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Abstract:This article reviewed the moments of the author spending with Professor WANG Yunhua as a supervisor and a pioneer in studying trace element for crops in China based on the 7-year academic learning and studies from undergraduate to postgraduate at Huazhong Agricultural University.The outstanding contributions of Professor WANG Yunhua on promoting researches and application of trace element fertilizers in China were elaborated.There will be no guarantee for food security without trace-element fertilizer. Professor WANG Yunhua has developed a technical system for applying boron in cotton， and molybdenum in winter wheat in China.He has established the Trace Element Research Center and the Department of Plant Nutrition Genetics at Huazhong Agricultural University， and trained a group of senior talents in the field of micronutrient fertilizer.Many of them have become the backbone of education， research， management， production， and administration of plant nutrition in China.Professor WANG Yunhua took boron and molybdenum as the starting point， connecting the national sentiment and mission with trace element fertilizers.Professor WANG Yunhua has played a crucial role in the sustainable development of modern agriculture in China and will always be learned and memorized by the followers.

Abstract:Boron （B） is an essential micronutrient for plants，and boron fertilizer is the most widely used trace element fertilizer in China.In 1975，Mr. WANG Yunhua found that the “budding but no flowering”symptom of cotton grown in large areas of farmland in Xinzhou County，Hubei Province was caused by boron deficiency，which initiated studies on crop boron nutrition at Huazhong Agricultural University.It has been nearly 50 years since then.It has gone through four stages with obvious characteristics and cross integration in the 50-year long history including the diagnosis of boron nutrition and application techniques of boron fertilizer in crops （1975-1985），which mainly established the diagnosis of boron nutrition and application technology of boron fertilizer for cotton in China； the absorption and utilization of boron in crops and their nutritional mechanisms （1985-1995），mainly focused on revealing the absorption，transport，distribution，and physiological functions of boron by cotton and rapeseed； the genetics and molecular mechanisms of boron nutrition in crops （1995-2015），mainly aimed at screening B efficient varieties and cloning B efficient genes of Brassica napus，and revealing the molecular regulatory mechanism of rapeseed response to B deficiency stress； the efficient regulation and utilization of boron in crops （2015-），mainly aimed at conducting in-depth study on boron efficient molecular regulation pathways in rapeseed，screening and cultivating boron efficient breeding materials and varieties，and carrying out integrated promotion and utilization of efficient varieties combined with specialized fertilizers and advanced cultivation techniques.The results of studying at different stages have made important contributions to the promotion and application of boron fertilizer in agricultural production in China，as well as to the increase of yield and economic benefits of crops.They also hold a place in the international application and basic research of boron nutrition in crops.On the occasion of commemorating the first anniversary of Mr.Wang Yunhua’s death，the author provides a review and summary of the main research in four stages mentioned above to enrich readers and express the author’s respect for Mr.Wang.

Abstract:Winter rapeseed （Brassica napus L.） is an important oil crop in China and a major winter rotation crop in southern China. Developing rapeseed production is of great strategic significance for ensuring the safe supply of food and oil in China. Since the beginning of the 21st century， the previous fertilization technology is no longer suitable for new production models due to the shift from transplanting rapeseed to direct seeding and light planting. The development of the rapeseed industry has put forward new requirements for the theory and technology of fertilization. This article summarized the progress in the field of rapeseed fertilization technology in China in the past 20 years. The workers from agricultural science and technology in China proposed a precise nutrient regulation strategy for winter rapeseed through collaborative efforts， which involves the combination of nitrogen， phosphorus， potassium， boron， and magnesium， particularly in the promotion of nutrients at the early stage of growth and stabilization of nutrients at the later stages of growth. A nutrient regulation method including “precise fertilization to strengthen seedlings and promote high yield” at the early stage and “relying on stable soil nutrient supply to promote efficient and stable yield” at the later stage for winter rapeseed was established. The “five precision” rapeseed efficient fertilization technology with “precise source， precise ratio， precise rate， precise time， and precise place” as the core was innovated. A series of new fertilizer products including balanced fertilizers with a specialized formula of required nutrients， slow-release fertilizers， and controlled-release urea were developed. A light， simple， and efficient fertilization model was established， optimized and applied at large-scale， supporting the green， high-quality， and efficient development of the rapeseed industry. In response to the new opportunities and challenges faced by winter rapeseed production in China， prospects including strengthening efficient fertilization techniques for short-growth-period rapeseed in southern China， developing fertilization techniques suitable for the multifunctional utilization of rapeseed， exploring nutrient management techniques to cope with climate change， further strengthening the research and development of new high-efficiency specialized fertilizer products and innovation in fertilization technology matching with the development of modern agriculture， and attaching importance to the breeding and application of rapeseed varieties with high nutrient efficiency are proposed from the perspective of fertilization technology.

Abstract:Trace elements are essential nutrients for plant growth and development， and fertilizers made from them play an important role in improving the yield， quality， and stress resistance of crops， and farmland health. Compared to traditional trace element fertilizers， new trace element carrier fertilizers have the characteristics of good water solubility， strong stability， difficulty in soil fixation， and easy absorption and utilization by plants through the organic combination of efficient carriers and trace elements. Screening or manufacturing efficiency enhancing carrier is the core of developing new trace element fertilizers. This article overviewed efficiency enhancing carrier and their types， as well as the status of studying and developing new trace element carrier fertilizers in recent years. The effects of applying new trace element carrier fertilizers in agricultural production， as well as the main effect mechanisms of various high-efficiency carriers in trace element fertilizers were summarized and analyzed. The status of applying new trace element fertilizers was clarified. The problems existing in the practical application of the new type of trace element fertilizer were pointed out， and targeted suggestions were put forward， and the future direction of efforts was prospected.

Abstract:The transformation of potassium （K） forms in soil plays an important role in the improvement and evaluation of potassium fertility in soil，efficient fertilization techniques of potassium，and regulation of potassium nutrition in plants.In recent years，the team of studying potassium in soil at Nanjing Institute of Soil Science，Chinese Academy of Sciences，has carried out a series of studies on the differentiation method and content range of different forms of potassium in soil，the mechanism of efficient utilization of potassium in soil by plants，the release mechanism of non-exchangeable potassium （NEK） in soil and its influencing factors，especially the method of evaluating the bioavailability of non-exchangeable potassium in soil.The content of non-exchangeable potassium in soil had a maximum value in different types of soil based on the results of soil K extraction with a strong sodium tetraphenylboron （NaTPB） method.The non-exchangeable potassium extracted through exchange and diffusion can account for 20% to 60% of the total potassium in the soil.The release of non-exchangeable potassium from minerals mainly depends on the content of other ions and the concentration of potassium in environment，and the efficient absorption of non-exchangeable potassium by plants depends on the ability of root systems to absorb potassium at low concentrations as well.It has been confirmed that the formation and release of non-exchangeable potassium in soil play an important role in the soil holding capacity and bioavailability of potassium in soil.The new methods for measuring the total amount of non-exchangeable potassium in soil，determining changes of potassium in soil，and grading plant-available potassium in soil have been established.It will provide powerful methods and means for accurately evaluating and predicting the potassium fertility in soil，and studies related to soil potassium，which will facilitate the transition of studying potassium in soil with the qualitative and semi-quantitative methods to the quantitative methods.

Abstract:Boron in plants is mainly present in cell walls and plays an important role in stabilizing the structure of cell wall and promoting the growth and development of plants.Eudicots require more boron and are sensitive to boron deficiency，but there are significant genotypic differences in the resistance of different species and varieties to boron deficiency.Professor Yunhua Wang from Huazhong Agricultural University led a team to screen boron efficient varieties of Brassica napus in the early 1990s，thus initiating studies on the genetic and molecular mechanisms of boron efficiency in plants in China.The results of studying over a decade showed that there were two different molecular regulatory pathways for plants to improve boron efficiency under boron deficiency.In the B transporter-dependent pathway，the expression of NIPs and BORs family genes is induced by boron deficiency，which enhances the absorption of B in root and the distribution of B in shoot，achieving efficient absorption and transport of boron，thereby improving the resistance and adaptability of plants under B deficiency.In the B transporter-independent pathway，plants improve the utilization efficiency of boron in their shoot by influencing hormone signals and the expression of genes related to cell wall synthesis and metabolism，regulating the growth and development of root，and the structure of cell wall component，thereby enhancing plant resistance to boron deficiency.On the 100th anniversary of boron being identified as an essential nutrient for plants，the author reviewed and summarized these researches to enrich readers.At the same time，on the first anniversary of Mr.Wang Yunhua’s pass away，it is to commemorate his groundbreaking contribution in initiating the field of genetic studies on crop boron nutrition at Huazhong Agricultural University.

Abstract:Molybdenum （Mo），as an essential trace element in plants，plays a crucial role in promoting the growth and development of plant and enhancing plant stress resistance.The absorption and transportation of molybdenum in plants are mainly regulated by the molybdate transporter genes MOT1 and MOT2.Molybdenum enters the plant and participates in the growth and metabolism of plant in the form of molybdenum containing enzymes.The regulation of plant stress resistance is mainly manifested as follows：molybdenum affects the photosynthetic carbon and nitrogen metabolism，hormone synthesis，and reactive oxygen species metabolism in the plant through molybdenum containing enzymes including nitrate reductase，aldehyde oxidase，and xanthine dehydrogenase，thereby regulating plant cold resistance.Molybdenum regulates root development，nutrient and water use，and drought resistance gene expression through signal transduction processes mediated by nitrate reductase and aldehyde oxidase，further affecting lipid synthesis and metabolism to regulate plant drought resistance.The recent studies have found that molybdenum plays an important role in plant adaptation to salt stress and alleviating heavy metal stress as well.It will provide new insights into improving plant stress resistance via regulating molybdenum nutrition.

Abstract:Iron is an essential micronutrient for the normal development of all living things. In particular， cultivating iron-rich seeds through biofortification is an important technical solution to solve the "hidden hunger" of human beings， and chelated iron fertilizer is widely used due to its high efficiency. Therefore， the research and development of novel micronutrient chelators is always a competitive hotspot in the world.The plant-secreted mugineic acids and microbial-secreted siderophores， which can efficiently activate insoluble iron to be bioavailable for plants， are potential novel biochelates， especially microorganisms that can efficiently secrete siderophores have application potential. These novel iron fertilizers can improve the iron nutrition of plants without external iron input， but can activate the rich iron resources in the soil effectively by utilizing the strong chelating property of the active substance of the strain itself， and provide enough bioavailable iron for plants. Therefore， these findings offer applied opportunities for novel biochelates to improve plant iron nutrition and crop yield and sustainable development of agriculture. To further explore and develop those novel and green biochelates， provide new pathways for the development of green intelligent fertilizer， and achieve the sustainable development of agriculture， based on the research progress of the molecular and physiological mechanism of iron uptake and utilization by plants and microorganisms， the research progress and application of novel iron biochelates from plants and microorganisms were reviewed. The study covers the status and causes plant iron deficiency， ways to improve iron nutrition， molecular ecological advantages of iron absorption and utilization by plant root exudates under mechanism Ⅱ， as well as the potential of microbial siderophores to improve plant iron nutrition. It is expected that further research and development will lead to a deeper understanding of the mechanism of these novel biochelates to improve the efficiency of iron nutrient uptake in plants， and provide new ways for realizing the sustainable development of green agriculture. It is expected that further research and development will lead to a deeper understanding of the mechanism of these novel biochelates to improve the efficiency of iron nutrient uptake in plants， and provide new ways for realizing the sustainable development of green agriculture.

Abstract:Metal-organic framework （MOF） material is a class of ecologically and environmentally friendly and functional cluster compound， which can be pre-designed topologically to achieve targeted loading and complexation of specific nutrients at the molecular level. In this article， the iron ions were used to synthesize a new Fe based MOF （Fe-MOF） fertilizer under mild hydrothermal conditions to study and evaluate the potential of Fe-MOF materials for application in iron fertilizers. The elemental composition and structural features of Fe-MOF were characterized using techniques including powder X-ray diffraction （PXRD）， mid infrared spectroscopy （FTIR ATR）， X-ray photoelectron spectroscopy （XPS）， and scanning electron microscopy （SEM）. The behaviors of releasing nutrient were investigated by using hydrostatic dissolution and soil incubation experiments. The results showed that Fe-MOF was composed of iron， nitrogen， phosphorus， carbon， oxygen， and hydrogen elements， with a loading capacity of 19.7% for iron， a ratio of 1∶1 for trivalent and divalent iron， and a loading capacity of 5.1% and 14.7% for nitrogen and phosphorus， respectively. The cumulative release rate of iron in aqueous solution for 84 days was 4.7%， while the cumulative release rate in soil reached 58.7%， showing the characteristic of excellent slow and controlled release. It is indicated that the synergistic compatibility and directional assembly of trace elements （iron） and macro elements （nitrogen， phosphorus） have been achieved by using environmentally friendly materials as substrates and a simple and green process of hydrothermal synthesis. It will provide a feasible pathway for designing a new type of iron fertilizers.

Abstract:“Huayouza 9” was used to study the differences in the growth and boron absorption and utilization of rapeseed with two different forms of boron including boric acid and diglycerol borate under water culture to explore whether organic boron （diglycerol borate） has the effect of boron fertilizer.The results showed that boron deficiency treatment led to thickening，curling of rapeseed leaves，and decreased biomass，while the application of organic or inorganic boron promoted the growth of rapeseed.Inorganic boron was more conducive to the growth of rapeseed than organic boron under the treatment with low boron （0.25 μmol/L）.Organic and inorganic boron had similar effects on the total biomass of rapeseed under the treatment with suitable boron （25 μmol/L）.Whether in a low boron or suitable boron environment，the content of photosynthetic pigments including chlorophyll a，chlorophyll b and carotenoids in rapeseed leaves after applying organic boron was significantly higher than that of rapeseed treated with inorganic boron.The photosynthetic rate of rapeseed after applying organic boron was significantly increased by 28.9% compared to applying inorganic boron under the treatment with suitable boron （25 μmol/L）.The accumulation of starch grains in leaves increased.The boron absorption per plant of rapeseed significantly increased by 11.7%，with the main increase being in the aboveground part of rapeseed.It is indicated that organic and inorganic boron have similar physiological functions in rapeseed under suitable boron environment.Organic boron is more conducive to the absorption，accumulation，and upward transportation of boron in rapeseed compared to inorganic boron，promoting the generation of photosynthetic pigments and thereby improving photosynthetic efficiency.

Abstract:Most agricultural products produced in naturally seleniferous areas have problems including large variation and instability of Se content. Therefore, it is of great significance to establish a suitable extraction method for the development and utilization of seleniferous soil resources. In this article, 40 soil samples were collected from the naturally seleniferous areas in Jianshi County, Enshi Tujia and Miao Autonomous Prefecture, Hubei Province and used for rice pot experiment to establish a method for extracting effective selenium from acidic and seleniferous soil. The sequential extraction method and 10 commonly used single step extraction methods were used to extract and determine the forms of selenium and available selenium in soil. The correlation between the content of effective selenium extracted by different extraction methods and the selenium absorbed by rice plants was analyzed. The results showed that the content of water-soluble and exchangeable selenium in the acidic and seleniferous soil in Jianshi was relatively low, ranging from 0.12 to 46.0 μg/kg and from 0.58 to 197.35 μg/kg, respectively. Selenium mainly existed in forms of organic bound and residual selenium that are difficult for plants to utilize. The content of selenium in iron manganese oxide bound state, organic bound state, and residual state was 0.01-0.34 mg/kg, 0.05-0.88 mg/kg, and 0.04-2.72 mg/kg, respectively. Among dozens of single step extractants, 0.5 mol/L NaHCO₃ and 0.1 mol/L KH₂PO₄ solutions had higher extraction efficiency for available selenium in soil. Among different forms of selenium in soil, the correlation between exchangeable selenium and the content of selenium in plant was the highest (r=0.80, P<0.01), while the correlation between other forms of selenium and the content of selenium in plant was lower than that of exchangeable selenium. Among the single step extraction methods, the content of available selenium in soil extracted with 0.1 mol/L KH₂PO₄ solution and 0.5 mol/L NaHCO₃ solution was higher, but the correlation between the former and the content of selenium in plant was more significant (r=0.83, P<0.01). It is indicated that the extraction method with 0.1 mol/L KH₂PO₄ is the most suitable method for extracting biologically available selenium from weakly acidic and seleniferous soil if considering the extraction efficiency and its correlation with the content of selenium in plant.

Abstract:A combination of the field survey and the collection and analysis of soil/fruit sample was conducted in 70 Bingtang orange orchards in Xinping County to clarify the current input of nitrogen，phosphorus，and potassium in orchards in Xinping County. The status of fertilization practices，available nutrient in soil，and nutrient removal of fruit in different Bingtang orange orchards in the county was investigated. The recommend amount of fertilizer for orchards was studied based on the yield. The results showed that orchards in Xinping County were fertilized 2-4 times throughout the year，with the main fertilization being 3 times，mainly concentrated in February-March，May，and December. The average input of nitrogen （N），phosphorus （P₂O₅），and potassium （K₂O） in the county was 444.43，407.07，507.35 kg/hm²，respectively，with an input ratio of 1∶0.92∶1.14. The soil pH value and average content of organic matter was 6.08 and 17.97 g/kg，respectively，generally at an appropriate level. The average content of alkaline hydrolyzed nitrogen in orchards was 74.43 mg/kg，generally at a deficiency level. 78.26% of orchards had lower content of alkaline hydrolyzed nitrogen. The average content of available phosphorus and available potassium in orchards was 91.57 and 245.05 mg/kg，generally at a high level. More than 50% of orchard had high content of available phosphorus/potassium in soil. The potential for reducing the application of nitrogen，phosphorus，and potassium in the Bingtang orange orchards in Xinping County was 8.53%-70.31%，56.95%-87.35%，and 33.64%-78.69%，respectively. According to the removal and utilization efficiency of nutrient in orchards，the recommended amount of nitrogen，phosphorus，and potassium for orchards with different yield levels is 82.39-386.80 kg/hm²，33.89-163.59 kg/hm²，and 69.20-299.25 kg/hm²，respectively. It is indicated that the large input of fertilizer in the Bingtang orange orchards in Xinping County has caused a surplus of nutrients in soil. Targeted fertilization should be applied to Bingtang orange orchards in Xinping County with different production capacities through increasing the input of organic fertilizer and optimizing application structure of fertilizer.

Abstract:In order to explore the effects of N，K，Ca，Fe，and Zn and their interactions on cassava yield，nutrient content and expression of genes related to the absorption and transport of five nutrient elements，using the edible cassava variety SC9 with low hydrocyanic acid content as the test material，an orthogonal experiment of two-level fertilization with five factors of N，K，Ca，Fe，and Zn was designed under the conditions of pot culture and field culture.Differences of cassava yield，chlorophyll content，accumulation of large，medium and trace elements，and the expression of genes related to the absorption and transport of five elements were compared among the treatments，and the best application range of N，K，Ca，Fe and Zn was selected.The results showed that both pot and field T5 （N₁K₁Ca₂Zn₁Fe₂） treatments could obtain the higher cassava yield.High N could promote the synthesis of chlorophyll under pot conditions，but the application of high levels of macronutrients would significantly reduce cassava yield，while the application of high levels of micronutrients would increase both chlorophyll synthesis and yields under both conditions.Under field conditions，high N levels not only promoted chlorophyll synthesis but also increased yield.Regarding element accumulation，the average accumulation of N，P，K，Ca，Fe，Mg in roots of low N and low K treatments was significantly higher than that of high N and high K treatments； the average accumulation of P，K，Zn in roots of high Ca treatment were significantly higher than those of low Ca treatment； the average accumulation of N，K，Ca，Zn in roots of high Zn treatment was significantly higher than that of low Zn treatment； the average accumulation of P，K，Ca，Zn，Fe，Mg in roots of high Fe treatment was significantly higher than that of low Fe treatment.From the perspective of gene expression，high concentration of N，K，Fe，Zn，fertilizer upregulated the expression of MeNRT1，MeAKT1，MeVIT1 and MeIRT1 genes，while low concentration of Ca and Zn fertilizer upregulated the expression of MeCBL7，MeCNGC14 and MeZIP4 genes.In summary，different fertilization treatments have significant effects on the synthesis of chlorophyll content in plant leaves，root yield，root nutrient accumulation，and the expression of nutrient transporter related genes.The lack or excess of elements as well as the relative imbalance are not good for the yield and quality of cassava and we should pay attention to the application of reasonable proportion to maximize the function of elements.Finally，for cassava pot experiment，the suitable fertilizer application amounts were 0.280-0.560 g/kg of N，0.210 g/kg of K，0.165-0.330 g/kg of Ca，0.081-0.163 g/kg of Zn and 0.111 g/kg of Fe，and the suitable fertilizer application amounts in field experiment were 150 kg/hm² of urea，86 kg/hm² of potassium chloride，20 kg/hm² of calcium chloride，90 kg/hm² of zinc sulfate heptahydrate and 35 kg/hm² of ferrous sulfate.

Abstract:The effects of different concentrations of γ-aminobutyric acid （GABA） on the growth，root morphology，and mineral nutrient uptake of trifoliate orange ［Poncirus trifoliata （L.） Raf.］ seedlings were studied to identify the regulatory effects of exogenous GABA on the growth and mineral nutrient uptake of trifoliate orange seedlings.A nutrient solution hydroponic culture was conducted with a control and five concentration gradients of GABA including G1 （0.01 mmol/L），G2 （0.05 mmol/L），G3 （0.1 mmol/L），G4 （0.5 mmol/L），and G5 （1 mmol/L）.The plant height，biomass，root morphology and the content of mineral elements in trifoliate orange seedlings were measured after 30 days of treatment.The results showed that low concentrations of GABA including 0.01 mmol/L，0.05 mmol/L，and 0.1 mmol/L had no significant effect on the plant height，total root length，and biomass accumulation of trifoliate orange seedlings，but significantly changed the root morphology，increased the root surface area，and the root volume.High concentrations of GABA including 0.5 mmol/L and 1 mmol/L inhibited the growth and root development of trifoliate orange seedlings.When the concentration of GABA reached 0.5 mmol/L，it significantly reduced the total root length，main root length，and lateral root length.When the concentration reached 1 mmol/L，it further inhibited the accumulation of plant height and biomass，and significantly reduced the root surface area.Low concentration of GABA promoted the content of N，P，Ca，B，and Mo in the roots of trifoliate orange seedlings，increased the content of K in the stems and the content of P in the leaves，and increased the accumulation of N，P，K，and Mo per plant.However，high concentrations of GABA reduced the content of mineral elements （excluding N） in various organs of trifoliate orange seedlings，and inhibited the nutrient accumulation of trifoliate orange seedlings.It is indicated that the effects of exogenous GABA on the root growth and mineral nutrient absorption of trifoliate orange seedlings had a trend of promoting at low concentrations and inhibiting at high concentrations.The appropriate concentration of GABA can promote the root development of trifoliate orange seedlings，increase the root nutrient absorption area，and facilitate the accumulation and upward transportation of mineral elements.The optimal concentration is 0.05 mmol/L-0.1 mmol/L.When the concentration is too high，it hinders the normal growth and mineral element absorption of trifoliate orange seedlings.It will provide a theoretical reference for the practical application of GABA in enhancing the growth of citrus seedlings.

Abstract:The autophagy-related gene CsATG3b was cloned from tea trees and its function in nitrogen utilization was verified in Arabidopsis thaliana to explore the potential role of CsATG3b in nitrogen utilization in tea trees.The results showed that the expression level of CsATG3b in tea leaves increased with the increase of tea leaves maturity.Compared with wild-type Arabidopsis （WT），the root to shoot ratio and content of nitrogen in CsATG3b overexpressing （CsATG3b-OE） lines under low nitrogen were significantly increased.Overexpression of CsATG3b changed the distribution of nitrogen within the plant.It promoted the distribution of nitrogen to stems under normal nitrogen，while it promoted the distribution of nitrogen to roots under low nitrogen.The CsATG3b overexpressing （CsATG3b-OE） lines significantly upregulated the expression levels of nitrogen absorption and transport related genes AtNRT1.1，AtNRT2.1，AtNRT2.2 in roots，amino acid transport genes AtAAP1，AtAAP4，AtAAP6 and autophagy related genes AtATG3，AtATG5，and AtATG8b in rosette-leaves under low nitrogen.The CsATG3b overexpressing （CsATG3b-OE） lines increased nitrogen accumulation under normal nitrogen and significantly improved nitrogen utilization efficiency under low nitrogen.It is indicated that the overexpression of CsATG3b can improve nitrogen utilization efficiency and tolerance to low nitrogen in Arabidopsis by regulating the expression of nitrogen absorption and transport genes and autophagy related genes.

Abstract:In this study， 102 species of angiosperms grown in the campus of Huazhong Agricultural University collected by Shishanlanzhi were systematically classified， and their mature leaves were sampled to determine the ions composition for the clarification of the ionome of angiosperms and their relationship with plant species， and the differences and connections in the ionome composition of the leaves of angiosperms from different families. The concentrations of mineral nutrients included nitrogen（N）， phosphorus（P）， potassium（K）， calcium（Ca）， magnesium（Mg）， sulfur（S）， iron（Fe）， manganese（Mn）， copper（Cu）， zinc（Zn）， boron（B）， molybdenum（Mo）and nickel （Ni） in the leaves were determined. The ionic fingerprints of these plants were established and the ionic components of these plants and their relationship with plant species were analyzed. The results showed that the concentrations of N， K and Ca were the highest， and that of seven micronutrients were the lowest in the leaves. The N concentration in the leaves of leguminous plants was higher than those of plants of other orders， while the P and K concentration in the leaves of caryophyllous plants was higher than those of plants of other orders. The concentration of seven micronutrients in the leaves of these 102 angiosperms also showed significant differences. Correlation analysis showed that there were significant correlations between each mineral nutrient and at least four other mineral nutrients in the leaves. Among them， the concentrations of Ca significantly positively correlated with the concentrations of Mg and B in plants. Additionally， there were highly significant positive correlations among N， P and K. However， there was a highly significant negative correlation between Zn and Ca， Mg， P， and Mn. Principal component analysis showed that the leaf ionome of plants in the same family were similar， but the leaf ionome of plants in different families were different. Cluster analysis showed that Ca， N， K， S， Mg， P have a great contribution to the variation of plant ionome in different families. These results indicated that the phylogeny of angiosperms is closely related to the leaves ionome， and the ionome in leaves of plants in the same family exhibit high similarity. We may be able to identify plant species by their leaf ionome.

Abstract:This article used decomposed pig manure， pond soil， cottonseed lint， and other waste materials as the substrate for cucumber seedlings to study an efficient and affordable formula of substrate for growing the seedlings. The suitable formulas of substrate for growing the seedlings were selected by studying the physicochemical properties of different ratios of substrates and its effects on growing the seedlings. The results showed that the substrate made of decomposed pig manure， pond soil， and cottonseed lint as partial replacement of peat vermiculite （peat︰vermiculite=2︰1， the same below） was suitable for the physical and chemical properties of the substrate compared to the control， and promoted the growth of cucumber seedlings and the accumulation of dry matter. Among them， the ratio of peat vermiculite︰ decomposed pig manure︰pond soil︰ cottonseed lint=50︰20︰20︰10 was suitable for the physical and chemical properties of the substrate， with the highest comprehensive evaluation index and the best comprehensive performance of the seedlings. It will provide a technical support for the efficient utilization of wastes including pig manure， pond soil， and cottonseed lint in the compound substrates for cucumber seedlings.

Abstract:997 natural Brassica napus varieties were used to screen rapeseed varieties sensitive to aluminum （Al） and study the tolerance mechanism of rapeseed to Al toxicity. The two-step screening method of soil culture initial screening and nutrient solution culture re-screening was conducted. The aboveground fresh mass and relative root elongation were used as indicators to screen Brassica napus varieties sensitive to aluminum. The physiological mechanism of aluminum tolerance in rapeseed was analyzed. The results showed that 997 natural Brassica napus varieties had significant genotypic differences at the stage of seedling in acidic soil. 142 extreme varieties with different aluminum sensitivity including 77 varieties tolerant to aluminum and 65 varieties sensitive to aluminum were screened. A nutrient solution culture system was used to re-screen the 142 rapeseed varieties under aluminum and no aluminum. The results of cluster analysis showed that 97 varieties exhibited good consistency of growth in two cultivation systems. Two aluminum varieties （806 and 985） tolerant to aluminum and two varieties （482 and 811） sensitive to aluminum were finally determined after multiple repeated phenotypic experiments. The biomass of varieties （482 and 811） sensitive to aluminum under aluminum toxicity decreased by about 45% compared to that under non-aluminum treatment， and root growth was significantly inhibited， while varieties tolerant to aluminum had no significant difference. Compared to varieties sensitive to aluminum， varieties tolerant to aluminum accumulated less aluminum in their roots under aluminum toxicity， had lower levels of reactive oxygen species， and significantly increased the activity of antioxidant enzymes including CAT and POD in their roots compared to that under no aluminum， indicating that it may be one of the important physiological mechanisms of aluminum tolerance in rapeseed.

Abstract:In order to explore the characteristics of acid tolerance of rapeseed at the seedling stage in acidic soil environment，113 rapeseed varieties were treated with acid stress and acid soil improvement by pot experiment. 10 traits including root length，plant height，shoot fresh mass，root fresh mass，total fresh mass，shoot dry mass，root dry mass，total dry mass，root/shoot ratio and SPAD were measured at the seedling stage. The acid resistance of different rapeseed varieties were evaluated by correlation analysis，principal component analysis，membership function method，cluster analysis，grey correlation degree and stepwise regression analysis，the acid-resistant evaluation model was established and the acid-tolerant rapeseed varieties were screened. The results showed that 113 rapeseed varieties showed extremely significant differences in 10 traits under two treatments. The coefficient of variation of 10 indicators ranged from 10.09% to 78.68%. The 10 indicators were converted into 4 independent comprehensive indicators，representing 88.688% of the information content of the original indicators. Based on the cluster analysis of the comprehensive evaluation value of acid tolerance （D value） of 113 varieties，they were divided into 5 groups，namely，extremely acid-resistant type （2 samples），acid-resistant type （16 samples），intermediate type （41 samples），sensitive type （50 samples） and extremely sensitive type （4 samples）. The optimal regression equation was constructed using D value and 10 indicators：D=-0.075+ 0.0403X _{total dry weight}+0.100X _{root fresh weight}+0.188X_SPAD+0.099X_{plant height}+0.092X_{root dry weight} （R²=0.982，F=1 154.562^***），and the suitable identification index of acid tolerance in rapeseed at seedling stage was screened out. In conclusion，acid stress could seriously inhibit the growth of rapeseed at the seedling stage，and there were great differences in acid tolerance among different rapeseed varieties. The acid tolerance of rapeseed could be evaluated by measuring total dry mass，root fresh mass，SPAD，plant height，root dry mass and combining with regression equation.

Abstract:As an important part of traditional medicine in our country，traditional Chinese medicine has attracted much attention both at home and abroad.However，in recent years，the human health risks caused by the accumulation of heavy metals in traditional Chinese medicine have brought some obstacles to its popularization and application.The health risks caused by heavy metals accumulation depend not only on their total amount，but also on their bio-accessibility and bioavailability.Therefore，it is of great scientific significance and application value to study the bio-accessibility and bioavailability of heavy metals in Chinese traditional medicine.In this paper，the present situation of heavy metal pollution in traditional Chinese medicine was reviewed，and the research progress on the bio-accessibility and bioavailability of heavy metals in traditional Chinese medicine was described.The key factors affecting the bio-accessibility and bioavailability of heavy metals in traditional Chinese medicine and its products were analyzed in depth，starting from the growth environment，self-properties，processing process and testing conditions of original Chinese medicine.We hope to be able to provide theoretical basis and technical support for the prevention and control of heavy metal pollution risks of traditional Chinese medicine.

Abstract:The heavy metals in the soil of an industrial agglomeration areas in Hebei Province were used to conduct a comparative study on the problem of characterization accuracy in handling non-stationary concentration and biased data with different interpolation methods including distance weighting（IDW）， ordinary Kriging（OK）， support vector machine（SVM）， and gradient enhanced decision tree（GBDT） to improve the accuracy of models for characterizing the soil pollution in industrial agglomeration areas. The results showed that the main pollutant in the soil of this site was arsenic， and GBDT exhibited the highest accuracy in characterizing arsenic pollution in soil （R²=0.911 5）. The results of GBDT visualization showed that the concentration distribution pattern of arsenic was "patchy aggregation" and had a good vertical migration capacity. The results of correlation analysis showed that the differentiation behavior of Arsenic concentration in the soil of this site was mainly related to the soil lithology and hydrogeological conditions. The results of Monte Carlo-based simulation showed that the total cancer risk index of both adults and children in the soil of this site exceeded the guidance value， and children suffered from higher non carcinogenic and carcinogenic risks than adults.

Abstract:The floating seedlings of "Honghua Dajinyuan" were used to study the effects of ciprofloxacin（CIP） and oxytetracycline（OTC） on the growth of flue-cured tobacco.Analyzed the growth status，the changes of chloroplast structure and the content of pigment，the changes of photosynthetic index and the accumulation of antibiotics in flue-cured tobacco seedlings under the concentrations of antibiotics including 0 mg/L，5 mg/L，15 mg/L，30 mg/L，45 mg/L，and 60 mg/L were analyzed.The results showed that low concentration of antibiotics（CIP<15 mg/L and OTC<5 mg/L） stimulated the growth of flue-cured tobacco seedlings，while high concentration inhibited the growth of flue-cured tobacco seedlings.Both antibiotics at low concentrations damaged the chloroplast structure of flue-cured tobacco leaves under transmission electron microscopy（TEM） observation.As the concentration of two antibiotics increased，the content of chlorophyll，the net photosynthetic rate（P_n），transpiration rate（T_r），and stomatal conductance（G_s） in the leaves of flue-cured tobacco seedlings gradually decreased，while the intercellular CO₂ concentration（C_i） increased gradually with the increase of the concentration of the two antibiotics.The accumulation of CIP and OTC in different parts of flue-cured tobacco seedlings decreased in a pattern of root > leaf >stem.It is indicated that low concentration antibiotics can promote the growth of flue-cured tobacco seedlings.Antibiotics damage the chloroplast structure of leaves，resulting in a decrease in the content of pigment and the photosynthetic capacity，ultimately affecting the growth and quality of flue-cured tobacco.Therefore，the use of antibiotics should be reduced in production to avoid potentially increased risks of plant enrichment.

Abstract:To investigate the effect of plant secondary metabolites on the yield increase of different crops，the metabolites of sugar beet and sugarcane were extracted and separated，optimized in proportion，and then chelated with humic acid to form a product according to the national standard of water-soluble fertilizers containing humic acid.Field and hydroponic experiments were conducted to study the yield increase effect and mechanism of this product on 15 crops such as wheat.Two treatments were set up in the experiment：（1） conventional fertilization； （2） conventional fertilization + plant-derived secondary metabolites products，which were applied by foliar spraying，fertilizer mixing，and root irrigation according to different crop types.The results showed that compared with the control，the yield of 15 crops were increased by 5.2% to 21.1% by applying plant-derived secondary metabolites.The germination potential of rice，corn，and cotton seeds increased by 6.6%，11.5%，and 15.2%，respectively，and the germination rate increased by 2.6%，3.5%，and 6.1%，respectively.The total root length，total surface area，and root tip number of wheat roots increased by 54.44%，60.57%，and 30.43%，respectively.The SPAD values of potato，Chinese cabbage，cabbage，and wheat leaves increased by 4.8%，8.7%，6.6%，and 9.7%，respectively.The net photosynthetic rate of wheat leaves increased by 7.9%，and the Vc content of potatoes，Chinese cabbage，and chili increased by 40.8%，22.9%，and 28.51%，respectively.However，the nitrate content decreased by 28.8%，23.9%，and 20.27%，respectively.The sugar content of grapes and beets increased by 21.81% and 15.75%，respectively.The above results indicate that plant secondary metabolites could increase the yield and improve the quality of crop by enhancing the root vitality，promoting nutrient absorption，increasing chlorophyll content，and promoting the accumulation of photosynthetic products，and have good effects of improving fertilizer quality and efficiency.