bluuebunny/crossref_metadata_2025 huggingface dataset:
TREE FORM: ARCHITECTURAL MODELS DO NOT SUFFICE
Authors: Sachs Tsvi , Novoplansky Ariel
Published: April 2013

Tree forms have been classified according to the aspects of their development that follow relatively invariable programs. However, a prominent variability or plasticity is apparent in the duration and rate of the development of individual shoot apices and the probability that a branch, once formed, remains on the tree. Even though overall form may be predictable, these variable processes have a major role in the detailed structure of tree canopies. It follows that there must be mechanisms that constrain or limit chance events after, rather than before, they have been expressed in tree development. Constraining mechanisms include the inhibition of the development of a branch by another branch that had already started growing. This inhibition is due to both internal signals and to mutual shading. It results in any available space in a canopy being occupied by one or more branches, even though the precise location of these branches is not specified. The development of leading branches is also constrained by a progressive differentiation and growth limitation which is a function of the distance of the apices of these branches from the roots. At both the cellular and the organ levels unpredictable details are a characteristic of advanced, late evolutionary groups. Their prevalence means that architectural models stress an important, but partial, picture. There could be no ideal models nor a correct tree classification; there is no alternative to comparing tree forms in relation to major characteristics chosen according to the problem at hand.
GENETIC AND CLONAL DIVERSITY IN KOREAN POPULATIONS OF CALYSTEGIA SOLDANELLA (CONVOLVULACEAE)
Authors: Tae Kim Seung , Chung Myong Gi
Published: April 2013

Calystegia soldanella(L.) Roem. et Schutt. is a herbaceous perennial vine with both sexual and asexual modes of reproduction. It grows only on the sand dunes and beaches of East Asia, Europe, and the Pacific. Allozyme study was conducted on leaves collected from 425 plants in 13 Korean populations. In addition, two populations ofIpomoea stolonifera(Cyrillo) Poiret., a beach dune plant species in the southeastern United States, were included in this study. The levels of genetic variability within populations ofC. soldanellaandI. stoloniferaare lower than average values for species with similar life history and ecological traits. Mean percentage of polymorphic loci within populations (Pp), mean number of alleles per locus across populations (Ap), mean effective number of alleles (Aep), and mean population genetic diversity (Hep) were: 28.2%, 1.44, 1.19, and 0.100 forC. soldanellaand 15%, 1.15, 1.12, and 0.066 forI. stolonifera.ForC. soldanella, the mean number of multilocus genotypes per population (G= 20) and mean genotypic diversity index (DG= 0.88) were relatively high. Analysis of fixation indices indicated considerable population substructuring within populations ofC. soldanella, partly resulting from inbreeding (meanFIS= 0.442) and/or artifacts of founder effect and clonal growth. About 85% of the total variation inC. soldanellais common to all populations. Significant differences in allele frequencies among populations were found in all but one locus (p< 0.05) and average genetic identity for all pairs of populations was 0.958. Indirect estimate of the number of migrant (Nm= 1.46, calculated fromFST) indicates that the level of gene flow is moderate among Korean populations probably via seed dispersal by water. Based on available data, several factors such as wide geographic distribution, high levels of clonal diversity, moderate levels of gene flow, restricted ecological distribution, inbreeding, and founder effect may have played roles in shaping genetic structuring ofC. soldanella.
ECOPHYSIOLOGY OF SEED GERMINATION IN ENDEMIC LABIATES OF CRETE
Authors: Thanos Costas A. , Doussi Maria A.
Published: April 2013

Ecophysiological aspects of seed germination were investigated in four aromatic labiate plants of Crete Origanum dictamnus (dittany), Sideritis syriaca L. ssp. syriaca (Cretan mountain tea), Salvia pomifera L. ssp. pomifera (gall-bearing sage), and Salvia fruticosa (three-lobed sage). Experiments were performed both at constant temperatures and darkness as well as under temperature and light conditions simulating those prevailing in nature during the main germination periods (i.e., start and middle of the rainy season, November and February-March, respectively). In three out of the four species, no particular dormancy was revealed and germination occurred rather promptly, although in a rather narrow range of cool temperatures and at a relatively slow rate; both characteristics determine and/or support an early, autumn seed germination and seedling establishment. In the fourth plant, Sideritis syriaca, germination was manifested at relatively warm temperatures and at a considerably faster rate, in accordance with its alpine distribution favoring spring seedling emergence and establishment. All four species tested showed an intermediate response towards light, as a result of their intermediate levels of active phytochrome maintained in darkness. Therefore seed germination was partially manifested in darkness but it was significantly enhanced (particularly at suboptimal temperatures) by white or red light; on the other hand, illumination with far-red light (simulating light conditions under a canopy) resulted in significant inhibition compared to dark controls.
GERMINATION STUDIES IN ENDEMIC PLANT SPECIES OF THE IBERIAN PENINSULA
Authors: Perez-Garcia F. , Iriondo J.M. , Gonzalez-Benito M.E. , Carnes L.F. , Tapia J. , Prieto C. , Plaza R. , Perez C.
Published: April 2013

The germinative behavior of nine plant species of the Iberian Peninsula, four of them catalogued as vulnerable or endangered by the International Union for the Conservation of Nature, was studied under controlled laboratory conditions. Most of the species studied germinated better at relatively low temperatures (15 °C and 20 °C) and, in general, high germination rates were also obtained at alternating temperatures (25/15 °C). Coronopus navasii germinated over 60% at 25 °C, the highest temperature used in this study. Lavatera oblongifolia did not surpass 20% germination under any of the conditions assayed. Seed coat scarification increased germination in Helianthemum squamatum, while seed pretreatments with hot water or sulfuric acid were effective in H. polygonoides. Less favorable results were obtained in Lavatera oblongifolia, whereas scarification was completely ineffective in Onobrychis peduncularis ssp. matritensis.
REGENERATION OF PLANTLETS FROM HYPOCOTYL DERIVED CALLUS OF MORUS ALBA
Authors: Kathiravan K. , Shajahan A. , Ganapathi A.
Published: April 2013

Plantlets were regenerated from hypocotyl callus of Morus alba cv. MR2. Calli were established from hypocotyl segments on Murashige and Skoog (MS) medium supplemented with indoleacetic acid (0.5 mg/1) and benzyladenine (BA) (0.5 mg/1). They were transferred to MS medium with different concentrations of naphthaleneacetic acid NAA and BA for four weeks. Adventitious shoot buds were observed by transferring callus onto fresh Linsmaier and Skoog (LS) medium containing NAA (0.5 mg/1) and BA (0.75 mg/1). Shoots produced in vitro were rooted on MS medium with indolebutyric acid (0.75 mg/1).
EFFECT OF GROWTH REGULATORS AND CULTURE ENVIRONMENT ON SOMATIC EMBRYOGENESIS OF ACACIA CATECHU WILLD
Authors: Rout G.R. , Samantaray S. , Das P.
Published: April 2013

Somatic embryogenesis was achieved from callus derived from immature cotyledons of Acacia catechu Willd on Woody Plant Medium (WPM) supplemented with 13.9 μM kinetin and 2.7 μM α-naphthaleneacetic acid. Somatic embryos formed when the calli were grown for 2 weeks in the dark followed by incubation in the light with a 16-h photoperiod. Embryogenesis did not occur with continuous incubation in either the dark or the light. The addition of L-proline (0.87–5.21 mM) to the medium promoted the development of somatic embryos and induced secondary somatic embryogenesis. The light-green somatic embryos germinated on half-strength Murashige and Skoog (MS) medium supplemented with 2% (w/v) sucrose devoid of growth regulators. Somatic embryos germinated into plantlets which were hardened in the greenhouse and subsequently transferred to the field.
FLOWER AND FRUIT DEVELOPMENTAL STAGES OF THE XEROPHYTE OPUNTIA FICUS-INDICA
Authors: Gutterman Yitzchak
Published: April 2013

The developmental stages of the flower bud ofOpuntia ficus-indica(prickly pear), from the initial active meristem of the axillary flower bud to the mature fruit, including pollination and seed development, are followed.

This xerophyte develops flower buds mainly from the axillary buds on the margin of the apical part of the terminal segment of the flat, leafless branch (platiclades). Flower bud meristems start to be active and secrete mucus in January. The red-bracted flower buds start to appear in March/April, flowers open during May/June, and fruit matures during June/August. The developmental stages were divided into 11 stages, and some were photographed by SEM.
DIVERSITY OF CRYPTOGAMIC PLANTS AND FUNGI IN “EVOLUTION CANYON”, NAHAL OREN, MOUNT CARMEL NATURAL PRESERVE, ISRAEL
Authors: Wasser S.P. , Nevo E. , Vinogradova O.N. , Navrotskaya I.L. , Ellanskaya I.A. , Volz P.A. , Virchenko V.M. , Tsarenko P.M. , Kondratyuk S.Ya
Published: April 2013

The diversity of cryptogamic plants and fungi has been studied, in the context of a research program of biodiversity across phylogeny, at the “Evolution Canyon” microsite. Lower Nahal Oren, Mount Carmel Natural Preserve, Israel. The opposite slopes of Evolution Canyon display dramatic biotic contrasts due to higher (up to 300%) solar radiation on the south-facing slope (S-slope) which is warmer, drier, and climatically more fluctuating than the north-facing slope (N-slope). Diversity of cryptogamic plants and fungi (198 species and intraspecific taxa) at Evolution Canyon is considerable. The list includes 46 taxa of Cyanophyta, 10 of Chlorophyta, 3 of Euglenophyta, 1 of Bacillariophyta, 29 of lichens, 2 of lichenicolous fungi, 59 of soil micromycetes, 39 ofAgaricaless.l., and 9 of mosses. Fifty species and infraspecific taxa are new for the biota of Israel, among them 22 taxa of algae, 9 of micromycetes, 8 ofAgaricaless.l., 9 of lichens, and 2 of lichenicolous fungi. Some of them are new for the biota of Asia. While fungi (especiallyAgaricaless.l.) and mosses primarily range on the more wet and humid “temperate European” N-facing slope, or in the valley bottom (mosses), algae, primarily due to the number of cyanobacteria, predominate on the warm and dry “tropical African” S-facing slope.
REGENERATION OF TREMA ORIENTALIS (BLUME) LINN.: EFFECT OF GROWTH REGULATORS, CULTURE CONDITIONS, AND AGE AND SOURCE OF EXPLANTS
Authors: Rout G.R. , Samantaray S. , Das P.
Published: April 2013

Optimal conditions for high frequency shoot bud regeneration from leaf callus of Trema orientalis (Blume) Linn. were studied. The regeneration rate was controlled by the growth regulators, the age and the source of the explants, and the illumination conditions. Irrespective of illumination conditions, shoot bud regeneration was achieved only in media containing benzyladenine (BA) + α-naphthaleneacetic acid (NAA) combinations, with the best results being obtained in the presence of 2.5 mg/1 BA and 0.25–0.5 mg/1 NAA. The morphogenic response was less frequent in the calluses derived from leaf explants of the mature trees compared to those of the in vitro-grown seedlings. The rate of shoot bud regeneration was more pronounced in the cultures maintained for 4 weeks in the light (16-h photoperiod) than the cultures incubated in the dark. Regenerated shoots were rooted on the medium containing 1/2 strength basal Murashige and Skoog (MS) salts supplemented with 0.01 mg/1 NAA or indole-3-butyric acid (IBA). The rooted plantlets were established in the greenhouse.
CHLOROPLAST ARRANGEMENT ALONG INTERCELLULAR AIR SPACES
Authors: Psaras G.K. , Diamantopoulos G.S. , Makrypoulias P. Chr.
Published: April 2013

The intracellular distribution of chloroplasts in the mesophyll was studied in leaves taken from seven plant species from different groups: the evergreen sclerophylls Olea europaea and Nerium oleander; the drought semideciduous and seasonally dimorphic shrub Coridothymus capitatus; the winter deciduous Capparis spinosa, which grows entirely during summer; and the cultivated species Hordeum vulgare, Vigna unguiculata, and Citrus aurantium. In all leaves and mesophyll types, chloroplasts were found to line the parts of the walls exposed to the internal leaf atmosphere. The arrangement of the chloroplasts adjacent to intercellular air spaces might be a universal phenomenon facilitating the inward diffusion of CO2.
LEAF MORPHOLOGY AND CARBON ISOTOPE DISCRIMINATION VALUES IN PURPLE SPURGE (EUPHORBIA PEPLIS L.)
Authors: Patrignani G. , Carraro L. , Iacumin P. , Orsenigo M.
Published: April 2013

Among the numerous species of the family Euphorbiaceae the photosynthetic carbon fixation follows three pathways: C3, C4, CAM. The object of the present research was Euphorbia peplis L., grown and collected on a Mediterranean coast. Leaf anatomy and ultrastructure together with carbon isotope discrimination measurements indicated that E. peplis is ascribable to the NADP-malic enzyme C4 photosynthetic type.
CHARACTERIZATION OF THE WHEAT cDNA ENCODING THE β SUBUNIT OF THE MITOCHONDRIAL ATP SYNTHASE
Authors: Abulafia Suzy , Graur Dan , Devos Katrien , Breiman Adina
Published: April 2013

A wheat cDNA encoding an open reading frame of 553 amino acids with a deduced amino acid sequence corresponding to the mitochondrial β subunit of the synthase was isolated. The expression of the β ATPase was investigated in leaves of 7-day-old wheat plants, and a decrease in the abundance of transcripts along the leaf was observed. The cDNA of the β ATPase was mapped on the group 1 chromosomes of wheat. Phylogenetic analysis of the mitochondrial β subunit of the ATPase complex is described.
ASEPTIC BROOMRAPE INFECTION OF TOMATO ROOT CULTURE
Authors: Losner-Goshen Dalia , Ben-Hod Graham , Mayer M. Alfred , Joel M. Daniel
Published: April 2013

The parasitic plants of the genus Orobanche (broomrape) are important pathogens of numerous agricultural crops throughout the world. The understanding of biochemical mechanisms involved in the penetration of Orobanche haustorium into host root tissues faces difficulties due to the presence of microorganisms. Here we describe an aseptic in vitro system, in which normal broomrape seedlings infect host roots grown in culture, instead of the previously reported infection of intact host plants by Orobanche calli. This system is based on divided Petri plates with two different culture media: one part of the dish contains a rich medium suitable for the support of host root culture, the other part contains a medium with no organic nutrients and no hormones and is therefore suitable for infection of host roots by Orobanche. Roots that are supported by the first medium pass to the other side of the petri dish where they stimulate broomrape seed germination and are infected by the emerging broomrape seedlings.
MORPHOMETRICAL CHARACTERIZATION OF CYTISUS AND ALLIES (GENISTEAE: LEGUMINOSAE) AS AN AID IN TAXONOMIC DISCRIMINATION
Authors: González-Andrés Fernando , Ortiz Jesús-María
Published: April 2013

Twenty-four accessions belonging to the genusCytisusand allied taxa were characterized by adult plant morphometry. Twenty-six characters were measured in flowers, 9 in leaves, and 5 in fruits. Two data sets were prepared, the first including only floral parameters and the second with all the parameters. Two different multivariate analyses were carried out for every data set: cluster analysis and principal components analysis. All these studies produced a similar grouping of the operational taxonomic units. Four clear groups were defined: (i)Cytisophyllum sessilifolium;(ii)Cytisus baeticus, C. reverchonii, C. scoparius., (iii)Chamaecytisusspecies; (iv)Genistaspecies. On the other hand,Cytisus villosusshowed an intermediate position betweenCytisusandChamaecytisus, andCytisus heterochrousand C.purgansan intermediate position betweenCytisusandGenista.This grouping agrees with that obtained by other recent seed morphometry and biochemical studies, and supports the generic arrangement presented by Bisby (1981).
STRUCTURE AND FUNCTION OF THE MUCILAGINOUS SEED COATS OF PLANTAGO CORONOPUS INHABITING THE NEGEV DESERT OF ISRAEL
Authors: Gutterman Yitzchak , Shem-Tov Shachar
Published: April 2013

Plantago coronopus var. crassipes is a common annual plant in many areas of the Negev Desert highlands.

The dry seed coat cross section and surface structure of P. coronopus seeds before the first wetting were examined by SEM, as were the freeze-dried mucilage and adhesion of the seeds to the soil crust. When wetted, the mucilaginous layer forms, and seeds on the soil surface adhere to the soil crust. Some P. coronopus mucilaginous seeds may be dispersed by rain, even after less then 10 min of wetting. The dry seeds can float on run-on water for 10–44 min and are then dispersed along runnels into depressions, or adhere within a few minutes to the wet soil crust near the dry mother plant. Seeds matured on dry plants in a natural habitat in spring 1995, germinated in December 1995 to 96% after 72 h at 20 °C in light, but only to 2% in dark.

The importance of mucilaginous seeds for the survival of the plant species under desert conditions is discussed.
CHANGES IN LEAF WATER POTENTIAL, OSMOTIC ADJUSTMENT, AND PROLINE METABOLISM IN MULBERRY DURING WATER STRESS
Authors: Ranjitha Kumari B.D. , Veeranjaneyulu K.
Published: April 2013

The influence of water stress on amino acid content and proline metabolism was studied in 3-month-old mulberry plants at four levels of water stress. Leaf water potential and osmotic potential were significantly decreased in all stress treatments. Though leaf area and relative water content decreased, significantly, a marked decrease was observed only in severe stress treatment. Accumulation of total amino acids and proline was observed both in roots and leaves in stress treatments, with amino acid accumulation greater in leaves than in roots. In contrast, proline accumulation was greater in roots than in leaves. Activities of proline dehydrogenase and proline oxidase were inhibited under stress conditions. Inhibition of proline oxidase was greater in roots than in leaves.
A PROTOCOL FOR HORSEGRAM [MACROTYLOMA UNIFLORUM (LAM.) VERDC.] CALLUS INDUCTION
Authors: Mohamed S. Varisai , Jayabalan N.
Published: April 2013

Calli of Macrotyloma uniflorum (Lam.)Verdc.) Co.1 and Bgm.1 were established from expiants of epicotyl, hypocotyl, cotyledon, and young leaf on MS medium supplemented with auxins and cytokinins (2, 4-D, IAA, NAA, BAP, KN, and CM). When they were cultured subsequently on various combinations and different concentrations, BAP and 2,4-D were found to yield green compact callus in all expiants. Yellow friable calli were obtained on MS medium supplemented with auxins (2,4-D or NAA or IAA). Browning of callus was observed at a higher concentration of (2.5 mg1−1) auxins after 25 days.
CHECKLIST OF THE LICHENS OF ISRAEL
Authors: Galun Margalith , Mukhtar Avihay
Published: April 2013

This checklist reports on 250 lichen species of Israel (as well as the Sinai peninsula). The following species have not been recorded before: Bacidia naegelii, Caloplaca holocarpa, Catapyrenium squamulosum, Collema coccophorum, C. crispum var. metzleri, C. flaccidum, Dermatocarpon walthekii, Dirina massiliensis, Hyperphyscia adglutinata, Lecanora chlarotera, Lecidea lurida, Leptogonium corniculatum, Ochrolechia pallescens, Peltula euplaca, Physcia semipinnata, Placicliopsis dalmatica, Clauzadea chondrodes, Teloschistes villosus, and Thelenella hassei.
THE BARBALOIN CONTENT AND DISTRIBUTION IN ALOE ARBORESCENS LEAVES ACCORDING TO THE LEAF PART, AGE, POSITION, AND SEASON
Authors: Chauser-Volfson Elena , Gutterman Yitzchak
Published: April 2013

The distribution of the secondary phenolic compound, barbaloin, in Aloe arborescens leaves depends on the leaf part, age, and position of the leaf, as well as on seasonal influences. Young and old leaves of A. arborescens were cut from plants monthly and the exudate was immediately freeze-dried. The barbaloin levels were determined spectrophotometrically at λmax, 360–362 nm after separation by TLC. In all leaves the tissue of the basal third of the leaf had the lowest barbaloin content, the upper third contained the highest percentage, and the middle part contained the intermediate percentage. After cutting young leaves, the new basal part that grows after replanting has a higher barbaloin content after about five months when compared with the same part before cutting.

In the 16 leaves of a cutting rooted two years before the experiment, the highest barbaloin content was found in the four upper young leaves (63%). In all the other leaves the barbaloin content was found to be only between 13 and 22%.

There are also seasonal influences on the barbaloin content of young leaves. When old and young leaves were compared, the higher barbaloin content was found in the young leaves harvested at the same time.
EFFECTS OF AGRICULTURE ON EPIPHYTIC LICHEN VEGETATION IN CENTRAL ITALY
Authors: Loppi Stefano , De Dominicis Vincenzo
Published: April 2013

The influence of agriculture, i.e., of fertilizers and ammonia emissions from crops and sheep grazing, on epiphytic lichen vegetation, and the use of nitrophytic lichen species in bioindication of air pollution were investigated in a geothermal area in central Italy. Floristic analysis showed that the lichen vegetation is only slightly influenced by agriculture. Analysis of the lichen data and chemico-physical parameters of tree bark supporting lichen growth failed to demonstrate marked differences between agricultural and non-agricultural sites, the higher total frequency of nitrophytic species in agricultural sites being the only parameter discriminating between the two site types. Bark nitrogen and pH were not discriminant. Factors determining the higher total frequency of nitrophytic species in agricultural sites may include dust impregnation of bark and the drier microclimate of trees in these sites. It is concluded that nitrophytic lichens can be included in the calculation of the Index of Atmospheric Purity in the study area.
STAGES OF PLANT SUCCESSION IN FAGUS SYLVATICA L. AND PINUS SYLVESTRIS L. FORESTS OF TEJERA NEGRA NATURAL PARK (CENTRAL SPAIN), THREE YEARS AFTER FIRE
Authors: Herranz J. M. , Martinez-Sanchez J. J. , De Las Heras J. , Ferrandis P.
Published: April 2013

In August 1991 a fire in Tejera Negra Natural Park (Guadalajara Province, Central Spain) burned 300 ha. A study of the stages of succession inFagus sylvaticaL. andPinns sylvestrisL. forests was carried out during the first 3 years after the fire (1992–1994) in order to evaluate the dynamics of floristic richness, vegetation cover, diversity, plant density, and fugacity of the colonizing species by sampling of 10 permanent plots. Two years after the fire, vegetation cover in the burnt plots was similar to that of unburnt plots. However, floristic richness, diversity, and fugacity values were significantly higher in the burnt plots. At the end of the study,Fagus sylvaticawas replaced byGenista floridashrubs andPinus sylvestriswas replaced byCytisus scoparius.
GROWTH-FORM AND INTRASPECIFIC TAXONOMY IN WESTERN MEDITERRANEAN DAPHNE (THYMELAEACEAE)
Authors: Feliner Gonzalo Nieto
Published: April 2013

Two architectural patterns can be distinguished among western Mediterranean species of Daphne. Sympodial growth is displayed by D. cneorum, D. oleoides, D. alpina, D. rodriguezii, D. gnidium, and D. mauritanica, while monopodial growth occurs in D. laureola and D. mezereum. Based primarily on specific features related to growth-form, the taxonomic value of several intraspecific taxa frequently recognized within D. laureola and D. oleoides is assessed. The name D. philippi, largely applied to plants from high altitudes in the Pyrenees, is likely to represent a female plant from a gynodioecious population of D. laureola. With the support of a morphometric multivariate analysis, recognition of D. laureola subsp. latifolia from Southern Spain and Northern Africa is also questioned. It is concluded that characters previously proposed as diagnostic for intraspecific taxa within D. Iaureola and D. oleoides are the result of different duration of the growing season. In the absence of sound evidence, the taxonomic value of all the intraspecific names applied to western Mediterranean plants is questioned. Synonymy of the taxa involved is provided.
ELECTROPHORETIC ANALYSIS OF DIVERSITY WITHIN CUPRESSUS SEMPERVIRENS L. GROWING IN ISRAEL
Authors: Schiller Gabriel , Korol Leonid
Published: April 2013

Isoenzyme variants withinCupressus sempervirensL. planted in Israel have been identified using starch gel electrophoresis of enzymes extracted from the megagametophytic and perisperm seed tissue. Single-tree cone collection from 493 trees growing in 27 populations at holy sites and in plantations planted at the end of the 19th and the beginning of the 20th century in the country was done in 1986–1987. In 1994 viable seeds were available from only 267; of them, 140 trees were phenotypically identified as var.pyramidalisand 67 as being of var.horizontalis; the other 60 trees were not identified phenotypically. The results gained show that in the plantedC. sempervirensL. under investigation 11 (47.8%) out of the 23 gene loci in 13 enzyme systems analyzed were polymorphic; they contain a relatively high gene diversity of 0.479. The genetic distance between the two varieties planted in Israel is 0.007. Differences in allele frequencies between the two varieties occurred only in 5 loci, viz., IDH2PGI2, MDH3, PGM1, and ACO1.
MANGANESE TOXICITY IN ECHINOCHLOA COLONA: EFFECTS OF DIVALENT MANGANESE ON GROWTH AND DEVELOPMENT
Authors: Samantaray Sanghamitra , Rout Gyana Ranjan , Das Premananda
Published: April 2013

Manganese (Mn2+) toxicity is probably the second most important growth-limiting factor (after aluminum toxicity) for plants in acidic soils. The objective of our study was to determine the toxic effects of different concentrations of divalent Mn (MnCl2) on the growth of Echinochloa colona in hydroponic culture. Seed germination was not inhibited by Mn concentrations of 9.1 to 910 μM in distilled water. However, the higher Mn concentration (910 μM) in nutrient solution completely suppressed root development. Although chlorophyll content decreased with increased Mn concentrations in solution, dry weights of shoots were increased by the higher Mn treatments. These treatments also produced toxicity symptoms of leaf chlorosis and necrosis. Histological studies showed that the higher Mn concentrations caused disorganization of conductive and mesophyll tissues.
WHY RED FLOWERS ARE NOT INVISIBLE TO BEES
Authors: Chittka Lars , Waser Nickolas M.
Published: April 2013

A pervasive idea among pollination biologists is that bees cannot see red flowers. This idea has led many workers to assume that red coloration is an adaptation by which flowers exclude bees as visitors. However, recent empirical and theoretical evidence strongly supports the alternative view, that red flowersarevisible to bees. Our purpose is to marshal this evidence from physiology, behavior, and ecology. First, we define the spectral boundary between orange and red, and show that the visual spectrum of all bee species studied to date extends enough into long wavelengths to provide sensitivity to red light. Such sensitivity differs from the ability to discriminate different monochromatic lights, and we argue that bees will be unable to discriminate such lights above about 550 nm. Second, we point out that flowers do not reflect monochromatic lights. Instead many of them, particularly those that appear red, orange, yellow, and white to humans, have reflectance patterns that are essentially step functions. We predict that bees should be able to discriminate such reflectance patterns over a range of 550–650 nm, since reflectance functions with steps at such wavelengths will occupy different loci in bee color space and thus be distinguishable. In this sense, bees should distinguish between green-, yellow-, orange-, and red-reflecting objects, even if these do not reflect in shorter wavelengths (including UV). A behavioral experiment shows that bumblebees can indeed perform this task. Third, we present information on the spectral reflectance of some typical “red” flowers, combined with field observations of bee visitation to such flowers. We end with a preliminary reassessment of the adaptive significance of red flower coloration, using North American “hummingbird” flowers as an example; we also stress some of the pitfalls facing evolutionary biologists who continue to assume that bees are blind to red objects.
FLORAL COLOR CHANGE AND INSECT POLLINATION: A DYNAMIC RELATIONSHIP
Authors: Weiss Martha R. , Lamont Byron B.
Published: April 2013

Flowers in a wide range of angiosperm taxa (at least 456 species in 253 genera and 78 families) undergo dramatic ontogenetic color changes that serve as signals to their insect pollinators. The changes affect a diversity of floral parts, involve all three major classes of floral pigments, and produce a broad spectrum of initial and final colors. A diverse array of insect pollinators (in at least 21 families in four orders) recognize and respond to floral color phases, visiting pre-change flowers preferentially, relative to their contribution to the total floral display. A variety of hypotheses have been proposed to explain the functional significance of floral retention and color change. Experimental results demonstrate that in some cases retention of older flowers on the plant results in increased visitation by pollinators from a distance, while at close range, color change directs visitors towards the rewarding and sexually viable younger flowers. The interaction does not require a long coevolu- tionary association: both native and exotic insect species discriminate between floral color phases on native and introduced plant species. This flexibility is based at least in part on learning by the insect, although innate color preferences may also be important.
FLOWER SIZE AND SHAPE: IMPLICATIONS IN POLLINATION
Authors: Dafni Amots , Kevan Peter G.
Published: April 2013

In 42 plant species, the flowers' en face planar projected areas, contour lengths, and the ratios between them (= contour densities) were measured in relation to their pollinators, type of reward, and flower shape. A significant correlation exists between the planar projected area and contour density, which indicates that small flowers have broken outlines. Beetles were found to be associated more with large, rounded (bowl-shaped) flowers. Small bees, in contrast to medium and large bees, were associated significantly more with small flowers having broken outlines (i.e., high contour densities). Each factor examined (pollinator, flower shape, and reward) and each possible interaction among them, is significantly related to the values of each morphological variable. This implies that each category of pollinator (beetles, small, and medium-large bees) is associated with a syndrome of dependent floral characteristics (size, shape, and reward). We propose that the greater contour density of smaller flowers compensates for their smaller size by increasing visibility and the broken outline shapes act as “form guides” in the orientation, landing, and foraging by pollinators of flowers.
SPONTANEOUS AND LEARNED PREFERENCES FOR VISUAL FLOWER FEATURES IN A DIURNAL HAWKMOTH
Authors: Kelber Almut , Pfaff Michael
Published: April 2013

Macroglossum stellatarumis a diurnal member of the otherwise crepuscular sphin- gid family. The moths of this species are known to visit flowers of almost all colors, sizes, and patterns, but at a time, they are flower-constant. They are mainly attracted by the visual cues of flowers, odors being less important. The choices for flower-like objects differing in color, size, and pattern were analyzed in flight cages with free-flying animals of the laboratory livestock.

Newly eclosed moths spontaneously choose 440 nm and 540 nm more frequently than other colors, radial patterns rather than ring patterns, and paper disks with a central spot more often than those without it. They are attracted to disks of about 32 mm diameter with a large distance to the background. These spontaneous choices enable them to find a first nectar reward. The moths can be trained to colors and sizes. They learn spectral colors much faster than paper colors, and their choices after color learning are compatible with true color vision phenomena. Most probably they also have a time-place memory.
THE RESPONSE OF AMPHICOMA SPP. (COLEOPTERA; GLAPHYRIDAE) BEETLES TO RED MODELS DIFFERING IN AREA, SHAPE, AND SYMMETRY
Authors: Dafni Amots
Published: April 2013

Field experiments investigating the attraction ofAmphicomaspp. beetles to red, nonrewarding, scentless models have shown that (1) attractiveness is positively and linearly related to model size; (2) for models of similar size, contour density does not affect attractiveness; (3) bilateral models are more attractive than radially symmetrical models with the same area. The results are discussed in comparison to the spatial vision of honeybees and with regard to the flower preference of beetles.
CHARACTERIZATION OF THE AUXIN SYNTHESIS GENES OF ERWINIA HERBICOLA PV. GYPSOPHILAE
Authors: Gafni Yedidya , Manulis Shulamit , Kunik Talya , Lichter Amnon , Barash Isaac , Ophir Yakir
Published: April 2013

We present the DNA sequence of some 3590 base pairs from the virulence plasmid of the crown-gall-forming bacteriumErwinia herbicolapv.gypsophilaestrain PD713. This region includes the entire transcription unit of an operon encompassing the IAA synthesis genes. These genes, designatediaaMandiaaH, reside on a 78-MDa native plasmid. The sequence analysis indicates that the operon contains two open reading frames of 562 (iaaM) and 460 amino acids (iaaH), corresponding to proteins with molecular weight of 62,473 and 49,300 daltons, respectively. When cloned and expressed in minicell-producingE. coli, this sequence encodes production of two proteins, 49 and 62 kDa. Both genes show moderate to high homology to IAA synthesis genes from other plant-associated bacteria. Analysis by primer extension of the transcription initiation site located it 63 bases upstream of the translation initiation codon.
POST-FIRE VEGETATION DYNAMICS IN A NATIVE PINUS HALEPENSIS MILL. FOREST ON MT. CARMEL, ISRAEL
Authors: Schiller Gabriel , Ne'eman Gidi , Korol Leonid
Published: April 2013

Israel's largest naturalPinus halepensisMill. forest is on the Mt. Carmel range and belongs to the distinct East Mediterranean genetic group. Most of this forest is the result of invasion of abandoned fields and grazing lands, resulting in a heterogeneous pine forest with an understory of broad-leaf shrubs and trees. Species composition, vegetation cover, pine-stand structure, and pine genetic diversity of plots in sites of known fire history, burned 5, 11, and 20 years ago, were studied with adjacent unburned sites forming a chronosequence.

Except for annual species, no species replacement took place during post-fire succession. The main observed changes were in the cover of species and of plant life forms. The ratio of tree/dwarf-shrub cover was found to be linearly related to the number of years elapsed since the last fire. Therefore, this ratio could serve as an index to determine the successional stage of Aleppo pine stands with unknown fire history. It is estimated that 30–40 years are needed for full recovery of Aleppo pine stands after fire, depending upon site quality. The stands of post-fire regeneration are of uniform age and are less variable in their structure than unburned stands. The genetic distance among the variousPinus halepensissubpopulations was found to be very small; most of the genetic variability was due to within-subpopulations variability, with almost no variability among subpopulations. Alleles that are typical of West MediterraneanP. halepensispopulations or ofP. brutia, were found in two post-fire subpopulations (stands), indicating pre-fire cross pollination between nativePinus halepensistrees and trees in adjacent pine plantations of foreign origin.

The conclusion is that fire has little effect on species composition and on vegetation structure, but that it alters the Aleppo pine stand structure.
REGULATION OF SEX EXPRESSION IN DESERT AND MEDITERRANEAN POPULATIONS OF AN ANDROMONOECIOUS PLANT (GAGEA CHLORANTHA, LILIACEAE)
Authors: Wolfe Lorne M.
Published: April 2013

This study examined issues related to the ecology of andromonoecy in Gagea chlorantha (Liliaceae), a perennial geophyte that grows in desert and Mediterranean-type habitats in Israel. Andromonoecy is a plant sexual system where individuals produce both male and hermaphrodite flowers and is thought to have evolved to optimize resource allocation to male and female function. Individuals of this species produced 1–6 flowers, and flower production was significantly correlated with the size of the storage organ (bulb). Three sexual phenotypes were found to exist: those that made only male flowers, plants that made only hermaphrodite flowers, and those that produced both flower types. Two lines of evidence suggest that hermaphroditic reproduction is more costly than male reproduction: (1) hermaphroditic flowers were heavier than male flowers in terms of dry biomass; (2) bulb size was greater on single-flower plants that were hermaphrodite compared to male. In addition, bulb size was greater on multiple-flowered plants that made a hermaphrodite flower as the last flower, compared to those that made a male flower. The floral sex ratio varied extensively along a latitudinal rainfall gradient within Israel. The five Mediterranean populations were male-biased. In contrast, the production of males in the three Negev desert populations was extremely rare, and approximately 94% of the flowers were hermaphrodite. The difference in sex ratio between the two habitat types is explained in terms of environmental unpredictability.
COMPARATIVE STUDY OF LEAF ANATOMY AND ESSENTIAL OILS OF THE HYBRID MENTHA X VILLOSO-NERVATA AND ITS PARENTAL SPECIES M. LONGIFOLIA AND M. SPICATA
Authors: Gavalas Nikos , Bosabalidis M. Artemios , Kokkini Stella
Published: April 2013

Leaves of the hybrid Mentha x villoso-nervata are covered with nonglandular trichomes of intermediate length between those of its parental taxa M. longifolia and M. spicata. Glandular trichomes producing essential oils are more numerous on the lower leaf surface than on the upper one in all three mints. Their number per mm2 is higher in M. spicata and it decreases in M. longifolia and M. x villoso-nervata. Stomata are also more numerous on the lower leaf surface of the three taxa, with M. longifolia predominating. The leaf lamina of M. x villoso-nervata is ca. 83% thicker than that of M. longifolia and ca. 9% thicker than that of M. spicata. The number of chloroplasts per mm2 of mesophyll section (leaf cross section) is higher in M. X villoso-nervata. In leaf paradermal sections, the sizes of the epidermal, palisade, and spongy parenchyma cells of M. X villoso-nervata have intermediate values between those of its parental species M. longifolia and M. spicata.

M. x villoso-nervata leaves are the lowest in essential oil content. As concerns the essential oil composition, the hybrid resembles one parent, M. longifolia, in the derivatives of piperitenone and piperitone, and the other parent, M. spicata, in the high amount of limonene. It differs, however, from its parental species in that it contains a higher amount of germacrene D.
SOMACLONAL VARIATION IN CULTURED IN VITRO TOBACCO PLANTS FROM THE HYBRID NICOTIANA GOSSEY DOMIN. X N. TABACUM L.
Authors: Nikova Violeta , Palakarcheva Maria , Pundeva Roumiana , Krusteva Dobrinka
Published: April 2013

Incompatibility between the speciesNicotiana gosseyDomin. andN. tabacumL., resulting in complete sterility of F1hybrid, was overcome using in vitro techniques. Explants of stem parenchyma were put in culture and were regularly subcultured on Murashige and Skoog basal medium, supplemented with different compounds: α-naphthaleneacetic acid (2 mg L−1) and kinetin (0.5 mg L−1) for callus induction, kinetin (2 mg L−1) and indule-3-acetic acid (0.5 mg L−1) for organ formation, and ferulic acid (2 mg L−1) for rooting. The regenerants obtained showed significant morphological and cytological variability. They differed from each other as well as from the initial material in stem length, leaf size, and flower morphology. Most of the plants examined were mixoploids. A great number of aberrations were established during the meiotic division of the regenerants. Pollen viability varied from 0 to 92%. The results of our investigations showed that the tissue culture method could be successfully applied not only for overcoming species incompatibility but also for inducing somaclonal variation and creation of a large variety of plant forms.
BIOLOGICAL CONTROL OF FUSARIUM WILT OF MUSKMELON BY FORMULATIONS OF ASPERGILLUS NIGER
Authors: Mukherjee Krishanu , Sen Bineeta
Published: April 2013

Aspergillus niger van Tiegh. (An 27) was shown to be a promising biocontrol agent against Fusarium oxysporum Schlecht f. sp. melonis Sny. and Hans., which causes muskmelon wilt. Fruit wastes, such as carrot waste, citrus peels and pomace, mixed fruit pomace, and pineapple peels and pomace, proved to be a promising and cheap alternative source for mass multiplication of A. niger. These wastes are readily available throughout the year and can replace some of the highly priced media used for mass production of biocontrol organisms. Citrus pomace extract (20%) was found to be an excellent liquid medium for mass production. In solid fermentation, fruit wastes were superior to other media used as substrates. A short period of 10 days of incubation was sufficient for the production of 108 colony forming units (cfu) per gram of the material. The extent of control achieved by the seed coating formulation (FSC) was at par with Carbendazim. Formulation for soil application (FSO), a new contribution to the formulation science, could reduce Fusarium wilt disease by 78.31%, when applied at the rate of 8 g/kg of soil. Both FSC and FSO formulations can be stored at room temperature (14–35 °C) for more than a year.
PATTERNS OF VARIATION IN ALGAL COMMUNITIES ALONG THE MEDITERRANEAN COAST, ISRAEL
Authors: Lundberg Barbro , Olsvig-Whittaker Linda
Published: April 2013

Algal species composition and cover data were collected from sixteen stations along 150 km of the Mediterranean coast of Israel during 1973–1995. The samples produced 185 composite samples from three habitat types, platform, wall, and rocky sea floor, which were analyzed using numerical classification and ordination techniques (TWINSPAN and RDA) to determine whether habitat, season, site, or yearly patterns correlate with observed differences between the algal communities. We conclude that habitat is the most important factor determining algal community composition, followed by season and site. Community patterns fluctuate between years but show no trends. Some recommendations for future monitoring are given.
TOXINS FROM CYANOBACTERIA AND THEIR POTENTIAL IMPACT ON WATER QUALITY OF LAKE KINNERET, ISRAEL
Authors: Sukenik Assaf , Rosin Claudia , Porat Ram , Teltsch Benjamin , Banker Roni , Carmeli Shmuel
Published: April 2013

A number of different species of cyanobacteria (blue-green algae) produce toxins of several different types. Cyanobacterial Wooms present a serious health concern when they occur in water bodies that supply potable water. Lake Kinneret, the major water source in Israel, was characterized for many years by relatively stable phytoplankton populations which fluctuated with the seasons in a quite predictable manner. An exceptional bloom of the filamentous cyanobacteriumAphanizomenon ovalisporum, which produces hepatotoxin, was observed for the first time in Lake Kinneret during the fall of 1994. Cylindrospermopsin, a toxin produced byA. ovalisporum, was purified and chemically characterized. The potential implications of cylindrospermopsin-producingA. ovalisporumbloom in Lake Kinneret on water quality is discussed, together with a general description of cyanobacterial toxins and their occurrence in natural waters.
PHOTOACCLIMATION IN PHOTOSYNTHETIC MICROORGANISMS: AN ULTRASTRUCTURAL RESPONSE
Authors: Berner Tamar , Sukenik Assaf
Published: April 2013

Photosynthetic microorganisms are able to modify their chemical composition, cellular structure, and organization of their chloroplasts in response to the level of irradiance. The photosynthetic apparatus adjusts itself to any new light regime by changing the ultrastructural properties of the chloroplast to provide space and area needed to match other biochemical changes in order to optimize light harvesting and utilization. Acclimation to low light intensity is characterized by an increase in thylakoid number in cyanobacteria, and in the chloroplast volume in eukaryotic plants. In the Eukaryota, these changes allow the packaging of more thylakoids within this organelle to harbor the addition of photosynthetic complexes, i.e., light harvesting antennae, reaction centers, and electron transport components. These changes are essential for optimal operation of the photosynthetic apparatus at low light intensity, mainly to increase the absorption of light energy. Acclimation to high irradiance is characterized by a reduction of the surface density of thylakoid membranes and reduction in the specific volume of the chloroplast. The accumulation of storage bodies containing starch and lipids is yet another typical feature of high light acclimated cells in response to the high rate of photosynthetic activity.
BIOSYNTHESIS OF THE CELL WALL POLYSACCHARIDE IN THE RED MICROALGA RHODELLA RETICULATA
Authors: Cohen Arava(Katz) , Arad Shoshana(Malis)
Published: April 2013

This research forms part of our ongoing study to elucidate cell wall biosynthesis in red microalgae. Cell wall formation during the cell cycle of the red microalgaRhodella reticulatawas followed in cultures synchronized by a regime of dark (12 h), light (12 h), and dilution of the culture thereafter to 1–1.5 × 106cells/ml. Under these conditions, cell number doubled after 24 h, DNA replication occurred between the 6th and 12th hours, and cell division took place between the 8th and 14th hours of the cycle. Cell wall constituents increased only during the light hours, peaking as follows: sulfur at the 2nd hour, protein at the 11th hour, and the various sugars (each at different times) between the 6th and 12th hours of the cycle. Since xylose predominated from the beginning of the cycle, it appears that this sugar was produced first and formed the basic polymer skeleton to which other sugars were attached. Two polymers were produced during the cycle, their sizes (as determined by gel filtration) being 0.5 × 106and 1.15 × 106daltons. It thus seems likely that the smaller 0.5 × 106dalton polymers are produced inside the cells and then excreted into the medium, where they are further polymerized to produce the final-size polymers. The herbicide 2,6-dichlorobenzonitrile (DCB), an inhibitor of cellulose biosynthesis, was previously found to inhibit cell wall formation in red microalgae. When it was added to the cultures at the beginning or at the end of the cycle, no inhibition in cell division was detected, but when it was added at the 8th hour, cell division was significantly inhibited (38%), resulting in an increase in mean cell volume. Addition of DCB did not affect DNA replication or cell wall polysaccharide content or composition, as measured after 24 h of the cycle. It seems that DCB affects an inhibitory phase in cell division and that this inhibition is not necessarily coupled with its inhibition of formation of the sulfated polysaccharide.