Raphael A. Stern

Bio: Raphael A. Stern is an academic researcher from Tel-Hai Academic College. The author has contributed to research in topics: Pyrus communis & PEAR. The author has an hindex of 24, co-authored 81 publications receiving 1546 citations.

The synthetic auxin 3,5,6-TPA reduces fruit drop and increases yield in `Kaimana' litchi

Abstract: SummaryThe effects of the synthetic auxin 3,5,6-TPA on fruit retention and yield of `Kaimana' litchi (Litchi chinensis Sonn.) was examined in Israel. This cultivar is characterized by a heavy initial set and then heavy fruit drop. 3,5,6-TPA decreased fruit drop and increased yield by 130 to 170% relative to untreated control trees. The best response occurred with an application of 25 or 50 mg l21 three weeks after full female bloom (FFB) (when fruit weighed ca. 0.5.g) compared with applications at 2, 4 or 5 weeks. Further commercial trials are warranted.

Plant growth regulators increase the fruit size of 'Spadona' and 'Coscia' pears (Pyrus communis) in a warm climate

Abstract: SummaryThe two main pear cultivars grown in the warm climate of Israel, ‘Spadona’ and ‘Coscia’, produce relatively small fruit. Over five consecutive years (2001 – 2005), the application of 0.12% (v/v) BoleroTM [8.6 mg l–1 gibberellic acid (GA3) plus 6 mg l–1 2,4-dichlorophenoxyacetic acid (2,4-D) plus 6 mg l–1 naphthaleneacetic acid (NAA)] at full-bloom, caused an appreciable and significant increase in fruit size without any deformation of the calyx-end, which is typical of GA3 treatment when applied at the same phenological stage to improve fruit set. GA3 alone did not increase fruit size. Application of 0.125% (v/v) PerlanTM [25 mg l–1 benzyladenine (BA) plus 25 mg l–1 GA4+7] at full-bloom + 14 d, increased fruit size via stimulation of fruit cell division (BA) and fruit cell enlargement (GA4+7), with no negative effect on fruit shape.

Control of Fruit Cracking by Shaping Skin Traits – Apple as a Model

Abstract: Skin cracking limits fruit quality and marketability. Suggested causes are environmental conditions, orchard management, and failure of the skin to resist surface tension due to fruit expansion. Fr...

Molecular Identification of a New Apple S-RNase—S29—Cloned from `Anna', a Low-chilling-requirement Cultivar

Abstract: ‘Anna’, a low-chilling-requirement (LCR) apple cultivar is the progeny of an hybridization between ‘Golden Delicious’ and ‘Hadassiya Red’, which was carried out by Abba Stein in 1956 (Brooks and Olmo, 1972). It has become an economically important cultivar especially in South America, since it can be grown in moderate climate regions, which are not suitable for the common apple cultivars (Hauagge and Cummins, 2000). ‘Golden Delicious’ is one of the classic, most popular, apple cultivars, while ‘Hadassiya Red’ is a Middle Eastern, low-quality, LCR variety which has not been cultivated for >40 years. Apples (Rosaceae) carry the gametophytic self-incompatibility (GSI) (Kao and Tsukamoto, 2004) system, and therefore apple orchards contain at least two cultivars that are compatible with each other. GSI, which was first identified in Solanaceae and is also found in Scrophulariaceae and other families, is determined by a single genetic locus (S-locus). The S-locus encodes, among other genes, for a multi-allelic RNase (S-RNase) that inhibits pollen growth in the style in a haplotype specific manner (Kao and Tsukamoto, 2004). Thus, compatibility may be full, when the cultivars carry different S-RNase alleles and semi when they share one of their two S-RNase alleles. Semi-compatibility may lead to reduction in fruit set and yield (Goldway et al., 1999). Many S-RNase alleles have been identified, including 15 from apples (Broothaerts, 2003). Molecular analysis of the S-RNase allele content of cultivars enables the determination of their genetic compatibility. Here we present the SRNase content of ‘Anna’, which includes the identification of a new S-RNase, S29. Since ‘Golden Delicious’ is S2 S3 (Broothaerts et al., 1995), it would be expected that one of ‘Anna’s S-RNases would be either S2 or S3, while its second S-RNase, inherited from ‘Hadassiya Red’, remained to be identified. As shown in Fig. 1, PCR analysis, of DNA extracted from ‘Anna’, with specific primers for S2 and S3 (primers for S2 were OWB122 and OWB123, and for S3, OWB145 [Broothaerts et al., 1995] and AM12, 5'-TAA TCT GCC TCG CTG -3', generated according to the nucleotides 21-35 of the sequence with the accession number U12200), revealed that it carries S3. For identification of ‘Anna’s second S-RNase, universal primers NSS2 and NSA1 (NSS2, 5'-CAC GGT/A TTG TGG CCT TC-3' and NSA1, 5'-GAC CTC AAC C/TAA TTC AG -3' corresponding respectively, to nucleotides 244-260 and 635-651, from sequence accession number U12199), were used and a single PCR product was obtained. The segment was cloned and sequenced. It contains 811 bp, which makes up most of the gene, spanning between the conserved regions, C1 to C5. Like other S-RNases it contains an intron (232 bp). DNA alignment by the Blast program of NCBI revealed that it is a new S-RNase. To avoid confusion with identification-numbers appearing in the literature, we have named the new allele S29 (accession number AY039702). Alignment of the exon regions (579bp) (Fig.

Light-induced expression of a MYB gene regulates anthocyanin biosynthesis in red apples.

Abstract: Anthocyanins are secondary metabolites found in higher plants that contribute to the colors of flowers and fruits. In apples (Malus domestica Borkh.), several steps of the anthocyanin pathway are coordinately regulated, suggesting control by common transcription factors. A gene encoding an R2R3 MYB transcription factor was isolated from apple (cv Cripps' Pink) and designated MdMYB1. Analysis of the deduced amino acid sequence suggests that this gene encodes an ortholog of anthocyanin regulators in other plants. The expression of MdMYB1 in both Arabidopsis (Arabidopsis thaliana) plants and cultured grape cells induced the ectopic synthesis of anthocyanin. In the grape (Vitis vinifera) cells MdMYB1 stimulated transcription from the promoters of two apple genes encoding anthocyanin biosynthetic enzymes. In ripening apple fruit the transcription of MdMYB1 was correlated with anthocyanin synthesis in red skin sectors of fruit. When dark-grown fruit were exposed to sunlight, MdMYB1 transcript levels increased over several days, correlating with anthocyanin synthesis in the skin. MdMYB1 gene transcripts were more abundant in red skin apple cultivars compared to non-red skin cultivars. Several polymorphisms were identified in the promoter of MdMYB1. A derived cleaved amplified polymorphic sequence marker designed to one of these polymorphisms segregated with the inheritance of skin color in progeny from a cross of an unnamed red skin selection (a sibling of Cripps' Pink) and the non-red skin cultivar Golden Delicious. We conclude that MdMYB1 coordinately regulates genes in the anthocyanin pathway and the expression level of this regulator is the genetic basis for apple skin color.

Biodiversity, Ecosystem Functioning, and Human Wellbeing: An Ecological and Economic Perspective

Abstract: In an age of accelerating biodiversity loss, this timely and critical volume summarizes recent advances in biodiversity-ecosystem functioning research and explores the economics of biodiversity and ecosystem services. The book starts by summarizing the development of the basic science and provides a meta-analysis that quantitatively tests several biodiversity and ecosystem functioning hypotheses. It then describes the natural science foundations of biodiversity and ecosystem functioning research including: quantifying functional diversity, the development of the field into a predictive science, the effects of stability and complexity, methods to quantify mechanisms by which diversity affects functioning, the importance of trophic structure, microbial ecology, and spatial dynamics. Finally, the book takes research on biodiversity and ecosystem functioning further than it has ever gone into the human dimension, describing the most pressing environmental challenges that face humanity and the effects of diversity on: climate change mitigation, restoration of degraded habitats, managed ecosystems, pollination, disease, and biological invasions.However, what makes this volume truly unique are the chapters that consider the economic perspective. These include a synthesis of the economics of ecosystem services and biodiversity, and the options open to policy-makers to address the failure of markets to account for the loss of ecosystem services; an examination of the challenges of valuing ecosystem services and, hence, to understanding the human consequences of decisions that neglect these services; and an examination of the ways in which economists are currently incorporating biodiversity and ecosystem functioning research into decision models for the conservation and management of biodiversity. A final section describes new advances in ecoinformatics that will help transform this field into a globally predictive science, and summarizes the advancements and future directions of the field. The ultimate conclusion is that biodiversity is an essential element of any strategy for sustainable development.

In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning

Abstract: In mammals, cadmium is widely considered as a non-genotoxic carcinogen acting through a methylation-dependent epigenetic mechanism. Here, the effects of Cd treatment on the DNA methylation patten are examined together with its effect on chromatin reconfiguration in Posidonia oceanica. DNA methylation level and pattern were analysed in actively growing organs, under short- (6 h) and long- (2 d or 4 d) term and low (10 mM) and high (50 mM) doses of Cd, through a Methylation-Sensitive Amplification Polymorphism technique and an immunocytological approach, respectively. The expression of one member of the CHROMOMETHYLASE (CMT) family, a DNA methyltransferase, was also assessed by qRT-PCR. Nuclear chromatin ultrastructure was investigated by transmission electron microscopy. Cd treatment induced a DNA hypermethylation, as well as an up-regulation of CMT, indicating that de novo methylation did indeed occur. Moreover, a high dose of Cd led to a progressive heterochromatinization of interphase nuclei and apoptotic figures were also observed after long-term treatment. The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase. Such changes are linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin. Overall, the data show an epigenetic basis to the mechanism underlying Cd toxicity in plants.

Regulation of floral initiation in horticultural trees

Abstract: The intention of this review is to discuss floral initiation of horticultural trees. Floral initiation is best understood for herbaceous species, especially at the molecular level, so a brief overview of the control of floral initiation of Arabidopsis (Arabidopsis thaliana (L.) Heynh.) precedes the discussion of trees. Four major pathways to flowering have been characterized in Arabidopsis, including environmental induction through photoperiod and temperature, autonomous floral initiation, and regulation by gibberellins. Tropical trees are generally induced to flower through environmental cues, whereas floral initiation of temperate deciduous trees is often autonomous. In the tropical evergreen tree mango, Mangifera indica L., cool temperature is the only factor known to induce flowering, but does not ensure floral initiation will occur because there are important interactions with vegetative growth. The temperate deciduous tree apple, Malus domestica Borkh., flowers autonomously, with floral initiation dependent on aspects of vegetative development in the growing season before anthesis, although with respect to the floral initiation of trees in general: the effect of the environment, interactions with vegetative growth, the roles of plant growth regulators and carbohydrates, and recent advances in molecular biology, are discussed.