Astringent tannins of Acer species

All 25 species of Acer examined contain condensed (proanthocyanidins) and hydrolysable (gallo- and/or ellagi-) tannins, but each of these varies ov     

Systematic aspects of the astringent tannins of Acer species

Leaves of a further 25 species of Acer, mostly from Asia and N. America, show similar levels of astringency and distribution of condensed and hydrolysable tannins to those previously examined. The results are tabulated and discussed in accordance with de Jong's recent rearrangement of the genus.     

Astringent tannins of Viburnum and Hydrangea species

The tannins of the leaves of Viburnum and Hydrangea species consist of proanthocyanidins only, but in each genus the range is very wide. In several species of Hydrangea the proanthocyanidins are of the A type, otherwise they are mostly tri- or tetrameric B type. Tannin content is correlated with evolutionary advancement, the more advanced and more widely dispersed species having the less. Species with most tannin occur in E. Asia and E. N. America, but species with little or no tannin are present in both areas. The occurrence in both genera of globose inflorescences with sterile flowers is correlated neither with morphological nor with chemical characters.     

Haemanalysis of tannins: The concept of relative astringency

The astringency of tannins, that is their efficiency as precipitants of proteins, is determined by their reaction with the proteins of haemolysed blood and calorimetric determination of residual haemoglobin. The method is accurate and sensitive because of the narrow range of concentration of tannin between that required to initiate precipitation (the threshold concentration) and that for complete precipitation. ‘Relative astringency’ (RA) is the ratio of the concentration of the tannic acid to that of the tannin which effects the same degree of precipitation. The RA of certain esters of hexahydroxydiphenic acid and of certain procyanidins of known constitution has been determined and the results applied to the ellagitannins and/or leucoanthocyanins present in species of Shorea, Geranium and other plants. The homology of each of these classes of tannins is discussed in the light of the results.     

The systematic distribution of tannins in the leaves of angiosperms: A tool for ecological studies

The systematic distribution of tannins in foliar tissues has not been comprehensively reviewed for the Angiosperms in over 20 years. Here their systematic distribution is assessed using data based on protein precipitation or chemically specific tests. Fewer families are characterized by the typical presence of tannins than has previously been reported, and a greater variation in the occurrence of tannins in species sampled from within single plant families has been detected. This study presents the proportion of tannin-containing species in angiosperm families arranged according to the system of Cronquist for the first time. The potential utility of these data in testing ecological ideas about the distribution of tannins, such as those based on plant habit or life-history, is discussed.     

Cytotaxonomy of Commelinaceae: chromosome numbers of some African and Asiatic species

Chromosome counts are reported for 32 taxa (31 species and 1 subspecies) belonging to 10 genera of Commelinaceae from seven African and Asiatic countries. Counts for 13 species and 1 subspecies are recorded for the first time. Published chromosome numbers for Anhicopsis and Polyspatha are confirmed. It is suggested that Pdisota, Pollia and Stanfieldidla each has a single basic number (x = 20, 16 and 11, respectively). The known cytological diversity in Floscopa is extended. The third continental African species of Coleolrype is found to have the same chromosome number (2n = 36) as the other two. The preponderance of the basic number x = 15 in Commelina is supported. The uncommon basic number x = 13 is reported in four taxa of Cyanotis together with karyotypic differences. The basic number x = 6 is found in a second species of Murdannia . Karyotypic data in addition to chromosome numbers are presented for 24 of the 32 taxa investigated. Karyotypes are found to be useful in assessing relationships in the family, and evolutionary trends in the karyotype are noted.     

Distribution of lipoxygenase and hydroperoxide lyase in the leaves of various plant species

The enzyme activity responsible for volatile C₆-aldehyde formation was accompanied by lipoxygenase and hydroperoxide lyase in the green leaves of 28 plant species tested, but the level of each enzyme's activity varied. Lipoxygenase activity rather than hydroperoxide lyase activity appears to affect the overall C₆-aldehyde formation. There was a positive correlation (r = 0.712) between hydroperoxide lyase activity and the chlorophyll content of the green leaves; no correlation was found between lipoxygenase activity and chlorophyll content.     

The correct nomenclature of the Nigerian species of Xanthosotna Schott (Araceae)

A literature survey showed that taxonomists retain both Xanthosotna sagittifolium (L.) Schott and X. mafajfa Schott as separate species. The diagnostic features of these species are clearcut as X. sagittifolium (L.) Schott has overlapping leaf lobes and a tapering male portion of the spadix in contrast to the divergent leaf lobes and symmetrical male region of the spadix of X. mafaffa Schott. Field studies indicate that features of the Nigerian members of the genus agree with those of X. mafaffa Schott which is the correct name of the Nigerian taxon.     

Volatile components of sugar beet leaves

Extracts of both young and old sugar beet plants were obtained using a modified Likens and Nickerson apparatus. Constituents were identified by GC/MS, and using selected ion monitoring it was shown that the previously determined phenylacetonitrile was probably not of glucosinolate origin. Some unsaturated aldehydes, alcohols and derivatives (enzymic lipid degradation products) were formed to greater extents by the younger leaves, but otherwise such quantitative differences were relatively few and generally random. An interesting range of chlorinated compounds was obtained only from the older plants; a pesticide origin is suggested.     

Occurrence of tannins in leaves of beech trees (Fagus sylvatica) along an ecological gradient, detected by histochemical and ultrastructural analyses

Sclerophylly and synthesis of phenolic compounds are active responses of plants subjected to environmental stress (drought, low nutrient supply, u.v.-B radiation, ozone). Here we describe the morphological and histochemical alterations occurring in field-grown leaves of Fagus sylvatica L. from three sites located along an ecological gradient: from a site in cool and protected conditions to one located on a mountain ridge, where the trees grow on a thin layer of soil and are exposed to the wind and to intense solar radiation in summer. The morphological data show that, as the ecological conditions of the stand worsen, individual leaf surface decreases, while the thickness of the leaves and their specific d. wt (i.e. d. wt per unit leaf area) increases. Histochemical and ultrastructural tests show a marked increase of phenolics during the course of the year. These substances, present primarily in the leaves of trees growing in stress conditions, have been identified mainly as tannins. They accumulate in the vacuoles, especially those of the upper epidermal layer and the palisade mesophyll; at a later stage they appear to be solubilized in the cytoplasm and retranslocated, eventually impregnating the outer wall of the epidermal cells amidst the cellulose fibrils, where they cluster together and form an electron-opaque layer between the wall and the cuticle. Observation of the epidermal cells also reveals that the outer cell wall is thicker. The paper discusses the roles of secondary metabolites in protection and detoxification processes; the possible ecological significance of these alterations in the ecophysiology of beech trees.     

Hydroxytropane tiglates in the roots of Mandragora species

Roots of Mandragora autumnalis and M. vernalis contain hyoscyamine, hyoscine, cuscohygrine, apoatropine 3α-tigloyloxytropane and 3,6-ditigloyloxytropane. Belladonnine is present in the dried roots but could not be detected in fresh roots. No major differences were found in the alkaloids present in the two species. This is the first time the presence of tiglic acid esters has been reported in Mandragora species and the significance of this in the chemotaxonomy of the genus is indicated.     

Four new yeast species of the genus Sporobolomyces from plant leaves

Among the ballistoconidium-forming yeast strains isolated from various plant leaves collected in North and Northeast China, 12 strains forming orange to orange-red colored colonies were revealed to represent four novel species of the genus Sporobolomyces by conventional, chemotaxonomic and molecular phylogenetic studies, based on the 26S-rDNA D1/D2 domain and internal transcribed spacer (ITS) region sequences. Sporobolomyces beijingensis sp. nov., represented by eight strains (type strain CB 80T = AS 2.2365T = CBS 9730T), and Sporobolomyces jilinensis sp. nov., represented by two strains (type strain CB 118T = AS 2.2301T = CBS 9728T), clustered in the Johnsonii clade of the Sporidiobolus lineage. Sporobolomyces clavatus sp. nov., represented by strain CB 281T (= AS 2.2318T = CBS 9729T), belonged to the Agaricostilbum lineage and showed a close relationship to Sporobolomyces ruber and Sporobolomyces dracophylli. Sporobolomyces symmetricus sp. nov., represented by strain CB 64T(= AS 2.2299T = CBS 9727T), formed nearly symmetrical ballistoconidia and was closely related with Sporobolomyces vermiculatus and Sporobolomyces gracilis in the Gracilis clade of the Erythrobasidium lineage.     

Membrane-degrading enzymes in the leaves of Solanum tuberosum

When homogenates of potato leaves were prepared under conditions which are typical for organelle isolation (pH 7.5 and 4°), membrane lipids underwent rapid hydrolysis (17% of phosphatidylcholine was hydrolysed in 2 hr). Leaves of 41 potato cultivars were surveyed for phospholipase activity to determine whether certain cultivars might be more suitable for the preparation of organelles. Phospholipase activities ranged from 1.04 to 11.60, μmol/min · g fr. wt and p-nitrophenyl palmitate hydrolase activity ranged from 0.0119 to 0.0502,μmol/min · g fr. wt. These phospholipase values were several hundred-fold higher than previously reported for potato leaves and nearly as high as in potato tubers. Most of the phospholipase activity in leaves was soluble and not membrane-associated as previously reported.     

Distribution, chromosome numbers and nomenclature conspect of Arabidopsis halleri (Brassicaceae) in the Carpathians

Arabidopsis halleri represents an important model species for the study of phytoremediation. In the Carpathians it is represented by three subspecies: A. halleri subsp. halleri, A. halleri subsp. tatrica and A. halleri subsp. dacica. All three subspecies are diploid with chromosome number 2n = 16. They differ mainly in indument of flower parts, colour of petals and in the position of the longest leaf on stem. A. halleri subsp. halleri occurs in the Eastern and Southern Carpathians and in the northern and eastern part of the Western Carpathians, subsp. tatrica is endemic of the Western Carpathians and subsp. dacica occurs in the Eastern and Southern Carpathians most probably extending in its distribution further to the south to the Balkan mountains. Full synonymy of these three taxa and also a fourth European subspecies, A. halleri subsp. ovirensis is presented including the information on type specimens. Lectotypes are selected for several names. List of the examined herbarium specimens is given as well.     

Purification and properties of the three o-diphenol-O-methyltransferases of tobacco leaves

Three o-diphenol-O-methyltransferases (OMTs I, II and III) which catalyse the monomethylation of various o-diphenols using S-adenosyl-L-methionine as methyl donor were isolated and purified about 210-, 70-, and 70-fold, respectively, from leaves of Nicotiana tabacum cv Samsun NN. They had slightly different MWs (93 000, 90 000 and 100000 for OMTs 1, 11 and Ill respectively) and slightly different pls (5.21, 4.80 and 4.74). The activities of all three enzymes were very stable when stored at 0° but they had different sensitivities to ultrafiltration and to heat treatment (45°). In none of the enzymes was there any change in reaction rate when Mg²⁺ ions or EDTA were added. The three enzymes exhibited very high and similar affinities towards the substrate S-adenosylmethionine and the reaction product S-adenosylhomocysteine, but they differed markedly in specificities towards the various o-diphenolic substrates. Relative methylation efficiencies were estimated from the calculation of the V/K_m ratios that led to the following decreasing order of best substrates: 5-hydroxyferulic acid > caffeic acid > homo-catechol > esculetin > protocatechuic aldehyde > catechol > hydrocaffeic acid > chlorogenic acid, for OMT I, and: homocatechol > catechol > protocatechuic aldehyde > esculetin ≈ cafreic acid > 5-hydroxyferulic acid, for both OMTsIIandIII. Most of the o-diphenols assayed were methylated exclusively in the meta position, but all three tobacco OMTs showed both para and meta-directing activities with protocatechuic acid, protocatechuic aldehyde and escultin. Since K_m values towards the two position of methylation were always found to be identical, we conclude that each enzyme bears only one catalytic site.     

Salicyloylaspartate as an endogenous component in the leaves of Phaseolus vulgaris

An amide conjugate of o-methoxybenzoic acid and aspartic acid has been isolated from bean leaves. After extraction and methylation of plant material, this compound was isolated as two isomeric monoethyl monomethyl esters. The ethylation of the aspartyl carboxyl groups was shown to be a likely result of an extraction procedure utilising acidified ethanol, the methylation of the aromatic hydroxy of the methoxy group to be due to the derivatisation procedure. Studies with pentafluorobenzylation confirmed that the endogenous compound is o-hydroxybenzoylaspartate.     

Purification of acyl hydrolase enzymes from the leaves of Phaseolus multiflorus

Acyl hydrolase activities have been purified from the leaves of Phaseolus multiflorus. The purification procedure involved heat treatment, DEAE-cellulose chromatography, Sephadex G-100 filtration and hexyl agarose chromatography. The elution pattern from hexyl agarose columns together with substrate competition experiments indicated the presence of two hydrolase enzymes. The first could hydrolyse oleoylglycerol and phosphatidylcholine while the second would deacylate glycosylglycerides and oleoylglycerol. Overall purification of both enzymes was ca 70-fold and the MW of the glycosylglyceride-hydrolysing enzyme was in the range 70–78000.