Sequential Expression of Trypsin Inhibitors in Developing Fruit of Cowpea (Vigna unguiculata (L.) Walp)

Trypsin inhibitor (TI) activity was followed in the pod (pericarp),seed coat, cotyledon and embryo axis during fruit developmentof cowpea. On the basis of seed fresh weight, three phases couldbe distinguished from anthesis to fruit maturity. In the podTI activity increased from the beginning of Phase I to a maximumin the middle of the phase. From then on the activity declineduntil no activity could be detected before the end of phaseII. The cotyledons did not contain any TI in Phase I. TI activitywas first detected in the cotyledon in the beginning of PhaseII at the same time that globulin synthesis started. The TIactivity in the cotyledon increased to a maximum at the endof Phase II before decreasing in Phase III. In the embryo axisa similar pattern of TI activity to that of the cotyledon wasfound. No protein TI could be detected in the seed coat at anystage. In the pod there is a TI with a mol. wt of 12500 andpI of 4.4. Mature cotyledon and embryo axis have two TI withmol. wt 10800 and 24700 with pI 4.7 and 5.0 respectively. Duringdevelopment the smaller TI (mol. wt 10800) was synthesised beforethe larger TI (mol. wt 24700). There were large differencesbetween the maximum absolute amounts of TI present in the pericarp,cotyledon and embryo axis.     

Protein Body Formation in Cotyledons of Developing Cowpea (Vigna unguiculata) Seeds

The sequence of protein body formation in cotyledonary cellsof developing cowpea seeds has been followed by electron microscopy.Some protein bodies are formed by sub-division of the main vacuolesof the cotyledon cell but most are formed by expansion of cytoplasmicvesicles which may originate from Golgi bodies. Protein depositionis accompanied by a massive proliferation of rough endoplasmicreticulum and Golgi body production.     

Regulation of Leaf Senescence by Reproductive Sink Intensity in Cowpea (Vigna unguiculata L. Walp)

The relationship between seed number per pod and senescenceof the leaf in its axil was examined in a determinate cowpea(Vigna unguiculata L. Walp) variety C.779. The seed number perpod was reduced at all fruiting nodes by surgical excision ofpart of the 4-d-old pod. Leaf senescence as measured by lossof leaf area, chlorophyll content and soluble protein was sloweddown in leaves supporting the development of an artificiallyreduced number of seeds. Diminished nitrogen mobilization fromthe leaf could not account for the reduced rate of leaf senescence.The result suggests the involvement of a senescence signal fromthe developing seeds to the leaf in its axil. Development ofthe basal half of the excised pod in the cowpea provides a uniquesystem for manipulating seed number per pod. Senescence, monocarpic, chlorophyll, protein, Vigna unguiculata, cowpea     

Effect of pO(2) on Growth and Nodule Functioning of Symbiotic Cowpea (Vigna unguiculata L. Walp.)

Nodulated cowpea (Vigna unguiculata L. Walp. cv Vita 3:Bradyrhizobium CB 756) plants were cultured with their whole root system or crown root nodulation zone maintained for periods from 5 to 69 days after planting in atmospheres containing a range of pO₂ (1-80%, v/v) while the rest of the plant grew in normal air. Growth (dry matter yield) and N₂ fixation were largely unaffected by pO₂ from 10 to 40%. Decrease in fixation at pO₂ below 5% was due to lower nodulation and nodule mass and, at pO₂ above 60%, to a fall in specific N₂-fixing activity of nodules. Root:shoot ratios were significantly lower at pO₂ below 2.5%. The effect of pO₂ on nitrogenase activity (acetylene reduction), both of whole nodulated root systems and crown root nodulation zones, varied with plant age but was generally lower at supra- and subambient extremes of O₂. H₂ evolution showed a sharp optimum at 20% O₂ but was at most 4% of total nitrogenase activity. The ratio of CO₂ evolved to substrate (C₂H₂+H⁺) reduced by crown root nodulation zones was constant (6 moles CO₂ per mole substrate reduced) from 2.5 to 60% O₂ but at levels below 2.5 and above 80% O₂ reached values between 20 and 30 moles CO₂ per mole substrate reduced. Effects of long-term growth with nonambient pO₂ on adaptation and efficiency of functioning of nodules are discussed.     

Comparative Response of Nodulated and Nitrogen-Supplied Cowpea (Vigna unguiculata (L.) Walp. var. Tuy) Plants to Infection by Cowpea Mosaic Virus

The effect of infection by the Cowpea Mosaic Virus (CpMV) onseveral parameters relevant to symbiotic nitrogen fixation wasdetermined in cowpea (Vigna unguiculata (L.) Walp. var. Tuy)plants nodulated with two strains of Rhizobium cowpea: IVIC–124and IVIC–38. Plants were virus-infected at the seedlingstage before Rhizobium inoculation. The effect of CpMV infectionon plant growth was analysed in nodulated and nitrogen-suppliedplants at 18, 25 and 35 d after germination. At all developmentalstages of nodulated plants CpMV infection caused a reductionof leaf chlorophyll content, leaf area, dry weight of shootsand roots, total nodule weight and nodule number. Most of thenodules from 18- and 25-d-old CpMV-infected plants did not exhibitleghaemoglobin pigmentation. CpMV infection delayed the onsetof nitrogenase activity in nodules of the rhizobial strain IVIC–124and the enzyme activity measured on a per plant basis was reducedin both strains at the first and second harvests. Significantnitrogenase activity was detected in 35-d-old infected plants.Some of the nodules of the rhizobial strain IVIC-124 and mostof the nodules from plants nodulated with the strain IVIC-38developed leghaemoglobin; however, the nodule-specific nitrogenaseactivity, estimated on a milligram nodule dry weight basis,was always higher in virus-infected plants, particularly in18-d-old CpMV-infected plants harbouring the IVIC–124strain. CpMV-infected nodules had a larger peribacteroidal space,a reduced number of peribacteroid units, a greater number ofbacteroids per unit, a lower number of vesicles and 88% lowertotal reducing sugar content. Starch accumulation was detectedin infected leaves of nodulated plants during the first harvest,while high levels of leaf reducing sugars and protein were presentat the second harvest. In healthy nodulated plants the rhizobialstrain IVIC–124 was shown to be more efficient than IVIC–38in promoting plant growth. However, the results indicate thatnodulation by rhizobial strain IVIC–124 and growth ofplants harbouring this strain were affected to a greater extentby virus infection. The effect of CpMV infection on leaf chlorophyllcontent, leaf area, carbohydrate level, leaf proteins and growthof nitrogen-supplied plants, as well as the symptoms inducedin the leaves, were less conspicuous than in nodulated plants. Key words: Cowpea, Rhizobium, virus infection, nodule untrastructure     

Seed Protein Pattern of Cowpea (Vigna unguiculata L.) and Its Distant Species

Seed protein was extracted from two varieties of cowpea (CO 2, CO 6) and eight distant species of Vigna and was analysed by SDS-PAGE. The relative migration (Rm) and Similarity Index (SI) were worked out. There was no difference in protein profiles of varieties CO 2, a vegetable type cowpea and CO 6, a grain type cowpea (SI = 100%). A high SI has been exhibited by V. glabrescens with V. radiata (62.5%) and V. umbellata (45.4%), the probable progenitors of the natural amphidiploid V. glabrescens. V. sublobata and V. trilobata trevealed greatest SI (90.9%) indicating a close evolutionary relationship, on the contrary, V. mungo and V. umbellata exhibited a zero value revealing a greater evolutionary distance. The electrophoretic variability study indicates difficulty in obtaining interspecific hybrids through conventional methods for cowpea improvement (SI < 26.67%).     

Allantoin and Allantoic Acid in the Nitrogen Economy of the Cowpea (Vigna unguiculata [L.] Walp.)

The ureides, allantoin and allantoic acid, represented major fractions of the soluble nitrogen pool of nodulated plants of cowpea (Vigna unguiculata [L.] Walp. cv. Caloona) throughout vegetative and reproductive growth. Stem and petioles were the principal sites of ureide accumulation, especially in early fruiting.

Labeling studies using ¹⁴CO₂ and ¹⁵N₂ and incubation periods of 25 to 245 minutes indicated that synthesis of allantoin and allantoic acid in root nodules involved currently delivered photosynthate and recently fixed N, and that the ureides were exported from nodule to shoot via the xylem. From 60 to 80% of xylem-borne N consisted of ureides; the remainder was glutamine, asparagine, and amino acids. Allantoin predominated in the soluble N fraction of nodules and fruits, allantoin and allantoic acid were present in approximately equal proportions in xylem exudate, stems, and petioles.

Extracts of the plant tissue fraction of nitrogen-fixing cowpea nodules contained glutamate synthase (EC 2.6.1.53) and glutamine synthetase (EC 6.3.1.2), but little activity of glutamate dehydrogenase (EC 1.4.1.3). High levels of uricase (EC 1.7.3.3) and allantoinase (EC 3.5.2.5) were also detected. Allantoinase but little uricase was found in extracts of leaflets, pods, and seeds.

Balance sheets were constructed for production, storage, and utilization of ureide N during growth. Virtually all (average 92%) of the ureides exported from roots was metabolized on entering the shoot, the compounds being presumably used as N sources for protein synthesis.

     

Physiological and Biochemical Aspects of Symbiotic Nitrogen Fixation in Cowpea (Vigna unguiculata (L.) Walp. var. Tuy) Plants Infected by Cowpea Mosaic Virus

Three-day-old cowpea seedlings were inoculated with the severestrain of Cowpea Mosaic Virus (CpMV) and 24 h later with Bradyrhizobiumsp. cowpea, strain I-125, when virus translocation to rootsstill had not taken place. Plants were harvested at 22, 30,45 and 59 d after germination. Active virus replication wasassociated with increased protein content, detected in the leavesof 22-d-old plants. CpMV infection reduced the total leaf area,dry weight of shoots and the chlorophyll content of the firsttrifoliolate leaf at all experimental times. Low sugar contentwas recorded in leaves of 22- and 30-d-old CpMV-infected plantsand in nodules and roots of 30- and 45-d-old CpMV-infected plants.Up to 45 d, the nodule mass of CpMV-infected plants was lowerthan in controls, but reached control values at the 4th harvest.In CpMV-infected nodules, massive agglomeration of virus particles,crystalline virus inclusions and the proliferation of the endoplasmicreticulum were observed only in those cells containing bacteroids.In 30- and 45-d-old plants, CpMV infection decreased the contentof ureides in nodules, roots, and petioles. Virus infectiondid not alter the -amino-N content of roots and nodules butinduced a transient 74% reduction in the level of -amino-N inpetioles of 45-d-old plants. At the 1st and 2nd harvests theactivity of uricase (EC 1.7.3.3 [EC] ) in the nodules and of pyruvatekinase (EC 2.7.1.40 [EC] ) in the nodules and leaves were decreasedseverely by virus infection. CpMV did not hinder the allantoinase(EC 3.5.2.5 [EC] ) activity in the leaves but caused a 9% transitorydecrease in the activity of this enzyme in nodules of 45-d-oldplants. Measurements of NAD-malic enzyme (EC 1.1.1.38 [EC] ) in nodulesalso showed the non-effect of CpMV on this enzyme, except fora temporary 16% reduction at the 2nd harvest. As compared tocontrols, the relative abundance of ureides in 30-d-old CpMV-infectedplants indicated a 15%, 10%, and 51% reduction in the nodules,roots, and petioles, respectively. Results indicate that atthe time of the 4th harvest the symbiotic process, measuredin terms of ureide content and enzymatic activities, was functioningat a near normal level despite nodule infection by CpMV. Key words: Cowpea Mosaic Virus, nitrogen fixation, cowpea, enzymes, ultrastructure     

Economy of Carbon and Nitrogen in Nodulated and Nonnodulated (NO(3)-grown) Cowpea [Vigna unguiculata (L.) Walp.

The response of non-nodulated cowpea (Vigna unguiculata (L.) Walp. cv Caloona) to a wide range of NO₃ levels in the rooting medium was studied 40 days after sowing by in vitro assays of plant organs for NO₃ reductase (EC 1.6.6.1) and analyses of root bleeding (xylem) sap for nitrogenous solutes. Plants fed 1, 5, 10, 20, and 40 millimolar NO₃ showed, respectively, 64, 92, 94, and 91% of their total reductase activity in shoots and 34, 30, 66, 62, and 58% of the total N of their xylem sap as NO₃. These data, and the absence in the plants of significant pools of stored NO₃, indicated that shoots were major organs of NO₃ assimilation, especially at levels of NO₃ (10 to 40 millimolar) that maintained plant growth at near maximum rates. Partitioning and utilization of C and N were studied in nodulated, minus NO₃ plants and non-nodulated plants fed 10 or 20 millimolar NO₃, the levels of NO₃ which gave rates of growth and N assimilation closest to those of the symbiotic plants. The conversion of the C of net photosynthate to dry matter was similar in nodulated plants (67%) and NO₃-grown plants (64%), but greater proportions of photosynthate were translocated to below ground parts of nodulated plants (37%) than of NO₃-fed plants (23 to 26%). Greater photosynthate consumption by nodulated roots was associated with proportionately greater root growth and respiration and 2-fold greater export of C in xylem than in the NO₃-fed plants. Theoretical considerations suggest that the elevated CO₂ output of nodulated roots was due not only to CO₂ loss associated with nodule function, but also to a much greater nonassimilatory component of respiration in the supporting root of the nodulated plant compared to roots of the NO₃-fed plants. Data are compared with previously published information from other legumes.     

Serological and Biological Comparisons of Blackeye Cowpea Mosaic and Cowpea Aphid-borne Mosaic Potyvirus Isolates Seed-borne in Vigna unguiculata (L.) Walp. Germplasm

Serological and biological comparisons were made among 45 seed-borne isolates of blackeye cowpea mosaic (BICMV) and 54 seed-borne isolates of cowpea aphidborne mosaic (CAbMV) potyviruses derived from cowpea seedlots or young nursery-grown seedlings comprising 2112 germplasm accessions or pre-introduction seedlots of Vigna unguiculata. Isolates were identified by DAS-ELISA using polyclonal immunoglobulin G specific for these viruses. Twenty isolates of BICMV and 32 isolates of CAbMV were also compared by ACP-ELISA with selected monoclonal antibodies and by SDS-immunodiffusion. By all approaches, isolates of BICMV were clearly distinguished from CAbMV isolates. Isolate comparisons on selected cowpea genotypes (TVu-401, TVu-1582, TVu-2657, and TVu-3433) partitioned most isolates into two distinct groups. A few isolates seed-borne in Indian cv. Pusa Phalguni, however, were clearly BICMV by all serological tests, but behaved as CAbMV in definitive cowpea genotypes. Although BICMV is generally considered to be a 'new world virus', both BICMV and CAbMV occurred in V. unguiculata seedlots originating in 'old-world regions', including Afghanistan, Botswana, Nigeria, Senegal, and South Africa. Seedborne CAbMV was isolated from 6 of 155 tested US V. unguiculata Germplasm accessions originating, respectively, in Afghanistan (2), Botswana (2), India (1), and Pakistan (1).     

Biosynthesis of Ureides from Purines in a Cell-free System from Nodule Extracts of Cowpea [Vigna unguiculata (L) Walp.

The synthesis of ¹⁴C-labeled xanthine/hypoxanthine, uric acid, allantoin, allantoic acid, and urea from [8-¹⁴C]guanine or [8-¹⁴C]hypoxanthine, but not from [8-¹⁴C]adenine, was demonstrated in a cell-free extract from N₂-fixing nodules of cowpea (Walp.). The ¹⁴C recovered in the acid/neutral fraction was present predominantly in uric acid and allantoin (88-97%), with less than 10% of the ¹⁴C in allantoic acid and urea. Time courses of labeling in the cell-free system suggested the sequence of synthesis from guanine to be uric acid, allantoin, and allantoic acid. Ureide synthesis was confined to soluble extracts from the bacteroid-containing tissue, was stimulated by pyridine nucleotides and intermediates of the pathways of aerobic oxidation of ureides, but was completely inhibited by allopurinol, a potent inhibitor of xanthine dehydrogenase (EC 1.2.1.37). The data indicated a purine-based pathway for ureide synthesis by cowpea nodules, and this suggestion is discussed.     

Unusual Network of Internal Phloem in the Pod Mesocarp of Cowpea [Vigna unguiculata (L.) Walp. (Fabaceae)]

A mycelium-like network of internal phloem was observed in theinner mesocarp of the lateral pod walls of the fruit of certaingenotypes of cowpea [Vigna unguiculata (L.) Walp.] In the cultivarVita 3, the network consists of single, or rarely double, strandsof sieve elements and associated phloem parenchyma, orientedmainly parallel with the fibres of the adjacent endocarp, andstretching marginally beyond the sheets of fibres to connectabove and below with the outermost phloem of the longitudinalstrands of the dorsal and ventral sutures of the fruit. Theinternal phloem network does not relate conformationally to,or interconnect with the conventional (xylem+phloem) vasculatureof the mid mesocarp of the pod wall. In Vita 3, sieve elementsdifferentiate in the internal phloem after those in the majorveins of the pod, but before the presumptive endocarp fibrescommence wall thickening. The pod walls of twenty-one otherspecies of legumes proved negative for internal phloem, whileof nine varied genotypes of cowpea examined, six proved positive,three negative for the trait. Presence of internal phloem incowpea is not always associated with presence of endocarp fibresor necessarily with large fruits with large seeds. Possiblefunctions suggested for the phloem network are to provide assimilatesfor fibre wall thickening or to transport solutes to or fromsites of temporary storage in the fleshy inner layers of thepod wall. Internal phloem, legume fruit, translocation, mesocarp, pod wall, Vigna unguiculata, cowpea     

Allozyme diversity of cultivated cowpea Vigna unguiculata (L.) Walp.

A survey of allozyme variation in cultivar-groups of cowpea [Vigna unguiculata (L.) Walp.] was undertaken by examining 21 enzyme systems encoded by 36 loci in 271 accessions representing the five cultivar-groups. Very low levels of variation were found within accessions, which is typical of self-pollinating species. Little variation was also found among accessions. Compared with other legume crops, V. unguiculata is depauperate in allozyme variation. We found an average of 1.61 alleles per locus with 42% of the loci polymorphic and a total heterozygosity of 0.061. Of the variation present, 90% was found within cultivar-groups, while 10% was among cultivar-groups. Data analyses revealed continuous variation among cultivar-groups and geographic regions with the accessions failing to segregate into discrete morphophysiological or geographic clusters. However, evolved cultivar-groups (cv.-gr. Melanophthalmus and cv.-gr. Sesquipedalis) appear to be less diverse than their putative primitive cultivar-group progenitors. Due to the lack of availability of critical material, no clear center of origin can be established. However, the data presented suggest that Northeast Africa could be a possible center of domestication. Received: 18 February 1999 / Accepted: 4 November 1999     

Effect of pO(2) during Growth on the Gaseous Diffusional Properties of Nodules of Cowpea (Vigna unguiculata L. Walp.)

Adaptations of nodules of cowpea (Vigna unguiculata L. Walp. cv Vita 3: Bradyrhizobium CB 756) to growth in pO₂ ranging from 1 to 80% O₂ (volume/volume) involved both readily reversible mechanisms of adjustment and more stable alterations which together resulted in nodules with widely ranging resistance to diffusion of gases. Those grown in subambient pO₂ (1-5% O₂ were altered such that rapid diffusional adjustment was unable to prevent irreversible loss of nitrogenase on their transfer to higher levels of O₂. Those cultured in 80% had adapted to over-supply of O₂ such that their transfer to lower levels of O₂ limited both nitrogenase and respiratory CO₂ release. There was also some evidence for `protective respiration.' Measurement of diffusional properties based on gas exchange kinetics indicated that gaseous permeability values for nodules from 5 to 40% O₂ were relatively constant around 20 × 10⁻³ millimeters per second, while those for nodules from 1% O₂ were as high as 67.7 × 10⁻³ millimeter per second and from 80% as low as 6.8 × 10⁻³ millimeters per second. Estimates of the thickness of the diffusion barrier ranged from 7.5 micrometers for nodules from 1% O₂ to 71.9 micrometers in those from 80% O₂.     

Effects of Decapitation and Benzyladenine on Growth and Yield of Cowpea [Vigna unguiculata (L.) Walp.]

A study was undertaken to define more clearly the role of theearly loss of apical dominance on yield of cowpea [Vigna unguiculata(L.) Walp. cv. Vita-5]. Decapitation at the fifth leaf stageresulted in an increase in branching components, yields andharvest indices, while vegetative d. wt accumulation was reduced.Foliar-applied sprays of 6-benzyladenine had no effect on branchingunless combined with decapitation and no significant effectson yield over that of controls were observed. However, harvestindices were increased by 50 per cent. Vigna unguiculata (L.) Walp., cowpea, apical dominance, decapitation, 6-benzyladenine     

Nodulation and symbiotic nitrogen fixation of cowpea (Vigna unguiculata (L.) Walp)

Summary Rhizobium strains CIAT 301, CIAT 79 and SLM 602 were tested and found effective in the nodulation and nitrogen fixation of cowpea cv. MI-35 (Vigna unguiculata (L.) Walp) plants in growth chamber experiments. Fresh weight of nodules increased with plant age initially and stabilized in 20–30 days from planting, followed by a secondary flush of nodule growth after 30 days. Apparent nitrogen fixation per gram nodule fresh weight reached a maximum in 20–30 days after planting and then decreased, even though a flush of new nodules was produced.     

De Novo Purine Synthesis in Nitrogen-Fixing Nodules of Cowpea (Vigna unguiculata [L.] Walp.) and Soybean (Glycine max [L.] Merr.)

Partially purified, cell-free extracts from nodules of cowpea (Vigna unguiculata L. Walp. cv. Caloona) and soybean (Glycine max L. Merr. cv. Bragg) showed high rates of de novo purine nucleotide and purine base synthesis. Activity increased with rates of nitrogen fixation and ureide export during development of cowpea plants; maximum rates (equivalent to 1.2 micromoles N₂ per hour per gram fresh nodule) being similar to those of maximum nitrogen fixation (1-2 micromoles N₂ per hour per gram fresh nodule). Extracts from actively fixing nodules of a symbiosis not producing ureides, Lupinus albus L. cv. Ultra, showed rates of de novo purine synthesis 0.1% to 0.5% those of cowpea and soybean. Most (70-90%) of the activity was associated with the particulate components of the nodule, but up to 50% was released from this fraction by osmotic shock. The accumulated end products with particulate fractions were inosine monophosphate and aminoimidazole carboxamide ribonucleotide. Further metabolism to purine bases and ureides was restricted to the soluble fraction of the nodule extract. High rates of inosine monophosphate synthesis were supported by glutamine as amide donor, lower rates (10-20%) by ammonia, and negligible rates with asparagine as substrate.     

The Effect of Nitrogen Source on Transport and Metabolism of Nitrogen in Fruiting Plants of Cowpea (Vigna unguiculata (L.) Walp.)

Nitrogen metabolism and transport were studied during reproductivedevelopment of cowpea (Vigna unguiculata (L.) Walp. cv. Vita3) under three contrasting nitrogen regimes: (1) nitrate suppliedcontinuously (plants non-nodulated), (2) symbiotic N₂ fixation(no combined nitrogen), (3) nitrogenstarvation post-anthesisof previously N₂-fixing plants. The last treatment involveddaily flushing of the root systems with 100% oxygen which suppressedpost-anthesis N₂-fixation by 76–79%, thereby making fruitgrowth almost entirely reliant upon mobilization of previouslyaccumulated nitrogen. The bulk of the xylem nitrogen (root bleedingsap or peduncle tracheal sap) of nitrate-fed plants was nitrateand amide, that of symbiotic and O₂-treated plants largely ureide.The composition of fruit cryopuncture phloem sap, however, wasclosely similar in all treatments, with most nitrogen as amidesand amino acids. The evidence suggested intense metabolic transferof root derived nitrate-N or ureide-N to amino acids by vegetativeplant parts prior to translocation to fruits. All tissues offruits showed patterns of development of enzymic activitiesconsistent with release of nitrogen from both ureides and amidesand re-assimilation of ammonia to form amino acids. Althoughthe levels of enzyme activities varied between treatments thedifferences could not be readily associated with individualpatterns of nitrogen transport in the treatments. Nitrogen sufficiencyin the NO₃-fed plants was marked by elevated vegetative biomassand low harvest indices for dry matter and nitrogen, while nitrogendeficiency of the O₂-treated plants was associated with seedabortion, small seed size and low seed nitrogen concentration,and efficient mobilization of nitrogen from vegetative partsto fruits. Key words: Nitrogen, Translocation, Cowpea     

Potassium and magnesium relationship in cowpea (Vigna unguiculata (L.) Walp.)

Summary The effects of K and Mg application on dry matter yield and uptake of K, Mg and Ca in cowpea were studied in greenhouse at Haryana Agricultural University, Hissar (india). Dry matter yields of leaves, stems and roots increased by 17, 30 and 27 per cent over control due to application of 150 ppm K and 17, 16 and 26 per cent by 40 ppm Mg respectively. Potassium application has antagonistic effect on Ca concentration of leaves, stems and roots and synergistic on root Mg concentrations upto 25 ppm K. However, Mg had a synergistic effect on concentration of K upto 20 ppm Mg and antagonistic at 40 ppm Mg in all plant parts. Uptake of K, Mg and Ca increased by Mg application, but K increased only K uptake.