Ontogeny of Somatic Embryos of Vigna aconitifolia, Vigna mungo and Vigna radiata

Callus cultures were initiated from immature cotyledons of Vignaaconitifolia, V. mungo and V. radiata on MS medium supplementedwith NAA, picloram or 2, 4-D. On transfer to L-6 liquid mediumsupplemented with low concentrations of picloram, GA₃ and cytokinins,large number of somatic embryos differentiated from the callus.The cells destined to become somatic embryos divided to formspherical or filamentous proembryos. From the filamentous proembryo,the embryo proper developed either at single or multiple sites.Development of somatic embryos from multiple sites resultedin several embryos connected by a common suspensor at the radicleend. Continued divisions of the proembryos led to globular,heart shaped and dicotyledonary stages of somatic embryogenesis.The somatic embryos of V. mungo and V. aconitifolia differentiatedinto tiny plantlets at low frequency (1%) in liquid suspensioncultures supplemented with zeatin, picloram and GA₃. Vigna aconitifolia Jacq, Marechal, mothbean, Vigna mungo L. Hepper, urdbean, Vigna radiata L. Wilczk, mungbean, somatic embryo     

Symbiotic hydrogenase activity in Bradyrhizobium sp. (Vigna) increases nitrogen content in Vigna unguiculata plants

Bradyrhizobium sp. (Lupinus) and Bradyrhizobium sp. (Vigna) mutants in which hydrogenase (hup) activity was affected were constructed and analyzed. Vigna unguiculata plants inoculated with the Bradyrhizobium sp. (Vigna) hup mutant showed reduced nitrogenase activity and also a significant decrease in nitrogen content, suggesting a relevant contribution of hydrogenase activity to plant yield.     

Expression of a-Amylase in Phaseolus vulgaris and Vigna mungo Plants

Levels of starch and soluble sugar in pods of Phaseolus vulgarisand Vigna mungo plants were analyzed during the course of maturationof fruits. The results suggest that the immature pods of P.vulgaris function to some extent as temporary reservoirs ofcarbohydrates for growth of seeds. A less clear pattern of accumulationof starch was observed in pods of maturing fruits of Vigna mungo.Measurements of a-amylase activites in pods of maturing fruitsand immunoblotting with an antiserum against     

The role of non-symbiotic haemoglobin and nitric oxide homeostasis in waterlogging tolerance in Vigna species

The objective of this study was to examine the role of nitrate reductase, nitric oxide and non-symbiotic hemoglobin in imparting waterlogging tolerance in mung bean genotypes. Experiment was conducted with two cultivated mung bean [Vigna radiata (L.) Wilczek] genotypes T 44 (tolerant) and Pusa Baisakhi (susceptible) and a highly tolerant wild species Vigna luteola (Jacq.) Benth. The content of nitric oxide increased up to 6 d of waterlogging in Vigna luteola and T 44, and up to 4 d of treatment in Pusa Baisakhi. Increase in nitrate reductase (NR) activity was observed only up to 4 d of waterlogging in Vigna luteola and T 44, and up to 2 d of treatment in Pusa Baisakhi, and thereafter the activity decreased in all the genotypes. The increase in NO content and NR activity was greater in Vigna luteola and T 44 than in Pusa Baisakhi. Non-symbiotic hemoglobin (NSHb) and cNR mRNA expressions were observed only in waterlogging treated roots of Vigna luteola and T 44, while very little expression was observed in control plants of Vigna luteola and T 44, and in control and waterlogged plants of Pusa Baisakhi. PCR bands of Hb and cNR were cloned, and nucleotide and deduced amino acid sequences were obtained and conserved regions and domains were identified using database.     

Identification of Acetylcholine as a Natural Constituent of Vigna Seedlings

An acetylcholine-like substance extracted from etiolated seedlingsof Vigna sesquipedalis was purified by Sephadex G-15 columnchromatography, paper chromatography and a newly devised spottest. It was identified as acetylcholine by field desorptionmass spectrometry. Vigna acetylcholine also could be separatedby the use of a liquid cation exchanger, sodium tetraphenylboronin n-butyronitrile. (Received December 3, 1982; Accepted April 13, 1983)     

In Vitro Responses of Brassica Juncea and Vigna radiata to the Antibiotic Kanamycin

Growth responses of Brassica juncea and Vigna radiata were studiedin vitro in the presence of the antibiotic kanamycin. The dataindicate that the kanamycin concentration for the inhibitionof growth varied considerably in both the species as well asin different explants of the same species. Brassica juncea, mustard, kanamycin, Vigna radiata, mung bean     

Barriers to interspecific hybridization between Vigna unguiculata and Vigna vexillata

Summary Interspecific hybridization between Vigna unguiculata and V. vexillata always failed: no seed was obtained in both crossing directions. Two different barriers to crossability were found: a pre-zygotic barrier and a post-zygotic one. Many abnormalities were observed in pollen-tube development, which reduced the percentage of fertilization to 18–30%. Differences in the percentage of fertilization were detected between the two accessions of V. vexillata involved in the interspecific crosses. The development of the interspecific embryo was analyzed and the embryo and endosperm nuclei always degenerated 5–8 days after pollination. The growth of the embryo stopped at a globular stage, which is too early for excision and in vitro culturing.     

Two new species of Vigna (Leguminosae) from Somalia

The new species Vigna monantha ( V. subgen. Vigna sect. Catjang ) from coastal dunes of northern and central Somalia, and V. virescens ( V. subgen. Macrorhynchus ) from the inland of central and southern Somalia are described and illustrated. V. virescens is unique in Vigna by having branched stylar hairs, a character indicating a relationship between V. subgen. Macrorhynchus and the monotypic Wajira.     

Effect of Ethanol, Methanol and Acetone on Rooting Etiolated Cuttings of Vigna radiata in Presence of Sucrose and Auxin

Root formation on etiolated hypocotyl cuttings of Vigna radiataL. is greatly enhanced in the presence of ethanol, methanoland acctone. Low concentrations of solvents plus sucrose slightlypromoted the formation of roots. Vigna radiata, alcohol, rooting, auxin     

Metabolism of Galactosylononitol in Seeds of Vigna umbellata

In this paper, we describe the occurrence of a new galactosylononitolsynthase activity (GOS) in seeds of Vigna umbellata. The enzymecatalyzed the reversible galactosyl transfer from galactinolto D-ononitol (lo-4-O-methyl-rnyo-inositol), yielding galactosylononitol(0-     

Nitrogen Relationships of Vigna mungo in Pure Stands and in Celosia argentea Mixtures

Dynamics of the nitrogen relationships of Vigna mungo in pureand in mixed stands with Celosia argentea, a common weed ofleguminous crops in certain regions of India, were investigated.The weed significantly depressed nodulation and reduced thedry matter and nitrogen yield of the legume which was lowestat the highest density of the weed. A significant amount ofnitrogen transfer occurred from the legume in the weed mixtureswhich appeared to be taken up by the weed plants. Therefore,weed plants benefited from their association with the legumeby accumulating more dry matter and nitrogen in the legume mixtures.The possible competitive or biochemical interference of theweed with nitrogen relationships of the legume in mixtures isdiscussed. Vigna mungo, Celosia argentea, pure stands, mixed stands, total nitrogen, interference     

Structure and Expression of a-Amylase Gene from Vigna mungo

A single copy of the a-amylase gene, composed of three intronsand four exons, was found in Vigna mungo. Examination of levelsof a-amylase and its mRNA in detached cotyledons indicated thatattachment of the embryonic axis is not required for expressionof the gene in cotyledons of germinating seeds. (Received December 21, 1993; Accepted March 14, 1994)     

Kinetin regulation of growth and secondary metabolism in waterlogging and salinity treated Vigna sinensis and Zea mays

Waterlogging mostly increased fresh weight and water content in shoots and roots of Vigna sinensis and Zea mays while salinity seemed to have a decreasing effect. There was a marked induction of proline in shoots and roots of both plants by salinity with lower values in logged plants. In addition, anthocyanin content was increased in Vigna sinensis by both treatments and in Zea mays only by salinity. Meanwhile the treatments significantly accumulated phenolic compounds in plant shoots. Also there were increased activities of phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) in shoots and roots of both plants. Foliar application of kinetin equilibrated, if any, the effects of both treatments on contents of proline, anthocyanin and phenolic compounds as well as activities of PAL and TAL in shoots and roots of treated plants. These findings reveal that kinetin alleviates the stress symptoms and regulates the changes in phenolic metabolism of waterlogged or salinity treated Vigna sinensis and Zea mays.     

Bradyrhizobium elkanii, Bradyrhizobium yuanmingense and Bradyrhizobium japonicum are the main rhizobia associated with Vigna unguiculata and Vigna radiata in the subtropical region of China

Cowpea (Vigna unguiculata) and mung bean (Vigna radiata) are important legume crops yet their rhizobia have not been well characterized. In the present study, 62 rhizobial strains isolated from the root nodules of these plants grown in the subtropical region of China were analyzed via a polyphasic approach. The results showed that 90% of the analyzed strains belonged to or were related to Bradyrhizobium japonicum, Bradyrhizobium liaoningense, Bradyrhizobium yuanmingense and Bradyrhizobium elkanii, while the remaining represented Rhizobium leguminosarum, Rhizobium etli and Sinorhizobium fredii. Diverse nifH and nodC genes were found in these strains and their symbiotic genes were mainly coevolved with the housekeeping genes, indicating that the symbiotic genes were mainly maintained by vertical transfer in the studied rhizobial populations.     

Aminopeptidases Isolated from Cotyledons of Cowpea, Vigna unguiculata

Three aminopeptidases have been separated from cotyledon extractsfrom cowpea, Vigna unguiculata (L.) Walp., and numbered in orderof decreasing affinity for the anion exchange medium DEAE-Sephacel.API showed a wide acceptance of model substrates, with highestactivity under standard conditions against arginyl ß-naphthylamide(NA). AP2 did not act on basic substrates and preferred phenylalanylß-NA. AP3 displayed the narrowest substrate specificity,with strong activity against only alanyl ß-NA andglycyl ß-NA. The chelator 1,10-phenanthroline completelyor almost completely inhibited forms AP1 and AP3, whereas AP2was insensitive to phenanthroline at the same concentration(5 mM). All three aminopeptidases were totally inhibited byAg⁺ or Zn²⁺ ( 0.5 mM). Vigna unguiculata (L.) Walp., aminopeptidase, cotyledon, cowpea, isoenzyme, 1, 10-phenanthroline     

Colorimetric Estimation of Glutamate Dehydrogenase in Leaf Tissue of Vigna mungo (L.) Hepper

Glutamate dehydrogenase (E.C. 1.4.1.2 [EC] ) is usually assayed bythe disappearance of NAD(P)H from the assay medium. A new technique,in which the enzyme level in leaf tissue of Vigna mungo (L.)Hepper is estimated by the disappearance of 2-oxoglutarate,is described. It provides a simple visible-range colorimetricassay for the enzyme. Vigna mungo, black gram, glutamate dehydrogenase, colorimetry     

Separation and Characterization of Two Endopeptidases from Cotyledons of Germinating Vigna mungo Seeds

Two major endopeptidases were present in cotyledons of germinating Vigna mungo seeds, as detected by the zymogram after polyacrylamide gel electrophoresis. They were not detectable in cotyledons of dry seeds, but their intensities on the zymogram increased during germination. During incubation of detached cotyledons, however, the activities showed only a slight increase for 5 days. These two endopeptidases could be separated by Sephacryl S-200 column chromatography. One of them was found to be a serine-endopeptidase as judged by phenylmethylsulfonylfluoride and diisopropyl fluorophosphate inhibition. The other was a sulfhydryl-endopeptidase because of its dependency on 2-mercaptoethanol and inhibition by leupeptin, chymostatin, and antipain. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis indicatd that the two endopeptidases digested the Vigna mungo seed globulin subunits at different rates. The serine enzyme digested the 56 kilodalton subunit at first, but the sulfhydryl enzyme digested the 54 kilodalton peptide more efficiently than the 56 kilodalton peptide. The pattern of digestion of globulin by the combination of the serine- and sulfhydryl-endopeptidases was similar to that using crude enzyme extracts.     

Enzymatic degradation of polar lipids in Vigna unguiculata leaves and influence of drought stress

¹⁴C-labelled polar lipids (monogalactosyl-diacylglycerol [MGDG], digalactosyl-diacylglycerol [DGDG], phosphatidylcholine [PC] and phosphatidylglycerol [PG]), purified from Vigna unguiculata leaves, were used as substrates to study the lipolytic activities of Vigna unguiculata leaf extracts. Analysis of the radioactive degradation products revealed the presence of at least three enzyme activities contributing to the hydrolysis of the four main leaf membrane lipids: Lipolytic acyl hydrolase (LAH) activities responsible for the deacylation of galactolipids and phospholipids, phospholipase D (PLD, EC 3.1.4.4) activity which gives rise to phosphatidic acid, and as suggested by the presence of diacylglycerols in minor quantities after phospholipid hydrolysis, phosphatidate phosphohydrolase (PAP, EC 3.1.3.4) and/or phospholipase C (PLC, EC 3.1.4.3.) activity. Under the conditions described in the present paper, the presence of phospholipase A (PLA₁, EC 3.1.1.3 and PLA₂, EC 3.1.1.4) activities remains hypothetical, due to the absence of lysophospholipids. LAH and PLD were partially soluble and partially associated with the membranes. When Vigna unguiculata plants were submitted to drought, the enzymatic degradation of galactolipids and phospholipids increased. The stimulation of lipolytic activities was greater in the drought-sensitive cultivar of Vigna unguiculata (cv. 1183) than in the drought-tolerant (cv. EPACE-1) one. In cv. 1183, MGDG- and DGDG-LAH activities in the membrane fractions were dramatically stimulated at a rather moderate water deficit (?0.75 MPa). A sharp increase in membrane phospholipolytic activities was also observed at mild drought stress (?1.2 MPa). In contrast, in cv. EPACE-1, the stimulation of lipolytic activities was less drastic and occurred at lower leaf water potentials (below ?1.2 MPa for galactolipases, and below ?1.4 MPa for phospholipases). Our results confirm the presence in leaves of higher plants of a very active LAH acting on galactolipids, whereas PLD is the main enzyme responsible for the degradation of phospholipids, particularly when plants are submitted to drought stress. The differences in stimulation of lipolytic activities between the two Vigna cultivars was in accordance with the different levels of membrane lipid degradation shown previously and could explain their different capacity to sustain drought.     

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     

Acid Phosphatase in Cotyledons of Germinating Vigna mungo Seeds

A marked increase in acid phosphatase activity took place incotyledons of germinating Vigna mungo seeds. The attachmentof axis organs was not required for this development of enzymeactivity in cotyledons. DEAE-cellulose column chromatographyrevealed that the phosphatase is composed of at least threeforms. (Received August 19, 1981; Accepted October 30, 1981)