Alterações anatômicas, físicas e fisiológicas induzidas por estresses mecânicos em melão Gália

• Ano de defesa: 2008
• Autor(a) principal: Rocha, Railene Hérica Carlos
• Orientador(a): Salomão, Luiz Carlos Chamhum
• Banca de defesa: Ventrella, Marília Contin , Bruckner, Claudio Horst
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Cucumis melo; Injúrias mecânicas; Armazenamento
• Palavras-chave em Inglês: Cucumis melo; Mechanical injuries; Storage
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1093

The objectives of this work was to characterize the morphoanatomical structure of Galia melon, hybrid Solar King, at harvest time and evaluate the effect of mechanical stress by impact, compression and cutting on structural, physical, chemical and physiological characteristics over fruit storage. Melons were purchased from a commercial farm in the Municipality of Mossoró, RN, establishing the harvest time on the basis of percent soluble solids, around 10%. At harvest time, fruits were characterized morphologically (mass, pulp thickness, longitudinal and cross length, shape index and reticulation index) and anatomically, using light and electron scanning microscopies and nuclear magnetic resonance tomography. To evaluate the effect of mechanical injuries during postharvest handling, fruits were submitted to the following treatments: T1, control; T2, 5 min of 12 kg compression force from peduncle to apex and perpendicular to the same line; T3, fruits submitted to impact, a single fall with impact point on the equatorial plane, from a height of 50 cm, over a 2.7-mm thick rubber blanket; T4, two parallel cuts were done sequentially using a blade 6.5 cm long and 1 mm thick; and T5, melons submitted to damages of treatments T2 towards apex, T3 and T4. The structural analyses considered treatments T1, T2, T3 and T4, whereas or anatomical analyses, fruits were kept at 24 ± 2 °C and 72 ± 5% UR and analyzed soon after injuries and at three, six and eight days of storage, or chilled for 21 days at 8 ± 2 °C and 85 ± 5% UR and analyzed after 21 days of refrigeration and at three, six and eight days after moving the fruits to ambient conditions (24 ± 2 °C and 72 ± 5% UR). Nuclear magnetic resonance tomographies were performed approximately 48 h after injuries and at three, six and eight days after moving the fruits to ambient conditions. Physical and chemical evaluations were carried out at harvest, after 21 days of refrigeration (8 ± 2 °C and 85 ± 5% UR) and at 3, 6, 9 and 12 days after moving the fruits to ambient conditions (24 ± 2 °C and 72 ± 5% UR), considering the external and internal appearance of fruits, Hue angle of peel and pulp, total color difference of peel and pulp, loss of fruit fresh matter, skin and of pulp firmness, soluble solids content, total soluble sugars, total titrable acidity, pH and SS/TA ratio for pulp. Respiratory activity and ethylene production were analyzed daily during fruit storage at 18 ± 2 °C and 90 ± 5% UR. The Galia melon was described as a berry of round shape, with reticulated yellow skin and pale-green pulp. Fruits were shown structurally complete in images of nuclear magnetic resonance tomography, approximately 48 h after harvest. The epicarp consisted of thick and lignified wall cells, reticulated surface, epicuticular waxes, stomata and trichomes. The mesocarp closest to the exocarp consisted of smaller and denser cells, and the most inner cells were more voluminous, with larger intercellular spaces. Comparing stresses by compression, impact and cutting, cutting was the most severe, causing clearly perceptible mechanical injury just after the incision and intense desiccation of pericarp, collapse and death of mesocarp tissues lateral to the lesion, with elapsing of storage period. Fruits showed great resistance to anatomical changes related to mechanical stresses by impact and compression and the long storage period. The reticulated parts, together with epicuticular waxes and denser structure of the first parenchymatic layers, contributed to control moisture loss and reduce injuries. Higher respiratory activity and ethylene production occurred in fruits with mechanical injury compared with non-injured ones. Ethylene production was higher in fruits with mechanical injuries, between the third and the fifth day of storage (18 ± 2 °C and 90 ± 5% UR). Overall, all fruits maintained good quality until approximately six days after removing them from the cold chamber (21 days at 8 ± 2 °C and 85 ± 5% UR), when the recorded scores were equal or above 3 for the external and internal appearance, soluble solids content around 8.5 and pulp firmness about 4 N, independently of the presence or not of mechanical injury.