Differences and Mechanism of Waxy Corn Starch and Normal Corn Starch in the Preparation of Recrystallized Resistant Starch (RS3).

This study prepared resistant starch (RS) from waxy corn starch and normal corn starch and analyzed the effects of its molecular and microstructural characteristics on RS content. The RS content of waxy corn resistant starch (RS-WCS) was highest at 57.8%, whereas that of normal corn resistant starch (RS-NCS) was 41.46%. The short-chain amylose contents of RS-WCS and RS-NCS were 47.08% and 37.24%, respectively, proportional to their RS content. Additionally, RS content positively correlated with crystallinity, short-range order degree, and degree of polymerization (DP), exceeding 25. Electron microscopic images, before and after enzymolysis, revealed that RS-WCS was hydrolyzed from the surface to the center by pancreatic α-amylase, while RS-NCS underwent simultaneous hydrolysis at the surface and center. These results indicate that the higher RS content in RS-WCS, compared to RS-NCS, is attributable to the synergistic effects of molecular structure and microstructure.

[Effect of No-tillage on Soil Aggregates in Farmland：A Meta Analysis].

In order to clarify the impact of no-tillage on the quality of farmland soil aggregates in China and promote the adaptive application of no-tillage practices， a Meta-analysis was conducted by collecting data from 116 published studies. The effects of no-tillage on aggregate size distribution， mean weight diameter （MWD）， and aggregate-associated C were studied. The results showed that compared with that under tillage， no-tillage significantly increased the proportion of macroaggregates （10.9%） and MWD （12.8%） and decreased the proportion of clay and silt （-15.5%） but had no significant effect on soil microaggregate and aggregate-associated C. The subgroup and Meta regression analysis showed that no-tillage significantly increased the proportion of macroaggregates in Northwest China （17.6%） and MWD in North China （15.4%）. In upland and clay loam， no-tillage increased MWD by 12.6% and 18.4%， respectively. The effect of no-tillage on increasing the proportion of macroaggregates increased with the soil pH. When straw returned， no-tillage significantly increased the proportion of macroaggregates （9.6%） and MWD （11.6%）， but no significant effect of no-tillage on aggregates was found after straw removal. Regarding test duration， short-term （ < 5 a） no-tillage could significantly increase the proportion of macroaggregates， whereas long-term （ > 10 a） no-tillage could improve the MWD. In different soil layers， no-tillage could only significantly improve the aggregate size distribution and MWD in topsoil （0-20 cm） but had no effect in subsoil （ > 20 cm）. In summary， no-tillage could improve aggregate size distribution and stability but had no effect on aggregate-associated C. Production region， soil properties， field management methods， and other factors should be fully considered in production practice to effectively improve the quality of soil aggregates.

[Effect of Biochar on Agricultural Soil Aggregates and Organic Carbon: A Meta-analysis].

As a soil amendment, biochar has been widely used to ameliorate agricultural soil. To ensure the effect of biochar on the carbon sequestration of farmlands in China, a Meta-analysis was carried out via collecting published literatures. We quantitatively analyzed the response of biochar application to soil aggregates, aggregate carbon, and soil organic carbon to different experimental conditions. The results showed that the application of biochar significantly increased the proportion of soil macroaggregates(10.8%) and MWD(13.3%) but had no significant effect on soil microaggregates and silty-clay compared with those in the non-biochar-added treatment. Moreover, biochar addition significantly increased soil organic carbon content(56.9%), with the largest increased area in North China(39.4%), and enhanced intra-aggregate carbon contents of each particle size. Biochar could significantly increase soil organic carbon content under different experimental designs. Compared with that under non-fertilization, biochar combined with fertilization could also significantly improve soil structure and soil fertility. We also found that more than two years of biochar application significantly increased the proportion of macroaggregates(15.7%), MWD(21.2%), macroaggregate carbon(31.7%), and soil organic carbon(40.0%). Meanwhile, biochar produced from crop straw had better soil improvement effects than that of wood and sawdust. Biochar applied in high-nitrogen soil was more beneficial to improve soil stability. Thus, we concluded that biochar could meliorate soil structure and promote the accumulation of soil organic carbon, which was of importance for the fertility maintenance and improvement of the farmland.

[Optimizing Straw Management to Enhance Carbon and Nitrogen Efficiency and Economic Benefit of Wheat-Maize Double Cropping System].

The optimization of annual straw management can improve the yield, income, and carbon and nitrogen efficiency of wheat-maize double cropping systems. Based on a long-term positioning trial started in 2012, five straw management methods were considered, C100 (100% return), C75 (75% return+25% harvest), C50 (50% return+50% harvest), C25 (25% return+75% harvest), and C0 (100% harvest). We analyzed the effects of farmland carbon and nitrogen inputs and their ratios on crop yield, carbon and nitrogen use efficiency, and economic benefits in wheat and maize anniversaries with different straw managements. The results showed that: ① the amount of straw returning to the field resulted in a significant difference in carbon and nitrogen input. The annual carbon and nitrogen inputs from crop residues decreased by 1.76 t·hm-2 and 34.28 kg·hm-2, respectively, with a 25% reduction in straw returning. The C/N ratios under the C100-C0 treatment were 18.62, 17.03, 15.64, 12.54, and 9.61, respectively. ② Grain yield first increased and then decreased with the decrease in the C/N input ratio, and the effect of straw management on wheat yield was greater than that on maize. Compared with that under C100 and C0, the average grain yield of wheat and maize under the C50 treatment increased by 13.34%-13.67% and 16.10%-17.71%, respectively, and the total grain yield of wheat and maize increased by 14.98% and 15.68%. ③ The annual grain yield and carbon agronomy efficiency were the best with the C/N input ratio of 15.64 (in the C50 treatment), which were 15.71% and 0.29 kg·kg-1, respectively. The carbon production efficiency continued to increase with the decrease in the C/N input ratio, and there was a significant negative correlation between them. The nitrogen production efficiency increased first and then decreased with the decrease in the C/N input ratio. The nitrogen production efficiency of the C50 treatment was the highest (0.64 kg·kg-1), which was significantly higher than that of C100 by 32.63%. ④ The C50 treatment had the highest economic income and net income, which were 46200 yuan·hm-2 and 33400 yuan·hm-2, respectively. Compared with that of C100, the economic income of grain and straw feed increased by 5600 yuan·hm-2 and 3200 yuan·hm-2, respectively. In conclusion, the optimal C/N input ratio can be achieved by optimized straw management; 50% straw returning and 50% harvest in a wheat-maize double-cropping intensive production system can promote carbon agricultural efficiency and nitrogen production efficiency and obtain the maximum grain yield and economic benefits.

[Structure and Function of Soil Fungal Community in Rotation Fallow Farmland in Alluvial Plain of Lower Yellow River].

This study was conducted to clarify the structure and function of the fungal community and the microecology change characteristics of farmland soil fertility response to different fallow rotation patterns. It aimed to provide a reference for promoting farmland ecological restoration and farmland quality improvement in the alluvial plain of the lower Yellow River. Farmland soil subject to a long-term rotation fallow experiment since 2018 was studied using Illumina MiSeq high-throughput sequencing technology, and the 'FUNGuild' fungal function prediction tool was used to analyze differences in soil fungal community structure and function under the following four rotation fallow regimes: long fallow (LF), winter wheat and summer fallow (WF), winter fallow and summer maize (FM), and annual rotation of winter wheat and summer maize (WM). The results showed that LF (fallow lasting two years) increased the richness and diversity of fungal communities in the topsoil (0-20 cm layer), whereas WF increased the richness and diversity of fungi in the deep soil (20-40 cm layer) after winter wheat harvest. A total of 2262 OTU were obtained from all soil samples, which were divided into 14 phyla, 34 classes, 75 orders, 169 families, 309 genera, and 523 species. OTU shared by the two soil layers included 420 types (0-20 cm layer) and 253 types (20-40 cm layer), respectively. The fungal community structure of the four rotation fallow soils was similar at the phylum level, mainly including Ascomycota, Basidiomycota, and Mortierellomycota. The total abundances of the three dominant bacteria were 91.69%-96.91% (0-20 cm layer) and 91.67%-94.86% (20-40 cm layer), respectively. Principal component analysis showed that the first principal component (PC1) and the second principal component (PC2) could explain the difference in community structure by 45.56% (0-20 cm layer) and 46.20% (20-40 cm layer). Additionally, the LDA results of LEfSe (threshold was 4.0) showed that there were 64 fungal evolutionary branches in LF, FM, WF, and WM with statistically significant differences (P<0.05). According to RDA analysis, total organic carbon (TOC), total phosphorus (TP), available nitrogen (AN), and soil water content (SWC) were the main environmental factors that significantly affected fungal community in the 0-40 cm soil layer (P<0.05). The functional prediction with FUNGuild showed that the main nutrient types among different treatments in different soil layers were saprotrophic, saprotrophic-symbiotrophic, pathotrophic-saprotrophic-symbiotrophic, and pathotrophic. In LF, the nutrient type of topsoil was mainly pathotrophic-saprotrophic-symbiotrophic, whereas in deep soil, the relative abundance of pathotrophic fungi was the highest. Additionally, in the treatments with planted wheat or corn (FM, WF, and WM), saprotrophic was the main type in both soil layers. Therefore, different fallow patterns were linked to variation in the structure, diversity, and nutrient types of soil fungal communities. Based on these results, seasonal fallow practices could regulate the farmland soil micro-ecological environment of intensive planting and promote the health and harmony of farmland soil ecosystems.

Interaction Effects of Nitrogen Rates and Forms Combined With and Without Zinc Supply on Plant Growth and Nutrient Uptake in Maize Seedlings.

Previous studies have shown that zinc (Zn) accumulation in shoot and grain increased as applied nitrogen (N) rate increased only when Zn supply was not limiting, suggesting a synergistic effect of N on plant Zn accumulation. However, little information is available about the effects of different mineral N sources combined with the presence or absence of Zn on the growth of both shoot and root and nutrient uptake. Maize plants were grown under sand-cultured conditions at three N forms as follows: NO3 - nutrition alone, mixture of NO3 -/NH4 + with molar ratio of 1:1 (recorded as mixed-N), and NH4 + nutrition alone including zero N supply as the control. These treatments were applied together without or with Zn supply. Results showed that N forms, Zn supply, and their interactions exerted a significant effect on the growth of maize seedlings. Under Zn-sufficient conditions, the dry weight (DW) of shoot, root, and whole plant tended to increase in the order of NH4 + < NO3 - < mixed-N nutrition. Compared with NH4 + nutrition alone, mixed-N supply resulted in a 27.4 and 28.1% increase in leaf photosynthetic rate and stomatal conductance, which further resulted in 35.7 and 33.5% of increase in shoot carbon (C) accumulation and shoot DW, respectively. Furthermore, mixed-N supply resulted in a 19.7% of higher shoot C/N ratio vs. NH4 + nutrition alone, which means a higher shoot biomass accumulation, because of a significant positive correlation between shoot C/N ratio and shoot DW (R 2 = 0.682***). Additionally, mixed-N supply promoted the greatest root DW, total root length, and total root surface area and synchronously improved the root absorption capacity of N, iron, copper, manganese, magnesium, and calcium. However, the above nutrient uptake and the growth of maize seedlings supplied with NH4 + were superior to either NO3 - or mixed-N nutrition under Zn-deficient conditions. These results suggested that combined applications of mixed-N nutrition and Zn fertilizer can maximize plant growth. This information may be useful for enabling integrated N management of Zn-deficient and Zn-sufficient soils and increasing plant and grain production in the future.

[Characteristics of Bacterial Community Structure in Fluvo-aquic Soil Under Different Rotation Fallow].

The aim of this study was to provide a reference for promoting ecological restoration of farmland and the green development of agriculture in the alluvial plain of the lower Yellow River by determining the effects of different rotation fallow patterns on the bacterial community of the fluvo-aquic soil. Farmland soil subject to a long-term rotation fallow experiment since 2018 was studied using Illumina MiSeq high-throughput sequencing technology, and the 'Tax4Fun' bacterial function prediction tool was used to analyze differences in soil bacterial community structure and function under the following four rotation fallow regimes:long fallow(LF), winter wheat and summer fallow(WF), winter fallow and summer maize(FM), and annual rotation of winter wheat and summer maize(WM). The environmental factors affecting changes in the soil bacterial community structure and function were also analyzed. In total, 44 phyla, 146 classes, 338 orders, 530 families, 965 genera, and 2073 species of bacteria were detected in the soil samples from the different rotation fallow regimes, and the dominant bacterial groups were Actinobacteria, Proteobacteria, Acidobacteria, and Chloroflexi in 0-20 cm and 20-40 cm soil layers. However, the relative abundances of the dominant bacteria groups were varied between the rotation fallow regimes. In the 0-20 cm layer of the seasonal fallow soils(WF and FM), bacteria were more abundant and community diversity was higher than that of the WM and LF soils. In 20-40 cm soil layer, the WF soil was more abundant in bacterial and the community was more diverse. Based on the prediction function of the 'Tax4Fun' tool, six primary metabolic pathways, 40 secondary metabolic pathways(18 types with relative abundance greater than 1%), and 264 tertiary metabolic pathways were identified in the soil bacteria of the different rotation fallow regimes. Seasonal fallow(WF and FM) was found to increase the relative abundance of beneficial bacterial metabolic pathways involved in metabolism, environmental information processing, and genetic information processing. According to RDA analysis, the soil bacterial community in the 0-20 cm soil layer was significantly affected by soil moisture, total phosphorus, available phosphorus, available potassium, pH, and C/N ratio(P<0.05), and the soil bacterial community in 20-40 cm soil layer was significantly affected by soil total phosphorus and available phosphorus(P<0.05). Therefore, different fallow patterns were linked to variation in the structure, diversity, and metabolic functions of soil bacterial communities. Based on these results, seasonal fallow practices could promote the health and stability of farmland soil ecosystems.

Texture and bio-functional characteristics of a Chinese steamed bread prepared from lotus root powder partially replacing wheat flour.

Making low GI of the Chinese steamed bread (CSB) with acceptable eating quality is a challenge. A CSB prepared from wheat flour partially substituted by lotus root powder (LRP) showed good prospects. RVA profile and texture profile were determined to evaluate the texture, while animal test were used to confirm the bio-functional attributes. The addition of LRP effectively changed the RVA profile of lotus-wheat incorporated flour (LWIF). CSB prepared from 30% LWIF showed acceptable eating quality with higher springiness, cohesiveness, and recovery while lower hardness. After 12 weeks of 30% LWIF administrating, the fast blood glucose of diabetic rat decreased from 17.6 to 5.8 mmol/L together with the reduction of serum TC, TG and LDL-C. The hepatic histopathological examination and serum levels changes of SOD, CAT and FFA confirmed LWIF could effectively protect the liver of the diabetic rats from damage caused by oxidative stress.

Characterization of the Powdery Mildew Resistance Gene in Wheat Breeding Line KN0816 and Its Evaluation in Marker-Assisted Selection.

Wheat powdery mildew, caused by Blumeria graminis (DC.) Speer f. sp. tritici is a destructive disease seriously threatening yield and quality of common wheat (Triticum aestivum L., 2n=6x=42, AABBDD). Characterization of resistance genes against powdery mildew is useful in parental selection and for developing disease-resistant cultivars. Chinese wheat breeding line KN0816 has superior agronomic performance and resistance to powdery mildew at all growth stages. Genetic analysis using populations of KN0816 crossed with different susceptible parents indicated that a single dominant gene, tentatively designated PmKN0816, conferred seedling resistance to different B. graminis f. sp. tritici isolates. Using a bulked segregant analysis, PmKN0816 was mapped to the Pm6 interval on chromosome arm 2BL using polymorphic markers linked to the cataloged genes Pm6, Pm52, and Pm64, and flanked by the markers CISSR02g-6 and CIT02g-2, both with genetic distances of 0.7 cM. Analysis of closely linked molecular markers indicated that the marker alleles of PmKN0816 differed from those of other powdery mildew resistance genes on 2BL, including Pm6, Pm33, Pm51, Pm64, and PmQ. Based on the genetic and physical locations and response pattern to different B. graminis f. sp. tritici isolates, PmKN0816 is most likely a new powdery mildew resistance gene and possesses effective resistance to all the 14 tested B. graminis f. sp. tritici isolates. In view of the elite agronomic performance of KN0816 combined with the resistance, PmKN0816 is expected to become a valuable resistance gene in wheat breeding. To transfer PmKN0816 to different genetic backgrounds using marker-assisted selection (MAS), closely linked markers of PmKN0816 were evaluated, and four of them (CIT02g-2, CISSR02g-6, CIT02g-10, and CIT02g-17) were confirmed to be applicable for MAS in different genetic backgrounds.

Systematic analysis of lysine 2-hydroxyisobutyrylation posttranslational modification in wheat leaves.

Lysine 2-hydroxyisobutyrylation (Khib) is a recently discovered post-translational modification (PTM) showing diverse biological functions and effects in living organisms. However, the study of Khib in plant species is still relatively limited. Wheat (Triticum aestivum L.) is a global important cereal plant. In this study, the systematic Khib analysis was performed in wheat leave tissues. A total of 3004 Khib sites in 1104 proteins were repeatedly identified. Structure characterization of these Khib peptides revealed 12 conserved sequence motifs. Function classification and enrichment analysis indicated these Khib proteins showed a wide function and pathway distribution, of which ribosome activity, protein biosynthesis and photosynthesis were the preferred biological processes. Subcellular location predication indicated chloroplast was the dominant subcellular compartment where Khib was distributed. There may be some crosstalks among Khib, lysine acetylation and lysine succinylation modification because some proteins and sites were modified by all these three acylations. The present study demonstrated the critical role of Khib in wheat biological and physiology, which has expanded the scope of Khib in plant species. Our study is an available resource and reference of Khib function demonstration and structure characterization in cereal plant, as well as in plant kingdom.

Diagnostic Kompetitive Allele-Specific PCR Markers of Wheat Broad-Spectrum Powdery Mildew Resistance Genes Pm21, PmV, and Pm12 Developed for High-Throughput Marker-Assisted Selection.

Wheat powdery mildew is a devastating disease that seriously threatens yield worldwide. Utilization of host resistance is considered an effective strategy to minimize powdery mildew damage. Pm21, PmV, and Pm12 confer broad-spectrum resistance to wheat powdery mildew in China, of which Pm21 and PmV are allelic genes derived from the 6VS chromosome of Dasypyrum villosum, and Pm12 is derived from the 6SS chromosome of Aegilops speltoides and most likely orthologous to the former two genes. To accurately and efficiently transfer and pyramid these genes using marker-assisted selection (MAS), distinctive single-nucleotide polymorphisms (SNPs) among the exon sequences of Pm21, PmV, and Pm12 and their homologous sequences in the common wheat genome were identified and then used for developing diagnostic Kompetitive Allele-Specific PCR (KASP) markers. The markers were validated in different genotypes including transgenic vectors, transgenic lines, translocation lines, resistance stocks with documented Pm genes, and in multiple susceptible cultivars without Pm genes. As a result, we initially developed a KASP marker that can simultaneously diagnose Pm21, Pm12, and PmV. Subsequently, we obtained a highly diagnostic KASP marker for each of the three genes that could distinguish among the three genes and also accurately distinguish them from other resistant stocks with documented Pm genes and from multiple susceptible genotypes. Compared with previously reported markers, the highly diagnostic KASP markers developed in this study have the advantages of low cost, easy assay, accuracy, and potentially high throughput for MAS.

Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain.

The polyphenol distribution in fresh waxy corns of different color varieties and their functional activities, which may be useful for treating various chronic diseases, were investigated. The in vitro antioxidant activity, and hypoglycemic and hypocholesterolemic effects of the free and bound corn phenolics were determined to evaluate the edible value of fresh waxy corn. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 6637.73 µg/g DW (dry weight), which was slightly higher (P > 0.05) than that of the total bound form (6276.65 µg/g DW). The total free flavonoid content was 5850.09 µg/g DW, which was higher (P < 0.05) than that of the total bound form (4874.51µg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86-100 % and 70-78 % of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100 % of the ferric reducing capacity. The free phenolics in fresh waxy corn showed better (P < 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed better (P < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.

Transcriptome analysis of maize inbred lines differing in drought tolerance provides novel insights into the molecular mechanisms of drought responses in roots.

Maize (Zea mays) is an important food and forage crop, as well as an industrial raw material, that plays important roles in agriculture and national economies. Drought stress has negative effects on seed germination and seedling growth, and it decreases crop production. In this study, we selected two maize inbred lines with different drought-tolerance levels: drought-tolerant 287M and drought-sensitive 753F. The physiological results showed that drought stress resulted in a large accumulation of reactive oxygen species (ROS) in maize root cells. However, in 287M, the activity levels of the ROS scavenging enzymes superoxide dismutase and ascorbate peroxidase also increased, resulting in a higher ROS scavenging ability than 753F. We used Illumina RNA sequencing to obtain the gene expression profiles of the two maize inbred lines at the seedling stage in response to drought stress. The transcriptome data were analyzed to reveal the mechanisms underlying the drought tolerance of 287M at the gene regulatory level. The differences in drought tolerance between 287M and 753F may be associated with different ROS scavenging capabilities, signal interaction networks, and some transcription factors. Our results will aid in understanding the molecular mechanisms involved in plant responses to drought stress.

Driving forces of disaggregation and reaggregation of peanut protein isolates in aqueous dispersion induced by high-pressure microfluidization.

Our previous report described that high-pressure microfluidization (HPM) treatment can disaggregate peanut protein isolates (PPIs) to prepare antihypertensive peptide fractions. In the present study, we investigated the driving forces of disaggregation and reaggregation of PPIs in aqueous dispersion induced by HPM treatment and discussed the mechanism. The driving forces of hydrogen bonds, surface hydrophobicity, sulfhydryl/disulfide bonds (SH/SS) and ζ-potential, which are responsible for disaggregation and reaggregation, were studied. HPM treatment changed the polar environment and promoted surface hydrophobicity and the formation of disulfide bonds (SS), while the free sulfhydryl (SH) group content was decreased. The magnitude of the ζ-potential and ß-sheet content increased when the pressure was ≤120 MPa. However, the magnitude of those values decreased when the pressure was >120 MPa. Hydrophobic interactions, SH/SS interchange reactions, hydrogen bonds and electrostatic interactions cannot individually induce changes in PPIs. Combination of the applied forces drove the disaggregation and reaggregation of PPIs in aqueous dispersion.

Nitrogen increases drought tolerance in maize seedlings.

Drought and nitrogen availability are two important environmental factors that affect plant growth and the global distribution of plants. We examined the effect of nitrogen on PSII in the leaves of maize seedlings under drought stress using three nitrogen concentrations (0.5, 7.5 and 15mM) and three levels of water availability (normal conditions, mild drought and severe drought). Shoot fresh and dry weights and root fresh weight decreased with increasing drought conditions. In maize leaves subjected to drought stress, the chlorophyll a (Chl a) and chlorophyll b (Chl b) contents, net photosynthetic rate, transpiration rate, stomatal conductance, maximum chemical efficiency (Fv/Fm), and photochemical efficiency of PSII (ΦPSII) were significantly reduced. Moderate nitrogen supply relieved the drought stress and enhanced the photosynthetic capacity. Malondialdehyde, H2O2 and O2-• accumulated in maize leaves under drought stress. Superoxide dismutase and ascorbate peroxidase activities increased in maize leaves under mild drought stress, but were significantly reduced under severe drought stress. The NO3- content and nitrate reductase (NR) activity of maize leaves were significantly reduced under drought stress, while moderate nitrogen supply promoted the accumulation of NO3- and an increase in the nitrate reductase activity. The abscisic acid content increased significantly; this increase was positively correlated with the nitrogen concentration under drought stress. Together, these results indicate that moderate nitrogen supply increases plant resistance to drought stress, while high or low nitrogen concentrations increase the sensitivity of maize to drought stress. These findings are important for guiding the agricultural use of nitrogen fertilisers.

[Effect of sulfate supply level on characteristics of N and S metabolism and on root vigor of corn].

The effects of different sulfate supply level on N and S metabolism and on root vigor of corn were quantitatively studied with Hoagland solution under greenhouse conditions. The results showed that in S-deficient solution, root vigor and leaf nitrate reductase (NR) activity significantly rdduced, top root ratio (T/R) increased, and S and N accumulation in tops and roots decreased. The partition of S decreased in roots and incompletely expanded leaves, but increased in senescent leaves and sheaths-stems; while the partition of N increased in roots, but decreased in incompletely and fully expanded leaves. The content of protein, protein N, protein S, and sulfate S significantly reduced, percentage of non-protein N increased, inorganic S/total S ratio decreased, and total N/total S ratio increased. The protein N/protein S ratio in tops had no observable changes, but increased significantly in roots, showing that root was a sensitive organ to S-deficiency. There was a close relationship between protein content and NR activity in S-deficiency. Deficient or excessive S supply limited N and S metabolism of corn plant. N/S or inorganic S/total S ratio in roots was a sensitive index to indicate the deficiency of S supply, which was 10.7 or 0.302 under normal condition, respectively.