Early plant domestications in southern India: some preliminary archaeobotanical results

Analysis of flotation samples from twelve sites in Karnataka and Andhra Pradesh (south India) provides clear evidence for the predominant subsistence plants of the Neolithic period (2,800–1,200 cal b.c.). This evidence indicates that the likely staples were two pulses (Vigna radiata and Macrotyloma uniflorum) and two millet-grasses (Brachiaria ramosa and Setaria verticillata) which were indigenous to the Indian peninsula. At some sites there is evidence for limited cultivation of wheats (Triticum diococcum, Triticum durum/aestivum) and barley (Hordeum vulgare), and a few crops that originated in Africa, including hyacinth bean (Lablab purpureus), pearl millet (Pennisetum glaucum) and finger millet (Eleusine coracana). In addition there is evidence for cotton (Gossypium sp.), and linseed (Linum sp.), as well as gathered fruits of Ziziphus and two Cucurbitaceae. This evidence suggests that the earliest agriculture in south India, dating to the third millennium b.c., was based on plants domesticated in the region, and that subsequently from the late 3^rd millennium b.c. through the 2^nd millennium additional crops from other regions were adopted into the subsistence system.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00334-004-0036-9     

Effects of Abscisic Acid Application on Photosynthesis and Photochemistry of Stylosanthes guianensis under Chilling Stress

In our previous study, it was found that abscisic acid (ABA) improved the chilling resistance of Stylosanthes guianensis. In order to determine the effects of ABA on photosynthesis and photochemistry of S. guianensis, an experiment was conducted under controlled condition to determine the effects of exogenous ABA on stomatal conductance (g_s), transpiration (E), photosynthetic rate (A) and chlorophyll a fluorescence of this pasture legume. The results showed that ABA treatment reduced A, g_s, and E under both chilling (8 °C) and control temperature (28 °C). A of the ABA treated plants returned to a high rate, while that of the water-treated plants remained low when plants were rewarmed after chilling treatment. ABA-treated plants had higher maximum photochemical efficiency (F_v/F_m), non-photochemical quenching (NPQ), quantum efficiency of PS II photochemistry (Φ_{ps ii}) than water-treated ones during chilling. Although the biomass of S. guianensis was reduced by ABA under control temperature, ABA-treated plants had higher biomass than water-treated ones after 7 days of recovery.     

Regeneration and large-scale propagation of bamboo (Dendrocalamus strictus Nees) through somatic embryogenesis

A complete protocol for large-scale propagation of Dendrocalamus strictus Nees by somatic embryogenesis has been developed. Seeds cultured on agar-solidified Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D; 3×10^–5 m) produced embryogenic callus from proliferation of the embryo. Somatic embryos formed in vitro multiplied rapidly (two- to five fold every 5 weeks) on semi-solid MS medium containing 2,4-D (1×10^–5 m), kinetin (Kn) (5×10^–6 m), 1-indolebutyric acid (IBA) (2×10^–6 m) and soluble polyvinylpyrrolidone (PVP) (250 mg l^–1), or MS with 2,4-D (1×10^–5 m), 6-benzylaminopurine (BAP) (1×10^–5 m), and soluble PVP (250 mg l^–1). Upon transfer to MS containing 1-naphthaleneacetic acid (NAA) (5×10^–6 m), Kn (5×10^–6 m) and soluble PVP (250 mg l^–1), the dark-green embryos developed into healthy plantlets. Unrooted shoots, if any, obtained on the multiplication media were rooted on MS major salts reduced to half strength supplemented with NAA (3×10^–6 m) and IBA (2.5×10^–6 m). The rooted plants were successfully transferred to soil in polythene bags with over 80% survival. Using this methodology, more than 100,000 plants have been produced. Received: 16 April 1998 / Revision received: 25 September 1998 / Accepted: 10 October 1998     

Larval and pupal parasites ofLymantria dispar and notes on parasites of otherLymantriidae [Lep.] in Poland 1975

Larvae and pupae ofLymantria dispar (L.) were collected periodically from infestations on Linden trees at Nieborów near Skierniewice and at Alexandrowa, south of Poznan, Poland during May–July 1975. The following parasites were recovered:Braconidae: Apanteles liparidis (Bouché),A. melanoscelus (Ratzeburg),A. porthetriae Muesebeck,Meteorus pulchricornis (Wesmael);Ichneumonidae: Coccygomimus instigator (F.),Hyposoter tricoloripes (Viereck),Phobocampe n. sp.,P. disparis (Viereck);Tachinidae: Blepharipa pratensis (Meigen),Blondelia nigripes (Fallén),Carcelia separata (Rondani),Compsilura concinnata (Meigen),Parasetigena silvestris (Robineau-Desvoidy),Palexorista sp. Similar but less extensive collections were made of larvae ofOrgyia antiqua (L.). These yieldedApanteles sp.,A. melanoscelus, Tramosema rostrale (Brischke),Meloborus sp.,B. nigripes andP. silvestris; larvae ofLeucoma salicis (L.) yieldedA. melanoscelus andMeteorus versicolor (Wesmael). OnlyBlondelia sp. was recovered from the few larvae ofPorthesia similis (Fuessly) collected.

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Résumé Des chenilles et des chrysalides deLymantria dispar (L.) ont été ramassées périodiquement en Pologne de mai à juillet 1975 dans les peuplements de tilleuls infestés, à Nieboróv près de Skierniewice et à Alexandrowa, au sud de Poznan. Les parasites obtenus ont été les suivants: lesBraconidae: Apanteles liparidis (Bouché),A. melanoscelus (Ratzeburg),A. porthetriae Muesebeck,Meteorus pulchricornis (Wesmael); lesIchneumonidae: Coccygomimus instigator (F.),Hyposoter tricoloripes (Viereck),Phobocampe n. sp.,P. disparis (Viereck); lesTachinidae: Blepharipa pratensis (Meigen),Blondelia nigripes (Fallén),Carcelia separata (Rondani),Compsilura concinnata (Meigen),Parasetigena silvestris (Robineau-Desvoidy), etPalexorista sp. Des collectes du même type mais moins importantes de chenilles d’Orgyia antiqua (L.) ont permis d’obtenir les parasites suivants:Apanteles sp.,A. melanoscelus. Tranosema rostrale (Brischke),Meloborus sp.,B. nigripes, etP. silvestris. Des chenilles deLeucoma salicis (L.) ont donnéA. melanoscelus etMeteorus versicolor (Wesmael). SeulBlondelia sp. a été obtenu à partir de quelques chenilles dePorthesia similis (Fuessly).

     

Observations on the seasonal incidence of microsporidiosis in European corn borer populations in Illinois

Summary Examinations of living and dead larvalPyrausta nubilalis (Hübner) collected in the field over a four-year period indicate that infections caused byPerezia pyraustae Paillot are widely distributed within populations ofP. nubilalis in Illinois. Observed fluctuations in the incidence of the parasite among living and dead insects collected in various seasons was taken as evidence that the disease interacts with temperature to cause mortality in populations of the host.

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Résumé Des examens des larves vivantes et mortes dePyrausta nubilalis (Hübner) collectées dans les champs pendant quatre années consécutives indiquent que des infections parPerezia pyraustae Paillot sont très fréquentes dans les populations deP. nubilalis en Illinois (états-Unis). Les fluctuations observées dans l'incidence du parasite dans les insectes vivants et morts recueillis pendant plusieurs saisons montrent que la maladie est influencée par la température, celle-ci occasionnant la mortalité dans les populations de l'h?te.

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An abridgment of a portion of a thesis submitted in partial fulfillment of the requirements for the degree Doctor of Philosophy in the Graduate College of the University of Illinois, 1958.     

Microbial transformation of ginsenoside Rb<Subscript>1</Subscript> by <Emphasis Type="Italic">Acremonium strictum</Emphasis>

Preparative-scale fermentation of ginsenoside Rb₁ (1) with Acremonium strictum AS 3.2058 gave three new compounds, 12β-hydroxydammar-3-one-20 (S)-O-β-d-glucopyranoside (7), 12β, 25-dihydroxydammar-(E)-20(22)-ene-3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (8), and 12β, 20 (R), 25-trihydroxydammar-3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (9), along with five known compounds, ginsenoside Rd (2), gypenoside XVII (3), ginsenoside Rg₃ (4), ginsenoside F₂ (5), and compound K (6). The structural elucidation of these metabolites was based primarily on one- and two-dimensional nuclear magnetic resonance and high-resolution electron spray ionization mass spectra analyses. Among these compounds, 2–6 are also the metabolites of ginsenoside Rb₁ in mammals. This result demonstrated that microbial culture parallels mammalian metabolism; therefore, A. strictum might be a useful tool for generating mammalian metabolites of related analogs of ginsenosides for complete structural identification and for further use in pharmaceutical research in this series of compounds. In addition, the biotransformation kinetics was also investigated.     

Die Kinetik der Ionenaufnahme durch junge und alte Sprosse von Mnium cuspidatum

Zusammenfassung Die Kinetik der Ionenaufnahme durch junge und alte Sprosse von Mnium cuspidatum wurde untersucht. Die verschieden alten Sprosse unterscheiden sich vor allem durch das Vorhandensein einer aktiven Gipfelknospe bei den jungen Gametophyten, die bei den alten offenbar ihre Tätigkeit eingestellt hat. Im niedrigen Konzentrationsbereich (0–0,5 mM) haben jungen und alte Sprosse hyperbolische Isothermen der Ionenaufnahme, die sich etwas hinsichtlich der apparenten Michaeliskonstanten und der Maximalgeschwindigkeit unterscheiden. Im hohen Konzentrationsbereich (1–10 mM) ist der Unterschied qualitativ. Mit jungen Sprossen erhält man eine lineare oder exponentielle Isotherme, mit alten Sprossen eine hyperbolische Kurve. Der vermutete Einfluß der Gipfelknospe kann mit Effekten von Wuchsstoffen auf den Stofftransport zusammenhängen und läßt einen Einfluß dieser Regulationssysteme auf die Membranfunktion vermuten.

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The kinetics of ion uptake by young and old branches of mnium cuspidatum

Summary Isotherms of K(Rb)-, Cl- and SO₄-uptake by young and old branches of the moss Mnium cuspidatum were investigated. Old moss gametophytes from the 1966 vegetation period were collected in the forests surrounding Darmstadt from February to mid-April 1967 and from the 1967 season in late September 1967. Young plants were sampled from mid-April to the end of May 1967 and they were also grown by water culture of old plants.Both young and old branches have hyperbolic isotherms of ion uptake in the low concentration range (0–0.5 mM) (Fig. 1–3), which slightly differ in K _mand V _max (Table). Isotherms in the high range (1–10 mM), however, are drastically different, changing from linear or exponential with young moss branches to hyperbolic with old gametophytes (Figs. 1–3).The linear or exponential high-range isotherm obtained with young moss plants is compared with other examples reported in the literature (Fig. 4). As the leaflets of the moss plants, which constitute 2/3 of the fresh weight of the material used in the experiments, have well developed vacuoles, the correlation between hyperbolic isotherms and vacuolation does not apply here (Fig. 4a, Torii and Laties, 1966).The change in shape of the high-range moss isotherm with age resembles the change from exponential to hyperbolic kinetics in isolated potato discs during washing (Fig. 4b, Laties, Macdonald and Dainty, 1964). The events triggered by isolation of potato discs from the interior of the tuber may be similar to the changes in the moss material under the control of the terminal bud, which is only active in the young branches.The suggested influence of the active terminal bud of young moss plants on the ion absorption process of cells in the tissue may be related to effects of growth substances on translocation reported in the literature and may point to a direct effect of these regulatory systems on membrane function.In this respect the comparison of corn root stele and cortex is of interest. Isolated steles, both freshly isolated and after washing, have exponential isotherms in the high range (Fig. 4c), whereas cortex displays a hyperbolic isotherm which changes little with ageing (Lüttge and Laties, 1967). In contrast to the case in potato and moss materials, this phenomenon is not simply due to ageing but involves morphogenetic differences.Temperature is another factor which influences the shape of the high range isotherm. All examples discussed so far refer to experiments at room temperature. At low temperatures high-range isotherms for proximal root tissue or aged potato discs have an exponential shape (Torii and Laties, 1966; Laties, Macdonald and Dainty, 1964). It thus appears that the exponential isotherm of young moss branches indicates that as in freshly isolated potato discs or in corn root stele the metabolic high-range uptake system is not developed.

     

Rhizosphere bacteria antagonistic to soybean cyst (Heterodera glycines) and root-knot (Meloidogyne incognita) nematodes: Identification by fatty acid analysis and frequency of biological control activity

Rhizosphere bacteria were isolated from roots of young and mature plants with known antagonism to phytopathogenic nematodes, including velvet bean (Mucuna deeringiana), castor bean (Ricinus communis), sword bean (Cannavalia ensiformis), and Abruzzi rye (Secale cereale). Isolates from antagonistic plants were compared to soybean isolates for the frequency of antagonism to the root-knot (Meloidogyne incognita) and soybean cyst (Heterodera schachtii) nematodes in a disease assay with soybean. Bacterial isolates were identified using fatty acid analysis, and isolates which exhibited a significant reduction in incidence of soybean damage from both nematodes were characterized physiologically. The bacterial taxa associated with antagonistic plants were markedly different from soybean bacteria. Isolates from soybean were predominantly Bacillus spp., while those from antagonistic plants included more coryneform and Gram-negative genera. Pseudomonas cepacia and Pseudomonas gladioli were predominant among Gram-negative bacteria on antagonistic plants but were not isolated from soybean. Four to six times the number of bacteria from antagonistic plants, compared to soybean, significantly reduced disease incidence of both nematodes. No single pattern of physiological reactions was common among all these bacteria, suggesting that multiple mechanisms accounted for the observed biological control. The results suggest that rhizospheres of antagonistic plants may be useful sources of potential biological control agents for phytopathogenic nematodes.     

Direct production of L-lysine from raw corn starch by Corynebacterium glutamicum secreting Streptococcus bovis alpha-amylase using cspB promoter and signal sequence

Corynebacterium glutamicum is an important microorganism in the industrial production of amino acids. We engineered a strain of C. glutamicum that secretes α-amylase from Streptococcus bovis 148 (AmyA) for the efficient utilization of raw starch. Among the promoters and signal sequences tested, those of cspB from C. glutamicum possessed the highest expression level. The fusion gene was introduced into the homoserine dehydrogenase gene locus on the chromosome by homologous recombination. L-Lysine fermentation was conducted using C. glutamicum secreting AmyA in the growth medium containing 50 g/l of raw corn starch as the sole carbon source at various temperatures in the range 30 to 40°C. Efficient L-lysine production and raw starch degradation were achieved at 34 and 37°C, respectively. The α-amylase activity using raw corn starch was more than 2.5 times higher than that using glucose as the sole carbon source during L-lysine fermentation. AmyA expression under the control of cspB promoter was assumed to be induced when raw starch was used as the sole carbon source. These results indicate that efficient simultaneous saccharification and fermentation of raw corn starch to L-lysine were achieved by C. glutamicum secreting AmyA using the cspB promoter and signal sequence.     

Pothos crassipedunculatus,a new species ofPothos sect.Allopothos (Araceae) from India

Pothos crassipedunculatus Sivadasan & Mohanan (Araceae), a new species closely related to the SW. Indian endemic and little known speciesP. thomsonianus Schott is described. It is characterized by the the non-ligulate, shortly vaginate petiole, thickly peduncled inflorescence, broadly ovate spathe and a sessile spadix. It is included in ser.Brevivaginati Engler of sect.Allopothos Schott.     

Induced sporulation of Botryodiplodia theobromae Pat. isolated from Araucaria cunninghamii Ait. in Malaysia

Summary Botryodiplodia theobromae Pat. isolated fromAraucaria cunninghamii Ait. in Malaysia was grown on a series of standard media and inoculated into both living and dead leaves ofAraucaria. A few pycnidiospores were produced in stromata on aged cultures on 2% malt medium whereas pycnidia were produced rapidly in living and dead leaves. Pycnospores were generally two-celled and either hyaline or dark brown and bore longitudinal striations. The validity of includingBotryodiplodia theobromae as a synonym ofDiplodia natalensis Pole Evans is discussed.     

Parasites recovered from pupae ofLymantria dispar [Lep.: Lymantriidae] in Romania, 1978

In a survey at 5 sites in southern Romania for parasites of pupalLymantric dispar (L.), 8 species were recovered: 3Tachinidae (Dip.); Blepharipa pratensis (Meigen),Parasetigena silvestris (Robineau-Desvoidy), andExorista larvarum (L.); 1Chalcididae (Hym.); Brachymeria intermedia (Nees); 4Ichneumonidae (Hym.); Theronia atalantae atalantae (Poda),Coccygomimus instigator (F.),C. turionellae turionellae (L.), andEphialtes compunctor compunctor (L.). This was the 1 st reported recovery ofE. c. compunctor from L.dispar. Overall parasitism was low, and it is unlikely that additional surveys in this area will yield new parasites for introduction into the U.S.

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Résumé Cinq localités dans le sud de la Roumanie ont été prospectées pour recenser les parasites des nymphes deLymantria dispar (L.). Huit espèces de parasites ont été obtenues:Blepharipa pratensis (Meigen),Parasetigena silvestris (Robineau-Desvoidy),Exorista larvarum (L.),Brachymeria intermedia (Nees),Theronia atalantae atalantae (Poda),Coccygomimus instigator (F.),C. turionellae turionellae (L.), etEphialtes compunctor compunctor. Cette dernière espèce étant nouvelle surL. dispar. Le parasitisme total étant très bas, les auteurs en déduisent que des prospections supplémentaires dans cette région ont peu de chance d'être valables en vue de l'introduction aux états-Unis de nouvelles espèces contreL. dispar.

     

Some effects of enhanced UV-B irradiation on the growth and composition of plants

Barley (Hordeum vulgare), corn (Zea mays), bean (Phaseolus vulgaris), and radish (Raphanus sativus) seedlings were continuously irradiated under a lighting device for 5–10 d at an increased ultraviolet (UV)-B fluence rate. In their growth parameters, composition, and leaf surface, these four species responded differently to the increased UV-B exposure. Bean seedlings suffered the most serious effects, radish and barley less, and corn was hardly influenced at all. In all plant species, the fresh weight, the leaf area, the amounts of chlorophylls, carotenoids and the galactolipids of the chloroplasts were reduced. The lipid content of the corn and bean seedlings also diminished. But all the irradiated plants showed a rise in their protein content compared to the control plants. The content of flavonoids increased in barley and radish seedlings by about 50%. The effects on growth parameters and composition were more extensive with increasing UV-B fluence rates, at least as shown in the case of barley seedlings. The fresh weights fell proportionally with the chlorophylls and carotenoids. In contrast, the flavonoid content of barley leaves rose parallel to the increasing UV-B fluence rates and reached 180% of the value in the control plants with the highest UV-B fluence rate. Scorching appeared regularly in the form of bronze leaf discoloration at the highest UV-B fluence rates. Scanning electron micrographs of the leaf surface of UV-B irradiated plants showed deformed epidermal structures.Abbreviations MGDG monogalactosyldiglyceride - DGDG digalactosyldiglyceride - SL sulfoquinovosyldiglyceride - PG phosphatidylglycerol - PC phosphatidylcholine - PE phosphatidylethanolamine - PI phosphatidylinositol - LA leaf are - FW fresh weight - DW dry weight - SEM scanning electron microscopy - C total carotenoids - Chl total chlorophyll     

Late Neolithic agriculture in eastern Austria: archaeobotanical results from sites of the Baden and Jevišovice cultures (3600–2800 b.c.)

The article presents archaeobotanical results from six late Neolithic excavation sites in eastern Austria. Two of the sites belong to the Jevišovice culture (3200–2800 cal b.c.), the remaining four to the Baden culture (3600–2900 cal b.c.). Results show that farmers around 3000 cal b.c. were relying on the use of Triticum monococcum and Hordeum vulgare as principal cereals, with Triticum dicoccum and Panicum miliaceum as additional crops. Common millet was found in quantity at one of the Jevišovice sites and shows the remarkably early westward spread of this species. Single records of Triticum spelta are discussed in the light of the recently proposed ideas about an independent central European origin of spelt. Another record concerns the “new-type” glume wheat, providing further evidence for the once widespread occurrence of this cultivar. Triticum aestivum (hexaploid naked wheat) and Setaria italica (foxtail millet) were found as rare admixtures at the Jevišovice settlements. Pulses were represented by Pisum sativum and Lens culinaris, oil plants by Papaver somniferum and Linum usitatissimum. One of the Jevišovice sites offered a good opportunity for a study of the undisturbed spatial distribution of charred plant remains within a burnt house. Among wild plants, the occurrence of Stipa sp., Teucrium chamaedrys, Asperula cynanchica and Plantago media point to the presence of dry steppe grassland in the vicinity of the settlements, which was probably used for grazing. Woodland plants were mainly represented by fruit-bearing plants growing in clearings and forest edges, reflecting both the deliberate collection of wild fruits and the growing human impact on the vegetation.     

Eine neue mediterrane Reliktart der GattungTaraxacum

Zusammenfassung Aus Griechenland, Peloponnes, wird vom Kyllene-Oros ein neues endemischesTaraxacum, T. cylleneum, beschrieben; es trägt den Namen des Berges, auf dem es 1966 in Gipfelnähe entdeckt wurde.T. cylleneum gehört in die SektionMicrocephala v. S. (ined. ?) (bzw. in die GroßsektionRhodotricha Hand.-Mzt.), die damit erstmalig für Europa nachgewiesen wurde. Es unterscheidet sich vonT. glaciale Huet D. Pav. exHand.-Mzt., mit dem es früher offenbar verwechselt wurde, durch den rötlichen bis roten Pappus sowie den kurzen aber deutlich abgesetzten Schnabel der Achäne und durch die (nahezu) ungehörnten Hüllblätter, durch welche sich die Art auch vonT. primigenium Hand.-Mzt. sicher unterscheidet. VonT. microcephalum Pom., dem wahrscheinlich nächstverwandten Taxon, unterscheidet sie sich wieder durch die Form der Achänen bzw. des Schnabels und durch die Form der Hüllblätter des Blütenstandes. Die bisher untersuchten Pflanzen dieser Art waren allesamt diploid mit 16 Chromosomen. Die Pflanze zeigt nur bei künstlicher Fremdbestäubung einen einigermaßen befriedigenden Fruchtansatz. Die Art scheint streng sexuell zu sein, Kreuzungsexperimente mit anderen diploiden Arten der Gattung schlugen jedoch fehl, was auf die geringe Fertilität der Pflanzen sowie auf die systematisch isolierte Stellung zurückzuführen sein dürfte.

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Summary A new Greek endemicTaraxacum, T. cylleneum, is described, found on Kyllene-Oros, Peloponnesos. It has got the name of the mountain, on which, close by the top, it 1966 had been discovered.Taraxacum, cylleneum n. sp. belongs to the sectionMicrocephala v. S. (ined. ?) (respective in the great-sectionRhodotricha Hand.-Mzt.), whose presence in Europe by that could be proved for the first time. FromT. glaciale Huet D. Pav. exHand.-Mzt., which seems to have been mistaken for,T. cylleneum differs in its reddish to red pappus and the short, but abruptly constricted rostrum of the achenes and the almost incornuted leaflets of the involucrum, by which characteristic it is well distinguished fromT. primigenium Hand.-Mzt. FromT. microcephalum Pomel, which is probable to be the next related taxon,T. cylleneum differs in the shape of the involucrum-leaflets of its inflorescence.All plants of this species, that have been investigated till now, proved diploid with 16 chromosomes (2 n=2 x=16). Fruits are produced only with help of artificial pollination. The species seems to be strongly sexual and allogamous. Crossing experiments with other diploids of the genusTaraxacum were not successful, most probably caused by the low fertility of the plants and the species' systematical isolation.

     

Generation and properties of ascorbic acid-overproducing transgenic tobacco cells expressing sense RNA for <Emphasis Type="SmallCaps">l</Emphasis>-galactono-1,4-lactone dehydrogenase

l-Galactono-1,4-lactone dehydrogenase (GalLDH; EC 1.3.2.3) is the last enzyme in the putative l-ascorbic acid (AsA) biosynthetic pathway of plants. Here, we show for the first time that the overexpression of GalLDH can increase AsA content in tobacco (Nicotiana tabacum L.) BY-2 cells. To see the effect, we analyzed the properties of these AsA-overproducing transgenic cell lines, especially in relation to AsA content of cells, cell division, senescence and resistance to oxidative stress. The mitotic index in AsA-overproducing cells was higher than in wild-type cells. Moreover, the browning of these cells was markedly restrained, and the proportion of dead cells was reduced, especially in the later period of culture. These AsA-overproducing cells also acquired resistance to paraquat (methyl viologen), which produces active oxygen species. These results contribute to the previous insights about AsA and raise the possibility of the generation of plants that have resistance to environmental stresses by increasing their AsA content.     

Root Rot and Wilt of Kangaroo Paw (Anigozanthos manglesii) Caused by Pythium myriotylum (Drechs.) in Israel

A root rot and wilt disease of Anigozanthos manglesii (Kangaroo Paw) grown in greenhouses in Israel, for exporting as cut flowers to Europe, was characterized. Pythium myriotylum (Drechs.) and Rhizoctonia solani (Kühn) were the prevalent pathogens in diseased plants collected from commercial greenhouses. Fusarium oxysporum, Fusarium spp. and Myrothecium sp. were also isolated, but P. myriotylum or R. solani were not detected in samples from symptomless plants in tissue cultures (Australian origin) or plants at different stages in the nursery; non‐pathogenic F. oxysporum and Fusarium spp. were detected in several samples. In pathogenicity tests carried out in pots, plant mortality occurred 7 days after inoculation with P. myriotylum. In a field experiment carried out in methyl bromide‐fumigated soil, the incidence of dead plants following inoculation with P. myriotylum alone was 22% 10 days after inoculation, increasing to 78% after an additional 25 days. The incidence of dead plants following inoculation with R. solani alone was only 5% and in plants inoculated simultaneously with both pathogens, disease incidence was 88% 35 days after inoculation. Mortality reached 90–100% in plants inoculated with P. myriotylum, either singly or combined with R. solani 60 days after inoculation, whereas in plants inoculated with R. solani it was 5%. The maximum mortality in plants inoculated with R. solani was 25%, 76 days after inoculation. These results clearly demonstrate that P. myriotylum was the dominant pathogen in the root rot and wilt of A. manglesii.     

Reduced Mythimna separata infestation on Bt corn could benefit aphids

Use of genetically engineered plants that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) have been proven efficacious for managing lepidopteran pests. However, in some cases herbivores that are not targeted by the Bt trait have increased in importance. It has been suggested that reduced caterpillar damage to Bt crops could lead to decreased levels of induced plant defensive compounds which might benefit other non-target herbivores. Here we investigated the potential effect of reduced damage by larvae of Mythimna separata on aphid populations in Bt corn. We compared the performance of Rhopalosiphum maidis feeding on non-Bt corn plants that had been infested by M. separata larvae or were uninfested. The results showed that caterpillar-infested corn plants significantly reduced the fitness of R. maidis leading to a prolonged nymphal development time, reduced adult longevity and fecundity compared to uninfested plants. Consequently, the population growth rate of corn aphids feeding on caterpillar-infested corn plants was significantly lower than on uninfested plants. As expected, the aphids performed significantly better on Lepidoptera-resistant Bt corn than on non-Bt corn when plants were infested with M. separata, since the caterpillars caused very little damage to the Bt plants. The current findings indicate that reduced M. separata infestation could benefit aphid development in Bt corn. Bt corn has the potential to be commercialized in China in the near future and aphids and other non-target pests should be monitored in the farming fields.     

Establishment of in vitro plants, cell and tissue cultures from Oldenlandia affinis for the production of cyclic peptides

In vitro cultured plants from Oldenlandia affinis were established from seeds and grown on a hormone-free medium. In vitro plants produced the cyclic peptide kalata B1 in concentrations of 0.67 mg g⁻¹ dry weight after growth of 30 days. This was approximately 50% of the concentration analysed in green house plants (shoot tips), where different concentrations have been determined in leaves (1.82 mg g⁻¹), shoot tips (1.36 mg g⁻¹), stems (0.36 mg g⁻¹), and in flowers (0.16 mg g⁻¹). Callus and cell suspension cultures could be initiated from aseptic root, stem and leaf explants of O. affinis seedlings and plants. Different light intensities were shown to affect culture growth as well as chlorophyll synthesis. The friable callus was then used for the establishment of a cell suspension culture. Fresh and dry weight measurements showed that growth was optimal on MS medium supplemented with 0.4 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-d). Leaf suspensions cultured on this medium showed a 4-fold increase of biomass by the first week of incubation. No quantifiable amounts of kalata B1 were produced under these conditions. Morphological differentiation seems to be essential for cyclic peptide production. Therefore, several undifferentiated as well as organised cell lines of O. affinis have been developed. These cell lines will constitute a worthwhile starting point for the optimisation of kalata B1 synthesis in liquid media to the objective of producing cyclic peptides under controlled and defined conditions in bioreactors.