Developmental regulation of aldoxime formation in seedlings and mature plants of Chinese cabbage (Brassica campestris ssp. pekinensis) and oilseed rape (Brassica napus): Glucosinolate and IAA biosynthetic enzymes

The first steps in the biosynthesis of glucosinolates and indole-3-acetic acid (IAA) in oilseed rape (Brassica napus L.) and Chinese cabbage (Brassica campestris ssp. pekinensis) involve the formation of aldoximes. In rape the formation of aldoximes from chain-extended amino acids, for aromatic and aliphatic glucosinolate biosynthesis, is catalysed by microsomal flavin-containing monooxygenases. The formation of indole-3-aldoxime from l-tryptophan, the potential precursor of both indole-3-acetic acid and indolyl-glucosinolates, is catalysed by several microsomal peroxidases. The biosynthesis of glucosinolates and indole-3-acetic acid was shown to be under developmental control in oilseed rape and Chinese cabbage. No monooxygenase activities were detected in cotyledons or old leaves of either species. The highest monooxygenase activities were found in young expanding leaves; as the leaves reached full expansion and matured the activities decreased rapidly. The indole-aldoxime-forming activity was found in all of the tissues analysed, but there was also a clear decrease in foliar activity with maturity in leaves of rape and Chinese cabbage. Partial characterisation of the Chinese cabbage monooxygenases showed that they have essentially identical properties to the previously characterised rape enzymes; they are not cytochrome P450-type enzymes, but resemble flavin-containing monooxygenases. No monooxygenase inhibitors were detected in microsomes prepared from either cotyledons or old leaves.Abbreviations DHMet dihomomethionine - FMO flavin-containing monooxygenase - HPhe homophenylalanine - IAA indole-3-acetic acid - l-Phe l-phenylalanine - l-Trp l-tryptophan - MO monooxygenase - IAALD indole-3-acetaldehyde - IAOX indole-3-aldoxime - THMet trihomomethionine     

A preliminary phylogeny for the NeotropicalRubiaceae

The sequence of subfamilies,Cinchonoideae, Antirheoideae andRubioideae, attemps to show their natural affinities and phylogeny. The subfamilies are those ofVerdcourt, and the order in which they are presented is that ofBremekamp. A list is presented of the subfamilies, tribes and genera of theRubiaceae to be utilized in the Catálogo Ilustrado de las plantas de Cundinamarca, Colombia.     

Chemosystematics of theRutaceae: Comments on the interpretation ofda Silva & al.

The revision of theRutaceae into 17 provisional tribes, based primarily on the distribution of secondary metabolites (da Silva & al. 1988) is critically reviewed. In three areas where sufficient phytochemical data is available, i.e. the proto-Rutaceae, (provisional tribesZanthoxylum, Phellodendron, Toddalia, andEuodia pro parte), the AfricanToddalioideae sensuEngler, (provisional tribesEuodia pro parte,Acronychia), andClauseneae sensuSwingle, (provisional tribesClausena, Glycosmis, Micromelum, Merrillia), it is shown that the proposals made byda Silva & al. are seriously flawed. It is suggested that for other areas of the family insufficient phytochemical information is available to justify these proposals. In a wider context it is suggested that this approach, based on only one set of characters and on a wholly insufficient data base, is unhelpful to the task of producing a new classification of the family.     

cpDNA intergene sequences corroborate restriction site data for reconstructingRubiaceae phylogeny

Representatives of seven genera from five tribes ofRubiaceae have been compared in respect to a non-coding intergene cpDNA region of about 1000 bp, situated between the atpB and the rbcL genes. The resulting most parsimonious PAUP cladogram corresponds very well with one based on total cpDNA restriction site data obtained byBremer & Jansen (1991). The two different molecular analyses thus corroborate each other and contribute to an improved systematic arrangement of the large family, e.g., in respect to placing the tribeHedyotideae clearly into the subfamilyRubioideae, closer toRubieae than toPsychotrieae.     

Accumulation of seed storage proteins and the taxonomy ofPoaceae

The accumulation of specific seed proteins is a taxonomically valuable feature and can be used to additionally characterize plant taxa. To date, mainly crop proteins have been analysed in thePoaceae. In this investigation seed proteins from 147 species were screened with emphasis on legumin-like proteins and prolamins. The groups resulting from evaluation of the protein profiles correspond with well-known subfamilies and tribes.Panicoideae are clearly separated fromPooideae. WithinPooideae, theBromeae plusTriticeae tribes revealed obvious similarities.Lolium, Festuca andVulpia, generally included in the tribeFestuceae, revealed a protein profile similar to the profile of theBromeae/Triticeae. Legumin-like proteins are accumulated abundantly inBambusoideae andPooideae exceptBromeae/Triticeae, however, only the species included in theAveninae subtribe produce soluble (globulin-type) legumins as already known fromAvena sativa. Dedicated to emer. Univ.-Prof. DrFriedrich Ehrendorfer on the occasion of his 70th birthday     

Enhanced photosynthesis at low oxygen concentrations: Differential response of temperate and tropical grasses

Summary When leaves of grasses of the tribes Oryzeae, Festuceae, Hordeae, Aveneae, Phalarideae, Agrostideae and Stipeae were exposed to air containing a low oxygen concentration, photosynthesis was enhanced between 23 and 60%. No such increase was observed in grasses of the tribes Paniceae, Andropogoneae, Maydeae, Zoisieae, Chlorideae and Eragrosteae which are known (Hatch et al., 1967) to possess the C₄ carbon pathway of photosynthesis. The latter group consists of tropical grasses and the former, except for the Oryzeae, are grasses of temperate regions.     

甘蓝型油菜BnCYP79B1基因的克隆与表达

硫苷是十字花科植物的一种次生代谢产物,其合成途径受细胞色素P450的CYP79家族蛋白的调控,该实验采用同源克隆技术在甘蓝型油菜中克隆到了CYP79B1基因,命名为BnCYP79B1(GenBank登录号为JX535391.1)。BnCYP79B1基因cDNA全长1 625bp,编码一个含有541个氨基酸、理论等电点为8.88。序列对比结果显示,BnCYP79B1与花椰菜CYP79B1在DNA序列上的相似性为98.83%,推测蛋白氨基酸序列的相似性为99.26%。通过不同时期不同部位BnCYP79B1基因表达量的分析,发现BnCYP79B1基因在高秆高硫苷品系的根中表达量较高,而对矮秆高硫苷品系则是叶中表达量较高。在BnCYP79B1表达总量上,高秆品系较矮秆品系高,高硫苷品系较低硫苷品系高。     

A phylogenetic analysis of the lichen familySphaerophoraceae (Caliciales); a new generic classification and notes on character evolution

A phylogenetic analysis of the familySphaerophoraceae (Caliciales, lichenized ascomycetes) has resulted in a new generic classification. Notes on character evolution are given. The generaSphaerophorus s. str.,Bunodophoron andLeifidium, gen. nov., are accepted.Pleurocybe andPseudosphaerophorus are considered synonyms ofBunodophoron andThysanophoron is considered synonym toSphaerophorus. The following new combinations are proposed:Bunodophoron coomerense (Ohlsson)Wedin,B. diplotypum (Vain.)Wedin,B. dodgei (Ohlsson)Wedin,B. flaccidum (Kantvilas & Wedin)Wedin,B. formosanum (Zahlbr.)Wedin,B. imshaugii (Ohlsson)Wedin,B. insigne (Laurer)Wedin,B. kinabaluense (M. Satô)Wedin,B. macrocarpum (Ohlsson)Wedin,B. madagascareum (Nyl.)Wedin,B. microsporum (Ohlsson)Wedin,B. murrayi (Ohlsson)Wedin,B. notatum (Tibell)Wedin,B. ohlssonii (Wedin)Wedin,B. patagonicum (C. W. Dodge)Wedin,B. ramuliferum (I. M. Lamb)Wedin,B. scrobiculatum (C. Bab.)Wedin,B. tibellii (Wedin)Wedin,B. whakapapaense (Wedin)Wedin, andLeifidium tenerum (Laurer)Wedin.     

A reconsideration of the genusRabdosiella (Lamiaceae,Nepetoideae, Ocimeae)

The two generaPlectranthus andIsodon are compared and found to be very dissimilar.Isodon ist considered to be misplaced inOcimeae subtribePlectranthinae and apparently is more closely related to subtribeHyptidinae. The disjunct genusRabdosiella is compared to these two genera and regarded to be polyphyletic. The AfricanR. calycina (Benth.)Codd is returned toPlectranthus and calledP. calycinus Benth., while the AsianR. ternifolia (D. Don)Codd is placed inIsodon sect.Pyramidium and calledI. ternifolius (D. Don)Kudo.     

On the Lichen generaPlacocarpus andPlacidiopsis (Verrucariaceae)

Verrucaria schaereri (Fr.)Nyl. is accorded generic status asPlacocarpus Trev. emend.O. Breuss. The main differences between the two genera concern the thallus anatomy and the spores which are halonate inPlacocarpus. The following new combinations are proposed:Placocarpus schaereri (Fr.)O. Breuss andPlacidiopsis cinerascens (Nyl.)O. Breuss.     

The application and citation of the generic nameParmeliopsis (Lecanorales,Parmeliaceae)

The nomenclatural history of the generic nameParmeliopsis is reviewed. Its correct citation is found to beParmeliopsis (Nyl. exStizenb.)Nyl., dating from 1866, not 1869 as commonly cited, withP. placorodia (Ach.)Nyl. as holotype species. There is consequently no nomenclatural problem to the adoption ofForaminella Fricke Meyer, typified byF. ambigua (Wulfen)Fricke Meyer for theParmeliopsis species with falcate conidia. A synopsis of the nomenclature of the North American and European species of both these genera is included.     

Some interesting agarics from eastern Austria

Four very rare species ofAgaricales of dry grassland of the Galgenberg near Röschitz (Niederösterreich) are described and their taxonomy, affinities, ecology and distribution are discussed.Marasmiellus graminis (Murr.)Sing. & Hausknecht andCrinipellis subtomentosa (Peck.)Sing. var.mauretanica (Mre.)Sing. & Hausknecht are proposed as new combinations;Campanella inquilina Romagn. apudRedhead is a synonym ofC. caesia Romagn.     

Neue Taxa vonTillandsia subgenusDiaphoranthema (Bromeliaceae) aus Bolivien und Argentinien

5 new taxa are described and illustrated; their position within the subgenus is discussed:T. hirta W. Till & L. Hromadnik,T. cotagaitensis L. Hromadnik,T. caliginosa W. Till, andT. gilliesii Baker subsp.polysticha W. Till & L. Hromadnik are members of a group includingT. myosura Grisebach exBaker,T. mandonii E. Morren exMez in DC.,T. retorta Grisebach exBaker em.Grisebach andT. andicola Gillies exBaker. T. brealitoensis L. Hromadnik is related toT. angulosa Mez in DC. but distinct and possibly of hybrid origin.

     

Interspecific hybridizations among species of theElymus semicostatus andElymus tibeticus groups (Poaceae)

Interspecific hybridizations were made between species of theE. semicostatus group, viz.,E. semicostatus (Nees exSteud.)Meld.,E. validus (Meld.)B. Salomon,E. abolinii (Drob.)Tzvel., andE. fedtschenkoi Tzvel., and species of theE. tibeticus group, viz.,E. pendulinus (Nevski)Tzvel.,E. tibeticus (Meld.)Singh,E. shandongensis B. Salomon, andE. gmelinii (Ledeb.)Tzvel., as well as among species within theE. tibeticus group. All species are tetraploid (2n = 4x = 28) and possess SY genomes. Meiotic pairing data from 24 hybrids involving 17 interspecific combinations are presented. The average number of chiasmata per cell ranged from 17.91 to 26.20 in hybrids within theE. tibeticus group, compared with 7.26 to 22.04 in hybrids between the two species groups. Despite the extensive collection of cytological data, there was no definite evidence for confirming or disproving the separate existence of the two groups.     

Effects of glucobrassicin, epiprogoitrin and related breakdown products on locusts feeding: Schouwia purpurea and desert locust relationships

The glucosinolates of a Saharan crucifer Schouwia purpurea (Forskål) (Brassicaceae) were determined by liquid chromatography. Two of these glucosinolates and sinigrin were tested for their deterrent effect on Schistocerca gregaria (Forskål) (Orthoptera: Acrididae). Glucobrassicin, three indolyls and epigoitrin were synthesized for this purpose. Epiprogoitrin was extracted from Crambe seeds. Choice tests on artificial substrate compared feeding responses to glucosinolates and to related breakdown products released when the plant is eaten. Breakdown products were more efficient in deterring the generalist locust than were glucosinolates. Two patterns of dose responses were recorded: glucosidic compounds deterred or stimulated feeding, depending on the concentration tested; aglycones did not stimulate feeding at any concentration. Allyl isothiocyanate, a volatile compound, was a 100-fold higher deterrent than its substrate (sinigrin).     

The genusAntennaria (Asteraceae: Inuleae) in western North America: Morphometric analysis ofAntennaria alborosea,A. corymbosa,A. marginata,A. microphylla,A. parvifolia,A. rosea,andA. umbrinella

Multivariate analysis of vegetative and reproductive characters was used to examine morphological relatedness amongAntennaria alborosea A. E. Porsild,A. corymbosa E. Nels.,A. marginata Greene,A. microphylla Rydb.,A. parvifolia Nutt.,A. rosea Greene, andA. umbrinella Rydb. Both pistillate and staminate plants were examined. Some of the characters examined were variable in one species, but stable in another (i.e., presence or absence of papillae on the achenes). Our analyses indicate that the seven species are morphologically distinct. It is hypothesized that theA. rosea agamic complex arose through hybridization amongA. corymbosa, A. microphylla, A. umbrinella, and possiblyA. dioica (L.)Gaertn. However, hybridization between the three former species and others, as well as their subsequent morphological responses to different environmental conditions causes confusion in recognizing the taxa.Antennaria angustifolia Rydb.,A. arida E. Nels.,A. confinis Greene,A. scariosa E. Nels.,A. foliacea humilis Rydb.,A. concinna E. Nels., andA. viscidula E. Nels. are considered to represent F 1 hybrids.     

Normania,an endemic Macaronesian genus distinct fromSolanum (Solanaceae)

Morphological data and results from scanning electron microscopy of seeds and pollen show thatNormania Lowe [syn.Solanum L. subg.Potatoe (G. Don)D'Arcy sect.Normania (Lowe)Bitter] (Solanaceae: Solaneae) should be considered as a distinct genus fromSolanum L. It has two species, one restricted to the island of Madeira [Normania triphylla (Lowe)Lowe] and the other to Tenerife and Gran Canaria [Normania nava (Webb & Berthel.)Franc.-Ort. & R. N. Lester]. These species are extremely rare and had not been found for about 100 years, untilN. nava was rediscovered in two different localities in Tenerife in 1973 and 1982.Normania triphylla was reported in two different places from northern Madeira in 1991. Both species have the highest conservation priority in the Macaronesian region.     

Trebouxia aggregata undGloeocapsa sanguinea,Phycobionten inEuopsis granatina (Lichinaceae)

The green algaTrebouxia aggregata (Archibald)Gärtner (Chlorellales) and the procaryotic blue-green alga (cyanobacterium)Gloeocapsa sanguinea (C. Agardh)Kütz. emend.Jaag (Chroococcales) are reported to be the phycobionts inEuopsis granatina (Sommerf.)Nyl. (Lichinaceae). The ultrastructure of the two organisms, studied in the lichen thallus, is described.

Frau Prof. Dr.Elisabeth Tschermak-Woess zu ihrem 70. Geburtstag gewidmet.     

On the taxonomic position ofSilene thebana (Caryophyllaceae)

Silene thebana Orph. exBoiss. is transferred as a subspecies toS. fabaria (L.)Sm., resulting in the new combinationS. fabaria (L.)Sm. subsp.thebana (Orph. exBoiss.)Melzh. The chromosome count of 2n = 24 is recorded for the first time for this taxon.Dedicated to Prof. DrK. H. Rechinger on the occasion of his 80th birthday, 16th October 1986.     

Glucosinolates in <Emphasis Type="Italic">Brassica</Emphasis> foods: bioavailability in food and significance for human health

Glucosinolates are sulphur compounds that are prevalent in Brassica genus. This includes crops cultivated as vegetables, spices and sources of oil. Since 1970s glucosinolates and their breakdown products, have been widely studied by their beneficial and prejudicial biological effects on human and animal nutrition. They have also been found to be partly responsible for the characteristic flavor of Brassica vegetables. In recent years, considerable attention has been paid to cancer prevention by means of natural products. The cancer-protective properties of Brassica intake are mediated through glucosinolates. Isothyocianate and indole products formed from glucosinolates may regulate cancer cell development by regulating target enzymes, controlling apoptosis and blocking the cell cycle. Nevertheless, variation in content of both glucosinolates and their bioactive hydrolysis products depends on both genetics and the environment, including crop management practices, harvest and storage, processing and meal preparation. Here, we review the significance of glucosinolates as source of bioactive isothiocyanates for human nutrition and health and the influence of environmental conditions and processing mechanisms on the content of glucosinolate concentration in Brassica vegetables. Currently, this area is only partially understood. Further research is needed to understand the mechanisms by which the environment and processing affect glucosinolates content of Brassica vegetables. This will allow us to know the genetic control of these variables, what will result in the development of high quality Brassica products with a health-promoting activity.