Species Pisum Research Articles

Subterranean clover mottle sobemovirus: its host range, resistance in subterranean clover and transmission through seed and by grazing animals

SummarySubterranean clover mottle sobemovirus (SCMV) was transmitted by manual inoculation of sap to 27 cultivars belonging to three sub‐species of subterranean clover. The virus readily infected systemically all inoculated plants of five susceptible cultivars of ssp. subterraneum. Ten others showed partial resistance as not all infected plants developed systemic infection; cold winter conditions further delayed or prevented systemic movement in four of them. Two cultivars of spp. brachycalycinum and four of spp. yanninicum failed to develop systemic infection following inoculation and were considered highly resistant. Resistance to SCMV in three of the spp. yanninicum was further confirmed by the failure to establish detectable primary infections in most of the inoculated leaves. Moreover, when the four ssp. yanninicum cultivars were graft‐inoculated with SCMV, systemic infection eventually developed in them but the virus concentration was low. SCMV was also transmitted by manual inoculation of sap to a further 23 species of Trifolium, Medicago or Pisum. Three species were non‐hosts, five were infected only in inoculated leaves and 18 others developed systemic infection in some or all plants.SCMV reached very high concentrations and was stable in subterranean clover sap. It was transmitted experimentally between subterranean clover plants by brushing infected leaves against healthy ones and in swards was readily transmitted by the trampling and grazing of sheep, but only poorly by mowing. Seed transmission of SCMV to seedlings of five cultivars of subterranean clover was low (0–0.12%). SCMV was not transmitted by Myzus persicae.

The influence of prior ovipositional experience on host selection in four species of aphidiid wasps (Hymenoptera: Aphidiidae)

We evaluated the influence of prior ovipositional experience on host selection in four solitary parasitoids, Aphidius erviHaliday, A. pisivorusSmith, A. smithiSharma & Subba Rao, and Praon pequodorumViereck (Hymenoptera: Aphidiidae). When provided simultaneously with equal numbers of two species of aphids, Acyrthosiphon pisum(Harris) and Macrosiphum creeliiDavis (Homoptera: Aphididae), all four parasitoids showed a moderate to strong preference for A. pisum.This preference did not increase after sampling, except in P. pequodorum.Learning did not alter host selection behavior in A. erviand P. pequodorum.However, females of A. pisivorusconditioned on A. pisumselected fewer M. creeliithan unconditioned wasps and wasps conditioned on M. creelii.It is suggested that prior ovipositional experience influences a parasitoid's expectations of the kinds of hosts available, but it does not alter the (innate) rank order of hosts.

Cytological and Morphological Characterization of Pisum sativum and Pisum fulvum Tetraploids

AbstractTwo colchicine‐induced tetraploid lines, one belonging to Pisum sativum and the other to the wild species Pisum fulvum, were compared with their corresponding diploids and among themselves for chromosome number, meiotic behaviour and for pollen and pod fertility. For both lines, five generations were analyzed; the tetraploid level was maintained throughout the generations. In P. fulvum, aneuploids with 27, 29 and 30 chromosomes were observed, while in P. sativum aneuploids with 29 chromomes were found. Meiotic analysis evidenced a higher number of quadrivalents and a lower number of univalents in P. fulvum. This particular chromosomal behaviour may also have been responsible for determining the higher pollen and pod fertility in P. fulvum. Wild species of this genus seem to have better tolerance for ploidy variations.

Immunochemical analysis of lipopolysaccharides from free-living and endosymbiotic forms of Rhizobium leguminosarum

Rhizobium leguminosarum B556 and 8002 differ only with respect to carrying symbiotic plasmids with specificity for Pisum or Phaseolus hosts, respectively. Protease-treated samples derived from free-living cultures of both strains revealed a ladder of lipopolysaccharide (LPS-1) bands after periodate-silver staining of sodium dodecyl sulfate-polyacrylamide gels. These bands were arranged as doublets. After Western (immuno-) blotting, all LPS-1 bands reacted with monoclonal antibody JIM 21, whereas monoclonal antibody MAC 57 reacted only with the upper (slower-migrating) band and monoclonal antibody MAC 114 reacted only with the lower band of each doublet pair. Preparations obtained from bacteroids of Pisum or Phaseolus nodules showed significant differences in the size distribution and antigenicity of LPS. In bacteroids from Phaseolus sp., JIM 21 and MAC 57 each stained a ladder of LPS-1 bands on sodium dodecyl sulfate-polyacrylamide gels which corresponded in mobility to the upper band of each doublet pair seen in free-living cultures. MAC 114 did not react with the LPS from Phaseolus sp.-derived bacteroids. In bacteroids from Pisum sp., only fast-migrating (lower-molecular-weight) forms of LPS-1 could be visualized on gels, but both upper and lower bands of each doublet were still present and could be stained by the appropriate monoclonal antibody, MAC 57 or MAC 114, respectively. Similarly, bacteroids from R. leguminosarum 3841, which nodulates Pisum species, differed with respect to the structure and antigenicity of their LPS-1 from bacteroids of a related strain, B625, which nodulates Phaseolus species. Physiological factors were investigated that could account for these differences between the structures of LPS-1 from free-living cultures of B556 and 8002 and that from bacteroids. The following modifications in growth conditions each tended to reduce the expression of MAC 114 antigen and enhance the expression of MAC 57 antigen: succinate rather than glucose as the carbon source; microaerobic (2.5%, vol/vol) oxygen concentrations; and acidic (pH 5 to 6) culture medium. When all three of these conditions were combined, the LPS-1 that resulted was very similar to that in bacteroids from Pisum nodules. However, it was not possible to reproduce the LPS-1 pattern observed for bacteroids from Phaseolus nodules, which maintained a ladder of LPS bands reacting with MAC 57 antibody.

Nitrogen nutrition of seedling grain legumes: some taxonomic, morphological and physiological constraints

Abstract The growth of young plants of the epigeal species Phaseolus vulgaris and Glycine max is compared with that of the hypogeal species Pisum sativum and Vicia faba, with particular reference to synchronization between the exhuastion of seed reserves of N and the availability of fixed N. It is argued that the N stress symptoms which occur when these two processes are not synchronized are more common and obvious in Phaseolus or Glycine than in Pisum or Vicia. This is primarily because in these species (a) the first fixed N is used for nodule growth rather than being exported to the shoot system and (b) the first foliage leaves have a much greater area and contain a larger proportion of N reserves from the seed.It is further suggested that Phaseolus and Glycine may show the greater response to nitrogen fertilizer applied at sowing since (a) most of the applied nitrate is passed directly to the shoots (rather than being reduced in the roots as in Pisum or Vicia) and (b) in addition to being used for growth (following reduction), it may also be used prior to reduction as part of the osmotic force driving cell expansion.

Stomatal Behaviour and Water Relations of ChilledPhaseolus vulgarisL. andPisum sativumL.

Leaf diffusion resistance interpreted as stomatal resistance, leaf water potential ((//w), solute potential (y/s) and leaf turgor potential (^p) of the chilling sensitive species Phaseolus vulgaris were determined during chilling at 4 °C in the light. Both chill-hardened and non-hardened plants were used. For comparison, the chilling resistant species Pisum sativum was also used. The results for chilled P. sativum were similar to those obtained for chill-hardened P. vulgaris plants receiving a chilling treatment. In both cases a reduction in stomatal aperture and the maintenance of a positive leaf turgor were the responses to chilling. Leaves of chilled but non-hardened P. vulgaris plants were found to maintain open stomata throughout the chilling treatment despite a severe wilt developing after 7 h at 4 °C. This was in contrast to the chill-resistant P. sativum, which showed a rapid closing and subsequent re-opening of the stomata to a new reduced aperture. During the first 12 h of chilling i//w of P. vulgaris leaves changed from —0-47 MPa to - 1 -24 MPa. On more prolonged chilling y/w tended to return to pre-chilling values. In addition, i//p decreased from 0-42 MPa to zero after only 9 h of chilling, and remained at this value for the remainder of the chilling period. y/s changed rapidly from -0-89 MPa to -1-35 MPa in the first 7-5 h, and after 9 h. (//w and t//s were equal, i.e. zero i//p. In contrast, the chilling resistant plant P. sativum maintained a positive i//v throughout the chilling period, and there was little difference between values of i//w and i//s in control and chilled leaves.

Early development of the parthenogenetic egg in three species of aphids (homoptera : Aphididae)

Light microscope studies of the structure and function of the germarium in parthenogenetic morphs of 3 species of aphids, Acyrthosiphon pisum, Myzus persicae and Aphis fabae, are reported, with the emphasis on cytogenetic aspects of the development of the parthenogenetic egg. After a series of oogonial divisions, the cells of the germarium are arrested at an early prophase stage, in which the homologous chromosomes appear to show a partial synapsis. The first one or 2 oocytes develop directly from the most posterior of these germarial cells, with gradual condensation of chromatin throughout their growth phase. Only after one or 2 ovulations have occurred does a group of posterior cells become differentiated simultaneously from the rest as presumptive oocytes. The chromosomes of these cells enter a condensation phase which lasts until after each is released from the germarium. Separation of homologues precedes condensation, and no evidence could be found to support the theory of “endomeiotic recombination”. Trophic cords running from the germarial lumen to both the first and second follicles in an ovariole, and supplying embryos at least up to the blastula stage of development, were found in all 3 species.

Quantitative and qualitative investigations on the seed proteins of mutants and recombinants of Pisum sativum

The proteins of the seed flour of 26 X-ray induced mutants and 5 recombinants of the species Pisum sativum were analysed quantitatively and qualitatively. The values obtained were related to the seed yield of the genotypes In this way, the protein yield as well as the production of specific amino acids per genotype were determined. The following results were obtained. 1. The mean values for the character "total protein content of the seed flour" of the genotypes studied varied between 14 and 23%. The fasciated mutant 489C produced 18-23% more seed proteins than the initial line in three subsequent generations. The mean values of some other mutants and recombinants were 10-17% higher, the lowest value being 27% lower than that of the control values. In the material investigated there is no correlation between seed size and seed protein content. 2. The buffer-soluble seed proteins of 55 mutants were electrophoretically subdivided in different subfractions and the protein patterns were determined. They are extraordinarily variable. Distinct groups of mutants do not only differ from the initial line but also from one another with regard to the number, position and breadth of their bands. A correlation between the degree of morphological deviations of specific genotypes and the composition of their seed proteins was not observed. Moreover, differences in the concentration of specific protein fractions between the genotypes were densitometrically ascertained. 3. The globulins and albumins of some genotypes were quantitatively determined and electrophoretically subdivided into subfractions which differ between different mutants with regard to their number as well as their concentration. This is especially valid for the albumins which could be essentially stronger subdivided than the globulins. 4. The amino acid spectra of all the mutants investigated agree qualitatively with the spectrum of the initial line, however, clear quantitative differences in distinct amino acids were observed. The proportion of the essential amino acids is increased in two mutants by 5 and 20% in relation to the control line. 5. The protein production of the fasciated mutant 489C was 20-70% higher than the corresponding values of the initial line in three subsequent generations regarding its high seed production. The protein yield of the early flowering mutant 46C was about 20% lower and that of the bifurcated mutant 1201A 12-31% higher as related to the initial line. Mutant 1201A shows an equally favourable situation with regard to the total content of the essential amino acids. Its lysine production exceeded the control values by 20-40%. 6. The different components of the protein synthesis can negatively be influenced by the co-operation of the mutant genes. The protein production per plant, the total production of essential amino acids as well as the lysine production are lower in the recombinants 68C/176A and 68C/1201A as compared to the parental mutants. The combination of genes 68C and 46C does not show any negative interactions.

Isoperoxidase pattern and internode length genotype in Pisum

Inbred Pisum sativum lines of known constitution for the intemode length genes Le, La and Cry, and representing four height phenotypes, were grown to the 7-intemode stage in the light. Six cationic isoperoxidases, making up ca. 90% of the activity of stem extracts, were resolved by concave gradient elution from Dowex 50 columns and shown to run as single peroxidase bands on starch gel electrophoresis. They were all able to oxidise IAA in the presence of 2,4-dichlorophenol, but fell into two groups with widely differing IAA oxidase/peroxidase ratios. The isoperoxidase patterns were independent of both genotype and phenotype for internode length, thus making it unlikely that these loci exert their effect on internode extension via control of synthesis of a particular isoperoxidase. Amongst the lines screened polymorphism was detected involving two of the isoperoxidases, and limited F 2 data suggest that these two variants fire determined by alleles of a single gene. Isoperoxidase patterns of stem extracts of 6 other Pisum species did not differ significantly from the two found in P. sativum.

Emergence of Hypogeal and Epigeal Germinating Species of Phaseolus and Pisum in Compacted and Uncompacted Soil1

Abstract Emergence of 2 epigeal and 1 hypogeal species of Phaseolus and a hypogeal species of Pisum were compared under packed and unpacked soil conditions. Hypogeal entries consistently exhibited better emergence thiough packed and crusted soils than the epigeal entries.

Nodulation and frequencies of wild leguminous species in the northern Negev region of Israel

(1) The nodulation by Rhizobiurn of Old World leguminous range species occurring naturally under semi-desert conditions on soils of medium and lower fertility was assessed for reference to comparable areas in southern Australia and in connection with the development of ley farming practices in dry marginal wheat areas of the Middle East. (2) Nodules were present on all 33 legumes found on three soil associations in a transition zone between the Mediterranean and Irano-Turanian plant geographical territories. All species showed evidence of symbiotic nitrogen fixation; there was great variation between species in that some were uniformly well nodulated, but others were nodulated sparsely and at a low level of effectiveness. (3) In terms of amount and apparent effectiveness of nodulation per plant in spring, species of Lathyrus, Pisum, and Vicia were outstandingly good. A species each of Hymenocarpos and Lotus were well nodulated, and intermediate degrees of nodulation characterized species of Hedysarum, Hippocrepis, another Lotus, Medicago, Onobrychis, Scorpiurus, Trifolium, and Trigonella. Four species of Astragalus, one of Coronilla, and two of Ononis were poorly nodulated in the natural state on these lands. (4) Plants of Trigonella arabica Del. were present at greatest frequency over the three soil associations but species of Trifolium and Medicago were minor components. In terms of volume of active nodule tissue, however, Hymenocarpos circinnatus (L.) Savi was rated best over all soils; Onobrychis crista-galli(L.) Lam. was prominent in this respect in the most arid places.

Serological Studies in Medicago, Melilotus, Trigonella, and Certain Other Genera of the Leguminosae. I. Quantitative Precipitin Tests and Immunodiffusion Techniques

Thirty-four Medicago, 11 Melilotus and eight Trigonella species were compared serologically, using antisera developed against the four Medicago species: M. truncatula, M. intertexta, M. polymorpha, and M. orbicularis. Quantitative serological tests (Boyden method) disclosed a high degree of serological correspondence among the Medicago species with the exception of M. lupulina, M. orbicularis, and M. radiata. Antiserum against M. orbicularis could differentiate this species from other species of Medicago. The four antisera were able to differentiate Medicago from Melilotus and Trigonella antigens. However, a high degree of serological correspondence, on the order of 55%-80%, was found between species of the three genera. There was 35% or less serological correspondence between Medicago and Trifolium, Lupinus, and Pisum species. Double immunodiffusion tests failed to disclose differences among most Medicago species. The exceptions, M. lupulina and M. secundiflora, differed by having one precipitin band less. Two precipitin bands were absent in reactions with M. radiata and with several Trigonella species. Not less than three of the precipitin bands found in reactions between Medicago antigens and antisera were lacking in the tests with Melilotus species. These differences were confirmed by absorption experiments. Slight serological similarities were observed in reactions between Medicago species and various species of other genera of the Leguminosae. The serological data are conservative since they do not generally differentiate the individual Medicago species, which are often quite distinctive when classified by other criteria. However, the differences found in M. lupulina and M. secundiflora and in M. radiata suggest a need for a reappraisal of the taxonomic position of the sections Lupularia and Medicago, presently placed in the genus Medicago.

The Leaf-Base and the Interdone- Their true Morphology


 Development of the leaf primordium at the shoot apices of 14 species of dicotyledons has been studied.
 These include exstipulate, stipulate and sheathing leaves with or without a free base.
 The axial component which is laid down first during the initiation of a leaf development at the apex of a vegetative shoot is a part of the leaf and is to be considered as its base.
 In species where a free base is wanting, the axial component represents the only base and the cauline and discontinuous stipular scar, which led Ponzo, Cross and others to doubt the origin of stipules from the leaf-base, is explained.
 The development of a free base in the form of a sheath and/or a pair of stipules depends on the course and behaviour of the trace bundles through the axial component (e.g. in species of Centella, Polygonum, Ixora, Ervatamia, Rosa, Morus, Calotropis, Artocarpus, Ficus, Paederia, Hibiscus and Pisum).
 If the laterals change their vertical course, bend and follow an oblique horizontal course towards the median at the top of the axial component, the petiole appears to be inserted directly on the axis without any evident base (free) as in the species of Ficus, Paederia, Jasminum, Hibiscus, Morus and Pisum
 If during the horizontal course the laterals branch in the axial component, a single (Ficus elastica, Ervatamia divaricata, Polygonum orientale), or a pair of stipules (Ficus religiosa, Artocarpus integrifolia, Morus alba, Hibiscus rosa-sinensis, Pisum sativum and Rosa centifolia), or a composite stipule (Ixora parviflora and Paederia foetida), are formed with the branches as their traces, and the stipular scars appear cauline.
 If the laterals, two or many, run almost parallel to one another and to the median, even after leaving the axial component for some time before they turn towards the median, a sheathing but free base is formed which partially or completely encloses the axis, depending on the number and nature of the course of the laterals (e.g. Centella and Rosa).
 If in a multilacunar node the laterals branch during their horizontal course towards the median the stipule formed is either an ochrea (Polygonum), or bud scales (species of Ficus and Artocarpus).
 If, however, the laterals do not branch and gradually shift towards the median where they form with the latter a ring of vascular bundles, the sheath becomes oblique and tapering without any stipule (Centella).
 The base, i.e. the axial component, and its free portion, if there be any, can be anatomically distinguished by the nature and behaviour of the laterals, from the petiole: in the base they gradually approach the median without joining it and may branch, but in petiole they either join with the median (Rosa) or arrange themselves with the latter in the form of a ring of vascular bundles (Centella). They again branch in connection with leaflet and lamina formation.
 The internode is made up of an axial core and a mantle derived from two different zones of the eumeristem - the corpus and the flank meristems. The mantle is made by base or bases (axial component or components) of the leaves, and extends radially up to the pith as suggested by Hofmeister.