Understanding the Impact of Sheep Digestion on Seed Germination in the Cold Desert Annual Diptychocarpus strictus with Emphasis on Fruit and Seed Heteromorphism.

This study aimed to investigate the morphological characteristics of fruits and seeds from Diptychocarpus strictus, a plant species inhabiting the cold desert pastoral area of China. Furthermore, this study sought to evaluate the germination potential of these seeds following digestion by sheep. This study employed the sheep rumen fistula method to simulate rumen digestion at various time intervals. Subsequently, an in vitro simulation method was utilized to simulate true gastric and intestinal digestion after rumen digestion. Paper germination tests were then conducted to assess the impact of the digestive process on the heteromorphic seed morphology and germination. During rumen digestion, the seeds were protected by wide wings. The results revealed a highly significant negative correlation (p < 0.01) between seed wing length and digestion time. Post-rumen digestion, variations in the germination rate among seeds from fruits at different locations were observed. Indicators, such as germination rate, exhibited a highly significant negative correlation with rumen digestion time (p < 0.01). In vitro simulated digestion tests demonstrated that Diptychocarpus strictus seeds retained their ability to germinate even after complete digestion within the livestock's digestive tract. The polymorphic nature of Diptychocarpus strictus seeds, coupled with their capacity to survive and germinate through the digestive tract, facilitates the spread of these seeds. This finding has implications for mitigating desert grassland degradation and promoting sustainable ecological development.

Physiological and biochemical effects of biochar nanoparticles on spinach exposed to salinity and drought stresses.

The utilization of nanobiochar in agricultural practices has garnered substantial interest owing to its promising potential. Its nano-size particles possess an enhanced ability to infiltrate plant cells, potentially instigating biochemical and physiological responses that augment stress tolerance. In our study, we aimed to assess the impact and extent of exogenously applied nanobiochar on the growth dynamics and antioxidative responses in Spinacia oleracea L. (spinach) plants subjected to salt stress (50 mM NaCl) and drought stress (maintained at 60% field capacity) compared with respective controls (0 mM NaCl and 100% field capacity). Following a 15-day exposure to stress conditions, nanobiochar solution (at concentrations of 0, 1, 3, and 5% w/v) was sprayed on spinach plants at weekly intervals (at 14, 21, and 28 days after sowing). The foliar application of nanobiochar markedly improved biomass, net assimilation rate, leaf area, and various other growth parameters under drought and salinity stress conditions. Notably, the application of 3% nanobiochar caused the most significant enhancement in growth traits, photosynthetic pigments, and nutrient content, indicating its efficiency in directly supplying nutrients to the foliage. Furthermore, under drought stress conditions, the application of 3% nanobiochar elicited a notable 62% increase in catalase activity, a two-fold rise in peroxidase activity, and a 128% increase in superoxide dismutase activity compared to the control (without nanobiochar). Additionally, nanobiochar application enhanced membrane stability, evidenced by reduced lipid peroxidation and electrolyte leakage. The foliar application of 3% nanobiochar was found as a promising strategy to significantly enhance spinach growth parameters, nutrient assimilation, and antioxidative defense mechanisms, particularly under conditions of drought and salinity stress.

The impact of fertilization on ammonia-oxidizing bacteria and comammox Nitrospira communities and the subsequent effect on N2O emission and maize yield in a semi-arid region.

The control of nitrous oxide (N2O) emissions through nitrification and the optimization of maize yield are important in agricultural systems. However, within the semi-arid region, the impact of fertilization on the function of nitrification communities and its connection with N2O emissions in the rhizosphere soil is still unclear. Our study investigates the influence of fertilization treatments on the communities of ammonia-oxidizing bacteria (AOB) and the complete ammonia oxidizers of the Nitrospira known as comammox (CAOB) in a maize agroecosystem. Nitrous oxide production, potential nitrification activity (PNA), maize yield, and nitrogen use efficiency (NUE) were determined for the same samples. The fertilizer treatments included a control group without fertilization (NA), inorganic fertilizer (CF), organic fertilizer (SM), combined inorganic and organic fertilizer (SC), and maize straw (MS). The SC treatment indicated a lower cumulative N2O emission than the CF treatment in the 2020 and 2021 cropping seasons. The AOB community under the CF, MS, and SM treatments was predominantly composed of Nitrosospira cluster 3b, while the SC treatment was associated with the comammox Nitrospira clade A.1 lineage, related to key species such as Ca. Nitrospira inopinata and Ca. Nitrospira nitrificans. Network analysis demonstrated a positive potential for competitive interaction between hub taxonomy and distinct keystone taxa among AOB and comammox Nitrospira nitrifiers. The structural equation model further revealed a significant positive association between AOB nitrifiers and N2O emission, PNA, soil pH, SOC, NO3--N, and DON under organic fertilization. The keystone taxa in the comammox Nitrospira nitrifier and network Module II exhibited a positive correlation with maize productivity and NUE, likely due to their functional activities stimulated by the SC treatment. It is noteworthy that the AOB community played a more significant role in driving nitrification compared to the composition of comammox Nitrospira. Collectively, combined inorganic and organic fertilizer (SC) treatment exhibits high potential for reducing N2O emissions, enhancing maize productivity, increasing NUE, and increasing the sustainability of the nitrogen dynamics of maize agroecosystems in the semi-arid Loess Plateau.

Nitrogen fertilization promoted microbial growth and N2O emissions by increasing the abundance of nirS and nosZ denitrifiers in semiarid maize field.

Nitrous oxide (N2O) emissions are a major source of gaseous nitrogen loss, causing environmental pollution. The low organic content in the Loess Plateau region, coupled with the high fertilizer demand of maize, further exacerbates these N losses. N fertilizers play a primary role in N2O emissions by influencing soil denitrifying bacteria, however, the underlying microbial mechanisms that contribute to N2O emissions have not been fully explored. Therefore, the research aimed to gain insights into the intricate relationships between N fertilization, soil denitrification, N2O emissions, potential denitrification activity (PDA), and maize nitrogen use efficiency (NUE) in semi-arid regions. Four nitrogen (N) fertilizer rates, namely N0, N1, N2, and N3 (representing 0, 100, 200, and 300 kg ha-1 yr.-1, respectively) were applied to maize field. The cumulative N2O emissions were 32 and 33% higher under N2 and 37 and 39% higher under N3 in the 2020 and 2021, respectively, than the N0 treatment. N fertilization rates impacted the abundance, composition, and network of soil denitrifying communities (nirS and nosZ) in the bulk and rhizosphere soil. Additionally, within the nirS community, the genera Cupriavidus and Rhodanobacter were associated with N2O emissions. Conversely, in the nosZ denitrifier, the genera Azospirillum, Mesorhizobium, and Microvirga in the bulk and rhizosphere soil reduced N2O emissions. Further analysis using both random forest and structural equation model (SEM) revealed that specific soil properties (pH, NO3--N, SOC, SWC, and DON), and the presence of nirS-harboring denitrification, were positively associated with PDA activities, respectively, and exhibited a significant association to N2O emissions and PDA activities but expressed a negative effect on maize NUE. However, nosZ-harboring denitrification showed an opposite trend, suggesting different effects on these variables. Our findings suggest that N fertilization promoted microbial growth and N2O emissions by increasing the abundance of nirS and nosZ denitrifiers and altering the composition of their communities. This study provides new insights into the relationships among soil microbiome, maize productivity, NUE, and soil N2O emissions in semi-arid regions.

Physiological effects of some engineered nanomaterials on radish (Raphanus sativus L.) intercropped with pea (Pisum sativum L.).

Intercropping leguminous plant species with non-legume crops could be an effective strategy to maintain soil fertility. Additionally, the application of nano-Zn and Fe in trace amounts can substantially improve the bioavailable fraction of Zn and Fe. We studied the effect of foliar application of some nanomaterials on the agronomic, physio-biochemical attributes under a radish/pea intercropping system. The radish and pea were sprayed with different nanomaterials (Zn-Fe nanocomposite, nZnO, and nanobiochar) at 0 and 50 mg L-1 concentrations. Results indicated that the growth parameters of radish were higher in intercropping than in monocropping, while pea growth was inhibited in intercropping compared with monocropping. The shoot and root length, fresh weight, and dry matter of radish were increased by 28-50%, 60-70%, and 50-56% by intercropping than monocropping. Foliar spray of nano-materials further increased the growth traits of intercropped radish, such as shoot and root length, fresh weight, and dry matter, by 7-8%, 27-41%, and 50-60%, respectively. Similarly, pigments such as chlorophyll a, b, and carotenoids and the concentration of free amino acids, soluble sugars, flavonoids, and phenolics were differentially affected by intercropping and nanomaterials. The yield of the non-legume crop was increased by intercropping, whereas the legume crop exhibited significant growth inhibition due to competitive interactions. In conclusion, both intercropping and foliar spray of nanomaterials could be used as a combined approach to benefit plant growth and enhance the bioavailable Fe and Zn fractions of both crops.

Spinel nanocomposite (nMnZnFe2O4) synchronously promotes grain yield and Fe-Zn biofortification in non-aromatic rice.

Soils deficient in essential micro-nutrients produce nutritionally starved crops that do not fulfill human nutritional requirements. This is getting serious since progressively increasing nutritional disorders are being diagnosed in residents of third-world countries like Pakistan. During this study, we synthesized a spinel nanocomposite (nMnZnFe2O4) and investigated its effectiveness in improving the micronutrient status and yield traits of rice. The nMnZnFe2O4 exhibited a cubic structure at the most prominent peak (311); a crystallite size of 44 nm, and an average grain size ranging from 7 to 9 µm. Foliar application of this nanocomposite was performed to 45 days old plants at concentrations 0, 10, 20, 30, 40, and 50 mg L-1, and data from rice plant parts (straw, husk, and grain) was recorded at maturity. Agronomic traits like the number of tillers, straw dry weight, root dry biomass, and grain yield per plant were improved by nMnZnFe2O4 application (+34.4% yield). Whereas some biochemical traits like amino acids, soluble sugars, flavonoids, and phenolics varied significantly in rice plant parts compared to the control. Above all, the maximum Zn and Fe concentrations in rice grain were recorded through foliar application of spinel nanocomposite (40 and 50 mg L-1). Therefore, results indicated that micronutrient supply in the form of a nanocomposite could positively regulate nutritional quality and rice grain yield.

Zinc oxide nanoparticles as potential hallmarks for enhancing drought stress tolerance in wheat seedlings.

Drought is one of the major abiotic stresses which negatively affects plant growth and development. The current study evaluated the effects of drought on the growth, physiology, and biochemical attributes of wheat seedlings; and examined the role of foliar application of ZnO nanoparticles in alleviating drought-induced effects. Two wheat cultivars i.e., Anaj-2017 and FSD-2018 were grown in soil-filled pots and were subjected to 100% field capacity (FC) (well watered) and 50% of FC (drought stress). Whilst different treatments of ZnO nanoparticles spray included no spray, water spray, and 50, 100, and 150 ppm ZnO. Results demonstrated that drought caused a significant reduction in seedling fresh and dry weights, photosynthetic pigmentation, and antioxidant activities compared with a well-watered treatment. Nevertheless, the application of 100 and 150 ppm of ZnO nanoparticles effectively ameliorated the negative effects of drought and enhanced the performance of both cultivars under drought. Data revealed a significant increase in fresh and dry weight of shoot and root with the application of ZnO nanoparticles. A substantial increase of 73.68% and 28.51% in chlorophyll "a" and 26.15% and 50.02% in chlorophyll "b" was recorded with the application of 100 ppm of ZnO nanoparticles in Anaj-2017 and FSD-2018, respectively over control (0 ppm). The application of these nanoparticles also triggered the antioxidant defense system and protected the crop from oxidative damage. Averaged across different stress treatments, application of 150 and 100 ppm of ZnO nanoparticles increased the peroxidase activity by 60% and 72% in FSD-2018, and 15% and 23% in Anaj-2017, respectively compared with no spray. FSD-2018 outperformed Anaj-2017 regarding its overall performance under ZnO treatments and drought conditions. In a nutshell, it can be concluded that ZnO nanoparticles ameliorated the negative impacts of drought by improving the growth, physiology, and antioxidant defense of both wheat cultivars.

Impact of soil amendments on nitrous oxide emissions and the associated denitrifying communities in a semi-arid environment.

Denitrifying bacteria produce and utilize nitrous oxide (N2O), a potent greenhouse gas. However, there is little information on how organic fertilization treatments affect the denitrifying communities and N2O emissions in the semi-arid Loess Plateau. Here, we evaluated how the denitrifying communities are responsible for potential denitrification activity (PDA) and N2O emissions. A field experiment was conducted with five fertilization treatments, including no fertilization (CK), mineral fertilizer (MF), mineral fertilizer plus commercial organic fertilizer (MOF), commercial organic fertilizer (OFP), and maize straw (MSP). Our result showed that soil pH, soil organic carbon (SOC), and dissolved organic nitrogen (DON) were significantly increased under MSP treatment compared to MF treatment, while nitrate nitrogen (NO3 --N) followed the opposite trend. Organic fertilization treatments (MOF, OFP, and MSP treatments) significantly increased the abundance and diversity of nirS- and nosZ-harboring denitrifiers, and modified the community structure compared to CK treatment. The identified potential keystone taxa within the denitrifying bacterial networks belonged to the distinct genera. Denitrification potentials were significantly positively correlated with the abundance of nirS-harboring denitrifiers, rather than that of nirK- and nosZ-harboring denitrifiers. Random forest modeling and structural equation modeling consistently determined that the abundance, community composition, and network module I of nirS-harboring denitrifiers may contribute significantly to PDA and N2O emissions. Collectively, our findings highlight the ecological importance of the denitrifying communities in mediating denitrification potentials and the stimulatory impact of organic fertilization treatments on nitrogen dynamics in the semi-arid Loess Plateau.

Bacterial Diversity and Potential Functions in Response to Long-Term Nitrogen Fertilizer on the Semiarid Loess Plateau.

Bacterial diversity and its functions are essential to soil health. N fertilization changes bacterial communities and interferes with the soil biogeochemical N cycle. In this study, bacterial community and soil physicochemical properties were studied in 2018 after applying N fertilizers (0, 52.5, 105, 157.5, and 210 kg N ha-1) for a long (2003-2018) and a short (2003-2004) duration in a wheat field on the Loess Plateau of China. Soil bacteria were determined using 16S rRNA Illumina-MiSeq®, and the prediction function was analyzed through PICRUSt. The study showed that N fertilizer significantly changed the diversity and abundance of bacterial communities. The phyla Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi were most abundant, accounting for 74-80% of the bacterial community abundance. The optimum rates of N fertilizer application (N105) maintain soil health by promoting soil microbial diversity and abundance. The bacterial population abundance was higher after short-term N application than after N application for a long duration and lowest with the high N-fertilizer treatment (N210). High N enrichment led to more heterotrophic N-fixing microorganisms (Alphaproteobacteria), in which metabolism and genetic information processing dominated, while cellular processes, genetic information processing, metabolism, and organismal systems were the main functional categories under low N. The phyla Gemmatimonadetes, Actinobacteria, Bacteroidetes, and Chloroflexi were the key bacteria in the co-occurrence network. The genus Saccharimonadales of the superphylum Patescibacteria has a more significant impact under low N treatment. Long-term N fertilization affected the soil pH, NO3-N, and other physicochemical properties, and soil NO3-N was the highest indicator, contributing 81% of the bacterial community function under different N fertilizer treatments.

Exogenous spermidine modulates polyamine metabolism and improves stress responsive mechanisms to protect tomato seedlings against salt stress.

Salt stress negatively affects plant growth, development, and crop productivity causing serious economic loss to agricultural production. Here, we investigated the exogenous application of spermidine (Spd) on tomato seedlings grown under salt stress. Salt stress reduced plant growth, biomass accumulation and chlorophyll contents, thus negatively affecting photosynthesis. Alternatively, Spd application effectively reduced the salinity-induced adverse effects in tomato seedlings by activating the H2O2 mediated signaling involving the enhanced expression of RBOH1 and salt stress-responsive genes SlMYB102, SlHKT1, SlWRKY1 and SlDREB2, and improving detoxification through higher antioxidative activity and osmolyte (proline) accumulation under salt stress. It was further confirmed by significantly lower amount of H2O2, malondialdehyde and electrolyte leakage, and better ion homeostasis (Na+/K+ ratio) and photosynthetic performance of Spd-treated seedlings under salt stress. Furthermore, Spd application modulated endogenous polyamines and enhanced the biosynthesis of endogenous Spd and spermine from putrescine. Altogether, these results confirm the important role of Spd against salt stress and suggest that the increased endogenous Spd content in plants could regulate a number of stress-responsive mechanisms to protect tomato seedlings against salt stress. These results provide a good direction for further elucidation of the detailed interplay between polyamine metabolism and H2O2-mediated signaling, which would help to improve abiotic stress tolerance in plants.

Determination and detoxification of aflatoxin and ochratoxin in maize from different regions of Pakistan.

The contamination of food commodities with mycotoxins could be a serious health threat to humans and animals. Therefore, identification, quantification and reduction of mycotoxins in food commodities, particularly of aflatoxins (AFs) and ochratoxin A (OTA) in grain foods, is essentially required to guarantee safe food. This study determined the levels of AFs and OTA in 135 maize grains samples belonging to eight salient maize varieties cultivated in Pakistan, and evaluated the usefulness of radiations and adsorbents to reduce their levels. High performance liquid chromatography (HPLC)-based method was validated for the determination of AFs and OTA in maize grains. The results showed that 69 and 61% samples were positive for AFs and OTA, respectively and 54 and 22% of the respective samples had AFs and OTA above the permissible limits set by Pakistan Standards and Quality Control Authority. The concentration of AFs, AFB1and OTA in grains ranged from 14.5 to 92.4, 1.02 to 2.46 and 1.41 to 53.9 µg kg-1, respectively. Among the varieties, Pearl had the highest level of total AFs and OTA, whereas YH-5427 had the highest AFB1 level. The lowest concentration of AFs and OTA was found in Malaka and 30Y87, respectively. The use of 15 kGy gamma irradiation for 24 h, sunlight-drying for 20 h and UV irradiation for 12 h almost completely degraded the mycotoxins. The microwave heating for 120 s resulted in 9-33% degradation of mycotoxins. Moreover, the treatment of grains' extract with activated charcoal (5% w/w) removed > 96% of total AFs and AFB1, and up to 43% of OTA. The use of bentonite at the same rate removed OTA, total AFs and AFB1 by 93, 73 and 92%, respectively. Thus, it is concluded that contamination of maize grains with mycotoxins was fairly high in the collected maize grain samples in Pakistan, and treatment with radiations and adsorbents can effectively reduce mycotoxins contamination level in maize grains.

Changes in Ammonia-Oxidizing Archaea and Bacterial Communities and Soil Nitrogen Dynamics in Response to Long-Term Nitrogen Fertilization.

Ammonia oxidizing archaea (AOA) and bacteria (AOB) mediate a crucial step in nitrogen (N) metabolism. The effect of N fertilizer rates on AOA and AOB communities is less studied in the wheat-fallow system from semi-arid areas. Based on a 17-year wheat field experiment, we explored the effect of five N fertilizer rates (0, 52.5, 105, 157.5, and 210 kg ha-1 yr-1) on the AOA and AOB community composition. This study showed that the grain yield of wheat reached the maximum at 105 kg N ha-1 (49% higher than control), and no further significant increase was observed at higher N rates. With the increase of N, AOA abundance decreased in a regular trend from 4.88 × 107 to 1.05 × 107 copies g-1 dry soil, while AOB abundance increased from 3.63 × 107 up to a maximum of 8.24 × 107 copies g-1 dry soil with the N105 treatment (105 kg N ha-1 yr-1). Application rates of N fertilizer had a more significant impact on the AOB diversity than on AOA diversity, and the highest AOB diversity was found under the N105 treatment in this weak alkaline soil. The predominant phyla of AOA and AOB were Thaumarchaeota and Proteobacteria, respectively, and higher N treatment (N210) resulted in a significant decrease in the relative abundance of genus Nitrosospira. In addition, AOA and AOB communities were significantly associated with grain yield of wheat, soil potential nitrification activity (PNA), and some soil physicochemical parameters such as pH, NH4-N, and NO3-N. Among them, soil moisture was the most influential edaphic factor for structuring the AOA community and NH4-N for the AOB community. Overall, 105 kg N ha-1 yr-1 was optimum for the AOB community and wheat yield in the semi-arid area.

Tartaric acid soil-amendment increases phytoextraction potential through root to shoot transfer of lead in turnip.

The phytoextraction potential of turnip and comparative effectiveness of three different organic ligands towards removal of lead (Pb) was investigated under field conditions. The 20 d old turnip seedlings were exposed to different Pb levels (0.0218, 2.42 and 4.83 mM Pb) spiked in the soil. After 10 d of Pb application, the soil was spiked with 2.4 mM concentration of different chelates viz. ethylenediaminetetraacetic acid (EDTA), citric acid (CA) and tartaric acid (TA). The 60 d old plants were harvested for growth analyses and determination of photosynthetic pigments, while Pb-concentration in different plant parts was determined from 60 and 90 d old plants. Yield attributes were recorded at the harvesting stage (HS, 90 d old plants). No suppression (rather a stimulation) in the root and shoot growth was evident upon Pb exposure whereas, a reduction in the chlorophyll content occurred at 4.83 mM Pb level. Soil amendment with TA improved chlorophyll contents irrespective of Pb levels while the effect of CA and EDTA was differential. A reduction in the root length while an increase in its diameter was recorded particularly at 4.83 mM Pb stress in 90 d old plants. The turnip retained maximum Pb-fraction in the roots at early growth stages, while EDTA application further increased its retention in root at 4.83 mM Pb regime. Nonetheless, only TA amendment promoted the transfer of Pb to shoot (∼30%) irrespective of Pb regimes. At the HS, application of both TA and EDTA caused substantial uptake of Pb in the root while the maximum shoot Pb-fraction was recorded again due to TA application, particularly at 4.83 mM Pb level. Above all, TA was identified as the most effective chelate that mobilized Pb from root to shoot leading to better growth possibly due to dilution effect, and thus enhanced phytoextraction efficiency in turnip.

Callus Induction, Proliferation, Enhanced Secondary Metabolites Production and Antioxidants Activity of Salvia moorcroftiana L. as Influenced by Combinations of Auxin, Cytokinin and Melatonin

Abstract: Tissue culture technique is one of the best methods to reproduce salvia plant Therefore, the aim of this research was to enhance the in-vitro callus proliferation and production of secondary metabolites of S. moorcroftiana using different combinations of auxin, cytokinin and melatonin. Initially, callus induction was optimized using indole acetic acid (IAA), 2, 4-dichlorophenoxy acetic acid (2,4-D), and naphthalene acetic acid (NAA) applied at different concentrations in combination with 1 mg L-1 of 6-benzylaminopurine (BAP). The results indicates that earliest days to callus induction (14.67 days) was occurred in the media fortified with 2, 4-D+BAP (2.0+1.0 mgL-1). Whereas the highest callus initiation (100%) was induced on MS medium incorporated with 2,4-D+BAP (1+1mgL-1). Furthermore, maximum fresh weight was obtained when 2,4- D + BAP at the rate of (1+ 1mg L-1) was incorporated and dry weight was attained when 2,4- D + BAP at the rate of (2+1 mg L-1) was added to MS media. The maximum fresh and dry weight was obtained when melatonin at rate of 1.5 mg L-1 was supplemented with MS media including 2,4-D + BAP (1+1mg L-1), moreover the maximum DPPH scavenging activity, total phenolic and flavonoid content was noted when supplemented with melatonin at rate of 1.5 mg L-1. In conclusion, among various concentrations of plant growth regulators, 2,4- D + BAP at the rate of (1+ 1mg L-1) along with 1.5 g L-1 melatonin was the best for callus growth and production of secondary metabolites of S. moorcroftiana.

Combined foliar and soil selenium fertilizer improves selenium transport and the diversity of rhizosphere bacterial community in oats.

Agronomic selenium (Se) biofortification of grain crops is considered the best method for increasing human Se intake, which may help people alleviate Se-deficiency. To investigate the efficiency of agronomic Se biofortification of oat, four Se fertilizer application treatments were tested: topsoil (T), foliar (S), the combination of T and S (TS), and control without Se application (CK). Compared with CK, TS significantly increased the 1000-grain weight, grain yield, Se contents in all parts of oats, contents of soil available N, K, and organic matter by 18%, 8.70%, 19.7-60.2%, 6.00%, 8.02%, and 17.95%, respectively. Leaves, roots, and ears had the highest conversion rate of exogenous Se in S (644.63%), T (416.00%), and TS (273.20%), respectively. TS also increased the activities of soil urease, alkaline phosphatase, and sucrose and the diversity of soil bacterial communities. TS and T increased the relative abundance of bacteria involved in the decomposition of organic matter, such as Actinobacteria, Gemmatimonadetes, Chloroflexi, and Bacteroidetes positively correlated with soil nutrients and enzyme activities, and reduced Proteobacteria and Firmicutes negatively correlated with them, Granulicella, Bacillus, Raoultella, Lactococcus, Klebsiella, and Pseudomonas. Furthermore, TS significantly increased the relative abundance of Planctomycetes, Chlorobi, Nitrospinae, Nitrospirae, Aciditeromonas, Gemmatimonas, Geobacter, and Thiobacter. T significantly increased the abundance of Lysobacter, Holophaga, Candidatus-Koribacter, Povalibacter, and Pyrinomonas. S did not significantly change the bacterial communities. Thus, a combined foliar and soil Se fertilizer proved conducive for achieving higher yield, grain Se content, and improving Se transport, the diversity of rhizosphere bacterial community, and bacterial functions in oats.

Soil fertility, chemical properties, and pollutant removal efficiency of Salicornia europaea in response to different times and duration of wastewater irrigation.

Halophytes are the good candidates in coastal saline areas which could be irrigated with wastewater. The purpose of this study was to evaluate the soil-water-plant system under control and wastewater irrigation (containing toxic elements and organic matter) at three durations (vegetative, flowering, and reproductive stages) and two exposure times (2 and 4 days in each stage). The results obtained in the experimental tests for wastewater irrigation indicated that the Salicornia is efficient for the removal of chemical oxygen demand (61%), biochemical oxygen demand (74%), total suspended solids (47.6%), and ammoniacal nitrogen (64%) at the reproductive stage. At the same time, the average nitrate concentration increased to 51.3 mg L-1 with more solids. Regardless of wastewater irrigation duration, irrigation with wastewater significantly increased organic matter, nitrogen, phosphorus, and potassium of the soil. The Mg2+ and Ca2+ contents in the aboveground biomass of the plants were also high ranged from 0.58 to 1%, and 0.43 to 0.68 mg g-1 DW, respectively. All the exchangeable cations other than Na+ were higher for wastewater irrigation at the flowering stage. Plants maintained noticeably higher Ca2+/Na+ and K+/Na+ ratios in the roots than those in the shoots except for 4 days after the reproductive stage. S. europaea is well adapted to grow in wastewater irrigation and can tolerate hypoxic conditions through improving water and soil quality.

The Salicornia europaea potential for phytoremediation of heavy metals in the soils under different times of wastewater irrigation in northwestern Iran.

The use of wastewater for irrigation usually leads to the buildup of potentially toxic elements (PTEs) in soils. The objective of this study was to assess the capacity of Salicornia europaea L. to uptake heavy metal when irrigated with wastewater at the vegetative, flowering, and reproductive stages of S. europaea for 2 and 4 days (in each stage) in the coastal saline area of Lake Urmia. The concentrations of heavy metals were detected in irrigated water, soil, and plant samples, while transfer factor (TF), bioconcentration factor (BCF), and bioaccumulation factor (BAF) were calculated. The results revealed that metal concentrations in the wastewater were above the permissible limits. The wastewater irrigation caused higher shoot biomass despite the high uptake of PTEs. Levels of Fe and Cu in plants were higher when irrigated with wastewater at the reproductive stage as compared to flowering and vegetative stages. The TF of wastewater-irrigated plants was higher at the flowering stage. TF of different metals at the flowering stage were in order of Zn > Pb > Ni > Cd > Cu, while the BCF increased in the order Cd > Cu > Zn > Ni > Pb. The BAF of the investigated PTEs at the flowering stage increased in the order Cd > Pb > Ni > Zn > Cu. In conclusion, higher Pb and Zn in the shoot indicated that the plant exhibited the phytoextraction mechanism, while Salicornia used a phytostabilization mechanism for roots-Cu, Ni, and Cd.

The soybean GmNFY-B1 transcription factor positively regulates flowering in transgenic Arabidopsis.

Nuclear Factor Y (NF-Y) gene family regulates numbers of flowering processes. Two independent transgenic Arabidopsis lines overexpressing (OX) GmNFY-B1 and GmNFYB1-GR (GmNFYB1 fused with the glucocorticoid receptor) were used to investigate the function of NFY-B1 in flowering. Furthermore, GmNFYB1-GR lines were chemically treated with dexamethasone (Dex, synthetic steroid hormone), cycloheximide (Cyc, an inhibitor of protein biosynthesis), and ethanol to examine their effects on different flowering related marker genes. Our results indicated that the transgenic lines produced longer hypocotyl lengths and had fewer numbers of rosette leaves compared to the wild-type and nf-yb1 mutant plants under both long and short-day (LD and SD) conditions. The qRT-PCR assays revealed that transcript levels of all flowering time regulating genes, i.e. SOC, FLC, FT, TSF, LFY, GI2, AGL, and FCA showed higher transcript abundance in lines OX GmNFYB1-GR. However, FT and GI genes showed higher transcript levels under Dex and Dex/Cyc treatments compared to Cyc and ethanol. Additionally, 24 differentially expressed genes were identified and verified through RNA-seq and RT-qPCR in GmNF-YB1-GR lines under Cyc and Dex/Cyc treatments from which 14 genes were up-regulated and 10 were down-regulated. These genes are involved in regulatory functions of circadian rhythm, regulation of flower development in photoperiodic, and GA pathways. The overexpression of GmNF-YB1 and GmNF-YB1-GR promote flowering through the higher expression of flowering-related genes. Further GmNF-YB1 and its attachment with the GR receptor can regulate its target genes under Dex/Cyc treatment and might act as flowering inducer under LD and SD conditions.

Nitrogen Supply Affects Yield and Grain Filling of Maize by Regulating Starch Metabolizing Enzyme Activities and Endogenous Hormone Contents.

This study aimed to examine the effect of nitrogen (N) application rate and time on yield, grain filling, starch metabolizing enzymes, and hormones of maize based on a long-term field experiment initiated in 2012. The total N fertilizer dose [(0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg N ha-1] was split into two (T1, one-third at sowing and two-thirds at the six-leaf stage) or three (T2, one-third each at sowing, six-leaf, and eleven-leaf stage) times application. The results showed that the highest yield was obtained under N3T2, N2T1, and N3T2 in 2018, 2019, and 2020, which was 222.49, 185.31, and 194.00% than that of N0 in each year, respectively. N2 and N3 significantly increased the yield through enhancing ears ha-1, grains per plant, and 100-grain weight; however, N2 and N3 did not show a significant difference in yield and above-yield components. In addition, N application time did not significantly change yield under the same N rate. N0 limited the activities of starch metabolizing enzymes, resulting in insufficient accumulation of sucrose and starch. The contents of indole-3-acetic acid, cytokinin, abscisic acid, and gibberellin were decreased under N0 during grain filling. The average grain-filling rate and maximum grain-filling rate (G max) and grain weight increment achieving G max increased under N2 and N3, and the grain-filling parameters were positively correlated with 100-grain weight. In conclusion, 200 kg N ha-1 with one-third application at sowing and two-thirds application at the six-leaf stage is a suitable N supply way to improve starch metabolizing enzymes, regulate hormone content, and enhance grain-filling rates, and thus increasing the maize yield in the semiarid Loess Plateau of China.