Action Potentials in Lupinus angustifolius L. shoots

In Lupinus shoots electrical stimulus (DC) produces a voltagewave identical in character with the action potential in stimulatedsimple plant cells or in nerves. These action potentials wereregistered with a Kipp and Zonen Micrograph BD3, calomel electrodes,and an electrometer (input impedance, 10¹⁴ ). The wave form and its amplitude propagation velocity, pointof initiation, threshold value of the stimulus, and refractoryperiod were considered; the interdependence between these parametersand the magnitude and manner of application of the electricalstimulus are discussed. An analogy with Pflüger's laws was found.     

Isolation and Characterization of Protein Bodies in Lupinus angustifolius

Using Nycodenz, a novel density gradient medium, we isolated intact protein bodies from developing seeds of Lupinus angustifolius L. (cultivar Unicrop) and achieved excellent separation from the endoplasmic reticulum, mitochondria, and other organelles. The distribution of the storage protein conglutin-β was taken as evidence that up to 96% of the protein bodies remained intact on the gradients and banded at 1.25 grams per milliliter. The protein bodies also contained the three other abundant proteins present in L. angustifolius seeds: conglutins-α, -γ, and -δ. Pulse labeling experiments were carried out to determine the site of proteolytic processing of conglutin-α, a legumin-like 11Svedberg unit storage protein. Cotyledons aged either 33 or 40 days after flowering were pulsed with [³H]leucine. Protein bodies obtained from the cotyledons aged 33 days after flowering contained only the labeled precursors of conglutin-α with molecular weights 85,000, 72,000, and 64,000, even after a 4 hour chase of the radioactivity. Protein bodies obtained from the cotyledons aged 40 days after flowering contained the same radioactive precursors if the tissue had been pulsed for 2 hours, and the processing products of these precursors when the tissue had been chased for 4 hours. These studies confirm that the subcellular location of proteolytic cleavage of this legumin-like protein is the protein body, that this activity is detected only in protein bodies from lupin seeds aged between 33 and 40 days of seed development after flowering and that protein bodies from seeds younger than this contain only unprocessed conglutin-α.     

Characterization of a non-abscission mutant in Lupinus angustifolius. I. Genetic and structural aspects

A spontaneous mutant, Abs, that does not abscise any organs despite an apparently normal pattern of growth and senescence was isolated from among plants of Lupinus angustifolius cv. 'Danja'. Abs was found to be a recessive single gene mutation, and it was proposed that the gene for the original mutant phenotype, referred to as Abs, be designated abs1. An artificially induced mutant allelic to abs1 was also obtained and a non-allelic mutant phenotype, Delabs (delayed abscission), which was designated abs2. Morphological and cytological features of the abscission process under conditions of natural and ethylene-induced senescence were compared in the wild-type parent and Abs mutant. In the parent genotype abscission under natural conditions is similar to many other species, consisting of a stage of cell division forming an abscission zone, activation of the cytoplasm of zone cells, dissolution of the middle lamella, disorganization of fibrillar wall structure, and cell separation. A slightly different pattern of abscission zone development was observed for ethylene-treated explants of the parent, mainly with respect to features of cell division and cell enlargement. In Abs no abscission occurred for any abscission sites under conditions of natural senescence or with ethylene treatment of small shoot explants. However, relatively normal abscission zones were differentiated at all sites in the mutant except that extensive cell wall disorganization did not occur. Ethylene production by leaves or other organs of the mutant was no different from that of Danja. Application of copper salts or hydrogen peroxide, droughting, waterlogging, or application of abscisic acid (ABA) increased ethylene production equally in both genotypes but did not result in abscission in the mutant. Release of root cap border cells, the only other cell separation process examined, was similar in each genotype. The study concludes that the mutation is quite specific to the abscission process and may be due to a lack of or delay in the expression of hydrolytic enzyme(s) associated specifically with abscission zone differentiation and separation.     

Leaf water relations characteristics of Lupinus angustifolius and L. cosentinii

Summary Lupins (Lupinus angustifolius and L. cosentinii) growing in 321 containers in a glasshouse were exposed to drought by withholding water. Leaf water potential (₁), and leaf osmotic potential (_s) were measured daily as soil water became depleted. Leaf water relations were further assessed by a pressure-volume technique and by measuring _s and relative water content of leaves after rehydration. Analysis by pressure-volume or cryoscopic techniques showed that leaf osmotic potential at saturation (_s100) decreased from -0.6 MPa in well watered to -0.9 MPa in severely droughted leaves, and leaf water potential at zero turgor (_zt) decreased from about -0.7 to -1.1 MPa in well watered and droughted plants, respectively. Relative water content at zero turgor (RWC_zt) was high (88%) and tended to be decreased by drought. The ratio of turgid leaf weight to dry weight was not influenced by drought and was high at about 8.0. The bulk elastic modulus () was approximately halved by drought when related to leaf turgor potential (_p) and probably mediated turgor maintenance during drought. The latter was found to be negatively influenced by rate of drought. Supplying the plants with high levels of K salts did not promote adjustment or turgor maintenance.     

Das iberisch-nordafrikanische Heimatgebiet vonLupinus luteus L., Lupinus angustifolius L., Lupinus hirsutus L., Lupinus hispanicus Boiss. et Reut. undLupinus Rothmaleri Klink

Ohne ZusammenfassungDie Arbeit wurde durchgeführt mit Unterstützung des Forschungsdienstes und der Deutschen Forschungsgemeinschaft, denen an dieser Stelle herzlichst gedankt sei.     

High pH Causes Disintegration of the Root Surface in Lupinus angustifolius L.

The effect of high pH on the morphology and anatomy of the rootsof lupin (Lupinus angustifolius L. cv. Yandee) and pea (Pisumsativum L. cv. Dundale) was examined in buffered solution. Themorphology and anatomy of lupin roots were markedly altered,and root growth was reduced by increasing solution pH from 5·2to 7·5, whereas pea roots were unaffected. In lupin roots,pH 7·5 caused disintegration of the root surface andimpaired root hair formation. Lupin roots grown at pH 7·5also had decreased cell lengths but increased cell diameterin both the epidermis and the cortex in comparison to rootsgrown at pH 5·2. High pH reduced cell volume greatlyin the epidermis, to a lesser extent in the outer cortex andnot at all in the inner cortex. It appears that in lupins, theprimary detrimental effects of growth at pH 7·5 is reducedlongitudinal growth of cells near the root surface with a consequentreduction in elongation of the cells in inner cortex.Copyright1993, 1999 Academic Press Lupinus angustifolius L., Pisum sativum L., high pH, root morphology, root anatomy     

Precursors of storage proteins in Lupinus angustifolius.

The proteins that are synthesized during differentiation and development in the cotyledons of Lupinus angustifolius L. were characterized both in situ and after purification. The proteins present in situ were separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and subjected to 'Western'-blot analysis to identify immunologically related polypeptides. The major storage proteins of the lupin, conglutins alpha and beta, were both present in juvenile tissue only as higher Mr precursors. For conglutin beta, a family of at least three polypeptides of Mr 66 000-72 000 accumulated during the earliest phases of protein synthesis in the developing cotyledon (20-28 days after flowering). Later in development each of these polypeptides disappeared and there was the concurrent appearance in the cotyledon of the lower-Mr fragments characteristic of mature conglutin beta. For conglutin alpha, an equivalent family of precursor polypeptides of Mr 60 000-83 000 was detected. Multiple internal sites for proteolytic cleavage of all these precursors appeared to be present. However, processing of the precursors was sufficiently slow to allow them to accumulate to over 50% of total soluble protein in juvenile tissue. The precursors were purified by column chromatography under non-dissociating conditions and shown by ultracentrifugation to be multimeric proteins with Mr values in the range 150 000-200 000.     

Action Potentials in Lupinus angustifolius L. Shoots: III. DETERMINATION OF THE REFRACTORY PERIODS

The refractory periods for action potentials (AP) were investigatedin Lupinus shoots by application of pairs of electrical stimuli(d.c). The response (AP) for the second stimulus is characterized.The second response differs in amplitude, range, and propagationvelocity from the first, depending on the strength of the stimuliand the time interval between them. The absolute refractoryperiod determined on this basis lasts 12 min, and the relativeone from 12 to about 90 min. The character of the refractoryphenomenon is similar in the case of nerves, only the processesin Lupinus are 10³ to 10⁵ times slower. The possibility of transmission of excitation from cell to cellis discussed.     

Synthesis, transport and accumulation of quinolizidine alkaloids in Lupinus albus L. and L. angustifolius L

Each of the principal quinolizidine alkaloids (QA) found in both xylem and phloem exudates together with extracts from all component organs collected from bitter (cv. Lupini) and sweet (cv. Ultra) cultivars of Lupinus albus L. were quantified by gas chromatographic analyses throughout reproductive development. In addition to establishing the major translocated QA species estimates for fluxes of QA to developing fruits based on their sap composition and water economy showed that around half of the QA that accumulated in fruit tissues was due to synthesis in situ and half to translocation principally by phloem. Detailed analyses of QA in transport fluids and component organs were extended to reciprocal homo- and hetero-grafts using bitter (cv. Fest) and sweet (cv. Danja) cultivars of L. angustifolius L. These data confirmed that the majority of QA were synthesized in shoot tissues. In both lupin species feeding and analysis of deuterated QA (lupanine and 13-hydroxylupanine) were used as tracers to demonstrate direct redistribution of alkaloids by translocation from mature leaves in phloem.     

A high amount of satellite DNA in the genome of Lupinus angustifolius L.

Embryo DNA, isolated from ungerminated seeds of Lupinus angustifolius L., contains an exceptionally high amount of guanine-cytosine-rich satellite DNA. The thermal denaturation curve of total embryo DNA is biphasic with an inflexion point at 62% denaturation, indicating the presence of satellite DNA. The satellite fraction could be separated from the mainband DNA by three successive preparative CsCl-gradient centrifugations. The densities of the DNA fractions are 1.7045 g cm^-3 and 1.6925 g cm^-3, respectively. The percentages of guanine-cytosine calculated from these densities are comparable to the percentages of GC calculated from the melting temperatures. Finally, ressociation studies prove that foldback DNA and highly repeated sequences are much more frequent in the satellite DNA fraction than in the mainband DNA.Abbreviation C _o t the product of the DNA concentration (mol nucleotides l^-1) and the time (s) of incubation in a DNA reassociation reaction - GC guanine-cytosine - np nucleotide parirs - T temperature interval between 16 and 84% denaturation     

The reaction of Lupinus angustifolius L. root meristematic cell nucleoli to lead

The effect of 2–48 h treatment of Lupinus angustifolius L. roots with lead nitrate at the concentration of 10⁻⁴ M on the nucleoli in meristematic cells was investigated. In the lead presence the number of ring-shaped as well as segregated nucleoli increased especially after 12–48 h of treatment, while spindle-shaped nucleoli appeared after 24 h and 48 h. Lead presence also increased the frequency of cells with silver-stained particles in the nucleus and the number of these particles especially from the 12th hour of treatment. It was accompanied by significant decline of nucleolar area. Analysis of these cells in transmission electron microscope confirmed the presence of ring-shaped and segregated nucleoli. Moreover, electron microscopy revealed compact structure nucleoli without granular component. Additionally, one to three oval-shaped fibrillar structures attached to nucleolus or lying free in the nucleoplasm were visible. The possible mechanism of lead toxicity to the nucleolus is briefly discussed.     

Triterpene glycosides of Lupinus angustifolius

Investigation of whole seeds of Lupinus angustifolius L. (Leguminosae) yielded the two triterpenoid saponins with branched monosaccharide chain 3 beta,21 beta,22 beta,24-tetrahydroxyolean-12-en-3-O-alpha-L-rhamnopyranosyl-(1-->3)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranoside (3) and 3 beta,21 beta,22 beta,24-tetrahydroxyolean-12-en-3-O-alpha-L-rhamnopyranosyl-(1-->3)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-O-alpha-L-rhamnopyranoside (4) along with the known compounds soyasaponin I (1) and 3 beta,21 beta,22 beta,24-tetrahydroxyolean-12-en-3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-O-alpha-L-rhamnopyranoside (2). The structures of the compounds were elucidated using hydrolysis, FAB-MS and extensive NMR experiments. Compounds 2-4 showed moderate antifungal activity against Candida albicans with MIC values of 25, 25 and 30 microg/ml, respectively. Only soyasaponin I was found weakly hemolytic (HC(50) >500 microg/ml).     

High pH in the nutrient solution impairs water uptake in Lupinus angustifolius L.

Root growth in Lupinus angustifolius is greatly decreased when the nutrient solution has a pH above 6.0. This study examined the water relations in this species (cv. Yandee) in response to high pH in solution culture in a glasshouse.The dry weight of roots, the length of taproots and lateral roots and the number of lateral roots were significantly reduced at day 12 after transfer to solution with a pH of 7.5 compared to pH 5.2. This resulted in a marked reduction of total root surface area. However, shoot growth and total leaf area were not affected. In comparison with pH 5.2, plants grown at pH 7.5 in the nutrient solution had a 14–38% more-negative leaf water potential, and their stomatal resistance had increased by 67%.The observations indicate that the impairment of the water relations by high pH is mainly caused by decreased root growth.     

The Distribution of Nine Elements in Shoots of Lupinus albus L. and Lupinus angustifolius L. Compared with that of Silicon as a Measure of Passive Transport

The Ca, Mg, K, Na, P, Fe, Mn, Zn, Cu and opaline-Si contentsof leaves, stems and inflorescences from each order of shootaxis was determined in Lupinus albus L. and Lupinus angustifoliusL. The distribution of Si was used as a base for passive transportin the transpiration stream. All of the elements investigatedwere redistributed among the leaves, stems and inflorescencesof either L. albus or L. angustifolius. Most of the elementsinvestigated were enriched in the inflorescences and depletedin either the leaves or the stems. Sodium was enriched in thestems whereas Ca and Mn were redistributed only in L. albus.The pattern of element redistribution was similar in each ofthe lateral shoot axes except for the youngest. For the elementsenriched in the inflorescences, more than half was suppliedby redistribution. Calcium redistribution was similar to thatfor K, which is regarded as phloem mobile, but a mechanism forCa redistribution is uncertain. Lupinus albus L., Lupinus angustifolius L., mineral transport, leaves, inflorescences, transpiration, silicon, calcium     

Diurnal Patterns of Transport and Accumulation of Minerals in Fruiting Plants of Lupinus angustifolius L.

Fluctuations in mineral elements id xylem (tracheal) sap, fruitphloem sap, leaflets and dmloping fruits were studied in a fieldpopulation of Lupinus angustifolius L. by three-hourly samplingover a 39 h period. Elements usually reached maximum contentsor concentrations at or near noon, minimum levels during thenight. Amplitudes of diurnal fluctuations in minerals lay withinthe range ±4–33 per cent of the mean content ofleaflets, and ±17–157 per cent of the mean concentrationsin xylem and phloem sap. Most minerals elements fluctuatcd inphase with daily changes in sugar level of phloem sap and drymatter and carbohydrate fluctuations of leaflets, suggestinga coupling of translocation of photosynthate and minerals fromthe leaflets. Rates of import of minerals by shoots wereestimatedfrom shoot transpiration and mineral concentrations in trachealsap. Average day time rates of import of most elements were12–25 times those at night. Translocation of minerals,nitrogen and carbon to fruits also exhibited diurnal periodicity,average rates of import king three to seven times higher inthe day than at night. A model of transport based on the carbonand water economy of the fruit suggested that P, K, Fe, Zn,Mn and Cu were imported predominantly by phloem. Estimates ofvascular import accounted for 87–104 per cent of the fruit'sactual increment of these elements. Na and Ca were gauged tobe imported mainly by xylem, Mg almost equally by xylem andphloem. However, large discrepancies existed for these threeelements between estimated vascular import and actual intakeby the fruit. Lupinus angustifolius L., mineral transport, accumulation, fruits, xylem sap, phloem sap, transpiration