Antibacterial stilbenoids from the roots of Stemona tuberosa

Twelve dihydrostilbenes, stilbostemins N-Y (1-12), and a phenanthraquinone, stemanthraquinone (13), were isolated and identified from roots of Stemona tuberosa, along with five known dihydrostilbenes. Their structures were established on the basis of 1D and 2D NMR and other spectroscopic analyses. Dihydrostilbene 8 exhibited strong activity against Bacillus pumilus (MIT 12.5-25 microg/mL). Many tested compounds exhibited moderate antibacterial activities.     

Exudation of terpenoids by cotton roots

Summary The terpenoid aldehydes, desoxyhemigossypol, desoxy-6-methoxyhemigossypol, hemigossypol, 6-methoxyhemigossypol, gossypol, 6-methoxygossypol, and 6,6′-dimethoxygossypol, previously reported to be present in cotton roots (Gossypium hivsutum L.) were found on absorbing surfaces adjacent to roots. Infection of hypocotyls byRhizoctonia solani increased the quantity of terpenoids exuded by roots. Because these compounds are antimicrobial, their presence in the rhizosphere should be considered in studies of the microflora of cotton roots.     

Iridoid glucosides from Phlomis tuberosa L. and Phlomis herba-ventis L

A new iridoid glucoside, 5-desoxysesamoside, was isolated from Phlomis tuberosa L. (Lamiaceae) together with three known iridoid glucosides sesamoside, shanziside methyl ester and lamalbid. Lamiide was found in P. herba-ventis ssp. pungens in high concentrations.     

Plant regeneration from oca (Oxalis tuberosa M.): the effect of explant type and culture media

Shoot regeneration has been obtained from internode and petiole sections of oca on a number of culture media supplemented with 3 mgl^-1 naphthaleneacetic acid and 3 mgl^-1 of either benzylaminopurine or zeatin, the latter being more effective. A greater percentage of sections from the 4th, 5th and 6th internodes (numbered from the apex) produced shoots than sections from older or younger internodes. Of five locally available genotypes based on tuber colour, a weak-growing type white showed the greatest morphogenetic potential. Out of eight nutrient media tested, a modified B₅ medium containing casein hydrolysate and L-glutamate supported the most consistent shoot regeneration. Shoot regeneration was preceded by the formation of a dark red smooth-surfaced callus. This was usually followed by the formation of a short tapering root. Swellings arose at the base of the root and developed into single or multiple shoots. These shoots were excised, rooted in basal Murashige & Skoog medium and transferred to the field.Abbreviations BA 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - IBA indole-3-butyric acid - 2-iP (2-isopentenyl) adenine - Kn kinetin - NAA -naphthaleneacetic acid - Zn zeatin (mixed isomers)     

Exudation of peroxidase from roots of Festuca rubra and its effects on exuded phenolic acids

Peroxidase is exuded from roots of Festuca rubra under axenic conditions. No phenolase was detected. Peroxidase can use phenolic acids. probably differentially, as hydrogen donors for the H₂O₂ substrate and could thus have an effect on the qualitative and quantitative determinations of phenolic acids also exuded by plants.     

Origins of domestication and polyploidy in oca (Oxalis tuberosa : Oxalidaceae): nrDNA ITS data

As part of a study aimed at elucidating the origins of the octoploid tuber crop "oca," Oxalis tuberosa, DNA sequences of the internal trancribed spacer of nuclear ribosomal DNA (nrDNA ITS) were determined for oca and several wild Oxalis species, mostly from Bolivia. Phylogenetic analysis of these data supports a group of these species as being close relatives of oca, in agreement with morphology and cytology, but at odds with traditional infrageneric taxonomy. Variation in ITS sequences within this group is quite low (0-7 substitutions in the entire ITS region), contrasting with the highly divergent (unalignable in some cases) sequences within the genus overall. Some groups of morphologically differentiated species were found to have identical sequences, notably a group that includes oca, wild populations of Oxalis that bear small tubers, and several other clearly distinct species. The presence of a second, minor sequence type in at least some oca accessions suggests a possible contribution from a second genome donor, also from within this same species group. ITS data lack sufficient variation to elucidate the origins of oca precisely, but have identified a pool of candidate species and so can be used as a tool to screen yet unsampled species for possible progenitors.     

Expression of stylar incompatibility in the Andean clonal tuber crop oca (Oxalis tuberosa Mol., Oxalidaceae)

Long-, mid-, and short-styled clonal accessions of oca (Oxalis tuberosa) were intercrossed in a complete diallelic design. Pollen tube growth in styles was monitored in all diallelic crosses. Pollen fertility was estimated by two tests: staining of pollen grains with aceto-carmine and detection of β-galactosidase activity by the substrate X-Gal. The two methods of pollen fertility estimation were equally useful to detect fertility levels. Pollen originating from short stamens had the highest fertility (85%) and pollen from long stamens had the lowest fertility (70%). Pollen fertility was high throughout, but its degree varied with the stylar morph on which the pollen was formed. Long-styled accessions had the highest rates of fertile pollen. Differences in pollen fertility at different anther levels in the same style morph were also apparent. Pollen grain diameter of the six morph-anther level combinations was inversely correlated with pollen fertility. Pollen grains from long stamens were the largest and pollen grains from short stamens were the smallest. Neither pollen fertility nor pollen grain size had an influence on pollen tube growth in the style or on fruit and seed set. Pollen tubes growing within the styles were inhibited at a different level for each of the 18 cross combinations in the diallel. Although legitimate crosses had greatest pollen tube growth, some of the illegitimate inter- and intramorph crosses had equally high scores. Of all illegitimate crosses, mid-styled seed parents had the lowest level of stylar incompatibility. Fruit and seed set were highly correlated with the extent of pollen tube growth in the style. The number of pollen tubes entering ovules in a flower was in good agreement with the number of seeds produced per fruit. Therefore, it is concluded that stylar incompatibility is the major determinant of limited seed formation in oca even in the most successful legitimate cross combinations. Received: 1 September 1999 / Revision accepted: 4 April 2000     

12种酢浆草属植物核型分析

【目的】为了从细胞学角度明确12种酢浆草属（Oxalis）植物核型特征与亲缘关系,探究酢浆草属植物染色体的多样性,进一步为酢浆草种质资源鉴定与杂交育种亲本选择提供参考。【方法】应用根尖压片法对酢浆草属12个物种植物有丝分裂中期的染色体形态、数目及其核型进行观察分析。【结果】结果表明：（1）7个物种的染色体数目为首次报道,5种已报道物种中,兔耳酢浆草（O. fabaefolia）和黄花酢浆草（O. pes-caprae）染色体数目与前人报道一致,其余3种,与先前报道存在差异,其中2n=26为酢浆草属植物中首次报道的染色体数目,共发现7种染色体基数,其中x=13为首次报道,倍性范围从2x~6x;实际染色体大小范围为0.27~2.23 μm,着丝点位置为中部着丝点区（m）和亚中部着丝点区（sm）,核型类型共4种,核型不对称系数范围为56.31%~65.40%。（2）12种酢浆草属植物中兔耳酢浆草最为进化,扁平酢浆草（O. compressa）最为原始。（3）根据染色体核型相似性可将12个酢浆草属植物划分为4组。【结论】研究认为,12个酢浆草属物种具有广泛的核型多样性,核型分类结果与前人形态学分类不完全一致。     

Mutagens formed from beta-carbolines with aromatic amines

Norharman, widely distributed in our environment such as cigarette smoke and cooked foods, is not mutagenic to Salmonella strains, but becomes mutagenic to Salmonella typhimurium TA98 and YG1024 with S9 mix in the presence of aromatic amines, including aniline and o-toluidine. Therefore, we have designated norharman as a "co-mutagen". Since, humans are simultaneously exposed to norharman and aromatic amines in daily life, it is important to clarify the mechanisms of its co-mutagenic action to further understanding of the potential genotoxic effects in humans. Regarding the mechanisms of this action of norharman with aniline, a mutagenic compound, 9-(4'-aminophenyl)-9H-pyrido[3,4-b]indole[aminophenylnorharman (APNH)] is produced by their interaction, and converted to the hydroxyamino derivative which eventually forms the DNA adduct, dG-C8-APNH through possible ultimate reactive forms with esterification, and this induces mutations. Also other aminophenyl-beta-carboline compounds, such as 9-(4'-amino-3'-methylphenyl)-9H-pyrido[3,4-b]indole[amino-3'-methylphenylnorharman (3'-AMPNH)], 9-(4'-amino-2'-methylphenyl)-9H-pyrido[3,4-b]indole [amino-2'-methylphenylnorharman (2'-AMPNH)], 9-(4'-aminophenyl)-1-methyl-9H-pyrido[3,4-b]indole[aminophenylharman (APH)] and 9-(4'-amino-3'-methylphenyl)-1-methyl-9H-pyrido[3,4-b]indole[amino-3'-methylphenylharman (AMPH)], have been found on reaction of norharman or harman with aniline or toluidine isomers. These compounds showed mutagenic and clastogenic actions in bacterial and mammalian cells. Among them, APNH demonstrated the most potent activity, and it was most extensively studied. When APNH was administered as a single dose to F344 rats, severe testicular toxicity was observed after 6 days. Moreover, liver preneoplastic lesions (GST-P-positive foci) in the liver clearly developed in animals fed 10-50 ppm of APNH in the diet for 4 weeks. Since, APNH was detected in 24 h urine of rats upon simultaneous administration with norharman and aniline by gavage, it is likely to be also produced from norharman and aniline in the human body. From these findings, it is suggested that aminophenyl-beta-carboline derivatives may be classified as one of the novel types of endogenous mutagens and carcinogens.     

Exudation of amino acids by intact and damaged roots of wheat and peas

Summary Wheat and pea seedlings were grown aseptically in solution-culture and the total free amino nitrogen released by the roots was determined by a quantitative ninhydrin test. Amino nitrogen from wheat plants after 14 days growth was not detected by the test, indicating the release of less than 3 µg of amino nitrogen from a culture of 15 plants. Pea plants of the same age released from 2 to 7 µg per plant. Paper chromatograms of highly concentrated undisturbed solution-cultures revealed up to 13 amino compounds from wheat and 11 from pea. The pattern of amino acids in exudates was similar to that in crushed roots, except for an unidentified amino compound which was detected only in exuded material. The total amino nitrogen and relative proportions of several amino acids in the root exudates of sand-grown peas was influenced by several ratios of oxygen and carbon dioxide supplied to the root zone. Roots, experimentally damaged by swirling and rinsing in sand, released in 1 hour amino nitrogen of from 73 to 120 per cent of that released by normal exudation over a 2-week period. Our findings suggest that experimental and environmental root damage may be responsible for a large proportion of organic materials released by growing plant roots.Trade names are used in this publication to provide specific information. Their use does not constitute a guarantee of the products named and does not signify that they are approved by the U.S. Department of Agriculture to the exclusion of others of suitable composition.     

Congruence between morphological and molecular markers inferred from the analysis of the intra-morphotype genetic diversity and the spatial structure of Oxalis tuberosa Mol.

Oxalis tuberosa is an important crop cultivated in the highest Andean zones. A germplasm collection is maintained ex situ by CIP, which has developed a morphological markers system to classify the accessions into morphotypes, i.e. groups of morphologically identical accessions. However, their genetic uniformity is currently unknown. The ISSR technique was used in two experiments to determine the relationships between both morphological and molecular markers systems. The intra-morphotype genetic diversity, the spatial structures of the diversity and the congruence between both markers systems were determined. In the first experience, 44 accessions representing five morphotypes, clearly distinct from each other, were analyzed. At the molecular level, the accessions exactly clustered according to their morphotypes. However, a genetic variability was observed inside each morphotype. In the second experiment, 34 accessions gradually differing from each other on morphological base were analyzed. The morphological clustering showed no geographical structure. On the opposite, the molecular analysis showed that the genetic structure was slightly related to the collection site. The correlation between both markers systems was weak but significant. The lack of perfect congruence between morphological and molecular data suggests that the morphological system may be useful for the morphotypes management but is not appropriate to study the genetic structure of the oca. The spatial structure of the genetic diversity can be related to the evolution of the species and the discordance between the morphological and molecular structures may result from similar selection pressures at different places leading to similar forms with a different genetic background.     

Genetic diversity of the Andean tuber-bearing species, oca (Oxalis tuberosa Mol.), investigated by inter-simple sequence repeats.

The Andean tuber-bearing species, Oxalis tuberosa Mol., is a vegetatively propagated crop cultivated in the uplands of the Andes. Its genetic diversity was investigated in the present study using the inter-simple sequence repeat (ISSR) technique. Thirty-two accessions originating from South America (Argentina, Bolivia, Chile, and Peru) and maintained in vitro were chosen to represent the ecogeographic diversity of its cultivation area. Twenty-two primers were tested and 9 were selected according to fingerprinting quality and reproducibility. Genetic diversity analysis was performed with 90 markers. Jaccard's genetic distance between accessions ranged from 0 to 0.49 with an average of 0.28 +/- 0.08 (mean +/- SD). Dendrogram (UPGMA (unweighted pair-group method with arithmetic averaging)) and factorial correspondence analysis (FCA) showed that the genetic structure was influenced by the collection site. The two most distant clusters contained all of the Peruvian accessions, one from Bolivia, none from Argentina or Chile. Analysis by country revealed that Peru presented the greatest genetic distances from the other countries and possessed the highest intra-country genetic distance (0.30 +/- 0.08). This suggests that the Peruvian oca accessions form a distinct genetic group. The relatively low level of genetic diversity in the oca species may be related to its predominating reproduction strategy, i.e., vegetative propagation. The extent and structure of the genetic diversity of the species detailed here should help the establishment of conservation strategies.     

Purification and Electron Microscopy Studies of a Probable Potyvirus from Polianthes tuberosa L.

A partial purification procedure is described for a flexuous filamentous virus from leaves of the ornamental crop tuberose (Polianthes tuberosa L.) exhibiting mottle symptoms. Particular problems associated with the purification included particle aggregation and the highly viscous nature of the plant sap. The former difficulty was partially alleviated by the addition of 1.0 M urea to the extraction buffer and the latter by treatment of the extract with cellulase. The mean virus particle length from negatively stained leaf dips was 742 nm (SD = 54) which is characteristic of viruses belonging to the potyvirus group. In addition, electron microscopy of thin sections of infected leaf tissue demonstrated the presence of several types of inclusion bodies similar in appearance to inclusions previously described in association with potyvirus infections in other plants.     

秋茄(Kandelia candel (L))根系分泌低分子量有机酸及其对重金属生物有效性的影响

应用电感耦合等离子体质谱(ICP-Ms)与高效液相色谱(HPLC)分别对福建漳江口红树林湿地不同土壤结构(砂质与泥质)根际与非根际沉积物中重金属(Cu,Pb,Cd,Zn)含量,以及生长于砂质与泥质滩涂上的红树植物秋茄(Kandelia candel(L)Druce))幼苗根系分泌物中的低分子量有机酸进行测定。在室内模拟秋茄根系分泌的低分子量有机酸,作为重金属提取剂提取沉积物中可溶解态与碳酸盐结合态重金属,并与欧盟标准物质局(BCR)连续提取法相比较,探讨红树根系分泌的低分子量有机酸对红树林沉积物重金属生物有效性的影响。研究结果表明:漳江口红树林泥质沉积物中重金属含量大于砂质沉积物,根际沉积物大于非根际沉积物。两样地沉积物中重金属的赋存形态主要以铁锰氧化物结合态为主,根际沉积物中可交换态与碳酸盐结合态重金属含量均大于非根际沉积物。秋茄根系分泌低分子量有机酸为甲酸,丁酸,苹果酸,柠檬酸,乳酸。不同土壤结构对秋茄根系分泌的苹果酸,柠檬酸,乳酸有显著影响(P<0.05)。以低分子量有机酸作为提取剂对沉积物中可溶解态与碳酸盐结合态重金属的提取率表现为:柠檬酸>混合酸>苹果酸>乳酸>乙酸,低分子量有机酸对红树林沉积物重金属的生物有效性有促进作用。     

Acylated anthocyanins from leaves of Oxalis triangularis

The novel anthocyanins, malvidin 3-O-(6-O-(4-O-malonyl-alpha-rhamnopyranosyl)-beta-glucopyranoside)-5-O-beta-glucopyranoside (2), malvidin 3-O-(6-O-alpha-rhamnopyranosyl-beta-glucopyranoside)-5-O-(6-O-malonyl-beta-glucopyranoside) (3), malvidin 3-O-(6-O-(4-O-malonyl-alpha-rhamnopyranosyl)-beta-glucopyranoside)-5-O-(6-O-malonyl-beta-glucopyranoside) (4), malvidin 3-O-(6-O-(4-O-malonyl-alpha-rhamnopyranosyl)-beta-glucopyranoside) (5) and malvidin 3-O-(6-O-(Z)-p-coumaroyl-beta-glucopyranoside)-5-O-beta-glucopyranoside (6), in addition to the 3-O-(6-O-alpha-rhamnopyranosyl-beta-glucopyranoside)-5-O-beta-glucopyranoside (1) and the 3-O-(6-O-(E)-p-coumaroyl-beta-glucopyranoside)-5-O-beta-glucopyranoside (7) of malvidin have been isolated from purple leaves of Oxalis triangularis A. St.-Hil. In pigments 2, 4 and 5 a malonyl unit is linked to the rhamnose 4-position, which has not been reported previously for any anthocyanin before. The identifications were mainly based on 2D NMR spectroscopy and electrospray MS.     

Exudation from Aphid Stylets during the Period from Dormancy to Bud break in Tilia americana (L.)

Aphid stylet exudation during the period from dormancy to budbreak was studied in Tilia americana by means of detached branchesbrought from the woods into conditions of warmth and extendedphotoperiod. During physiological dormancy little exudationwas obtained. Thereafter until mid-March exudation was morevariable, but its onset accelerated progressively until mid-March,after which persistent exudation could be obtained from allbranches within 2 days. When the buds were removed from onebranch at this time, exudation persisted for only 5 days comparedwith 14 to 21 days for branches with buds. To account for theseresults it is suggested that a hormonal factor is produced bythe buds which results in sieve-tube activation, that the factoris virtually absent during physiological dormancy, and thereafterrequires a few weeks to become fully active. Determinations of sugar concentration, level of exudation, andbud dry weight indicated that exudation was most intense beforethe bud sinks were active and then rapidly falls off. It issuggested that the stylet acts as a sink competing with thenatural sinks for solutes from a limited region of the stem.Other interpretations are also considered.