and pro-caspase-1 in the damaged spinal cord were evaluated. Results: The expression levels of TXNIP and NLRP3 were significantly increased in the damaged anterior horn of the spinal cord following CSM. Injection of TXNIP siRNA significantly improved behavioral measures and decreased apoptosis in the damaged anterior horn of spinal cord. Furthermore, the levels of NLRP3 and pro-caspase-1 in the lesioned area were reduced by the TXNIP siRNA injection. Conclusion: Thioredoxin-interacting protein participated in NLRP3 mediated inflammation in a rat model of CSM, which indicated that TXNIP may be a potential therapeutic target in improving CSM.

Cacna2d2 inhibits axonal regeneration following surgical decompression in a rat model of cervical spondylotic myelopathy.

BACKGROUND: Cervical spondylotic myelopathy (CSM) is a clinically symptomatic condition due to spinal cord compression, leading to spinal cord dysfunction. Surgical decompression is the main treatment of CSM, but the mechanisms of axonal regeneration after surgical decompression are still fragmentary. METHODS: In a rat model of CSM, the cacna2d2 (α2δ2) expression levels in anterior horn of spinal cord were observed following compression and decompression by western blot and immunofluorescence. The expression levels of 5 hydroxytryptamine (5HT) and GAP43 were also analyzed by immunofluorescence. Furthermore, gabapentin intervention was performed for 4 weeks after decompression to analyze the changes of behaviors and anterior horn of spinal cords. RESULTS: Following decompression, the expression levels of α2δ2 in the anterior horn of spinal cord were decreased, but the expression levels of 5HT andGAP43 were increased. Compared with the vehicle treated rats, gabapentin treatment for 4 weeks ameliorated the behaviors of rats and improved the damaged anterior horn of spinal cord. Besides, inhibition of α2δ2 through gabapentin intervention enhanced the axonal regeneration in the anterior horn of damaged spinal cord. CONCLUSIONS: Inhibition of α2δ2 could enhance axonal recovery in anterior horn of damaged spinal cord induced by CSM after surgical decompression, providing a potential method for promoting axon regeneration following surgery.

Physiological and biochemical responses of Isatis indigotica to deficit irrigation in a cold and arid environment.

Water shortage and wastage are critical challenges to sustainable agricultural development, especially in arid and semiarid regions worldwide. Isatis indigotica (woad), as a traditional Chinese herb, was planted in a large area in a cold and arid environment of Hexi. Regulated deficit irrigation can reduce the growth of some vegetative organs by changing the accumulation and distribution of photosynthetic products in crops, thus increasing the economic yield of crops. In agricultural production, crop productivity may be improved by mulched drip irrigation and deficit irrigation. Hence, a field experiment was conducted to investigate the responses of photosynthesis, malondialdehyde, osmotic regulators, antioxidant enzyme activities, and the yield of woad to water deficit at different growth stages. The growth stage of woad was divided in four stages: seedling, vegetative growth, fleshy root growth, and fleshy root maturity. During vegetative growth, fleshy root growth, and fleshy root maturity, three water gradients were set for plants with mild (65-75% in field water capacity, FC), moderate (55-65% in FC), and severe (45-55% in FC) deficits, respectively. In contrast, an adequate water supply (75-85% in FC) during the growth period was designed as the control (CK). The net photosynthetic rate (Pn), transpiration rate, and stomatal conductance of woad significantly decreased (P< 0.05) by moderate and severe water deficits. Still, rehydration after the water deficit could produce a noticeable compensation effect. In contrast, malondialdehyde and proline accumulation significantly increased under moderate and severe water deficits. At the same time, the superoxide dismutase, peroxidase, and catalase all had high activities (increased significantly by 19.87-39.28%, 19.91-34.26%, and 10.63-16.13% compared with CK, respectively), but yields were substantially lower, compared to CK. Additionally, the net photosynthetic rate was negatively correlated with antioxidant enzyme activity. The economic yield of plants subjected to continuous mild water deficit during both vegetative and fleshy root growth was not significantly different from that in CK. Still, the water use efficiency improved significantly. Therefore, the continuous mild water deficit during vegetative and fleshy root growth could improve the physiological and biochemical mechanisms of the plant, representing an optimal irrigation strategy for woad in cold and arid areas.

Potato growth, photosynthesis, yield, and quality response to regulated deficit drip irrigation under film mulching in a cold and arid environment.

The effects of the amount and timing of regulated deficit drip irrigation under plastic film on potato ('Qingshu 168') growth, photosynthesis, yield, water use efficiency, and quality were examined from 2017 to 2019 in cold and arid northwestern China. In the four stages of potato growth (seedling, tuber initiation, tuber bulking, starch accumulation), eight treatments were designed, with a mild deficit was in treatments WD1 (seedling), WD2 (tuber initiation), WD3 (tuber bulking), and WD4 (starch accumulation); and a moderate deficit in WD5 (seedling), WD6 (tuber initiation), WD7 (tuber bulking), and WD8 (starch accumulation). The net photosynthetic rate, stomatal conductance, and transpiration rate decreased significantly under water deficit in the tuber formation and starch accumulation stages. Although water deficit reduced potato yields, a mild deficit in the seedling stage resulted in the highest yield and water use efficiency at 43,961.91 kg ha-1 and 8.67 kg m-3, respectively. The highest overall quality was in potatoes subjected to mild and moderate water deficit in the seedling stage. Principal component analysis identified mild water stress in the seedling stage as the optimum regulated deficit irrigation regime. The results of this study provide theoretical and technical references for efficient water-saving cultivation and industrialization of potato in northwestern China.

Maize productivity and soil properties in the Loess Plateau in response to ridge-furrow cultivation with polyethylene and straw mulch.

Ridge-furrow with full film mulching (RFFM) is widely used in the Loess Plateau (LP) to increase maize yield. However, continuous RFFM application may cause excessive depletion of soil organic carbon (SOC) and soil water storage (SWS). The present study tested four production systems, namely, (1) RFFM; (2) ridge-furrow with polyethylene film and straw mulching (RFFSM); (3) non-contoured seedbed with film mulching (FFM); and (4) non-contoured seedbed without mulching (CK) in 2013 and 2014 to identify an optimal technique to increase maize yield yet minimizing the negative effects. SWS under RFFSM was significantly higher by 5.4% and 13.4% compared to RFFM and CK, respectively. The changes in SOC were -0.2, -0.2, and -0.4 g·kg-1 for RFFM, FFM, and CK, respectively, and 0.3 g·kg-1 for RFFSM. Increased root residue and extra external carbon input to soil under RFFSM directly contributed to SOC recovery. RFFSM had a comparable grain yield but higher water use efficiency compared to RFFM. The combination of RFFSM is promising for improving SOC stocks, water storage, and maize productivity.

The complete nucleotide sequence of chloroplast genome of Gentiana apiata (Gentianaceae), an endemic medicinal herb in China.

Gentiana apiata N. E. Brown (Gentianaceae) is a perennial herb plant and only grows in Qinba Mountains in China. Here, we first characterized the complete nucleotide sequence of chloroplast (cp) genome of G. apiata via Illumina next generation sequencing platform. The complete chloroplast genome of G. apiata was 144,274 bp in length, comprising of a large single copy (LSC) region of 77,353 bp, a small single copy (SSC) region of 17,009 bp, and two inverted repeat regions (IRs) of 24,956 bp. The cp genome contains 127 genes, including 82 protein-coding genes, 35 tRNA, eight rRNA genes, and two pseudogenes. Phylogenetic analysis based on 18 cp genome sequences showed that G. apiata closely related to congeneric species.