Ecophysiology of Salt Excretion in Aeluropus litoralis (Graminae)

Various aspects of salt excretion from leaves of Aeluropus were investigated. Salt excretion exhibited an optimum-type of curve when measured against external salt concentration, while sodium content of the leaves increased linearly. The ‘relative excretion’, i.e. rate of excreted ions: change in leaf ion content, was maximal in the low salt concentration range, and decreased when external sodium chloride concentration increased. Concentration of the excreted droplets was higher than the external concentration when the leaves were exposed to low salt concentrations in the medium, but the reverse occurred when the external salt concentrations were high. The excretion process was sensitive to water-stress conditions, caused either by high external salt concentrations or by exposure to dry atmosphere. A considerable fraction of the leaf sodium content in salt-treated leaves was only slightly available for excretion. Salt excretion in Aeluropus was enhanced by light. Such enhancement was indirect and is attributed to the increase of salt transport via transpiration stream. Selectivity of the salt-excretion mechanism is in favour of sodium and against potassium. On the other hand, potassium has a high affinity for the accumulation systems within the leaves. The ecological significance of the results is discussed.     

Contribution of NaCl excretion to salt resistance of Aeluropus littoralis (Willd) Parl

Aeluropus littoralis is a perennial halophyte, native to coastal zones. Although it is usually exposed to high saline, this plant grows normally without toxicity symptoms. In order to assess leaf salt excretion, different growth parameters, Na(+), K(+), Ca(2+), Mg(2+) and Cl(-) concentrations, as well as excreted ions were examined in plants grown for 2 months in the presence of various salinity levels (0-800 mM NaCl). In addition, salt crystals, salt glands and other leaf epidermal structures were investigated. Results showed that total plant growth decreased linearly with increase to medium salinity. This reduction concerns mainly shoot growth. In addition, this species was able to maintain its shoot water content at nearly 50% of the control even when subjected to 800 mM NaCl. Root water content seemed to be unaffected by salt. Sodium and chloride ion contents in shoots and in roots increased with salinity concentrations, in contrast to our observation for potassium. However, calcium and magnesium contents were not greatly affected by salinity. Excreted salts in A. littoralis leaves were in favor of sodium and chloride, but against potassium, calcium and magnesium which were retained in plants. Sodium and chloride were excreted from special salt glands, which were scattered on the both leaf surfaces. In addition to salt glands, papillae were the most frequent epidermal structure found on A. littoralis leaves, and are likely involved in A. littoralis salt resistance.     

獐茅盐腺形态结构及其泌盐性

显微观察结果显示,獐茅盐腺为典型的双细胞结构,主要分布在叶脉附近,这样有利于它快速收集来自根部的盐离子。同时,X-ray微区分析结果表明,獐茅盐腺可以有效地将Na^＋从表皮细胞和叶肉细胞转运到基细胞,由帽细胞分泌到体外,从而降低植物体内盐分水平以适应盐渍环境。用不同盐类处理材料,獐茅对Na^＋、K^＋和Ca^2＋的吸收和分泌均表现为具有不同的选择性,分泌量的顺序为Na^＋〉K^＋〉Ca^2＋,并且仅仅24h内,盐分的分泌量就已经超过了叶片内的含量,结果植株体内的总离子含量水平几乎不变,说明獐茅具有较强的泌盐能力。     

Phytoremediation of Total Petroleum Hydrocarbons From Highly Saline and Clay Soil Using Sorghum halepense (L.) Pers. and Aeluropus littoralis (Guna) Parl

This study evaluated the effects of native plants (Sorghum halepense and Aeluropus littoralis), total petroleum hydrocarbons (TPH) concentrations, and nutrients on the removal of TPHs from a highly saline clay soil. For a period of 180 days, rhizosphere microbial number, plant biomass, and residual TPHs were determined monthly. Results showed that TPH removal from soil in the rhizosphere was 13% higher than that in the control (unplanted soil). In addition, the number of heterotrophic bacteria in the rhizosphere and non-rhizosphere soil was 7.407 and 6.629 log₁₀CFU/g, respectively. The maximum TPH removal, microbial numbers, and plant biomass were measured in the treated soil, polluted with 0.86% (w/w) of TPH. The high clay and salinity of the experimental soil had a negative effect on the phytoremediation efficiency. Hence, it was necessary to improve the physicochemical properties of the soil to provide a good condition for plants and microbes, thereby increasing the phytoremediation efficiency.     

黑松不定芽的增殖

以无菌条件下萌发22 d的黑松幼苗子叶/胚轴材料为起始外植体,在GD 3 mg·L~(-1)6-BA 0.3 mg·L~(-1)NAA培养基中诱导黑松不定芽的形成,其诱导率为96%。进一步探讨生长调节物质水平、基本培养基种类和继代周期对黑松不定芽增殖影响的结果表明:6-BA浓度为2 mg·L~(-1)、NAA浓度为0.2 mg·L~(-1)时的增殖率最高,达100%,增殖倍数也最高,为4.88;在5种基本培养基(GD、DCR、WPM、1/2MS和1/2GD)中,GD培养基比较适合不定芽的增殖,可以形成健壮有效的不定芽;此种条件下培养30 d的黑松不定芽增殖率可达4.6倍。     

Ecological differentiation and cladogenesis of Baldellia (L.) Parl. (Alismataceae)

The Iberian Peninsula is home to a large number of endemic species that often show strong genetic subdivisions which indicate possible isolation of populations in the past. Numerous phylogeographic and phylogenetic studies on Iberian flora and fauna have revealed this territory to be the origin of genetic differentiation during the Pleistocene Ice Age. To better understand the influence of Plio-Pleistocene climatic oscillations on the cladogenesis and population structuring of refugial taxa restricted to freshwaters of the Iberian Peninsula, we studied the evolutionary history of the small European genus Baldellia, both from a phylogenetic/phylogeographic perspective and regarding its ecological characteristics. Molecular analyses were based on four plastid regions and nuclear ITS2 ribosomal spacer from individuals belonging to geographically isolated Baldellia populations, while the relationships between climate and Baldellia species distribution was investigated by redundancy analysis applied to the climatic data with the occurrence of Baldellia species as external variables. The absence of a clear phylogenetic signal most likely reflects a common and recent cladogenesis for Baldellia. In contrast, the more rapidly evolving plastid sequences indicate a recent phylogeographic history of refugial repartition and ecological segregation probably occurring during the last glaciation, a scenario well supported by marked differences in species?? ecological preferences and climate analysis.     

Plant regeneration from callus of Puccinellia distans (L.) Parl

Callus was induced from seeds of Puccinellia distans (L.) Parl. on MS medium supplemented with 2 mgl^-1 2,4-dichlorophenoxyacetic acid and 0.5 mgl^-1 kinetin. Morphogenesis initiation was achieved during subculture on medium containing 0.1 mgl^-1 2,4-D. From the point of morphogenetic capacity, 3 types of callus were selected. High frequency of plant regeneration was obtained by selection of embryogenic type of callus, and culture on N₆ medium and N₆ medium supplemented with kinetin (5–10 mgl^-1), or kinetin (2 mgl^-1) and IAA (0.5 mgl^-1). A high ratio of albinos among regenerants was observed.     

Zur Verbreitungsbiologie der artVirga strigosa (Willd.) Holub

Die asiatische Art Virga strigosa hat sich in der letzten Zeit an den Schuttplätzen, Bachufern und in den Gebüschen in einigen Gebieten von Böhmen (besonders bei Praha, Jílové, Hradec Králové und Opo?no) eingebürgert. In dieser Mitteilung werden die Studienergebnisse über die Verbreitungsbiologie und Keimung derVirga-Früchte angefürt. Sie berichtet auch über das Vorkommen und die Verbreitung dieser Art bei der Stadt Jílové bei Praha in den letzten 6 Jahren und gibt die Unterschiede zwischen der fremden ArtVirga strigosa und der einheimischen ArtVirga pilosa an (Synonymik siehe beiHolub 1964).     

Antileishmanial phenylpropanoids from Alpinia galanga (Linn.) Willd

Hexane, chloroform and ethyl acetate extracts (100 microg/ml) of Alpinia galanga rhizomes exhibited significant activity in vitro against promastigotes of L. donovani. Twelve compounds namely, methyleugenol (1), p-coumaryl diacetate (2), 1'-acetoxychavicol acetate (3), 1'-acetoxyeugenol acetate (4), trans-p-acetoxycinnamyl alcohol (5), trans-3,4-dimethoxycinnamyl alcohol (6), p-hydroxybenzaldehyde (7), p-hydroxycinnamaldehyde (8), trans-p-coumaryl alcohol (9), galangin (10), trans-p-coumaric acid (11) and galanganol B (12) were isolated from these extracts. Of these, compounds 2, 3, 4 and 5 were found most active in vitro against promastigotes of L. donovani with IC50 values of 39.3, 32.9, 18.9 and 79.9 microM respectively. This is the first report of antileishmanial activity of the extracts and isolated constituents of A. galanga.     

Genetic relationships between wild and cultivated Vicia ervilia (L.) Willd.

The wild form of bitter vetch, Vicia ervilia , grows mainly in Turkey. Wild and cultivated V. ervilia have the same chromosome number (2n =14), share the same karyotype and are interfertile. Pod dehiscence in V. ervilia is governed by two loci and the domesticated phenotype is obtained with the homozygous recessive condition in either locus.     

Distribution of minerals in quinoa (Chenopodium quinoa Willd.) seeds

The distribution of minerals in quinoa (Chenopodium quinoa Willd.) seed was examined using energy dispersive X-ray microanalysis (EDX) in combination with scanning electron microscopy (SEM). Phosphorus, K, and Mg coincided in localization in embryonic tissue. Since phytin globoids have been known to localize in protein bodies in embryonic cells of quinoa seed, it is thought that P is attributed to phytic acid and that K and Mg form to phytate. Calcium and K were present in the pericarp, where the cell wall is thickly developed, suggesting that these minerals are associated with pectin. Sulfur occurred in embryonic tissues, which would be derived from sulfur amino acid residues of storage proteins concentrated in the tissues. Abrasion of quinoa seeds resulted particularly in decrease in Ca content.     

Differentiation of Non-articulated Laticifers in Poinsettia (Euphorbia pulcherrima Willd.)

Differentiation of non-articulated laticifers in poinsettia(Euphorbia pulcherrima Willd.) was studied ultra-structurally.Growing laticifers show: (1) a multinucleate apical region containingabundant ribosomes but few other differentiated organelles and(2) a sub-apical zone where the cytoplasm is dominated by vacuolesof diverse morphology with latex particles. These particlesappear first within narrow tubular vacuoles developed especiallyin the peripheral cytoplasm. During vacuolation of the laticifer,portions of cytoplasm, including some of the nuclei, becomeisolated by the enlarging and fusing vacuoles; eventually thesebecome lysed, except the latex particles which remain in thecentral vacuole. During differentiation of a laticifer branch,the cytoplasm contains the usual organelles, including a fewmicrobodies and coated vesicles. The plastids that lie withinthe peripheral cytoplasm differentiate into amyloplasts witha single elongated starch grain. Towards the end of differentiationthe cytoplasm becomes restricted to a thin parietal layer, withthe remaining organelles reduced or degenerate, surroundinga central vacuole filled with latex particles. Euphorbia pulcherrima Willd, poinsettia, ultrastructure, differentiation, laticifers     

博落回果实药材质量标准研究

目的:制定博落回果实药材质量标准,为该药用植物资源的开发利用提供科学依据.方法:生药学研究,理化鉴别,醇浸出物测定法,紫外/可见分光光度法,薄层色谱法及HPLC色谱法.结果:对博落回果实的性状、显微特征进行了描述;对6个不同产地及收集时间博落回果实的醇浸出物进行了测定;同时对其活性成分血根碱和白屈菜红碱进行了薄层定性鉴别和HPLC定量研究.结论:通过研究制定了博落回果实的质量控制标准.     

Leucas aspera (Willd.) A potential refuge for pollinators

Journal of Insect Conservation - A large number and diverse array of pollinator species are essential to provide effective and sustainable pollination of crops and wild plants. However, we are at...     

獐茅种群地上生物量及光合面积等的生长季动态

獐茅(Aeluropus littoralis var.sinensis)是渤海湾和黄海等滩涂盐生草甸的建群种之一(吴征镒等,1980)。以獐茅为优势种的草地是一种重要的农牧业资源。对獐茅种群生物量及光合面积的研究,理论上有助于阐明该种群生长发育的基本规律;实践上对于指导农牧业生产以及合理利用这一自然资源也具有参考价值。     

Occurrence of Intraxylary Phloem in Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg.

The occurrence of intraxylary phloem in Hevea brasiliensis isreported. The phloem elements were observed as strands associatedwith the protoxylem group in the pericentral region. The natureand importance of such tissue in this species are discussed. Hevea brasiliensis, intraxylary phloem, laticifers, tapping     

Breeding quinoa (Chenopodium quinoa Willd.): potential and perspectives

Quinoa (Chenopodium quinoa Willd.) originated in the Andean region of South America; this species is associated with exceptional grain nutritional quality and is highly valued for its ability to tolerate abiotic stresses. However, its introduction outside the Andes has yet to take off on a large scale. In the Andes, quinoa has until recently been marginally grown by small-scale Andean farmers, leading to minor interest in the crop from urban consumers and the industry. Quinoa breeding programs were not initiated until the 1960s in the Andes, and elsewhere from the 1970s onwards. New molecular tools available for the existing quinoa breeding programs, which are critically examined in this review, will enable us to tackle the limitations of allotetraploidy and genetic specificities. The recent progress, together with the declaration of “The International Year of the Quinoa” by the Food and Agriculture Organization of the United Nations, anticipates a bright future for this ancient species.     

Both weather and resources influence masting in chestnut oak (Quercus montana Willd.) and black oak (Q. velutina Lam.)

Plant Ecology - Masting is the synchronous and highly variable production of fruit within a population. Although several hypotheses have been proposed to explain why and how masting evolved in...