Seed Nitrogen Content Research Articles

Nitrogen Metabolism and Seed Composition As Influenced by Glyphosate Application in Glyphosate-Resistant Soybean

Previous research has demonstrated that glyphosate can affect nitrogen fixation or nitrogen assimilation in soybean. This 2-year field study investigated the effects of glyphosate application of 1.12 and 3.36 kg of ae ha(-1) on nitrogen metabolism and seed composition in glyphosate-resistant (GR) soybean. There was no effect of glyphosate application on nitrogen fixation as measured by acetylene reduction assay, soybean yield, or seed nitrogen content. However, there were significant effects of glyphosate application on nitrogen assimilation, as measured by in vivo nitrate reductase activity (NRA) in leaves, roots, and nodules, especially at high rate. Transiently lower leaf nitrogen or (15)N natural abundance in high glyphosate application soybean supports the inhibition of NRA. With the higher glyphosate application level protein was significantly higher (10.3%) in treated soybean compared to untreated soybean. Inversely, total oil and linolenic acid were lowest at the high glyphosate application rate, but oleic acid was greatest (22%) in treated soybean. These results suggest that nitrate assimilation in GR soybean was more affected than nitrogen fixation by glyphosate application and that glyphosate application may alter nitrogen and carbon metabolism.

Seed Nitrogen Mobilization in Soybean: Effects of Seed Nitrogen Content and External Nitrogen Fertility

ABSTRACT Soybean breeding programs have developed genetic lines with relatively low seed protein, which could negatively impact early seedling growth in low fertility conditions commonly encountered in the field. In these experiments, seed protein mobilization and its regulation in situ in soybean lines with different seed protein levels was investigated. The results showed that rates of nitrogen (N) release from cotyledons were much lower with decreasing levels of N in seed. Patterns of proteolysis of the storage proteins glycinin and β -conglycinin and their subunits were not different, but breakdown rates were slower. Seed N release rates increased somewhat when external N was supplied to roots of the developing seedlings, suggesting the involvement of source/sink controls. The effect appeared to be down-stream from proteolysis, as rates of protein breakdown were not altered. The results indicate that low seed protein levels will lead to reduced seedling fitness in low fertility soil conditions unless fertilizer N is applied.

Efeito da irrigação, épocas de corte da forragem e doses de nitrogênio sobre a qualidade de sementes de milheto (Pennisetum americanum (L.) Leeke)

O trabalho foi conduzido com o objetivo de avaliar o efeito da irrigação, da épocas de remoção da forragem e de quatro doses de nitrogênio (N) (0, 50, 100 e 150 kg/ha) sobre a qualidade de sementes de milheto (Pennisetum americanum (L.) Leeke). Os cortes foram realizados a uma altura de 20 cm, aos 41 dias apos semeadura, na E1 e aos 51 na E2 . Foram determinados o peso de mil sementes (PMS), o teor de nitrogênio, a germinação e o vigor pelos testes de: condutividade elétrica, envelhecimento acelerado a 48 e 72 horas, primeira contagem de germinação e teste de emergência a campo. A remoção precoce da forragem (E1) afeta positivamente a qualidade das sementes de milheto. Aplicações de nitrogênio podem contribuir para a melhoria da qualidade fisiológica da semente de milheto e associadas à irrigação proporcionam sementes com maior capacidade de emergência.O conteúdo de nitrogênio das sementes não e afetado em função da aplicação de nitrogênio em cobertura.

Combined metabolomic and genetic approaches reveal a link between the polyamine pathway and albumin 2 in developing pea seeds.

Several legume seed proteins that are potentially allergenic, poorly digested by farm animals, and/or have undesirable functional properties, have been described. One of these is the albumin protein in pea (Pisum sativum) called PA2. A naturally occurring mutant line that lacks PA2 has been exploited in studies to determine the biological function of this nonstorage protein in seed development. The mutant, which has a small seed, a tall plant phenotype, and lacks most of the PA2-encoding genes, has been crossed with a standard cultivar, 'Birte,' which contains PA2 to give rise to a recombinant inbred (RI) population. An F(3) line carrying the mutation and having a short plant phenotype has been used to generate backcross (BC) lines with 'Birte.' Despite having a lower albumin content, seeds from the mutant parent and RI lines lacking PA2 have an equivalent or higher seed nitrogen content. Metabolite profiling of seeds revealed major differences in amino acid composition and polyamine content in the two parent lines. This was investigated further in BC lines, where the effects of differences in seed size and plant height between the two parents were eliminated. Here, differences in polyamine synthesis were maintained as was a difference in total seed protein between the BC line lacking PA2 and 'Birte.' Analysis of enzyme activities in the pathways of polyamine synthesis revealed that the differences in spermidine content were attributable to changes in the overall activities of spermidine synthase and arginine decarboxylase. Although the genes encoding spermidine synthase and PA2 both localized to the pea linkage group I, the two loci were shown not to be closely linked and to have recombined in the BC lines. A distinct locus on linkage group III contains a gene that is related to PA2 but expressed predominantly in flowers. The results provide evidence for a role of PA2 in regulating polyamine metabolism, which has important functions in development, metabolism, and stress responses in plants.

Elevated CO2 concentration, nitrogen use, and seed production in annual plants

AbstractElevated atmospheric CO2 concentration ([CO2]) stimulates seed mass production in many species, but the extent of stimulation shows large variation among species. We examined (1) whether seed production is enhanced more in species with lower seed nitrogen concentrations, and (2) whether seed production is enhanced by elevated [CO2] when the plant uses more N for seed production. We grew 11 annuals in open top chambers that have different [CO2] conditions (ambient: 370 μmol mol−1, elevated: 700 μmol mol−1). Elevated [CO2] significantly increased seed production in six out of 11 species with a large interspecific variation (0.84–2.12, elevated/ambient [CO2]). Seed nitrogen concentration was not correlated with the enhancement of seed production by elevated [CO2]. The enhancement of seed production was strongly correlated with the enhancement of seed nitrogen per plant caused by increased N acquisition during the reproductive period. In particular, legume species tended to acquire more N and produced more seeds at elevated [CO2] than non‐nitrogen fixing species. Elevated [CO2] little affected seed [N] in all species. We conclude that seed production is limited primarily by nitrogen availability and will be enhanced by elevated [CO2] only when the plant is able to increase nitrogen acquisition.

Host‐associated variation in sexual size dimorphism and fitness effects of adult feeding in a bruchid beetle

AbstractWe studied the effect of larval host (two Convolvulus L. species, Convolvulaceae) on sexual size dimorphism and on the fitness consequences of adult feeding in the bruchid beetle Megacerus eulophus (Erichson) (Coleoptera: Bruchidae). Whereas Convolvulus chilensis Pers. occurs in low density in semiarid habitats, Convolvulus bonariensis Cav. occurs in less stressful environments and exhibits higher population density. Host plants neither differ in seed mass nor in seed nitrogen content, and there were no consistent host‐associated differences in female fitness. Consequently, host quality was considered to be similar. Sexual size dimorphism, expressed as the female:male ratio of body size, was significantly greater in C. chilensis than in C. bonariensis. A greater female size in the C. chilensis population could be selectively advantageous due to higher survival during host‐plant search in stressful environments. Female longevity was affected by food availability (starvation vs. honey‐pollen solution) and by the interaction between food availability and larval host. Fed females lived longer than starved females. This trend was found in both hosts, but it was of greater magnitude in C. chilensis than in C. bonariensis. Fecundity was significantly affected by adult feeding and larval host, and marginally affected by their interaction. Fed females laid more eggs than starved females. However, the increase in fitness of fed females was greater in C. chilensis. Results might be explained by differential selection on plasticity in life‐history traits in contrasting environments. Females in stressful environments should take a greater advantage of the transient availability of resources.

Nitrogenase activity, nitrogen content, and yield responses to glyphosate in glyphosate-resistant soybean

Transgenic glyphosate-resistant (GR) soybean [ Glycine max (L.) Merr.] expressing a glyphosate-insensitive 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme has provided new opportunities for weed control in soybean production. However, glyphosate is toxic to the soybean nitrogen-fixing symbiont, Bradyrhizobium japonicum, as its EPSPS enzyme is sensitive to glyphosate. The effects of glyphosate on symbiotic parameters, nitrogen accumulation, and yield in GR soybean under weed-free conditions were determined in a 3-yr field study during 2002–2004. Four glyphosate (0.84, 1.68, 2.52+2.52, and 0.84+0.84 kg ae/ha) treatments applied at 4 and 6 weeks after planting (WAP) soybean were compared to a no glyphosate, hand weeded (weed-free) control. In 2002 and 2003, soybean plants were harvested at 5, 6, 7, and 8 WAP, and roots assessed for nitrogenase activity (acetylene reduction assay, ARA), root respiration, nodulation, and root biomass. Soybean seed yield, leaf and seed nitrogen content were determined in all three years. No consistent effect of glyphosate was observed on either ARA or root respiration. In 2002, both ARA and respiration were about a third of that in 2003, attributed to early-season drought in 2002. All glyphosate treatments reduced foliar nitrogen content (26–42%) in 2002. In 2003 and 2004, three and two glyphosate treatments, respectively, reduced foliar nitrogen content (8–13%), with the greatest reduction when glyphosate was applied at the highest rate. Soybean yield was reduced by 11% with two applications of 2.52 kg ae/ha glyphosate compared to hand weeded control in 2002, but seed yield was not affected in 2003 and 2004. Total seed nitrogen harvested in 2002 and 2003 was reduced by 32% and 17%, respectively, when two applications of 2.52 kg ae/ha glyphosate were applied compared to hand weeded soybean. These studies indicate that nitrogen fixation and/or assimilation in GR soybean was only slightly affected at label use rate, but was consistently reduced at above label use rates of glyphosate and the greatest reductions occurred with soil moisture stress following glyphosate application.

Lack of 26 kDa globulin accompanies increased free amino acid content in rice ( Oryza sativa L.) grains

Seed nitrogen content, protein composition and free amino acid content were determined in rice mutant lines with altered storage protein composition and their parental cultivars. The Lgc1 gene, which causes low glutelin content and high content of 13 kDa prolamin and 26 kDa globulin, did not affect grain weight, nitrogen content, or free amino acid content. The glb1 gene, which lacks the 26 kDa globulin, did not affect grain weight or nitrogen content, but in mutant lines with glb1 gene the content of the major free amino acids was significantly (1.3–1.5 times) higher than those of their parental cultivars. These results suggest that absence of 26 kDa globulin is accompanied by an accumulation of a high level of free amino acids in rice grains.

Influence of seed nitrogen content on seedling growth and recovery from nitrogen stress

In low fertility conditions, germinating seedlings are heavily dependent upon N from seed reserves for growth and development. Experiments were conducted to examine the influence of seed N content and mobilization on leaf development and the ability to take up nitrate and up-regulate leaf growth processes during recovery from the period of N deprivation. Genetically homozygous soybean lines with a range of seed N contents were grown in hydroponics culture without an external N source. Microscopic analyses of the apical meristem and plant exposure to labeled 15N-nitrate allowed precise descriptions of changes in leaf initiation and nitrate uptake during recovery. In seedlings grown without N, inhibitions of leaf expansion and leaf initiation were detectible in the 2nd week after germination, and both were inversely related to the amount of N released from the seed. The S/R ratio decreased, indicating early N stress, but the S/R adjustments were not proportional to the degree of N stress as occurs with older plants, suggesting limitations in C availability. When external N was supplied to plants after 15 or 23 days of N deprivation, the induction period for nitrate uptake was longer than that normally observed with N-replete seedlings, and rates of growth during recovery from the N stress were correlated with initial seed N contents. The inhibition of individual leaf expansion was released only if leaves were at an early developmental stage. Leaf initiation at the apical meristem immediately responded to the presence of external nitrate, with initiation rates approaching those for +N controls. The results indicate that seedling vigor in infertile conditions and the ability to respond to available N are strongly influenced by seed resources.

How does temperature affect C and N allocation to the seeds during the seed-filling period in pea? Effect on seed nitrogen concentration.

The effect of moderate temperature on seed N concentration during the seed-filling period was evaluated in pea (Pisum sativum L.) kept in growth cabinets and the relation between plant assimilate availability and the variation of seed N concentration with temperature was investigated. Seed N concentration of pea was significantly lowered when temperature during the seed-filling period decreased from a day / night temperature of 25 / 20°C to 15 / 10°C. Our results demonstrate that during the seed-filling period mechanisms linked with assimilate availability can modify seed N accumulation rate and / or seed-filling duration between 25 / 20°C and 15 / 10°C. At the lower temperature (15 / 10°C), an increased C availability resulting from an enhanced carbon fixation per degree-day allowed new competing vegetative sinks to grow as pea is an indeterminate plant. Consequently N availability to filling seeds was reduced. Because the rate of seed N accumulation per degree-day mainly depends on N availability to filling seeds, the rate of seed N accumulation was lower at the low temperature of our study (15 / 10°C) than at 25 / 20°C while seed growth rate per degree-day remains unaffected, consequently seed N concentration was reduced. Concomitantly, the increased C availability at the lower temperature prolonged the duration of the seed-filling period.

Factors affecting nitrogen concentration in spring oilseed rape (Brassica napus L.)

The effect of the duration of the growth season, meaning daily temperature, precipitation rate, growing degree in days, nitrogen rates and application time, stand population density, soil nitrogen content and the interaction among these factors on nitrogen concentration in spring oilseed rape plants of aboveground dry matter. During the vegetative growth season, mature seeds and straw were studied in field experiment with spring oilseed rape (Brassica napus L.) cv. Star over five years. It was found that nitrogen concentration was the highest in the youngest plants. The increase of duration in growth season and precipitation rate had a negative effect on nitrogen concentration in mature seeds. Meanwhile, the increase in growing degree-days and mean daily temperature positively affected seed nitrogen concentration. The relationships between nitrogen concentration in spring oilseed rape plants at different growth stages and climate records was found. Stand population density occurred having a rather negligible effect on nitrogen concentration. Nitrogen fertilizer rates showed strong and positive effect on nitrogen concentration in aboveground dry matter as well as in seed and straw. With the delay of nitrogen application time concentration of nitrogen was increasing.

Accumulation of high levels of free amino acids in soybean seeds through integration of mutations conferring seed protein deficiency.

Soybean ( Glycine max [L.] Merr.) seeds are rich in protein, most of which is contributed by the major storage proteins glycinin (11S globulin) and beta-conglycinin (7S globulin). Null mutations for each of the subunits of these storage proteins were integrated by crossbreeding to yield a soybean line that lacks both glycinin and beta-conglycinin components. In spite of the absence of these two major storage proteins, the mutant line grew and reproduced normally, and the nitrogen content of its dry seed was similar to that for wild-type cultivars. However, protein bodies appeared underdeveloped in the cotyledons of the integrated mutant line. Furthermore, whereas free amino acids contribute only 0.3-0.8% of the seed nitrogen content of wild-type varieties, they constituted 4.5-8.2% of the seed nitrogen content in the integrated mutant line, with arginine (Arg) being especially enriched in the mutant seeds. Seeds of the integrated mutant line thus appeared to compensate for the reduced nitrogen content in the form of glycinin and beta-conglycinin by accumulating free amino acids as well as by increasing the expression of certain other seed proteins. These results indicate that soybean seeds are able to store nitrogen mostly in the form of either proteins or free amino acids.

Effect of Fertilizer, Inoculation and Sowing Time on Free Amino Acids and Mineral Nitrogen Content of Field Grown Mature Soybean Seeds

Effect of Fertilizer, Inoculation and Sowing Time on Free Amino Acids and Mineral Nitrogen Content of Field Grown Mature Soybean Seeds

Plant reproduction under elevated CO2 conditions: a meta‐analysis of reports on 79 crop and wild species

Summary Reproductive traits are key characteristics for predicting the response of communities and ecosystems to global change. We used meta‐analysis to integrate data on eight reproductive traits from 159 CO 2 enrichment papers that provided information on 79 species. Across all species, CO 2 enrichment (500–800 µl l −1 ) resulted in more flowers (+19%), more fruits (+18%), more seeds (+16%), greater individual seed mass (+4%), greater total seed mass (+25%), and lower seed nitrogen concentration, (N) (−14%). Crops and undomesticated (wild) species did not differ in total mass response to elevated CO 2 (+31%), but crops allocated more mass to reproduction and produced more fruits (+28% vs +4%) and seeds (+21% vs +4%) than did wild species when grown at high CO 2 . Seed [N] was not affected by high CO 2 concentrations in legumes, but declined significantly in most nonlegumes. Our results provide robust estimates of average plant reproductive responses to CO 2 enrichment and demonstrate important differences among individual taxa and among functional groups. In particular, crops were more responsive to elevated CO 2 than were wild species. These differences and the substantial decline in seed [N] in many species have broad implications for the functioning of future natural and agro‐ecosystems.

Reproduction and offspring competitiveness of Senna obtusifolia are influenced by nutrient availability.

• Senna obtusifolia (sicklepod) is a troublesome weed in many agronomic cropping systems in the southeastern USA with varying fertility regimes. This series of experiments was initiated to determine the impact of nutrient availability on reproductive output and maternal effects. • Experiments were conducted with plants growing in soil in growth chambers for 120d. Offspring growth was evaluated in hydroponics. • Plants grown under higher nutrient conditions had greater reproductive biomass, number of seeds and total seed biomass. Individual seed mass distributions were slightly affected, with negative skewness decreased at higher nutrition. Seed germination rates were influenced primarily by seed size, as small seeds germinated faster than large seeds. The nitrogen content of seeds increased with increasing seed size and was higher in the high nutrition treatment. Seedlings arising from maternal plants grown under high nutrition grew more rapidly than did seedlings arising from maternal plants grown in a low nutrient regime. • The results suggest that S. obtusifolia reproduction and offspring competitiveness can be strongly influenced by the fertilization regimes used in different agronomic crops and rotations.

Response of field-grown soybean to co-inoculation with the plant growth promoting rhizobacteria Serratia proteamaculans or Serratia liquefaciens, and Bradyrhizobium japonicum pre-incubated with genistein

Plant growth promoting rhizobacteria (PGPR) and genistein have been used separately to improve soybean nodulation, nitrogen fixation and yield. Field experiments were conducted to evaluate the combined effect of PGPR and genistein in 1996 and 1997 in Canada. Genistein was used to pre-incubate Bradyrhizobium japonicum strain 532C. Three factors were tested: two genistein concentrations (0 and 20 μM), two PGPR strains ( Serratia proteamaculans 102 and Serratia liquefaciens 2–68), and two soybean cultivars (‘AC Bravor’ and ‘Maple Glen’). The results indicated that genistein increased nodule number and nodule weight, while the two PGPR strains used affected the measured variables differently. In many cases treatment effects of PGPR were not significant. At maturity, the shoot nitrogen content of ‘AC Bravor’ in 1996, and seed nitrogen content and total nitrogen yield in 1997 were increased by genistein. Soybean yield was increased by genistein in 1997, and was not affected by both genistein and PGPR treatments in 1996. The results indicate that there were no additional improvement in nodulation and nitrogen fixation by using both genistein and these PGPR.

Effect of mineral nitrogen on nitrogen nutrition and biomass partitioning between the shoot and roots of pea (Pisum sativum L.).

The effect of mineral N availability on nitrogen nutrition and biomass partitioning between shoot and roots of pea (Pisum sativum L., cv Baccara) was investigated under adequately watered conditions in the field, using five levels of fertiliser N application at sowing (0, 50, 100, 200 and 400 kg N ha−1). Although the presence of mineral N in the soil stimulated vegetative growth, resulting in a higher biomass accumulation in shoots in the fertilised treatments, neither seed yield nor seed nitrogen concentration was affected by soil mineral N availability. Symbiotic nitrogen fixation was inhibited by mineral N in the soil but it was replaced by root mineral N absorption, which resulted in optimum nitrogen nutrition for all treatments. However, the excessive nitrogen and biomass accumulation in the shoot of the 400 kg N ha−1 treatment caused crop lodging and slightly depressed seed yield and seed nitrogen content. Thus, the presumed higher carbon costs of symbiotic nitrogen fixation, as compared to root mineral N absorption, affected neither seed yield nor the nitrogen nutrition level. However, biomass partitioning within the nodulated roots was changed. The more symbiotic nitrogen fixation was inhibited, the more root growth was enhanced. Root biomass was greater when soil mineral N availability was increased: root growth was greater and began earlier for plants that received mineral N at sowing. Rooting density was also promoted by increased mineral N availability, leading to more numerous but finer roots for the fertilised treatments. However, the maximum rooting depth and the distribution of roots with depth were unchanged. This suggested an additional direct promoting effect of mineral N on root proliferation.

Selection of Soybean Mutants with Increased Concentrations of Seed Methionine and Cysteine

Soybean [Glycine max (L.) Merr.] protein, which is deficient in the sulfur amino acids, especially methionine, is consumed world‐wide by both humans and other animals. Methionine deficiency is caused by an abundance of the β‐chain of β‐conglycinin, a seed storage protein that lacks methionine. De novo synthesis of the β‐chain is inhibited by an elevated concentration of methionine. The objectives of our investigations were to mutagenize soybean seeds, characterize a methionine over‐producing phenotype, and select several methionine over‐producing genetic lines. Mutant lines with a methionine over‐producing phenotype were isolated and crossed. Seeds from a cross, designated H82 × 20a2, contained a normal seed nitrogen concentration and an 18% increase in seed sulfur concentration. The S/N atomic ratio of line H82 × 20a2 was 16.2% greater than that of the parental line. Amino acid analyses of seeds from the derived and parental lines revealed mole percentages of 1.84 and 1.51, respectively, for methionine and 1.685 and 1.32, respectively, for cysteine. Thus, seed methionine and cysteine concentrations of H82 × 20a2 were each approximately 20% greater than those of the parental line. Protein produced by the derived line may fulfill nutritional requirements for methionine and cysteine.

Non-destructive Limits to Seed Growth and Leaf Protease Activities in Nodulating and Non-nodulating Soybean Isolines

Leaf senescence leads to a progressive decline in the photosynthetic competence of the leaf. This paper describes some effects of source:sink imbalance on leaf protein catabolism and senescence in soybean. We manipulated pod growth by restricting 100 or 50 % (PR-100 or PR-50, respectively) of young pods at the R4 stage in plastic drinking straws. This effectively reduces final seed mass without interrupting the vascular connections of pods. Nodulating (NOD+) and non-nodulating (NOD−) isolines of the ‘Clay’ soybean were grown in drainage lysimeters and three pod-restriction (PR) treatments were compared. Pod restriction decreased seed biomass per plant as a result of lower individual seed mass, which was only partially balanced by the increase in seed number. The nitrogen concentration in seeds remained unchanged in NOD+ plants, while it increased with the degree of sink restriction in seeds of NOD− plants. Leaf soluble protein, CO2 exchange rate and seed nitrogen content were consistently lower in NOD− plants; the leaf protein level remained stable with time in PR-100 plants, decreased for PR-50 and dropped for controls. Endoprotease (HBase) and carboxypeptidase (CPase) activities were significantly lower in leaves from PR-100 plants, while aminopeptidase activity was enhanced, indicating a de novo synthesis of leaf protein. This is consistent with the reported accumulation of vegetative storage proteins (VSPs) in soybean and other legumes after moderate or severe sink reduction. Thus, small modifications of the source:sink ratio such as those obtained by the non-destructive PR technique have an impact on leaf protein catabolism. Nodulating and non-nodulating soybean isolines showed similar responses to PR in terms of leaf senescence initiation and progression, but the rate of the processes appear to be largely influenced by plant N status.

Effect of extrusion cooking on structure and functional properties of pea and kidney bean proteins

Pea (Pisum sativum L cv Ballet) and kidney bean (Phaseolus vulgaris L cv Pinto) seeds were extruded at 148 and 156 °C respectively. Protein solubility at various pH values and in various solvents was determined and analysis of protein fractions was carried out by SDS-PAGE. Also, sulphhydryl and disulphide groups, water-holding capacity (WHC), water solubility index (WSI) and oil absorption capacity (OAC) were determined. No changes in total nitrogen content of pea and kidney bean seeds occurred as a result of thermal treatment. Protein solubility from raw and extruded legumes was significantly higher in saline solutions than in water in the pH range 2–10. The solubility of proteins from extruded pea and kidney bean flours was greatly decreased with respect to native flours when extraction was in buffer (pH 7.0) alone. Extraction with buffer containing 2-mercaptoethanol (2-ME) or sodium dodecyl sulphate (SDS), alone or in combination, greatly increased protein extractability. As a result, the relative solubility was nearly 100% in buffer with SDS and 2-ME for both raw and extruded samples. Total and free sulphhydryl group and disulphide contents decreased significantly (P < 0.05) after extrusion cooking. Moreover, extrusion treatment caused major changes in the band patterns of the albumin and globulin fractions obtained by SDS-PAGE. WHC and WSI of extrudates increased significantly in both peas and kidney beans. A significant reduction in OAC was observed in extruded kidney bean flour. © 2000 Society of Chemical Industry