Use este identificador para citar ou linkar para este item: http://repositorio.ufes.br/handle/10/10029
Título: Eficiência fotoquímica e qualidade pós-colheita da mangueira (Mangifera indica L.) cv. Ubá sob dois regimes hídricos e duas condições de luz
Autor(es): Silva, Leonardo Faria
Orientador: Silva, Diolina Moura
Coorientador: Gallon, Camilla Zanotti
Data do documento: 29-Fev-2016
Editor: Universidade Federal do Espírito Santo
Resumo: Este trabalho teve como objetivo avaliar a eficiência fotoquímica e a qualidade pós-colheita de mangueiras Ubá (Mangifera indica L.) submetidas a diferentes condições de cultivo. As plantas foram avaliadas durante quatro períodos de desenvolvimento, entre dezembro e janeiro, em dois pomares distintos pertencentes ao polo de manga do Espírito Santo. As condições de cultivo foram caracterizadas de acordo com o fornecimento de água, como plantas sob irrigação (IRR) e sob sequeiro (SEQ), e de acordo com a posição de cultivo em relação ao nascer do Sol, como plantas cultivadas do lado Leste (LL) e plantas cultivadas do lado Oeste (LO). Às 11h da manhã, com o aumento brusco da radiação e da temperatura, houveram danos fotoinibitórios nas plantas cultivadas do lado Oeste (LO) com queda no transporte de elétrons do fotossistema II (FSII) para o fotossistema I (FSI) e redução acentuada do índice de performance do FSII (PIABS). No período de pleno amadurecimento dos frutos, o déficit hídrico sofrido pelas plantas SEQ causou redução da densidade de centros de reações fotossinteticamente ativos do FSII por secção transversal (RC/CS0). Porém, após a colheita dos frutos, as plantas SEQ ainda estavam sob déficit hídrico e a produção de novos centros de reações foi retomada ao ponto de igualar estatisticamente às plantas IRR. Após a poda, mesmo com o retorno da chuva, as plantas de todas as condições de cultivo demonstraram queda acentuada no índice de desempenho fotoquímico total (PITOTAL). Quando os frutos foram colhidos verdes entre 10.8 e 13.1 ºBrix e armazenados entre 24 e 30ºC, alcançaram a razão SST/AT iguais aos frutos colhidos maduros, no quinto dia após a colheita. Os frutos originados das plantas LO apresentaram teores maiores de sólidos solúveis totais (SST) e a razão SST/AT mais alta do que os das plantas LL. Já os frutos originados das plantas IRR apresentaram menor perda de peso e volume durante o armazenamento, porém, ao alcançarem o estádio ideal para consumo, não houve diferença na razão SST/AT. Este estudo demonstrou que os estresses causados pela radiação solar e pelo déficit hídrico influenciaram a fotossíntese e a qualidade dos frutos da mangueira Ubá. Palavras-chave: Manga, fluorescência da clorofila a, estresse, radiação solar, irrigação.
This study evaluates the effects of irrigation and intensity of photosynthetically active radiation on photochemical parameters of 'Uba' mango tree leaves in two commercial orchards during four periods: I -Fruit growth, II –fruit ripening , III -After harvest and IV -After pruning the plants. We also analyzed the total soluble solids (TSS), the titratable acidity (TA), the ratio SST/AT, the weight and the fruit volume. In the first orchard, the treatments were characterized according to the water availability, as irrigated plants(IRR) and rainfed plants (RAI) conditions. The fruitswere harvested with the green peel (Gr), stored at 27 ± 3 °C and analyzed for seven days; themature harvestfruit (M) were analyzed in the same day of the harvest. Each day was considered a maturation stage (Gr1, Gr2, Gr3, Gr4, Gr5, Gr6, Gr7andM). In the otherorchard the treatments were characterized according to the incidence of the sunrise under the crop position: East Side plants (ES) and West Side plants (WS). The fruits of this orchard were harvested ripened and analyzed at the same day of theharvest. In plants conducted under two water regimes (IRR and RAI) the RC/CS0(reaction centers density assets by analyzed cross-section), dVG/dt0(rate of excitation energy transfer between reaction centers) and PITOTAL(total performance index) were the most representative photochemical parameters indicated by the principal component analysis (PCA).Damage caused by water stress were more evident in RAI plants especially during the period offruit ripening (period II) with decrease in RC/CS0. After fruit harvest (period III) RAI plants that were under water stress due to lack of rainning, recovered the efficiency producingnew reaction centers. The recovery in this period was significantly important to the point of RAI plants have RC/CS0statistically equal to the IRR plants, suggesting that drought stress occurred when the 'Uba' mango tree were withfruit in full ripening stage only. The period IV, regardless of the water system, was the period with the largest differences in photochemical performance and PITOTALwas lower than in all other analysis periods. There was a small decrease of PITOTALin RAI plants and was significantlygreater than on the IRR plants. In the second orchard, it was observed that the plants located on the West Side received at 11 am a sharp increase in radiation and temperature. Photoinhibitory damage were clearly observed, with a drop in the electron transport of photosystem II (PSII) to photosystem I (PSI) (ET0/TR0= ψE0) and with a marked decreasein the PSII performance index (PIABS). During the fruit ripening and after the pruning of plants, there was a decrease of PITOTALin both growing conditions. The WS plants were more susceptible to the PITOTALdecrease in the ES plants. The photoinhibition was more evident in WS plants and during the reproductive period. Thus, the fruit growth period, the lower values of the specific flow of energy captured and transported (TR0/RC and ET0/RC) while in fruit ripening period, besides the decrease in these parameters was also were observed fall of the quantum yield and electron transport efficiency after reducing the Quinone A (φE0and ψE0), flow reducers electrons (RE0/RC) and the efficiency of PSI (φR0) and sharp decrease ofPITOTAL. The fruit originated from WS plants wasTSS/TA higher than the ES plants while the fruits produced by RAI plants had lower weight and volume. However, the best quality for consumption (> TSS/TA and > weight) was achieved in Gr5stadium for the fruits of IRR plants and Gr6stadium for the fruits of RAI plants. These results indicated aphotoinhibition in WS plants influencingthe fruit quality, which presented fruit with greater accumulation of TSS and higherTSS/TA . Otherwise, e the water availability by irrigation has not affected the quality of the fruit at the end of the storage period
URI: http://repositorio.ufes.br/handle/10/10029
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