A chromatographic approach to the taxonomy ofVicia L.

Summary Paper chromatography was applied to investigate the distribution of flavonoids plus other not identified phenols in ten species ofVicia.Considerable biochemical differences were found between as well as within species. The extract ofV. cordata produced a chromatogram substantially different from other taxa of theV. sativa aggregate which confirms its separation as species. The similarity in flavonoids betweenV. villosa andV. dasycarpa supports the view of considering the latter as a subspecies of the former. Similar comments are made on the other species investigated.Cluster analysis may be useful for studying species relationships. It suggests the existence of a parallel between evolutionary advancement and degree of diversification. The results of this small survey would encourage the use of flavonoids and other secondary products for improving the existing classification of the genus.

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Ein chromatographischer Beitrag zur Taxonomie vonVicia L.

Zusammenfassung Papierchromatographie wurde zur Analyse des Vorkommens von Flavonoiden und weiteren nicht identifizierten phenolischen Verbindungen in 10Vicia-Arten genutzt.Betiächtliche biochemische Unterschiede wurden sowohl zwischen als auch innerhalb von Arten ermittelt. Der Extrakt vonV. cordata ergab ein wesentlich von anderen Taxa desV. sativa-Aggregats abweichendes Chromatogramm, das die Abgliederung dieser Sippe als eigene Art bestätigte. Andererseits stützt die Ähnlichkeit der Flavonoide vonV. villosa andV. dasycarpa deren Zusammenfassung als 2 Unterarten einer Art. Ähnliche Kommentare waren bei anderen untersuchten Arten möglich.Die Cluster-Analyse konnte erfolgreich zur Einschätzung der Verwandtschaft zwischen den Arten herangezogen werden. Mit ihrer Hilfe ergab sich eine Parallele zwischen dem Grad abstammungsgeschichtlicher Ableitung und dem Ausmaß der Differenzierung.Die Ergebnisse dieser ersten Übersicht ermutigen zur weiteren Verwendung von Flavonoiden und anderen sekundären Pflanzenstoffen bei der Optimierung der Klassifikation der Gattung.

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Vicia L.

10 Vicia. , . V. cordata , V. sativa, ¶rt; . , V. villosa V. dasycarpa . . . . .

     

Biochemical and cytological analyses in natural populations ofVicia benghalensis L.

Summary 27 accessions ofVicia benghalensis from different geographical origins constitute the pool on which the present study was performed. Genetic variation among the samples was biochemically and cytologically evaluated: seed storage protein profiles and C-banded karyotypes were analysed from single individuals of each accession. SDS-PAGE has shown the possibility to divide the samples into two groups, each characterized by specific protein profiles. The two patterns were indicated as A and B. From individual seed electrophoresis it was ascertained that samples possessing the pattern A showed a low level of individual variation, while those possessing the pattern B were highly polymorphic, thus suggesting differences in the allogamic rate. The cytological analysis demonstrated the presence of two groups of accessions, one being much richer in heterochromatin as evidenced by C-banding (H⁺) than the other (H^-). The analysis of biochemical and karyological data showed a constant association between pattern A and karyotype H⁻ and between pattern B and karyotype H⁺. On the basis of these results it is proposed to considerV. benghalensis as a highly heteromorphic species, in which two groups may be identified.     

Contribution to the taxonomy ofVicia species belonging to the sectionFaba

Summary Vicia faba belongs to the sectionFaba. While the other species of the sectionV. narbonensis, V. johannis andV. bithynica cross enough well each other,V. faba seems to be strongly isolated from them. In addition the chromosome morphology ofV. faba differs from the other species of the section which among themselves are enough homogenous in this respect.To contribute to a wider knowledge on the taxonomical position ofV. faba in its section, electrophoretical and karyological analysis of 500 individuals belonging to 50 populations of different origin were carried out.The analyzed species were:V. faba, V. narbonensis, V. serratifolia, V. bithynica, V. galilaea andV. johannis.

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Beitrag zur Taxonomie derVicia-Arten der SektionFaba

Zusammenfassung Vicia faba gehört zur sect.Faba. Während andere Arten der Sektion (V. narbonensis, V. johannis undV. bithynica) untereinander relativ gut kreuzbar sind, istV. faba von ihnen deutlich isoliert. Darüberhinaus unterscheidet sichV. faba in der Morphologie seiner Chromosomen von den anderen Arten der Sektion, die in dieser Hinsicht eine relativ einheitliche Merkmalsausprägung zeigen. Um zu einer besseren Kenntnis der systematischen Stellung vonV. faba innerhalb der Sektion beizutragen, wurden chromatographische und karyologische Analysen von 500 Individuen aus 50 Populationen verschiedener Herkunft durchgeführt. Analysiert wurdenV. faba, V. narbonensis, V. serratifolia, V. bithynica, V. galilaea undV. johannis.

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Vicia, Faba

Vicia faba Faba. (V. narbonensis, V. johannis, V. bithynica) ,V. faba ë . ,V. faba , . V. faba , 500 50 . :V. faba, V. narbonensis, V. serratifolia, V. bithynica, V. galilaea, V. johannis.

     

Collection, evaluation and classification of Greek populations of faba bean (Vicia faba L.)

Fifty-five Greek Vicia faba L. populations, collected from diverse areas, were planted at two dry and low fertility sites for evaluation and classification. Yield evaluation, which was carried out by Principal Component Analysis (PCA) on the basis of seven yield traits, showed the number of pods per plant, number of ovules and seeds per pod, and branching from the basal nodes to be the most important traits for population evaluation regarding yield. For population classification, four dissimilarity coefficients (Manhattan, Average Taxonomic Distance, Euclidean distance and squared Euclidean distance) and four multivariate methods (PCA, UPGMA, Neighbor-joining and Principal Coordinate Analysis) were evaluated using fifteen morphological and seven yield traits. Neighbor-joining was chosen as the most suitable multivariate method. This method combined with PCA for the seven yield traits, placed the populations into six groups. As revealed by the application of PCA on all twenty-two traits the grouping was based mainly on pod characteristics, stem thickness, plant height, 1000 seed weight and branching from basal nodes. Based on the results of the present study, a model is proposed for conserving cross-pollinated species, such as faba bean.     

Root turnover of faba beans (Vicia faba L.) and its interaction with P and K supply

An increased root turnover can be a mechanism of improved nutrient‐uptake efficiency. The objectives of this study were to investigate P and K efficiency of faba beans (Vicia faba L.), to determine their root growth and root turnover, and to assess the relevance of root turnover on P and K uptake at limited supply. Faba beans were grown as part of a long‐term fertilization experiment on fertilized plots (control) and plots that had not received any P or K fertilizer for 16 years (P0, K0). Although the unfertilized soils were low and very low in their P‐ and K‐supply level, respectively, no differences in shoot‐dry‐matter production occurred compared to the control. However, relative K concentration in dry matter of the K0 plants (control plants = 100) decreased during the experiment and was only 60% of the control at the final harvest. This indicated a high K‐utilization efficiency of faba bean. Relative phosphorus concentration increased in the P0 treatment and was not different from the control at the last harvest, indicating an improvement in P‐uptake efficiency with time. The size of the standing root system determined by sequential auger sampling (net development) was not influenced by P and K supply. Total root production as measured by the ingrowth‐core method was about 6 times higher than the average size of the standing root system and even increased under low‐K conditions. This indicated a fast root turnover. Modeling soil nutrient transport and uptake revealed that calculated uptake of the control was up to 48% higher when root turnover was taken into account, compared to calculations based on the net development of the root systems. This is due to a better soil exploitation. Under K shortage, root turnover resulted in a 117% higher calculated uptake, which was close to measured K uptake. Root turnover was also of benefit for P uptake, but calculated P uptake was significantly less than measured, indicating that root turnover was of little importance for P uptake of faba beans.     

Autofertility in a pure line faba bean (Vicia faba L.) germplasm collection

Summary A pure line faba bean germplasm collection (BPL) was derived by a process of cyclic single plant progenies starting in 1979 through 1985. In 1985/86, 840 of these pure line accessions from 677 original populations from 41 countries were evaluated for autofertility by comparing the mean of five plants where all flowers were tripped vs. five plants with no tripped flowers for number of seeds produced (seed index). In a replicated trial grown at the same time, seed yield, 100 seed weight, number of pods per plant, seeds per pod, and number of flowers per inflorescence were also evaluated. A high number of BPL accessions failed to set seeds in the screen houses without tripping, the mean seed index measure of autofertility was 0.51 with a C.V. of 74.2%. There were marked differences among countries of origin for autofertility, with Egypt having the highest (SI = 0.94) and the USSR the lowest (SI = 0.26) autofertility, however, most countries expressed a large range, suggesting that breeders should first look in their own material for this trait rather than searching in exotic germplasm. In general, there was a higher level of autofertility in Middle Eastern countries that may be due to natural selection for non-dependency on pollinators for high yield. Contrary to the findings of others, large seeded accessions had a high autofertility (SI = 0.704) compared to small seeded accessions (SI = 0.384), however, both had similar ranges. In general, there was no significant correlations among autofertility and yield and its components. The variability found in this large pure line collection for autofertility is of potential use for developing cultivars not dependent on insect populations for high yield and for developing self-pollinated faba bean.     

Phenolics, phytic acid, and phytase in Canadian-grown low-tannin faba bean (Vicia faba L.) genotypes

Thirteen low-tannin faba bean genotypes grown at two locations in north central Alberta in 2009 were evaluated to investigate the variation in seed characteristics, phenolic and phytate contents, and phytase and antioxidant activities and to elucidate the relationship of these components as a breeding strategy. Seed characteristics including color were predominantly genotype dependent. The faba bean genotypes with total phenolic content ranging from 5.5 to 41.8 mg of catechin equiv/g of sample was linearly related to tannin content and the best predictor of antioxidant activity. Phytic acid content and phytase activity varied significantly among genotypes and between locations, ranging from 5.9 to 15.1 g/kg and from 1606 to 2154 FTU/kg sample, respectively. Multivariate data analysis performed on 19 components analyzed in this study using principal component analysis (PCA) and cluster analysis demonstrate that differences in seed characteristics, phenolic components, phytic acid, and phytase are major factors in segregating faba bean genotypes. The relatively low phytic acid content and high phytase activity of these low-tannin faba bean genotypes are beneficial/essential traits for their use in human and animal nutrition.     

Purification and characterization of a phytate-degrading enzyme from germinated faba beans (Vicia faba Var. Alameda)

A phytate-degrading enzyme was purified approximately 2190-fold from germinated 4-day-old faba bean seedlings to apparent homogeneity with a recovery of 6% referred to the phytase activity in the crude extract. It behaves as a monomeric protein of a molecular mass of approximately 65 kDa. The phytate-degrading enzyme belongs to the acidic phytases. It exhibits a single pH optimum at 5.0. Optimal temperature for the degradation of sodium phytate is 50 degrees C. Kinetic parameters for the hydrolysis of sodium phytate are K(M) = 148 micromol L(-1) and k(cat) = 704 s(-1) at 35 degrees C and pH 5.0. The faba bean phytase exhibits a broad affinity for various phosphorylated compounds and hydrolyzes phytate in a stepwise manner. The first hydrolysis product was identified as D/L-myo-inositol(1,2,3,4,5)pentakisphosphate.     

Characterization of Greek populations of faba bean (Vicia faba L.) and their evaluation using a new parameter

Using data from four environments of a two-year experiment, a collection of 55 Greek faba bean populations wascharacterized on the basis of ten morphological and ten agronomical traits. The collection can be described ashaving flowers with medium intensity of streaks on standard petal, two to three flowers per inflorescence, leaveswith six leaflets per leaf, sub-elliptic leaflet shape and small or medium leaflet size. The stems had weak ormedium pigmentation at flowering time, were of low or medium thickness, had medium height and mediumbranching from basal nodes and high resistance to lodging. Pods were mainly basal with pendent attitude, flattenedin shape, had dark colour at maturity and were small with few ovules and seeds. Most seeds had testa of light greencolour. This characterization makes the present collection similar to other South European faba bean populations.Apart from characterization, collections should also be evaluated from the breeding point of view. Since themost desirable populations within a collection are those with valuable but 'low frequency' levels of traits, theparameter R (rareness) was proposed. For each trait, a partial rareness (R ) parameter is calculated using only ithose trait levels that can be considered as having 'low frequency'. The parameter R is the sum of the 'partialrarenesses'. Populations with high frequencies of the 'lowest frequency' levels of traits in the collection arecharacterized by high values of R and can, therefore, be more easily identified.     

Effects of intercropping and Rhizobium inoculation on yield and rhizosphere bacterial community of faba bean (Vicia faba L.)

The effects of intercropping with maize and Rhizobium inoculation on the yield of faba bean and rhizosphere bacterial diversity were analyzed by terminal restriction fragment length polymorphism, amplified 16S rDNA restriction analysis (ARDRA), and 16S rDNA sequencing. The results showed that intercropping but not Rhizobium inoculation significantly increased the faba bean yield. Probably the relatively high level of native rhizobia in soil annulled the effect of rhizobia inoculation. ARDRA results showed that intercropping did not affect bacterial diversity whereas Rhizobium inoculation decreased bacterial diversity. The canonical correspondence analysis showed that the composition of bacterial community was changed apparently by intercropping, and there was a positive correlation (P = 0.724) between faba bean yields and intercropping and an apparent correlation (P = 0.648) between intercropping and total N. The available content of K and P had a lower effect on the bacterial community composition than did the total N content, Rhizobium inoculation, and microbial biomass C. Rhizobium inoculation negatively correlated with microbial biomass C (P = −0.827). These results revealed a complex interaction among the intercropped crops, inoculation with rhizobia, and indigenous bacteria and implied that the increase of faba bean production in intercropping might be related to the modification of rhizosphere bacterial community.     

Effectiveness of native Rhizobium on nodulation and yield of faba bean (Vicia faba L.) in Eastern Ethiopia

This study was initiated to evaluate the effect of locally isolated Rhizobium on nodulation and yield of faba bean at Haramaya, Ethiopia for three consecutive years. Ten treatments comprising of eight effective isolates of rhizobia, uninoculated, and N-fertilized (20 kg N ha^?1) were laid out in a randomized complete block design with three replications. The result of the experiment indicated that all inoculation treatments increased nodule number and dry weight over the control check in all cropping seasons. The result, however, showed the non-significant effect of Rhizobium inoculation on shoot length, number of tiller per plant and 100 seed weight in all cropping season. Inoculating Haramaya University Faba Bean Rhizobium (HUFBR)-15 in 2011 and National Soil Faba Bean Rhizobium (NSFBR)-30 in 2012 and 2013 gave the highest grain yields (4330, 5267 and 4608 kg ha^?1), respectively. These records were 75%, 48%, and 5% over the uninoculated treatment of respective years. Over the season, NSCBR-30 inoculation resulted in the highest nodulation and grain yield production as compared to the other treatments. In general, isolates from central Ethiopia were better than those isolated from eastern Ethiopia and Tropical Agricultural Legume (TAL)-1035 in enhancing faba bean production at Haramaya site. Therefore, NSFBR-30 is recommended as a candidate isolate for faba bean biofertilizer production in eastern Ethiopia soils.     

Nodulation and N2 fixation of faba bean (Vicia faba L.) after soil amendment with crop residues

The effect of prior soil amendment with different N sources at 50 mg N (kg soil)^—1 on nodulation and N₂ fixation of faba bean (Vicia faba L. cv. Troy) using wheat (Triticum aestivum L. cv. Star) as reference crop was assessed in a pot experiment. Four treatments viz legume manure (LEGM) as clover shoots, cereal manure (CEREM) as barley straw, N fertilizer (FERT‐N) as Ca(NO₃)₂, and no‐manure control (NOMAN) were investigated consecutively at 45, 70, and 90 days after sowing (DAS). Faba bean nodulated profusely, with an increase on average from 629 nodules per pot at 45 DAS to nearly 2.3‐ and 3.3‐fold at 70 and 90 DAS, respectively. Low nodule numbers and nodule dry matter occurred under FERT‐N and CEREM, whereas high values were found for NOMAN and LEGM. Soil amendment affected percent N₂ fixation in relation to N source and plant age. Highest percent N₂ fixation (≥ 90 %) was found under the lowest N‐supplying amendments, no‐manure, and cereal manure, respectively. FERT‐N depressed N₂ fixation particularly at 45 DAS when N₂ fixation was reduced to as low as 23 %. The rise in N₂ fixation thereafter suggests that faba bean adjusted after depletion of mineral N in the soil. N₂ fixation was also decreased after cereal straw application, even though N concentration in faba bean plants was high. The results indicate that plant residues, both with high and low N concentration, applied to soil to raise its fertility may interfere with N₂ fixation of faba bean.     

小麦//蚕豆间作中的种间氮营养差异比较研究

通过根系分隔和15N标记土壤的盆栽试验,研究间作蚕豆和小麦对不同氮素来源利用的差异。结果表明,根系不分隔的处理小麦生长改善,其生物量、吸氮量都高于其它2种分隔方式;蚕豆的生长则表现被抑制,其生物量在根系不分隔时生物量和吸氮量皆最低。在尼龙网分隔的处理中,小麦植株体内15N%丰度高于其它2种分隔方式,而蚕豆则表现为根系未分隔的处理15N%丰度最低。表明小麦竞争肥料氮的能力强于蚕豆,小麦的竞争促进了蚕豆固定更多的空气氮。     

Effect of salinity on growth,nodulation and nitrogen assimilation in nodules of faba bean (Vicia faba L.)

A commercial cultivar (Alborea) of faba bean (Vicia faba L. var. minor) was inoculated with salt-tolerant Rhizobium leguminosarum biovar. viciae strain GRA19 in solution culture with different salt concentrations (0, 50, 75 and 100 mmoles l⁻¹ NaCl) added immediately at the time of inoculation. The results indicated that Rhizobium leguminosarum strain GRA19 formed an infective and effective symbiosis with faba bean under saline and nonsaline conditions. Salinity significantly decreased shoot and root dry weight, nodule weight and mean nodule weight. Roots were more sensitive than shoots, and N₂ fixation was more sensitive to salinity than was plant growth. Analyses of ammonium assimilating enzymes in the nodule showed that glutamine synthetase appeared to be more tolerant to salinity than glutamate synthase, and that it limits ammonium assimilation under saline stress.     

Jasmonic acid alleviates negative impacts of cadmium stress by modifying osmolytes and antioxidants in faba bean (Vicia faba L.)

We examined the role of jasmonic acid (JA) in faba bean under cadmium (Cd) stress, which reduces the growth, biomass yield, leaf relative water content (LRWC) and pigment systems. Hydrogen peroxide (H₂O₂) and lipid peroxidation (malondialdehyde [MDA]) levels increased by 2.78 and 2.24-fold, respectively, in plants under Cd stress, resulting in enhanced electrolyte leakage. Following foliar application to Cd-treated plants, JA restored growth, biomass yield, LRWC and pigment systems to appreciable levels and reduced levels of H₂O₂, MDA and electrolyte leakage. Proline and glycine betaine concentrations increased by 5.73 and 2.61-fold, respectively, in faba bean under Cd stress, with even higher concentrations observed following JA application to Cd-stressed plants. Superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase levels rose by 87.47%, 130.54%, 132.55% and 37.79%, respectively, with Cd toxicity, with further enhancement of antioxidant activities observed following foliar application of JA. Accumulation of Cd in roots, shoots and leaves was also minimized by external supplementation of JA. In conclusion, JA mitigates the negative impacts of Cd stress in faba bean plants by inhibiting the accumulation of Cd, H₂O₂ and MDA, and by enhancing osmolyte and antioxidant activities that reduce oxidative stress.     

Nitrogen yield and nitrogen fixation of winter faba beans

Introducing autumn-sown legumes into Central European farming systems could be beneficial for addressing two challenges for European agriculture, i.e., the substantial deficit of protein sources for livestock and expected changes in agroclimatic conditions. Therefore, a two-year field experiment was conucted under Pannonian climate conditions in eastern Austria to assess nitrogen (N) yield and N fixation of several winter faba bean varieties from different European countries as compared to a spring faba bean. Winter wheat was used as a reference crop for estimating atmospheric N fixation. Winter faba beans were susceptible to frost damage especially in the harder of the two winters. Winter faba bean varieties could not achieve a higher grain yield and a higher grain N yield than the spring faba bean but had a higher grain N concentration (except for one variety). Grain yield and grain N yield of faba beans were severely impaired by drought in one year (with a mean of varieties of 8.3 g N m^?2, winter wheat: 6.4 g N m^?2); in the other year, grain N yield of faba beans considerably surpassed that of winter wheat (with a mean of varieties of 21.5 g N m^?2, winter wheat: 8.8 g N m^?2). After harvest, faba beans left higher nitrate residues in the soil, especially in the subsoil, and higher amounts of N in above-ground residues compared to winter wheat. Faba beans showed high N fixation under optimum conditions (with a mean of varieties of 21.9 g N m^?2) whereas drought considerably impaired N fixation (with a mean of varieties of 6.3 g N m^?2; with no differences between autumn- and spring-sown faba beans). In conclusion, growing winter faba bean varieties in eastern Austria did not result in higher grain yield, grain N yield, and N fixation compared to growing a spring faba bean.     

Increasing root and leaf growth and yield in Mg‐deficient faba beans (Vicia faba) by MgSO4 foliar fertilization

Magnesium (Mg) deficiency reduces yield and quality of crops as Mg is involved in carbohydrate and protein anabolism. Foliar application of MgSO₄ represents a means of ameliorating the nutritional status of crops growing under conditions of deficiency. Foliar Mg application has been demonstrated to increase the chlorophyll concentration and vegetative yield of plants. However, in crop plants used for seed production, the limited number of available studies provides only conflicting results in terms of the efficiency of Mg leaf application on yield and quality. We have examined the effect of increasing Mg foliar application rates on differentially developed leaves and leaf stages with regards to Mg concentration, chlorophyll concentration and biomass formation. Our data reveal that in order to obtain significant effects MgSO₄ concentrations in the spraying solution should be higher than 50 mM, as lower concentrations did not lead to significant changes in the vegetative or generative material. Positive effects of the foliar application on chlorophyll concentration and leaf area were only measured in leaves treated with 200 mM foliar MgSO₄. The application of Mg did not affect the parameters chlorophyll, ion concentration and leaf area in the newly developing leaves, but it had an important influence with regard to yield traits, especially on the formation of pods. The quality of the seeds with regard to the protein concentration was reduced in response to the magnesium deficiency treatment, but the application of foliar magnesium prevented a significant loss of protein.     

Biological nitrogen fixation in faba bean (Vicia faba L.) in the Ethiopian highlands as affected by P fertilization and inoculation

 N₂ fixation by leguminous crops is a relatively low-cost alternative to N fertilizer for small-holder farmers in developing countries. N₂ fixation in faba bean (Vicia faba L.) as affected by P fertilization (0 and 20 kg P ha^–1) and inoculation (uninoculated and inoculated) with Rhizobium leguminosarium biovar viciae (strain S-18) was studied using the ¹⁵N isotope dilution method in the southeastern Ethiopian highlands at three sites differing in soil conditions and length of growing period. Nodulation at the late flowering stage was significantly influenced by P and inoculation only at the location exhibiting the lowest soil P and pH levels. The percentage of N derived from the atmosphere ranged from 66 to 74%, 58 to 74% and 62 to 73% with a corresponding total amount of N₂ fixed ranging from 169 to 210 kg N ha^–1, 139 to 184 kg N ha^–1 and 147 to 174 kg N ha^–1 at Bekoji, Kulumsa and Asasa, respectively. The total N₂ fixed was not significantly affected by P fertilizer or inoculation across all locations, and there was no interaction between the factors. However, at all three locations, N₂ fixation was highly positively correlated with the dry matter production and total N yield of faba bean. Soil N balances after faba bean were positive (12–58 kg N ha^–1) relative to the highly negative N balances (–9–44 kg N ha^–1) following wheat (Triticum aestivum L.), highlighting the importance of rotation with faba bean in the cereal-based cropping systems of Ethiopia. Received: 13 January 2000     

Response of Zea mays and Vicia faba to CULTAN fertilization

The response of broad bean (Vicia faba L.) and corn (Zea mays L.) to CULTAN fertilization was compared. Roots of broad bean turned black and were severely damaged by CULTAN fertilization, whereas corn roots were not affected. Consequently, dry matter production of roots and shoots of broad bean was significantly reduced. CULTAN fertilization caused a soil pH increase which may be attributed to hydrolysis of urea applied during CULTAN fertilization. It is assumed that the occurrence of high NH₃ concentration in soil due to CULTAN fertilization may be toxic to broad bean but not to corn.     

The role of potassium fertilizer in nodulation and nitrogen fixation of faba bean (Vicia faba L.) plants under drought stress

Three-week-old nodulated faba bean plants were subjected to different levels of drought stress (onehalf, one-quarter, or one-eighth field capacity) for 5 weeks. Half the stressed plants were treated with KCl at 10 mg kg^-1 soil or 150 mg kg^-1 soil at the beginning of the drought stress. Nodulation and nitrogenase activity were significantly decreased by increasing drought stress. Leghaemoglobin and protein contents of nodule cytosol were also severely inhibited by drought sttess. This decline was attributed to the induction of protease activity. However, carbohydrate contents of the nodule cytosol increased significantly. This accumulation was attributed to a sharp decline in invertase activity and low use of sugar by the bacteroids We conclude that harmful effects of water deficits can be alleviated by increasing K⁺ supplementation.