Global climate change will modify plants in terms of growth and physiology. To better understand the consequences of this effect, the responses of the leaf water relations and nitrogen (N) use efficiency of barley and tomato plants to elevated CO2 (e[CO2], 800 ppm) combined with progressive drought stress at two levels of N supply (N1, 0.5 g N pot−1 and N2, 1.0 g N pot−1) were studied. The plants were grown in two separate phytotrons at ambient CO2 (a[CO2], 400 ppm) and e[CO2], respectively. The leaf physiological parameters as well as carbon (C) and N concentrations were determined; plant growth, water and N use efficiencies were evaluated. The results showed that e[CO2] increased photosynthesis and water use efficiency (WUE) while decreased specific leaf area (SLA) in both species, whereas N supply level differentially influenced WUE in barley and tomato plants. The abscisic acid (ABA)-induced stomatal closure during progressive soil drying varied between the two species where the stomatal conductance (gs) of barley plants was more sensitive to leaf ABA than tomato plants, though CO2 environment did not affect the response in both species. Compared to a[CO2], e[CO2] reduced plant transpiration rate (Tplant) in barley but not in tomato. e[CO2] increased the leaf C:N ratio ([C:N]leaf) in plants by enhancing leaf C concentration ([C]leaf) in barley and by dilution of leaf N concentration ([N]leaf) in tomato, respectively, but N2 substantially decreased [C:N]leaf, and thus, N treatment was the dominant factor controlling [C:N]leaf. Collectively, appropriate N supply may modulate the acclimation of plants to e[CO2] and soil water deficits. This study provides some novel insights into N management of different plant species for adapting to future drier and CO2-enriched environment.
Appropriate water and nitrogen fertilizer management is crucial for achieving sustainable development in the apple industry. However, the soil nitrogen supply capacity and residual nitrate characteristics under drip fertigation remain poorly understood. Therefore, this study aims to (1) investigate the coupling effects of irrigation and nitrogen levels on the concentrations and distribution characteristics of soil soluble nitrogen fractions and residual soil nitrate; (2) explore the relationships between Christiansen uniformity coefficient (CU) of soil nitrate and apple yield, water productivity (WPc) and nitrogen use efficiency (nitrogen agronomic efficiency, AEn). The field experiment was conducted in a drip-fertigated apple orchard starting in 2017, which included two irrigation levels, 85% (W1) and 100% (W2) of field capacity (FC), and four nitrogen rates, 0 (N1), 120 (N2), 240 (N3) and 360 (N4) kg ha–1. The results showed that nitrogen inputs significantly increased soil soluble inorganic nitrogen and soluble organic nitrogen (SON) contents. However, the SON content significantly decreased when 360 kg N ha–1 was applied, particularly at W1. The maximum nitrate accumulation in the 0–3 m soil layer at N4 reached 2540.97 kg ha–1 in 2021, but the maximum value decreased to 1251.62 kg ha–1 in 2022 due to extreme rainfall. The average CU of residual nitrate across irrigation levels in the 0–3 m soil layer was highest at N3, with values of 0.68 and 0.57 in 2021 and 2022, respectively. High irrigation level increased the diffusion distances of nitrate both vertically and horizontally, resulting in a significant effect on CU. Apple yield and WPc first increased and then decreased with increasing nitrogen rates, while AEn consistently decreased, but they were all greater with a higher CU. The recommended combination of irrigation and nitrogen application was 85% FC and 240 kg N ha–1, which can achieve the dual goals of enhancing soil nitrogen supply capacity and minimizing environmental risks while improving orchard productivity.
The cause of double-yolk (DY) egg production in birds is unclear, but it is related to body weight and adiposity. We explored the causes of the high proportion (up to 26%) of DY eggs in the first clutch of Zhedong white geese. We recorded the egg production of Zhedong white geese during the first egg-laying cycle and counted the proportion of DY eggs. We found that 30% of geese had 3 sets of double or triple follicles of the same diameter in the abdomen, which was close to the DY egg rate. In addition, the mRNA expression levels of the steroidogenic acute regulatory protein (StAR) and luteinizing hormone receptor (LHR) genes in granulosa cells were similar within the same set of follicles. Furthermore, the IGF1 concentration in geese that had at least 3 sets of follicles of the same diameter was significantly higher than that in birds with 0–1 set of follicles of the same diameter. Thus, we proposed that, in the first egg-laying stage of geese, high plasma concentrations of IGF1 stimulate the development of pre-hierarchal follicles and cause more than one follicle to be selected at the same time, mature at the same rate under the same gonadotrophin milieu, and ovulate at the same time to produce DY eggs.
Inadequate fertilization may result in water pollution and nutrient leaching, especially in paddy fi elds.It is expected that the combination of organic and inorganic fertilizers reduces water pollution in addition to crop yield improvement.In this study, combined fertilization with organic and inorganic fertilizers was tested under controlled irrigation conditions.With the addition of organic fertilizer, the pH of paddy soil could be maintained in a rather neutral environment, and the soil organic matter concentration could increaseespecially under a controlled irrigation regime.Hydrolyzed nitrogen was noticed in the fertilized plots with an increasing trend compared to unfertilized plots.However, available phosphorus concentration decreased in all treatments after rice harvest.During the drainage process, the ammonium nitrogen was the main form of nitrogen loss.Organic fertilizer application signifi cantly improved productive panicles and thus increased paddy yield.We concluded that with the combination of organic-inorganic fertilizer application and controlled irrigation, the pollutants can be removed to some extent and the rice yield can be increased signifi cantly, which is favorable for environmental protection and yield promotion.
Abstract. Coniothyrium Minitans is a kind of biological fungicide with high control effect against Sclerotinia sclerotiorum. There is a potential and simplification method to deliver a mixture of compound fertilizer and Coniothyrium Minitans powder into seedbed simultaneously with rape seed by using combined seeder.For this purpose, the special slow-releas fertilizer, common compound fertilizer and Coniothyrium Minitans powder were taken as the research objects and the triaxial size, hygroscopicity, friction coefficient and caking property of the fertilizers and the mixture of the fertilizer and the powder were measured by the determinator for agricultural materials. The results showed that the natural repose angle of special slow-release compound fertilizer, common compound fertilizer and Coniothyrium Minitans powder was 30.45 °, 32.20 ° and 44.88 ° respectively. The static friction coefficient with iron plate was 0.35, 0.41 and 0.70, which was similar with the acrylic plate that was 0.45, 0.57 and 0.70. The moisture absorption ratio of special slow-release compound fertilizer, common compound fertilizer and Coniothyrium Minitans was 0.213%, 0.287% and 0.267% respectively in ten to twenty minutes. While later twenty minutes the ratio beginning to change, the average increment of moisture absorption ratio was 0.006%ã0.287% and 0.015%, respectively. The natural repose angle and static friction coefficient of the mixture increased with the increase of the addition of Coniothyrium Minitans. Although the moisture absorption of the mixture increased gradually with growth over time, it was significantly lower than the bare fertilizer in the first twenty minutes, which indicated that Coniothyrium Minitans could be effectively inhibited the moisture absorption of fertilizer. This study provided a reference for using the fertilizer and powder mixture by employed a combined seeder for rapeseed.
The objective of this study was to explore the effects of plant growth-promoting rhizobacteria (PGPR), strain Bacillus licheniformis, with softwood biochar amendment on potato growth and water use efficiency (WUE) under a deficit irrigation (DI) regime. A pot experiment was conducted in a greenhouse. The results showed that PGPR improved leaf gas exchange rates, including photosynthesis rate, stomatal conductance and transpiration rate at early seedling stage, while tended to depress these parameters gradually until final harvest. The effects of biochar on plant leaf physiology, plant growth and WUE were not evident. Plants were more affected by DI than PGPR inoculation and biochar amendment. DI significantly decreased leaf gas exchange rates after exposure to water treatment for around three weeks, and the negative effect was eliminated at final harvest. At final harvest, DI significantly decreased leaf area, specific leaf area, dry mass of leaf and stem, total dry mass, dry mass increment and plant water use. The synergistical effect of PGPR strain Bacillus licheniformis and DI on plant growth and WUE were not observed in our study. WUE was solely improved by DI, indicating that, compared to PGPR inoculation, DI was a more effective measure to enhance plant WUE.
Faced with the scarcity of water resource and irrational fertilizer use, it is highly important to supply plants with water and fertilizer at desiderated stages to improve yield with high water use efficiency (WUE). A pot experiment was conducted to investigate the effects of growth stage-specific water deficiency and potassium (K) fertilization on tomato yield and WUE. The entire growing season of tomato was divided into 5 stages: vegetative growth stage (VG), flowering and fruit setting stage (FS), early fruit growth stage (FG), fruit development stage (FD) and fruit maturity stage (FM). Three soil moisture (W) and three K fertilization levels were set up. W levels included W1, W2 and W3, indicating that soil water was maintained at 60–70% field capacity, 70–80% field capacity, and 80–90% field capacity, respectively. K levels included K1, K2 and K3, indicating that 0 g K2O per kg soil, 0.46 g K2O per kg soil and 0.92 g K2O per kg soil was applied. All combinations of the three W and three K levels were solely imposed at each of the five growth stages, for other four stages, plants were watered to 80–90% field capacity without K fertilizer (W3K1). The permanent W3K1 over the entire growth stage was taken as control (CK). The results showed that W deficiency imposed at all stages significantly affected tomato yield (P<0.01), except for VG stage in which W deficiency did not cause yield loss. K fertilization level during FS or FM stage had a significant effect on yield (P<0.01). A significant interaction effect of W and K on yield was only observed during FM stage. For WUE, significant effect of W deficiency at FS, FD and FM stages were observed, and a significant effect of K levels at FS, FD and FM stages was observed. Specifically, K fertilization was necessary during specific growth stage of tomato (i.e. FS and FM). During FS stage, even if a sufficient water supply seems necessary, a deficit irrigation with K fertilization could be applied as K fertilization could alleviate the negative effect of soil water deficit, however, excess of K fertilization during FM stage should be avoided to maintain tomato yield and WUE.
Abstract Protocatechuic acid (PCA), a phenolic acid that occurs widely in plants, is believed to be the major potential bioactive metabolites of cyanidin 3-glucoside against oxidative stress and inflammation, which are major causes of intestinal injury in weaned piglets. This study aimed to investigate the effect of PCA on growth performance, inflammatory status and immune indices in lipopolysaccharide (LPS)-challenged weaned piglets. Thirty six 21-day-old weaned PIC piglets were housed in pairs in cages with one ripple drinker and one hopper type feeder, and randomly allocated into 3 dietary treatments with 6 replicates per treatment and 2 piglets per replicate after fed a control diet for 7 days. The treatments were: control diets (CTL), CTL+50 ppm aureomycin, CTL+4000 ppm PCA, based on our pilot tests. The period of experiment was 21 days, and piglets were challenged by intraperitoneal injection of LPS (10 μg/kg) at day 14 and day 21. Blood samples were obtained from eighteen piglets (one from each replicate) one hour after LPS injection on day 21, and inflammatory cytokines, antioxidant capacity index, and immune indices were measured in blood serum. The results revealed that the average daily gain of piglets was increased by supplementing with PCA (P = 0.036), but not aureomycin (P = 0.184). Dietary supplement with PCA decreased serum levels of inflammatory cytokines including interleukin (IL)-1β (P < 0.05), IL-2 (P < 0.05), IL-6 (P < 0.05) and tumor necrosis factor alpha (TNF-α) (P < 0.05), while aureomycin only decreased IL-6 (P < 0.05) and TNF-α (P < 0.05). Both PCA and aureomycin attenuated lipid peroxidation with a lower level of thiobarbituric acid reactive substances (P < 0.05), but increased serum levels of immunoglobulin M (P < 0.05) and C-reactive protein (P < 0.05) in piglets. These data suggested that PCA may improve growth performance and immunity of weaned piglets, and thus can be a potential alternative for antibiotics in animal feeds.
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