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• The increasing importance of grapevine trunk diseases

  21-30.

  Cs. Kovács

  E. Sándor

  Views:

  458

  Grapevine trunk diseases (GTDs) are destroying the woody parts of the plants, resulting decline or dieback of the grapevine. More detailed research of the GTD began in 1950s, when Hewitt et al. (1957) observed that specific symptoms cannot be detected on the diseased trunks every year. Latest results have also proved that abiotic factors affect the appearance and the severity of the disease. Moreover several pathogenic fungi may play role as causative agents (Bertsch et al., 2013). Eutypa, Botryosphaeria, Phomopsis dieback, esca disease complex, and Petri disease are considered the major GTDs, where a variety of pathogens attack the woody perennial organs of the vine and ultimately lead to the death of the plant (Lehoczky, 1974; Larignon & Dubos, 1997; Rolshausen et al. 2010; Kotze et al., 2011; Bertsch et al., 2013; Fontaine et al., 2015).
  The GTD incidence has been reported to be increased during the last decades (Úrbez-Torres et al., 2014). The esca incidence has reached 60% to 80% in some old vineyards in southern Italy (Pollastro et al., 2000; Surico et al., 2000; Calzarano & Di Marco, 2007). The disease incidence of the esca was reported to be increased from 1.83% to almost 13%, between 2003 and 2007 in Hungary (Dula, 2011). There was detected a five times increase in the GTD disease incidence in the Tokaj Wine Region, Hungary between 2014 and 2016 (Bihari et al,
  2016).

• Linking bark anatomy to Eucalyptus Physiological Disorder (EPD) in commercial clones

  73-87.

  Edgard Picoli

  Franciely Jacomini

  Josimar Ladeira

  Maria Naruna Almeida

  Graziela Vidaurre

  Jordão Moulin

  Edival Zauza

  Lúcio Guimarães

  Rosy Mary Isaias

  Kelly Balmant

  Weverton da Costa

  Views:

  380

  Abiotic stresses trigger the Eucalyptus Physiological Disorder (EPD) which poses a threat to planted and native stands. This research seeks links between eucalyptus bark histological features and EPD, in which the descriptive bark anatomy and histochemistry are approached. Barks from 5-year eucalyptus trees, from commercial clones of E. grandis, E. urophylla and its hybrids, were collected at breast height (DBH), and 50% and 75% of the commercial height, and evaluated. The eucalyptus bark consisted of a periderm (or rhytidome) and a secondary phloem with conspicuous solitary sieve tube elements (STE). The outer bark revealed a secondary phloem with collapsed STE, whereas its inner counterpart displayed non-collapsed STEs. A region crowded with calcium oxalate (CaOx) crystals in axial parenchyma, covering the non-collapsed and partially overlapped collapsed secondary phloem, was observed. Eucalyptus barks exhibited similar anatomical organization at DBH, 50% and 75% of the commercial height, irrespective of expected EPD phenotype or scores. Notwithstanding, there are qualitative differences that are associated with the proportion of non-collapsed phloem and phloem with crystals, which were higher in the tolerant clones and in trees with score 0. The more resistant clones or samples with lower EPD scores exhibited a higher proportion of the regions of living phloem, phloem with CaOx crystals, and non-collapsed phloem. These results support the hypothesis that an increased proportion of STE collapse will occur concurrently with elevated EPD scores and are the basis for an ongoing histometric approach.