Phosphorus-based nanomaterials as a potential phosphate fertilizer for sustainable agricultural development.

Phosphorus-based nanomaterials (PNMs) have been reported to have substantial promise for promoting plant growth, improving plant tolerance mechanisms, and increasing resistance to pathogenic organisms. Recent scientific investigation has demonstrated that utilizing PNMs can enhance plant physiological growth, photosynthetic pigments, antioxidant system, metabolism, nutrient absorption, rhizosphere secretion, and soil nutrients activation. Previous research on PNMs mostly concentrated on calcium phosphate, zeolite, and chitosan, with little systematic summarization, demanding a thorough evaluation of PNMs' broader uses. In our current review article, we address the knowledge gap by classifying PNMs according to green synthesis methods and the valence state of phosphorus while elucidating the underlying mechanisms through which these PNMs facilitate plant growth. In addition, we also targeted some strategies to improve the bioavailability of PNMs, offering valuable insights for the future design and safe implementation of PNMs in agricultural practices.

Green synthesis of metal-based nanoparticles for sustainable agriculture.

The large-scale use of conventional pesticides and fertilizers has put tremendous pressure on agriculture and the environment. In recent years, nanoparticles (NPs) have become the focus of many fields due to their cost-effectiveness, environmental friendliness and high performance, especially in sustainable agriculture. Traditional NPs manufacturing methods are energy-intensive and harmful to environment. In contrast, synthesizing metal-based NPs using plants is similar to chemical synthesis, except the biological extracts replace the chemical reducing agent. This not only greatly reduces the used of traditional chemicals, but also produces NPs that are more economical, efficient, less toxic, and less polluting. Therefore, green synthesized metal nanoparticles (GS-MNPs) are widely used in agriculture to improve yields and quality. This review provides a comprehensive and detailed discussion of GS-MNPs for agriculture, highlights the importance of green synthesis, compares the performance of conventional NPs with GS-MNPs, and highlights the advantages of GS-MNPs in agriculture. The wide applications of these GS-MNPs in agriculture, including plant growth promotion, plant disease control, and heavy metal stress mitigation under various exposure pathways, are summarized. Finally, the shortcomings and prospects of GS-MNPs in agricultural applications are highlighted to provide guidance to nanotechnology for sustainable agriculture.

Physiological impacts of zero valent iron, Fe3O4 and Fe2O3 nanoparticles in rice plants and their potential as Fe fertilizers.

Fe-based nanoparticles (Fe-based NPs) have great potential as a substitute for traditional Fe-fertilizer; however, their environmental risk and impact on plant growth are not fully understood. In this study, we compared the physiological impacts of three different Fe-based NP formulations: zero-valent iron (ZVI), Fe3O4 and Fe2O3 NPs, on hydroponic rice after root exposure for 2 weeks. Fe-normal (Fe(+)) and Fe-deficiency (Fe(-)) conditions were compared. Results showed that low dose (50 mg L-1) of ZVI and Fe3O4 NPs improved the rice growth under Fe(-) condition, while Fe2O3 NPs did not improve plant growth and caused phytotoxicity at high concentration (500 mg L-1). Under Fe(+) conditions, none of the Fe-based NPs exhibited positive effects on the rice plants with plant growth actually being inhibited at 500 mg L-1 evidenced by reduced root volume and leaf biomass and enhanced oxidative stress in plant. Under Fe(-) condition, low dose (50 mg L-1) of ZVI NPs and Fe3O4 NPs increased the chlorophyll content by 30.7% and 26.9%, respectively. They also alleviated plant stress demonstrated by the reduced oxidative stress and decreased concentrations of stress related phytohormones such as gibberellin and indole-3-acetic acid. Low dose of ZVI and Fe3O4 NPs treatments resulted in higher Fe accumulation in plants compared to Fe2O3 NPs treatment, by down-regulating the expression of IRT1 and YSL15. This study provides significant insights into the physiological impacts of Fe-based NPs in rice plants and their potential application in agriculture. ZVI and Fe3O4 NPs can be used as Fe-fertilizers to improve rice growth under Fe-deficient condition, which exist in many rice-growing regions of the world. However, dose should be carefully chosen as high dose (500 mg L-1 in this study) of the Fe-based NPs can impair rice growth.

Physiological and biochemical response of wheat (Triticum aestivum) to TiO2 nanoparticles in phosphorous amended soil: A full life cycle study.

Nanoparticles (NPs) application in soil as nano-fertilizers to increase crop yield is getting attention due to their higher efficiency and less environmental risks. This study investigated the interactive effects of variable titanium dioxide nanoparticles (TiO2-NPs) levels (0, 30, 50 and 100 mg kg-1) superimposed to phosphorus (P) fertilizer application in soil at the rates of 0, 25 and 50 mg kg-1 on wheat crop. Physiological parameters of plants, their antioxidant enzymes activities (SOD, POD), and contents of crude protein, H2O2, MDA and metals/nutrients (Al, Ca, Mg, Fe, Zn and Cu) were measured. Data on physiological traits revealed that application of 50 mg kg-1 of TiO2-NPs without P fertilizer significantly enhanced the root and shoot length by 63 and 26%, respectively. Increased contents of nutrients in the shoots, viz., Ca (316%), Cu (296%), Al (171%) and Mg (187%) with 50 mg kg-1 TiO2-NPs treatment reflected improvement in crop growth and grain quality. Furthermore, P contents in plant tissues were raised up to 56% with 50 mg kg-1 of TiO2-NPs even in the absence of P fertilizer. In the soil, concentration of phytoavailable P was significantly increased up to 63.3% in the presence of 50 mg kg-1 TiO2-NPs as compared to control. Contents of crude protein in grain were also enhanced by 22.8% (at P50) and 17.4% (at P25) with 50 mg kg-1 TiO2-NPs application. Along with P application, TiO2-NPs triggered the activities of SOD (2.06-33.97%) and POD (up to 13.19%), and H2O2 production (50.6-138.8%). However, MDA contents were not elevated significantly at any level of TiO2-NPs, and remained at par with control. It was noteworthy that highest level of TiO2-NPs, viz., 100 mg kg-1 exhibited plant and nutrients response lower than that with 50 mg kg-1. Further, TiO2-NPs triggered the bioavailability of micronutrient heavy metals (Zn, Cu and Fe) and Al, which could have toxicity at higher concentrations. These results suggested that TiO2-NPs might have some affinities with phosphate compounds and metal ions in the soil to bring them in soluble form, which enhanced their bioavailability. Although it improved the crop yield and quality, but toxic or negative impact of TiO2-NPs was also apparent at higher dose. Therefore, investigations on the potential interactions of NPs with other nutrients and toxic metals are needed to enhance our understanding for the safer application of nano-fertilizer.

Goethite-modified biochar ameliorates the growth of rice (Oryza sativa L.) plants by suppressing Cd and As-induced oxidative stress in Cd and As co-contaminated paddy soil.

Co-contamination of soils with cadmium (Cd) and arsenic (As) in rice growing areas is a serious threat to environment and human health. Increase in soil Cd and As levels curtail the growth and development of rice plants by causing oxidative stress and reduction in photosynthetic activity. Therefore, it is necessary to formulate and evaluate different strategies for minimizing the Cd and As uptake in rice plant. We modified biochar (BC) with goethite and assessed the effects of goethite-modified biochar (GB) application on mitigating Cd and As stress in rice plant. Although BC supply to rice plants enhanced their performance in contaminated soil but application of different GB levels i.e.1.5% GB to the soil resulted in prominent improvements in physiological and biochemical attributes of rice plants grown in Cd and As co-contaminated paddy soil. It was observed that soil amendment with GB increased the plant growth, biomass, photosynthetic pigments, gas exchange attribute of rice plant and suppressed the oxidative stress in rice leaves and roots by increased antioxidant enzymes activities. Supplementing the soil with 1.5% GB incremented the iron plaque (Fe-plaque) formation and enhanced the Cd and As sequestration by Fe-plaque. Application of GB (1.5%) significantly improved the Fe content of Fe-plaque by 68.7%. Maximum Cd (1.57 mg kg-1) and As (0.85 mg kg-1) sequestration by Fe-plaque was observed with 1.5% GB treatment. Compared to the control, 1.5% GB treatment application prominently reduced the Cd content in the rice roots and shoots by 42.9%, and 56.7%, respectively and As content in the rice roots and shoots declined by 32.2%, 46.6%, respectively, compared to the control. These findings demonstrate that amending the soil with 1.5% GB can be a potential remediation strategy for checking Cd and As accumulation, reducing oxidative stress and increasing the growth of rice plant.

Phytotoxic Mechanism of Nanoparticles: Destruction of Chloroplasts and Vascular Bundles and Alteration of Nutrient Absorption.

This study focused on determining the phytotoxic mechanism of CeO2 nanoparticles (NPs): destroying chloroplasts and vascular bundles and altering absorption of nutrients on conventional and Bt-transgenic cottons. Experiments were designed with three concentrations of CeO2 NPs including: 0, 100 and 500 mg·L(-1), and each treatment was three replications. Results indicate that absorbed CeO2 nanoparticles significantly reduced the Zn, Mg, Fe, and P levels in xylem sap compared with the control group and decreased indole-3-acetic acid (IAA) and abscisic acid (ABA) concentrations in the roots of conventional cotton. Transmission electron microscopy (TEM) images revealed that CeO2 NPs were absorbed into the roots and subsequently transported to the stems and leaves of both conventional and Bt-transgenic cotton plants via xylem sap. In addition, the majority of aggregated CeO2 NPs were attached to the external surface of chloroplasts, which were swollen and ruptured, especially in Bt-transgenic cotton. The vascular bundles were destroyed by CeO2 nanoparticles, and more damage was observed in transgenic cotton than conventional cotton.

[Content of rare earth elements in wild Hypericum japonicum Thunb].

Rare earth elements are important nutritional elements for human health, and today more and more attention has been paid to the effective components in Chinese traditional medicine, especially to rare earth elements. Fifteen rare earth elements in wild hypericum japonicum Thunb were analyzed by the methods of ICP-MS. The results showed that the concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu and Y ranged from 6 ng x g(-1) x DW to 14 522 ng x g(-1) x DW, and among them the concentrations of La, Ce and Nd were higher than 2 000 ng x g(-1) x DW. Compared with the concentration of rare earth elements in rice, corn, wheat and barley, the total concentration of rare earth elements in hypericum japonicum Thunb was much higher, which could be the mechanism of curative effect of hypericum japonicum Thunb on liverish diseases. The character of elements and the content of rare earth elements in soil should be responsible for the difference, but the distributive mechanism of rare earth elements in hypericum japonicum Thunb should be further studied.

[Application of ICP-AES to detecting nutrients in grain of wheat core collection of China].

Deficiency of micronutrients, especially iron and zinc, has been a serious malnutrition problem worldwide in human health. Increasing Fe and Zn concentrations in grains by means of plant breeding is a sustainable, effective and important way to improve human mineral nutrition and health. However, little information on grain Fe and Zn concentrations in Chinese wheat genotypes is available. Therefore, to determine the nutrients status especially these of micronutrients in wheat grain is necessary and very useful. Two hundred sixty two genotypes were selected from the wheat mini-core collections, which contained 23090 wheat genotypes in China and represented 72.2% of total genetic variation. All 262 genotypes were grown in soils of similar geographical and climate location in order to minimize the environmental effect. After harvesting, the grains were washed with deionized water and dried (around 70 degrees C), then digested in HNO3 solution using a microwave accelerating reaction system (MARS). Nutrient concentrations in stock solution were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Remarkable genetic variations among grain nutrient concentrations (Fe, Mn, Cu, Zn, Mg, Ca, K and P ) in the tested genotypes were detected. The concentrations of Fe, Zn, Mn, Cu, Ca, Mg, K and P in wheat grain were in the ranges of 34.2-61.2, 26.3-76.0, 20.9-56.7, 3.4-9.8, 290-976, 1129-2210 mg x kg(-1); 0.34%-0.85% and 0.296%-0.580%, respectively. The corresponding average values were 45.1, 50.2, 37.9, 6.5, 515, 1772 mg x kg(-1), 0.55% and 0.451%, respectively. Significant positive correlations between micronutrients (Fe, Mn, Zn, and Cu) in wheat grains were detected, and the correlation coefficients were 0.395** (Fe and Mn), 0.424** (Fe and Zn), 0.574** (Fe and Cu), and 0.474** (Mn and Cu), respectively. However, no significant difference was found in grain nutrient concentrations between spring-wheat and winter-wheat genotypes. This study provides valuable and important information for breeding wheat genotypes which are enriched with minerals in grains, especially Fe and Zn

[Application of ICP-MS to detect rare elements in wild Cistanche deserticola Y. C. Ma].

Rare metals are important nutritional elements for human health. Fifteen rare metals in wild Cistanche deserticola Y. C. Ma were analyzed by the methods of ICP-MS. The results showed that concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Lu in Wild Cistanche deserticola Y. C. Ma were 144.89, 259.75, 36.41, 133.25, 25.38, 6.10, 30.20, 3.85, 20.36, 3.42, 8.55, 6.42, 1.15, 20.02 and 29.77 ng x g(-1) respectively, the character of elements and the content of rare earth elements in soil should be responsible for the difference, but the mechanism of distribution should be further studied.

[Application of ICP-MS to the detection of 22 elements in transgenic soybean oil].

With the rapid development of transgenic food, more and more transgenic food has been pouring into the market, and much attention has been paid to the edible safety of transgenic food. Transgenic soybean oils were studied by ICP-MS to detect 22 kinds of elements. The results showed that the contents of 7 kinds of macroelements range from 0. 13 to 12.52 microg x g(-1) in transgenic soybean oils, the range of the rest 15 kinds of microelements is from 0.15 ng x g(-1) to 7)0.00 ng x g(-1). The sequence of macroelement concentration is Ca>Na>K>Mg>Al>P>Si. There are 5 kinds of micoelements whose concentrations were higher than 200 ng x g(-1), including Zn>Ba>Cr>Fe>Ti, especially Zn, Ba, Cr and Fe.

[Determination of trace elements and heavy metals in spaceflight achyranthes].

Concentration of trace elements and heavy metals is an important aspect to appraise the quality of Chinese traditional medicine. Seven kinds of trace elements and five kinds of heavy metals in spaceflight achyranthes were analyzed by the method of ICP-MS. The results showed that spaceflight achyranthes contained many wholesome elements, such as Ca, Fe, Zn, Mn, Cu, Se and Mo, whose concentrations are 9182.252 microg x g(-1) x DW, 310.5 microg x g(-1) x DW, 24.718 microg x g(-1) x DW, 18416.97 ng x g(-1) x DW, 5518.97 ng x g(-1) x DW, 1747.692 ng x g(-1) x DW and 211.87 ng x g(-1) x DW respectively. But the content of heavy metals is also high, as the concentrations of As, Pb, Hg, Cd and Cr are 514. 332 ng x g(-1) x DW, 1657.65 ng x g(-1) x DW, 13.212 ng x g(-1) x DW, 49.22 ng x g(-1) x DW and 922.038 ng x g(-1) x DW respectively, which accords with the relevant standard.

[Determination of major elements in superphosphate by X-ray fluorescence spectrometry].

Phosphate fertilizer is one of the most important fertilizers. The authors determined nine kinds of major elements in superphosphate, the most important phosphate fertilizer, by X-ray fluorescence spectrometry. The detection range of SiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 is 15.0%-90.0%, 0.20%-25.0%, 0.20%-25.0%, 0.01%-0.35%, 0.20%-40.0%, 0.10%-35.0%, 0.10%-7.50%, 0.05%-7.50% and 1.00%-100.00% respectively, and the precision of the method for SiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 range from 0.20% to 0.005%, so the method of X-ray fluorescence spectrometry is a fast and effectual method for detecting the composition of phosphate fertilizer. The contents of the above elements showed (1) the detected superphosphate content is 18.101% of P2O5, which is accordant to the labeled level (> or = 16%); (2) the detected superphosphate contains much SiO2, TFe2O3, MgO, CaO and K2O, which are necessary for plant growth and the content of which is 16.954%, 1.495%, 1.580%, 21.428% and 1.585% respectively. These data showed that phosphate fertilizer sometimes can supply some trace elements for plants, but we should eliminate the interference effect of these elements when we research the role of phosphorus; (3) superphosphate contains 3.225% of Al2O3, so the authors should attention to the aluminium poison when superphosphate is used chronically.

[Determination of major elements in soil from cancer village by X-ray fluorescence spectrometry].

Many social problems arise from environmental pollution, cancer village is one of the many important problems caused by pollution. The authors selected a typical cancer village where 80-100 people died of cancer in the last five years, but there are only a total of 1 200 people in this village. The authors sampled soils from crops-planted areas and detected the major elements by X-ray fluorescence spectrometry. The results showed that the contents of SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 in soil of this village were 66.05%, 0.66%, 11.37%, 3.93%, 0.075%, 1.97%, 5.47%, 1.90%, 2.11% and 0.20% respectively; with the precision being +/- 0.20%, +/- 0.005%, +/- 0.10%, +/- 0.10%, +/- 0.005%, +/- 0.05%, +/- 0.04%, +/- 0.08%, +/- 0.02% and +/- 0.005% respectively, which showed that X-ray fluorescence spectrometry is a good method.