Effects of phosphorus and iron fertilizers on the growth of two soybean varieties at two soil temperatures

The influence of FeEDDHA (0, 0.2 and 2 μg Fe g⁻¹ soil) and NaH₂PO₄·H₂O (0 and 120 μg Pg⁻¹ soil) on the growth of two Fe-ineffective soybean (Glycine max L. Merr.) varieties (anoka and T203) on a calcareous soil at two soil temperatures (16 and 24°C) was compared under greenhouse conditions. The two soybean varieties differed in the following respects: (a) T203 accumulated smaller concentrations of Fe in washed tops than Anoka under comparable conditions; (b) T203 was more susceptible to Fe deficiency and its accentuation by high levels of fertilizer P than Anoka; (c) T203 accumulated lower quantities of Mn in tops than Anoka under comparable conditions; (d) T203, but not Anoka, developed Mn deficiency symptoms when treated with P and 2 μg Fe g⁻¹ at 16°C. Fe deficiency was more severe in both varieties at the higher soil temperature due apparently to: (a) greater plant concentration of P in tops at 24°C; and/or (b) an increased rate of plant growth and greater dilution of Fe in young tissue at 24°C. Foliar P concentration was increased much more than foliar Fe concentration by an increase in soil temperature. Severely Fe deficient T203 plants grown without FeEDDHA at 24°C accumulated less foliar Mn than their FeEDDHA counterparts. Comparisons of Fe effectiveness of various soybean cultivars based on relative responses to FeEDDHA can be influenced by differential effects on Mn nutrition.     

The inheritance of a urease-null trait in soybeans

Summary Four soybean seed urease nulls (lacking both the activity and antigen of the embryo-specific urease) were intermated and the F₁ and F₂ seed examined for urease activity. Both generations were without urease activity, and the nulls were therefore considered noncomplementing. In crosses of each null line to cultivars homozygous for the allelic, codominantly inherited urease slow or fast isozyme, the F₁ seed expressed the embryo-specific urease isozyme of the urease-expressing parent. A 3 1 segregation for presence and absence of urease was observed in progeny from F₁ and heterozygous F₂ plants. The F₂ and F₃ from fastXnull combinations revealed that urease-positive seed were all phenotypically urease fast, while the same seed from slowXnull combinations showed a segregation of one seed containing a fast urease, either exclusively or in a heterozygous state with the slow isozyme, for every 69 phenotypic slows. Data pooled from F₂ plants which segregate for both the presence (Sun) and absence (Sun) of urease and for the fast (Eu1-b) or slow (Eu1-a) urease allele indicate that the null lesion (Sun) is linked to Eu1 by approximately one map unit. The evidence is consistent with two models: (1) sun is an allele at the embryo-specific urease isozyme locus (Eu1) and that a high degree of exchange (and/or conversion) within the locus results in a 1% recombination frequency between the null trait and urease allozyme; (2) sun is at a distinct locus which is separated by one map unit from the embryo-specific urease isozyme locus (Eu1) upon which it acts in the cis position. Polyadenylated embryo RNA from one of the null lines, PI 229324, exhibited no urease template activity in vitro. Thus, the lack of urease antigen is due to lack of accumulation of translatable urease mRNA. The availability of soybeans lacking seed urease should be extremely useful to breeders as a trait for linkage studies and to geneticists as a transformation marker.Portions of this work were funded by the Illinois and Missouri Agricultural Experiment Stations, the SOHIO-University of Illinois Center of Excellence in Crop Molecular Genetics and Genetic Engineering and by grants PCM-8219652 from the National Science Foundation and USDA/SEA-CRCR-1-1374 from the USDA Competitive Grants Office     

Phosphorus fertilization and tillage effect on dinitrogen fixation in soybeans

Summary Tillage has been shown to affect the uptake of phosphorus (P) and yield of soybeans, [Glycine max (L.) Merr.], but there is little information concerning the effects of P fertilization on nitrogen (N₂) fixation in soybeans under no-tillage. Two field experiments were conducted in 1980 and 1981 to determine the effects of soil P on N₂ fixation under no-tillage and to study the interaction of P fertilization and tillage of N₂ fixation, nutrient uptake, and yield of soybeans. In Exp. I, P was applied in 1977 at five rates up to 384 kg P ha⁻¹ and the effects of residual soil P were evaluated in 1980 and 1981 under no-tillage management. Nitrogen fixation rates, as measured by acetylene reduction assay, were significantly affected by soil P in Exp. I, but the assay proved to be a poor technique for estimating total plant N in these tests. Acetylene reduction rates and plant P increased rapidly as soil P increased from 2 to 20 mg kg⁻¹, with little additional increase above 20 mg P kg⁻¹. In Exp. II, rates (0, 32, 64, and 128 kg P ha⁻¹) and time (fall, spring and fall plus spring) of P application were compared under conventional tillage and no tillage. However, plant P increased with increasing levels of applied P. Applied P had no affect on acetylene reduction rates but rates were greater for no-tillage than conventional tillage at the V9 and R5 stages of growth in 1981. Plant uptake of P was more efficient under no-tillage than under conventional tillage in 1980 and 1981. Application of 64 kg P ha⁻¹ under no-tillage resulted in equivalent plant P levels as the 128 kg P ha⁻¹ applied under conventional tillage.     

Manganese and iron interactions on their uptake and distribution in soybean (Glycine max (L.) Merr.)

Summary The uptake and distribution of iron and manganese were studied in a manganese-sensitive soybean cultivar (‘Bragg’) grown over a range of supply levels of these nutrients in solution culture. At high (90 and 275 μM) manganese levels, increasing the iron concentration in solution from 2 to 100 μM partially overcame the effects of manganese toxicity. Interactions between manganese and iron occurred for dry matter yields, rate of Mn absorption by the roots, and the proportions of manganese and iron transported to the tops. No interaction was observed for the rate of root absorption of iron. The percentage distribution of manganese in the plant top increased with increasing iron, despite a reduced rate of Mn uptake. On the other hand, iron uptake was independent of solution Mn concentration and increased with increasing solution Fe. Also more iron was retained in the roots at high Mn and/or Fe levels in solution. Concentrations of manganese and iron in roots, stems and individual leaves were affected independently by the manganese and iron supplyi.e. without any interaction occurring between the two elements. In general, the concentration in a plant part was related directly to the solution concentration. Symptoms resembling iron deficiency correlated poorly with leaf Fe concentrations whereas high levels of manganese were found in leaves displaying Mn toxicity symptoms.     

油丹生物碱的研究

从油丹中分到6种生物碱,其中4种经理化常数及光谱测定,鉴定为：番荔枝宁,杏黄罂粟碱,多略发宁及1－（4－甲氧基苄基）,6,7－亚甲二氧基1,2,3,4－四氢异喹啉生物碱。     

Sensitivity of soybean leaf development to water deficits

Abstract. Drought effects on the final leaf area of individual leaves were hypothesized to depend on the leaf developmental stage at which drought occurred. To evaluate this hypothesis, final leaf area and cell number were measured for soybean ( Glycine max (L.) Merr.) leaves that were at different stages of development when single or cyclical drought treatment was imposed. Leaf emergence rate from the meristem, as depicted by changes in the plastochron index, was not as sensitive as leaf expansion to cyclical droughts. For leaf expansion, small leaves, once they emerged from the meristem, suffered larger decreases in growth than leaves undergoing rapid leaf area expansion. Decreases in final leaf area as a result of a cyclical drought were correlated with decreases in final cell number. Decreases resulting from a single 8-d drought were dependent on the age of the leaf at the time of drought, because small leaves were found to have proportionately larger decreases in final cell number and area than larger leaves. These results indicated that age-dependent leaf responses to drought are based on the relative activity of cell division and expansion at the time stress was imposed.     

Alteration of the omega-3 fatty acid desaturase gene is associated with reduced linolenic acid in the A5 soybean genotype

Reducing the linolenic acid (18?:?3^{ω? 3,6,9}) concentration of soybean [Glycine max (L.) Merr.] oil may lessen the need for chemical hydrogenation and enhance flavor stability. Soybean genotypes A5 and A23 have reduced linolenic acid concentration compared with current cultivars. Seed linolenic acid is synthesized primarily by the ω-3 fatty acid desaturase located in the microsomes. The objective of this research was to study whether this enzyme has a role in reducing the fatty acid levels in the soybean genotypes A5 and A23. DNA from A5 and A23 was analyzed by gel-blot hybridization with a cDNA encoding the ω-3 fatty acid desaturase. A5 and lines selected from it have a DNA fragment missing compared to A23 and lines with normal linolenic acid concentration. Seventy F_4:5 lines from a population segregating for linolenic acid concentration were scored for presence or absence of the fragment. The absence of the fragment was significantly (P?0.0001) associated with a reduced linolenic acid level and accounted for 67% of the variation for linolenic acid in the population. These results suggest that the reduced linolenic acid concentration in A5 was at least partially the result of a full or partial deletion of a microsomal ω-3 desaturase gene. No DNA polymorphisms were found for the desaturase gene in A23, so no mutations could be studied in this line.     

Effect of soybean plant growth on spore production byGlomus mosseae

Plants of two soybean cultivars infected withGlomus mosseae were physiologically stressed by top removal and were harvested at seven bi-weekly intervals. Removing tops stopped root growth, stimulated branching, delayed plant growth stages by approximately two weeks, but did not affect spore production. Spore numbers were significantly related only to time of harvest. Pot variation in spore number was not significantly correlated with infection percentage or root dry weight. Harvest, cultivar, and cutting effects were highly significant for root and shoot weights and root/shoot ratios.Approved by the Director as a contribution from the Missouri Agricultural Experiment Station (Journal Series No. 8123).     

蔓三七叶中分离绿原酸和异绿原酸及其抗氧化活性研究

以蔓三七叶为原料,制备其中的绿原酸和异绿原酸A、B和C,并对它们进行结构鉴定;同时,采用DPPH法、水杨酸比色法、邻苯三酚自氧化法来对其进行体外抗氧化活性研究。结果表明,分离制备的绿原酸和异绿原酸A、B和C质量分数分别为96. 8%、98. 2%、97. 6%和98. 7%。在0. 5～10μg/mL范围内,绿原酸和异绿原酸A、B和C对DPPH和羟基自由基表现出了较好的清除作用,随浓度升高而逐渐增大;但它们对超氧自由基的清除作用时,浓度从5μg/mL升高到100μg/mL时,清除作用都未出现明显的剂量依赖性,各样品与阳性对照组(VC)相比较而言,其清除超氧自由基的作用明显较弱。本文揭示了蔓三七叶中的绿原酸和异绿原酸A、B和C具有不同的抗氧化效果。     

Metabolite profiling and assessment of metabolome compartmentation of soybean leaves using non-aqueous fractionation and GC-MS analysis

In the present study, non-aqueous fractionation (NAQF) and GC-MS were used to obtain a spatially resolved view of metabolism in mature leaves of soybean (Glycine max Merr.). NAQF of lyophilized soybean leaves was performed using CCl₄-n-heptane and ultracentrifugation that yielded a gradient comprised of six fractions. Chlorophyll content, and marker enzyme activities, phosphoenolpyruvate carboxylase (PEPC) and α-mannosidase, were utilized as stroma, cytosol and vacuole markers, respectively. GC-MS analyses of each fraction resulted in the identification of around 100 different metabolites. The distribution of these identified compounds showed a decreasing order from the vacuole to cytosol to chloroplast stroma. In other words, a greater number of identified compounds were found in the vacuole when compared to the cytosol or stroma. Levels of sugars, organic acids and fatty acids showed greater relative abundances in the vacuole with 50, 55, and 50% of the respective pools. A greater relative abundance of amino acids was observed in the cytosol where 45% of the total of amino acids content was recorded. The relatively large pool of sugars and phenolic acids in the vacuole compartment implies high levels of starch metabolism and phenylpropanoid biosynthesis. The low amino acids pool, on the other hand, suggests low nitrogen accumulation in the leaves of soybean. Hierarchical cluster analysis on the most abundant metabolites revealed three clusters containing 10, 20, and 2 of the 32 selected metabolites. The data were discussed in term of NAQF and GC-MS analysis of soybean mature leaves, and also in term of distribution and compartmentation of metabolites at subcellular levels.