bluuebunny/crossref_metadata_2025 huggingface dataset:
THE SHORT-TERM UPTAKE OF ZINC AND CELL MORTALITY OF THE SEAGRASS HALOPHILA STIPULACEA (FORSK.) ASCHERS.
Authors: Malea P. , Kevrekidis T. , Haritonidis S.
Published: April 2013

Zinc uptake in the upper (leaves) and lower ground parts (roots, stems, rhizoids) of Halophila stipulacea (Forsk.) Aschers, and leaf cell mortality were examined in laboratory experiments. The seagrass was incubated for 12 days in zinc concentrations between 10−4 and 10−7 M. At 10−6 and 10−7 M Zn concentrations, uptake was characterized by a rapid initial adsorption rate slowly decreasing up to the 4th day, after which an equilibrium was reached; the ‘equilibrium’ concentrations increased as the Zn in sea water increased. At the higher Zn concentrations (10−5 and 10−4M)the content in the plant continued to increase after the 4th day, perhaps due to the development of necrotic effects mainly evident in the teeth and epidermal cells as well as in the mesophyll cells of the leaves. A positive correlation between Zn content in the upper and lower parts of H. stipulacea was also found, whereas Zn uptake in leaves was significantly higher than in the root-rhizomes-rhizoids. It was also demonstrated that some zinc can leak from the tissues of this seagrass.
EFFECT OF KCl ON CHLOROPHYLL, TOTAL SUGARS, SOLUBLE PROTEIN, AND IN VIVO NITRATE REDUCTASE ACTIVITY IN LEAVES OF QUERCUS SERRATA AND CORRELATION STUDIES
Authors: Ghosh M.K. , Srivastava R.C.
Published: April 2013

Foliar treatment with different concentrations of potassium chloride (KC1) toQuercus serrataseedlings resulted in higher levels of total chlorophyll, total sugars, soluble protein, and in vivo nitrate reductase activity in the leaves. Optimal concentration was found to be 5.0 mM KC1. The results with foliar applications were further verified with excised shoots dipped in KC1 and with leaves treated directly with KC1. Regression and correlation coefficients were analyzed, and a strong positive correlation was found between chlorophyll and total sugars, and between soluble protein and in vivo nitrate reductase activity.
SENSITIVITY OF CROP PLANTS TO WATER STRESS AT SPECIFIC DEVELOPMENTAL STAGES: REEVALUATION OF EXPERIMENTAL FINDINGS
Authors: Plaut Zvi
Published: April 2013

It has been suggested that in many crops differences in sensitivity to water stress occur at different growth stages. Since identical amounts of water may be applied, irrespective of whether a crop is exposed to relatively severe and short periods of stress or to extended periods of mild stress, the responses to such differing conditions should be compared. Unfortunately, such a comparison has not been conducted in most studies on sensitivity to water stress at different growth stages. In the present study, based on three field experiments conducted for different purposes, such a comparison was made for three crops: corn, sunflower, and tomato. In corn, distinct responses of ear and kernel yields to the timing of water stress were found. Withdrawal of irrigation water during flowering and cob formation resulted in greater yield losses than during other stages, indicating that this is a critical growth stage. However, slight and uniform reduction of water during the entire growth period resulted in significantly less damage to kernel or ear production, although the total amount of water applied was similar to that under staged withdrawal. In sunflowers, the withdrawal of irrigation water even at noncritical growth stages caused a more marked reduction in grain yield than did a uniform reduction throughout the entire season. In tomatoes, on the other hand, the withdrawal of irrigation water during specific growth stages caused minimal damage to fruit and total soluble solids yield as compared with fully irrigated control; reduction of irrigation water throughout the season brought about a significant decrease in yield. The difference between these crops is interpreted on the basis of the determinance of their floral meristems.
ATTEMPTS TO OVERCOME THE BARRIER OF INTERSPECIFIC HYBRIDIZATION BETWEEN CUCUMIS MELO AND C. METULIFERUS
Authors: Beharav Alexander , Cohen Yigal
Published: April 2013

The crossability ofCucumis meloandC. metuliferuswas studied in order to find ways to effect the cross between the two species. In cross-pollination withinC. melo, the pollen tubes entered the ovarian cavity within 24 h, and fertilization occurred within 48 h. Pollen germinated well after cross-pollination between the species, but pollen tubes grew slowly.C. metuliferuspollen tubes were arrested in the stigma or the upper style ofC. meloflowers.

The influence of 100-, 150-, and 200-krad gamma radiation on in vitro germination, pollen tube growth ofC. meloandC. metuliferus, and on in vivo fertilization ofC. melowas studied. Pollen ofC. metuliferusappeared to be much less sensitive to gamma rays than that ofC. melo.Higher radiation doses were found to reduce fruit set ofC. melo.Irradiation of pollen ofC. meloalways resulted in “pseudo-fertilization”.

We attempted to overcome the prefertilization crossing barrier betweenC. meloandC. metuliferusby using techniques of bud pollination, benzyladenine (BA) treatment, and irradiated mentor pollen. Ten lines ofC. meloand 6 accessions ofC. metuliferuswere used as female and male parents, respectively. The techniques of BA and bud pollination were ineffective. Numerous fruits with few embryos were obtained on some of theC. melolines after using the irradiated mentor pollen technique. Embryos, which were isolated at the age of 20–25 days and cultured on medium consisting of 1/3 Murashige and Skoog medium, were observed to provide normal development. All nine surviving plants were similar to the maternal parent and were not interspecific hybrids.
TRADITIONAL SELECTIVE HARVESTING EFFECTS ON OCCURRENCE AND REPRODUCTIVE GROWTH OF GUNDELIA TOURNFORTII IN ISRAEL GRASSLANDS
Authors: Kaplan Didi , Pevzner Dror , Galilee Moshe , Gutman Mario
Published: April 2013

Gundelia tournfortiiis a perennial herb with a rosette and thickened root, growing in grasslands. In the Middle East, its leaf bases are used as a vegetable. Harvesting is by clipping the rosette at its base, and stripping the leaves from the leaf bases. In the last 20 years clipping and gathering has become more widespread, and a commercial trade has developed.

The aim of this study was to discover whether, as a result of the rise in demand, the density and distribution potential of this edible plant are liable to come under threat.

The percentage of flowering plants in the non-harvested areas was found to be significantly higher than that in the harvested areas. As a result the Nature Reserves Authority has adopted our recommendation to regard this plant as a protected species.
INNOVATIONS IN THE TRIBE VICIEAE (FABACEAE) FROM ISRAEL
Authors: Plitmann Uzi , Gabay Rakefet , Cohen Ofer
Published: April 2013

Recent extensive field and taxonomic studies have revealed new taxa of various ranks in the leguminous tribe Vicieae, whereas few other taxa had to be revised. Most of the findings were in the Northern districts of Israel and the Golan Heights. The article sums up these innovations, diagnostically describing two new taxa in Lathyrus and three in Vicia. Possible modes of differentiation in the tribe are briefly discussed.
SOIL MICROMYCETES OF SELECTED AREAS OF ISRAEL
Authors: Volz Paul A. , Wasser Solomon P.
Published: April 2013

Species content of soil micromycetes of different areas of Israel (Haifa, Akko, Caesarea, Kafr Kanna, Nazareth, Tiberias, Jordan River shore, Jericho, Jerusalem, Bethlehem, Masada, Dead Sea shore) is given. A total of 83 species belonging to 59 genera were found in 74 soil samples collected in Israel during February—March 1994. Many species belonging to the Deuteromycetes were found as well as a few species belonging to other classes, including Zygomycetes and Ascomycetes. Eighteen species are new or rare for the biota of Israel. Peculiarities of species and genera content of soil micromycetes of different regions of Israel are discussed. General, specific, and dominant taxons are described. The dermatophyte,Microsporium gypseum, and keratinophilic species of the genusChrysosporiumwere commonly found.
FREE-RADICAL-INDUCED LIPID PEROXIDATION IN SEEDS
Authors: Sathiyamoorthy P. , Nakamura S.
Published: April 2013

From the practical standpoint, it is desirable to prolong the shelf life of seeds not only under optimum conditions of storage but also under suboptimal conditions. Production of radicals and their intermediates during storage of low or high lipid-containing seeds, and their relationship to seed aging is poorly understood. Reactions involving free radicals are an inherent feature of seed deterioration. Evidence suggests that degradation of lipids in deteriorating seeds, releasing free fatty acids, initiates oxidative deterioration by providing substrate for lipoxygenase. Membranes are primary targets of free radical attack. Recent studies showed that low-vigor embryos contained significantly higher levels of free radicals than high-vigor ones, while embryos from medium-vigor lots showed intermediate values. Pretreatment of seeds with an appropriate ratio of vitamin C to vitamin E may result in a synergistic defense response to oxidative lipid damage and, thus, may prevent seed deterioration to some extent. Indeed, knowledge of identification, isolation, cloning, and plant transformation of genes controlling unsaturated fatty acid metabolism in relation to lipid peroxidation (seed aging) will be an added advantage for post-harvest seed storage technology.
RAPD ANALYSIS OF SHRUBS BELONGING TO THE GENUS CYTISUS AND ALLIES (GENISTEAE: FABACEAE), AS AN AID FOR TAXONOMIC DISCRIMINATION
Authors: González-Andrés Fernando , Ortiz Jesús-María
Published: April 2013

Twenty-five accessions belonging to the genus Cytisus and allied taxa (Genisteae: Fabaceae) were analyzed using RAPD (Random Amplified Polymorphic DNA) techniques in order to study the usefulness of this technique for characterization of species and genera and for estimation of its potential value for further populational studies and prebreeding programs. A high level of intrapopulational variability was detected. Nevertheless, when only common bands to all the studied individuals per accession were considered for numerical analysis, the technique was useful for characterization at the specific and generic levels. The dendrogram obtained supports the generic arrangement proposed by Bisby (1981), helping to elucidate the difficult taxonomy of the studied taxa. The high intrapopulational variability indicates that RAPD could be useful for populational studies and also as molecular markers.
REGULATION OF GENDER AND FLOWERING BEHAVIOR IN A SEXUALLY DIMORPHIC DESERT SHRUB (OCHRADENUS BACCATUS DELILE [RESEDACEAE])
Authors: Wolfe Lorne M. , Shmida Avi
Published: April 2013

The major goal of this study was to examine patterns of gender variation in Ochradenus baccatus, a shrub found in the Judean Desert and Arava Valley of Israel, whose breeding system was previously considered dioecious (separate male and female individuals). We conducted detailed measurements on 150 marked plants over two years to (1) quantitatively describe the variation in sex expression and elucidate the factors responsible for gender variation in males, (2) determine the role of plant size in regulating the flowering behavior through the year, and (3) document pollinator visitation to males and females. The variability in sex expression differed between males and females. Females only reproduced by seed. In contrast, gender in males was extremely variable: 35% of males reproduced only by pollen donation (pure males) and 65% produced pollen and varying amounts of fruit and seeds (inconstant males). The ability to produce fruit was highly correlated with individual plant size. Inconstant males were significantly larger than pure males. Individual plant size also determined the flowering pattern through the year. Unlike most other desert plant species that typically flower after the winter rains, large O. baccatus plants flowered all year. Small plants, regardless of sex, flowered only during the winter months. The flowers of O. baccatus were visited by a diverse suite of insects including wasps, bees, ants, beetles, flies, and butterflies. Perhaps owing to the greater attractiveness of the floral display of males (due to the presence of yellow pollen), males were visited by many more insects than females. Over four observation days, 526 insects were counted on male plants compared to only 39 on females.
SECRETORY STRUCTURES IN ARTEMISIA NITIDA BERTOL. (ASTERACEAE)
Authors: Corsi Gabriella , Nencioni Silvia
Published: April 2013

Artemisia nitida Bertol. has not been studied so far from a pharmaco-biological point of view. In the present work some results of morphological and histochemical studies on the secretory structures are given. The secretory structures are of two types: glandular trichomes, and secretory ducts whose secretion is quite similar but not identical. Taking all the precautions needed for the histochemical interpretation of the results, we can assume that the glandular trichomes and secretory ducts contain an oleoresin whose main constituents are terpenoids, steroids, and sesquiterpene lactones. Their presence in A. nitida justifies both biological and economic interest in this Italian species.
SOMATIC EMBRYOGENESIS IN CELL SUSPENSION CULTURE OF COWPEA (VIGNA UNGUICULATA (L.) WALP)
Authors: Kulothungan S. , Ganapathi A. , Shajahan A. , Kathiravan K.
Published: April 2013

Embryogenic callus was induced from seedling leaf explants of cowpea (Vigna unguiculata (L.) Walp. cv. C152 on Murashige and Skoog (MS) medium containing 2.0 mg 1−1 2,4-dichlorophenoxyacetic acid (2,4-D). The maximum frequency of somatic embryogenesis was noticed when this callus was transferred to MS liquid medium supplemented with 2 mg 1−1 2,4-D. Further studies on ontogeny of somatic embryos showed that the cells destined to become somatic embryos divided into spherical or filamentous proembryos. Subsequent divisions in the proembryo led to globular, heart, torpedo-shaped, and cotyledonary-stage somatic embryos. Tiny plantlets were obtained by transferring the cotyledonary-stage somatic embryos to MS liquid medium containing 0.5 mg 1−1 2,4-D.
HORMONAL INDUCED TRANSFORMATION OF THE TUBEROUS PURPLE NUTSEDGE (CYPERUS ROTUNDOS L.) INTO A TUBER-LESS PHENOTYPE
Authors: Yogev Menahem , Rubin Baruch , Negbi Moshe
Published: April 2013

Spraying benzyladenine and gibberellic acid over sprouting shoots of Cyperus rotundus L. did not adversely affect their aboveground development. However, the underground shoots (rhizomes) modified their potentially positive gravitropic growth response into a negative one, to become aboveground shoots. Under such conditions, virtually no tubers, the dominant propagating and perennating units of C. rotundus, were formed. Field experiments, where growth regulator treatments were followed by application of reduced rates of herbicide, open new possibilities to facilitate the control of this noxious weed.
INFLUENCE OF SALT CONTENT OF PLIOCENE CLAY SOIL ON THE EMERGENCE OF SIX GRASSES
Authors: Maccherini S. , Chiarucci A. , Torri D. , Ristori J. , De Dominicis V.
Published: April 2013

The effects of three soil salinity levels (450, 925, and 1150 μS/cm) on the emergence of six grasses from a clay badland area of central western Italy were investigated. The species were five annuals (Aegilops geniculata, Brachypodium distachyum, Hordeum maritimum, Parapholis incurva, and Parapholis strigosa) growing in the pioneer association Parapholido- Artemisietum cretaceae, and the perennial Bromus erectus, the dominant species of perennial grasslands. The tests were made in plastic pots filled with soils having different salt contents. A control, conducted in Petri dishes with distilled water, showed a high germination percentage for all species but different germination rates. In the soil tests, the emergence rate of all the species decreased with increasing soil salinity. Final emergence percentages were higher than 70% for all species and all salinities, except for P. incurva and P. strigosa (60 and 46.7%, respectively) at the highest salinity level. B. erectus showed the lowest emergence rate at all salinities, in line with its ecological features.
BIOLOGICAL CONTROL OF HETERODERA CAJANI AND FUSARIUM UDUM ON PIGEONPEA BY GLOMUS MOSSEAE, TRICHODERMA HARZIANUM, AND VERTICILLIUM CHLAMYDOSPORIUM
Authors: Siddiqui Zaki A. , Mahmood Irshad
Published: April 2013

Glomus mosseae, Trichoderma harzianum, and Verticillium chlamydosporium were used alone and in combination for the management of wilt disease complex of pigeonpea caused by the nematode Heterodera cajani and the fungus Fusarium udum. Treatment of plants inoculated with pathogens increased plant length, shoot dry weight, number of nodules, and reduced nematode multiplication and wilting index. Simultaneous use of biocontrol agents against pathogens gave better control than their individual application. T. harzianum had an adverse effect on root colonizaiton by G. mosseae. Parasitism of nematodes by V. chlamydosporium was also reduced in the presence of T. harzianum. The highest reduction in nematode multiplication was observed when all three biocontrol agents were used together.
MICROPROPAGATION AND IN VITRO STORAGE OF CENTAURIUM RIGUALII ESTEVE (GENTIANACEAE)
Authors: Iriondo José M. , Pérez César
Published: April 2013

Centaurium rigualiiEsteve, an endangered plant species from southeastern Spain with potentially useful secondary products, was successfully micropropagated from shoot tips using MS supplemented with 0.44 μM 6- benzylaminopurine (BA) and 0.05 μM 1-naphthaleneacetic acid (NAA) at the proliferation step, and MS medium alone or with varying concentrations of indole-3-butyric acid (IBA) at the rooting step. No incidence of somaclonal variation was detected among randomly chosen shoots from ten subclonal lines in eight isozyme systems studied and in chromosome counts. However, this does not preclude the existence of somaclonal variation at other levels of the genome. A 90% survival rate was obtained when shoots were stored for three years in MS medium supplemented with 4.92 μM IBA at 5 °C and with a 16-h photoperiod.
THE PREDICTION OF PHENOLOGICAL STAGES IN FOUR NAMAQUALAND EPHEMERAL SPECIES USING THERMAL UNIT INDICES
Authors: Steyn H.M. , van Rooyen N. , van Rooyen M.W. , Theron G.K.
Published: April 2013

Flowering time of ephemeral plant species in Namaqualand (South Africa) generally ranges from mid-July through September, depending on the timing of the first substantial winter rains. The precise timing of the flowering of species is determined by the individual's life history and the integrated effects of a complex of environmental factors. Phenological and climatic data were recorded and used to determine the number of thermal units required by four Namaqualand ephemeral species to reach a certain phenological stage.

Twenty-three thermal unit indices were used to calculate the number of thermal units needed to reach a specific phenological stage. The index combining cold units from sowing until flower initiation, with Growing Degree Days (heat units) from flower initiation until anthesis flowering or display/peak flowering, gave the most accurate predictive values.

Flowering time of Namaqualand ephemerals can therefore be predicted at the beginning of the growing season after the first substantial rainfall, and refinements made throughout the season by the use of actual temperature data.
FRUITING PHENOLOGY AND FRUIT SET OF CAROB, CERATONIA SILIQUA L. (CESALPINACEAE)
Authors: Bosch J. , Del Pino F.Garcia , Ramoneda J. , Retana J.
Published: April 2013

The fruiting phenology of two female and two hermaphroditic carob (Ceratonia siliqua L.) cultivars was studied in NE Spain. After flower pollination (September–November), fruit growth followed a sigmoidal curve, with an initial period of slow growth (December–March), a period of linear growth (April–June), and a final period of slow growth and maturation (June–Au–gust). Shedding of flowers and young fruits was high in October–December, and slowed down in January–February. Then, fruit drop again increased until May, and from June to August fruit shedding was almost nil. Fruit initiation was 12.6–35.0%, and fruit shedding was high (79.2–90.2% of the fruits initiated dropped before maturity). In the two female cultivars, larger inflorescences had higher rates of fruit initiation, fruit set, and seed set per flower than smaller inflorescences.
EFFICIENT CALLUS INDUCTION AND PLANT REGENERATION VIA SOMATIC EMBRYOGENESIS FROM IMMATURE LEAF-DERIVED PROTOPLASTS OF GROUNDNUT (ARACHIS HYPOGAEA L.)
Authors: Venkatachalam Perumal , Jayabalan Narayanasamypillai
Published: April 2013

High yields of protoplasts were obtained from immature leaves of aseptically grown plants ofArachis hypogaeausing an enzyme solution containing cellulase 2.0% (w/v) and Macerozyme 1.0% (w/v) in 0.6 M mannitol. Isolated protoplasts were cultured in Kao's medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The protoplasts started to divide after 3–5 days of culture. Sustained divisions resulted in mass production of cell colonies and mini calli in 4 weeks. After 4 weeks, protoplast colonies were transferred to the Murashige and Skoog (MS) medium supplemented with a-naphthalene acetic acid (NAA) and BAP. Colonies proliferated into actively growing calli. Further attempts to regenerate plants from such calli were not successful. However, protoclones differentiated roots on the same medium. Alternative methods for plant regeneration from protoplast derived callus cultures were tried through somatic embryogenesis. Protoplast-derived calli treated with 2,4-D and BAP formed somatic embryos. Somatic embryogenesis began in the proembryo stage and proceeded from globular to dicotyledonary stage. Embryos were then transferred onto hormone-free MS medium for germination. Five to ten percent of these embryoids germinated and grew to plantlets. Regenerated plants were transferred to plastic cups and grown to maturity.
BULB AND INFLORESCENCE DEVELOPMENT IN NERINE SARNIENSIS
Authors: Vishnevetsky Jane , Lilien-Kipnis Hannah , Azizbekova Nazilia , Ziv Meira
Published: April 2013

Nerine is an autumn flowering perennial bulbous plant native to southern Africa belonging to the family Amaryllidaceae. Irregular flowering is often encountered in commercial flower production. The annual life cycle ofNerine sarniensisis characterized by flowering in autumn prior to leaf emergence, active leaf growth during winter and early spring, followed by leaf senescence and a rest period during the hot dry summer. The objective of this study was to follow the ontogeny ofN. sarniensiscv. ‘Autumn Glory’ with special emphasis on differentiation and development of vegetative and generative apices under outdoor growing conditions in Israel. It was found that leaf development lasted approximately eleven months, with active leaf growth of up to five months, depending on the onset of high temperatures in late spring. For most of the year the bulb contains two inflorescences at different stages of development. Inflorescence development from initiation to anthesis lasted 21–22 months, i.e., active development occurred in the bulb during its rest period. Development was only arrested for approximately two months at the end of summer, just prior to flowering.
INHIBITION OF POLYAMINE BIOSYNTHESIS BY L-CANAVANINE AND ITS EFFECT ON MERISTEMATIC ACTIVITY, GROWTH, AND DEVELOPMENT OF ZEA MAYS ROOTS
Authors: Schwartz Martha , Altman Arie , Cohen Yael , Arzee Tova
Published: April 2013

The effects of L-canavanine, a structural analogue of L-arginine and a competitive inhibitor of arginine decarboxylase, were studied in corn (Zea mays L.) on primary root elongation and lateral root differentiation, meristematic activity, and on polyamine content and biosynthesis.

Incubation of seedlings in 10−3 M L-canavanine for 3 h inhibited both elongation of the primary root and differentiation of lateral root primordia. A marked decrease in cell division and DNA synthesis, along with an inhibition of the activation of the primary root quiescent center, was clearly evident in L-canavanine-treated roots. Putrescine content in subapical segments of the primary root decreased significantly during the first 24 h, while spermidine content increased at 48–72 h, coinciding with lateral root emergence and elongation. A 3 h incubation with 103 M L-canavanine completely inhibited the increase in spermidine content, thus modifying the ratio of putrescine to spermidine tissue concentrations. The activity of arginine decarboxylase, and less significantly that of ornithine decarboxylase, increased steadily during the 72 h period of lateral root differentiation and elongation. Activation of both enzymes was inhibited by L-canavanine. Addition of L-arginine at 10−3 M partially relieved the inhibitory effects of L-canavanine on primary root elongation, lateral root differentiation, activation of the quiescent center, changes in polyamine content, and the activity of arginine and ornithine decarboxylases.

These and previous data suggest that root development and meristematic activity in Zea mays are associated, perhaps causally, with changes in biosynthesis and content of polyamines.
WILD EMMER WHEAT IN JORDAN: II. GENETIC DISTANCES BETWEEN AND WITHIN POPULATIONS
Authors: Jaradat A.A.
Published: April 2013

Evaluation data on 17 morpho-agronomic traits for twelve populations of wild emmer wheat, Triticum dicoccoides, Korn. from central, peripheral, and marginal regions of its distribution in Jordan, were subjected to univariate, principal component, and canonical discriminant analyses. Interrelationships and adjustments in traits under study were used to identify genetic distances and spatial variation among and within these populations. Principal component analysis revealed that the interrelationships implied among traits, in the same principal component, were not the same among and within populations. This spatial variability in principal components reflects specific adaptation to, or interaction with, the environment. Three canonical variables explained 85.0% of total variation in these populations. Spikelet size, flag leaf width, and days to maturity were the most discriminating traits. Mahalanobis distances suggest that spatial distances are not indicative of genetic distances among and within central, peripheral, and marginal populations. A number of trait combinations arising through multilocus genetic association or developmental correlations, which are conserved by genetic linkage and natural selection, are readily available for wheat breeding and improvement.
WILD EMMER WHEAT IN JORDAN: III. A CORE COLLECTION
Authors: Jaradat A.A.
Published: April 2013

The germplasm base collection (BC) of wild emmer wheat,Triticum dicoccoides, from Jordan consists of over 2,000 accessions. Data on 10 quantitative and 8 qualitative traits were analyzed using multivariate statistical analysis procedures. A stratified and proportional sampling procedure was used to select 10 and 5% of the BC to form two core collections: CC10 and CC5, respectively. Phenotypic variation in the BC, as estimated by the phenotypic diversity index, hs,j, was unevenly distributed among accessions, among populations, and among ecogeographical regions. Moreover, its level differed significantly among and within quantitatively and qualitatively inherited traits. This characteristic led to successfully selecting a core collection which represents all levels of hierarchy in the base collection. Examination of the data for the same 18 traits in the BC, CC10, and CC5 indicated that CC10 and CC5 retained, on average, 86.0 and 74.3% of the variation in the BC, respectively. Percent discrete phenotypic classes, with frequency >0.10 (i.e., common widespread and common localized phenotypes). recovered in CC10 and CC5 were 79.6 and 51.5%, respectively. Results of hierarchical analyses of variance showed that percent contribution by traits to total variance in hs,j. estimates increased from 64.0% in the BC to 78.0% in CC10, and to 96.3% in CC5. Nevertheless, and as theoretically expected, CC10 was more efficient than CC5 in retaining the amount and composition of the variation originally found in the base collection.
TWO NEW RECORDS OF CANTHARELLOID FUNGI FOR TURKEY
Authors: Sesli Ertugrul
Published: April 2013

Cantharellus lutescensandGomphus clavatusare collected for the first time in Turkey. The members of Cantharelloid fungi recorded since the beginning of macrofungal studies in Turkey are given with the collection sites.
THE RESOLUTION OF INSECT COMPOUND EYES
Authors: Land Michael F.
Published: April 2013

The spatial resolution of compound eyes is determined by their interommatidial angles, by the optical quality and rhabdom dimensions of the ommatidia, and by illumination level. Among insects, interommatidial angles vary from tens of degrees in Apterygota, to as little as 0.24° in dragonflies. Resolution better than this is not attainable in compound eyes of realistic size, because of the limit imposed by diffraction. The smaller the interommatidial angle, the greater the distance at which objects—prey, predators, foliage, or flowers—can be resolved. Insects with different lifestyles have contrasting patterns of interommatidial angle distribution, related to forward flight, capture on the wing, and predation on horizontal surfaces.
HOW DO INSECT POLLINATORS DISCRIMINATE COLORS?
Authors: Vorobyev Misha , Brandt Robert
Published: April 2013

Basic concepts of color vision in animals and, in particular in the honeybee, are reviewed. Four models of color discrimination in honeybees are presented. Because visual systems in Hymenoptera are similar to that of the honeybee, such models can also be used to describe color discrimination in many hymenopteran pollinators. We compare predictive capacities of the models and give practical recommendations for their usage. Although models have different mathematical formulations, in most cases they give similar predictions. Examples where predictions of different models deviate are discussed.
BEE COLOR VISION IS OPTIMAL FOR CODING FLOWER COLOR, BUT FLOWER COLORS ARE NOT OPTIMAL FOR BEING CODED—WHY?
Authors: Chittka Lars
Published: April 2013

Model calculations are used to determine an optimal color coding system for identifying flower colors, and to see whether flower colors are well suited for being encoded. It is shown that the trichromatic color vision of bees comprises UV, blue, and green receptors whose wavelength positions are optimal for identifying flower colors. But did flower colors actually drive the evolution of bee color vision? A phylogenetic analysis reveals that UV, blue, and green receptors were probably present in the ancestors of crustaceans and insects 570 million years ago, and thus predate the evolution of flower color by at least 400 million years. In what ways did flower colors adapt to insect color vision? The variability of flower color is subject to constraint. Flowers are clustered in the bee color space (probably because of biochemical constraints), and different plant families differ strongly in their variation of color (which points to phylogenetic constraint). However, flower colors occupy areas of color space that are significantly different from those occupied by common background materials, such as green foliage. Finally, models are developed to test whether the colors of flowers of sympatric and simultaneously blooming species diverge or converge to a higher degree than expected by chance. Such effects are indeed found in some habitats.
THE DETECTION AND RECOGNITION OF COLOR STIMULI BY HONEYBEES: PERFORMANCE AND MECHANISMS
Authors: Giurfa Martin , Vorobyev Misha
Published: April 2013

In a detection paradigm, honeybees Apis mellifera were trained to distinguish between the presence and the absence of a rewarded colored spot, presented on a vertical, achromatic plane in a Y-maze. In a recognition paradigm, bees were trained to distinguish between a trained colored disk and alternative stimuli differing in their green contrast and/or chromatic contrast. Results from the first experimental paradigm allowed the establishment of αmin, the visual angle subtended by a colored target at the bee eye at which the bees detect a given stimulus with a probability Po = 0.6. This angle was 5° for stimuli presenting both chromatic contrast and green contrast, and 15° for stimuli presenting chromatic but no green contrast. Therefore, green contrast contributes decisively to the detection task. Results from the second experimental paradigm showed that chromatic and green contrasts are alternatively used depending on the visual angle subtended by a trained chromatic target and that bees also learn the green-contrast difference between a trained and a nonrewarded alternative. Finally, when trained at different visual angles with an achromatic stimulus providing green contrast, bees were capable of learning and detecting the achromatic target only for visual angles from 10° to 5°. Thus, green-contrast and chromatic-contrast channels are tuned to signals of different angular sizes: the chromatic channel conveys the signals of objects of large angular size, while the green contrast channel conveys those of objects of reduced angular size.
HONEYBEE'S USE OF SPATIAL PARAMETERS FOR FLOWER DISCRIMINATION
Authors: Lehrer Miriam
Published: April 2013

Early as well as recent behavioral studies on the bee's use of spatial cues for recognizing the food source are reviewed. The spatial parameters considered are those that natural flowers display, e.g., contrast, spatial frequency, geometry, symmetry, size, depth, edges, orientation of contours, and position in the visual field. It is concluded that bees use each of these parameters for learning and recognizing the food source. Intensity contrast as well as color contrast are involved in spatial vision. However, spatial cues extracted from image motion are processed by a color-blind system. Although the results reviewed here have been obtained using artificial food sources, it is argued that the spatial parameters under consideration are actually used by the bee for discriminating among natural flowers.
INTERACTION BETWEEN SILICON AND ALUMINUM IN TRITICUM AESTIVUM L. (CV. CELTIC)
Authors: Cocker Kay M. , Hodson Martin J. , Evans David E. , Sangster Allan G.
Published: April 2013

Seedlings ofTriticum aestivumL. (cv. Celtic) were suspended in plastic tubs containing 500 μmol L−1Ca(NO3)2and 31 μmol L−1KC1 as background solution. A1C13(0 and 100 μmol L−1) and Na2SiO3.5H2O (0 and 2000 μmol; L−1) were added to this basal nutrient medium, and solution pH was set at 4.2 or 4.6. Tubs were aerated and supplied with a continuous flow of pH-adjusted test solution. Plants were grown for 4 d in a growth cabinet at 25 °C with a 16 h photoperiod. At pH 4.2 and 4.6 root length of the seedlings was inhibited at 100 μmol L−1Al. An amelioration of Al-induced toxicity symptoms was observed in the 100 μmol L−1A1/2000 μmol L−1Si treatment at pH 4.6, but not at pH 4.2. Both the shoot (S) and root (R) dry weight of seedlings treated with 100 μmol L−1Al were reduced when compared with controls. Treatment with Al increased S:R ratios, and this effect was ameliorated by Si, but only at pH 4.6.

Al content of roots treated with 100 μmol L−1Al or 100 μmol L−1Al/2000 μmol L−1Si increased significantly when compared with controls. More Al accumulated in the roots of seedlings of the 100 μmol L−1Al/2000 μmol L−1Si treatment than in the 100 μmol L−1treatment. Al treatment reduced root and shoot K concentrations under both pH regimes, and Si did not ameliorate this effect. Al treatment had little effect on seedling Ca levels.

Three treatments were selected for a microanalytical investigation of the basal third of the root, and the zone 3.5 mm behind the root tip: 2800 μmol L−1Si; 75 μmol Al; and a combination of the two. When plants were grown in 2800 μmol L−1Si the major silica deposition sites in the roots were the endodermal walls. In the 75 μmol L−1Al treatment, Al was mainly located in the epidermal and hypodermal walls. Al treatment caused a leakage of phosphorus into these cell walls. When both 2800 μmol L−1and 75 μmol L−1Al were present in the nutrient solution, only Si was deposited in the endodermal walls, while both elements were present in the epidermal walls. Leakage of phosphorus appeared to be prevented in the presence of Si.
EFFECT OF PLANT GROWTH REGULATORS AND ORANGE JUICE ON GROWTH OF CALLUS FROM FRUIT TISSUES OF WASHINGTON NAVEL ORANGE
Authors: Amo-Marco Juan B.
Published: April 2013

The effect of the plant growth regulators kinetin, gibberellic acid (GA3), and 2,4- dichlorophenoxyacetic acid (2,4-D), either alone or in combination with orange juice, on the in vitro growth of mesocarp and endocarp explants from 90–120 day-old Washington Navel Citrus sinensis orange fruits has been determined.

Both fruit tissues formed callus. From endocarp 100% callus was formed in all cultures, even without growth regulators in the culture medium, while callus growth was lower from mesocarp. The addition of orange juice at a final concentration of 15% (v/v) to the basal medium without growth regulators increased the callus growth, specially that derived from endocarp. However, the high stimulant effect of orange juice observed on callus growth was markedly dependent on the addition of 2,4-dichlorophenoxyacetic acid, maximum callus growth from endocarp or mesocarp tissues being obtained with orange juice 15% (v/v) and 10 μM 2,4-D.
INFLUENCE OF FIRE ON PLANT REGENERATION IN A STIPA TENACISSIMA L. COMMUNITY IN THE SIERRA LARGA MOUNTAIN RANGE (SE SPAIN)
Authors: Jose Martínez-Sánchez Juan , Herranz Jose Maria , Guerra Juan , Trabaud Louis
Published: April 2013

The range of communities dominated byStipa tenacissimaextends from Ukraine to North Africa. They contain several endemic species in Spain. The post-fire response of a community ofS. tenacissimain semiarid SE Spain was studied by following the dynamics of the floristic richness and plant cover during the first four years. The importance ofS. tenacissimawas noticed during recolonization of these zones, where, three years after a fire, the high degree of cover was similar to that of unburned areas.

The prolonged drought during the study period was the probable cause of difficulties in recolonization of the burned area by the three obligate seeder species (Pinus halepensis, Rosmarinus officinalis, andCistus clusii) which were widespread in the unburned community.Juniperus phoeniceadid not sprout after the fire, and four years later no seedlings were encountered in the burned area. According to the results, the endemic plants living in theS. tenacissimacommunity were not negatively affected by fire; the twelve endemic species found in this community were all capable of responding to the fire either through new shoots or by reproduction through seeds.
THE INFLUENCES OF DEPRESSIONS MADE BY IBEX ON THE ANNUAL VEGETATION ALONG CLIFFS OF THE ZIN VALLEY IN THE NEGEV DESERT HIGHLANDS, ISRAEL
Authors: Gutterman Yitzchak
Published: April 2013

On the slopes leading to the edges of the cliffs of the Zin Valley, the Nubian ibex (Capra ibex nubiana) create thousands of depressions in the soil of slopes sheltered from strong winds, which they use as temporary beds at night. During the year the ibex groups alter in size and change their sleeping area according to the wind direction. These depressions measure from 60 to 105 × 80 to 140cm and are 6.5–10cm deep. In an area of 15 × 3m about 33 diggings were found and up to 70 diggings in an area 30 × 5m. Along 300m of the cliff about 345 diggings were counted. The depressions that the ibex abandon remain for several years and become special microhabitats for annual plants.

Runoff water, following a long and intensive rainfall, carries seeds that accumulate in these depressions, including mucilaginous seeds that may float on the runoff water. Annual plants later emerge in higher species and plant numbers than on similar sized areas upslope from the depressions. Plant species with wind- and rain-dispersed seeds were observed in greater numbers in these depressions which have similar influences on the annual plant vegetation as the porcupine diggings in the Negev highlands.
A NEW LATHYRUS L. FOR THE FLORA OF TURKEY: FLORISTIC NOTE
Authors: Ertekin A. Selçuk , Orcan Nermin , Misirdali Hüseyin
Published: April 2013

Lathyrus grandiflorus Sibth. and Sm., which is distributed in Greece, the Balkans, Italy, and Sicily is found to be a new record for Turkey. A brief description of the species is given.
INFLUENCE OF THE MODE OF SALINIZATION ON REPRODUCTIVE TRAITS OF FIELD-GROWN PROGENY IN SORGHUM BICOLOR
Authors: Amzallag G.Nissim , Nachmias Avi , Lerner R. Henri
Published: April 2013

The offspring ofSorghum bicolor(L.) Moench plants exposed to 150 mM NaCl eight or twenty-one days following germination were grown in field conditions, and were irrigated with non-saline water. As compared to the offspring of non-treated plants, the progeny of plants early-exposed to NaCl displayed an increase in shoot dry weight and stem height, but some of them showed a significant decrease in fertility. Similar changes were observed, but to a lesser extent, in the offspring of plants late-exposed to salinity. A similar increase in phenotypic variability was observed in populations of progeny from early-and late-treated plants. After verifying that the changes observed did not result from an artifactual selection, it was concluded that the NaCl treatment is able to influence characters expressed during the late development of the plant progeny. The nature of the induced change is discussed in relation to the plant response, adaptation or resistance, induced by the early or late exposure to salinity in the parent generation.
THE ACQUISITION OF INORGANIC CARBON IN MARINE MACROPHYTES
Authors: Beer Sven
Published: April 2013

The low diffusion rates of solutes in water call for a separation of photosynthetic carbon acquirement in aquatic plants into carbon transport and the subsequent photosynthetic reduction of CO2. This paper will focus on the transport of inorganic carbon from the external medium to the site of fixation in marine macrophytes. In accord with the much higher concentration of HCO3− than of CO2 in seawater, most marine macrophytes can utilize the ionic carbon form for their photosynthetic needs. The two known ways of HCO, utilization are (a) via extracellular, carbonic anhydrase catalyzed dehydration of HCO3− to form CO2, which then diffuses into the photosynthesizing cells, and (b) by direct uptake via a transporter. While the first way may be sufficient to support low rates of photosynthesis in temperate regions, it is viewed as futile under situations where high temperatures and irradiances would cause a high pH to form close to the uptake site of carbon and where, consequently, the CO2/HCO3− ratio would be very low. Therefore, it may well be that the direct HCO3− uptake mechanism described for Ulva from more tropical regions confers an adaptational advantage under conditions conducive to higher photosynthetic rates.
PHOTOSYNTHETIC CHARACTERIZATION OF A MUTANT OF NANNOCHLOROPSIS DEFICIENT IN THE SYNTHESIS OF EICOSAPENTAENOIC ACID
Authors: Sukenik Assaf , Schneider C. Jane , Roessler G. Paul , Livne Alexander , Berner Tamar , Kolber Zbigniew , Wyman Kevin , Prasil Ondrej , Falkowski G. Paul
Published: April 2013

Photosynthetic performance of an eicosapentaenoic acid (EPA; 20:5ω3) deficient mutant of the eustigmatophyte Nannochloropsis sp. was compared to the wild type (Wt) strain in order to evaluate the effect of fatty acid composition on the function of the photosynthetic apparatus. Cellular photosynthetic capacity and the cellular pool of pigments and of reaction centers were reduced in the mutant concomitant with a reduction in the amount of thylakoid membranes and their volume-specific density. Despite the changes observed in photosynthetic activity, the fluorescence properties of the mutant were virtually the same as those of the wild type, although the phase transition of thylakoid membrane was recorded at higher temperature in the mutant than in the Wt. The results suggest that the change in one double bond in a very long chain fatty acid of the thylakoid lipids plays a minor role in regulating photosynthetic electron transport, but that the mutation modified the ability of the mutant to acclimate to low-irradiance conditions.
DUNALIELLA—A MODEL EXTREMOPHILIC ALGA
Authors: Pick Uri
Published: April 2013

The unicellular algaDunaliellais unique in its ability to adapt to extreme environmental conditions. Adaptation to extreme salinity involves short-term and long-term responses. The former include osmotic adjustment by accumulation of large amounts of intracellular glycerol and efficient elimination of Na+ions by plasma membrane transporters. The latter involves synthesis of two extrinsic plasma membrane proteins: a carbonic anhydrase and a novel type of a transferrin-like protein. These proteins are associated with acquisition of CO2and Fe, respectively, whose availability is diminished in high salinity, limiting algal growth. Both proteins are functional over a wide range of salt concentrations and differ in structure from their mesophilic counterparts in possessing additional internal repeats and in having higher ratios of acidic: basic amino acids.Dunaliella acidophilasurvives at pH 0–1 by overexpression of a potent plasma membrane H+-ATPase which provides effective capacity for elimination of protons. Sequence comparisons of the ATPase genes from halophilic and acidophilic species reveals variations in charged amino acid composition within a distinct extrinsic C-terminal domain of the protein.Dunaliella bardawiladapts to high light intensity by several strategies: it accumulates large amounts of β-carotene which screens the photosynthetic system against photoinhibition and it modifies the photosynthetic machinery by synthesis of a special light-harvesting protein which presumably functions in dissipation of excessive light energy. Both responses depend on synthesis of special proteins and enzymes. Signal transduction mechanisms mediating stress responses inDunaliellaare poorly understood. Sensing osmotic/salinity changes involves specific plasma membrane sterols and activation of a plasma membrane protein kinase. Induction of β-carotene accumulation can be mimicked by reactive oxygen species generators.
NATURAL ANTIOXIDANT ACTIVITY IN SOME MICROALGAL SPECIES
Authors: Perelman Alexander , Matsukawa Ritsuko , Schlosberg Michal , Cohen Bat-Sheva , Fostik-Magyar Claude , Dubinsky Zvy
Published: April 2013

At the present time there is an increasing awareness of the potential harmful effects of various chemical food additives used to delay spoilage. This resulted in the search for natural substances which may prevent oxidation of various lipids, a main cause of the onset of rancidity. Various algae were examined for their potential as sources of antioxidants. As part of that search, the amount of doublebonds in their constituent compounds and their antioxidant (AO) and lipoxygenase (LOX) activities were followed in some microalgal species. The effect of light intensity, salinity, and temperature on the AO activity of lipid extracts from the microalgaNaviculasp. was studied. Maximum AO activity was obtained inNaviculagrown under low light intensity. AO activity of various algal fractions was studied both as inhibition of LOX activity and of linoleate autooxidation. Most of the LOX inhibitive activity was found in the membranal lipid-soluble fractions, whereas the inhibition of autooxidation was associated with the water-soluble components of the cell cytoplasm.