Trocas gasosas e produtividade de três cultivares de meloeiro conduzidas com um e dois frutos por planta

Abstract

ResumoObjetivou-se, no presente trabalho, avaliar as trocas gasosas e sua influência na produtividade e qualidade de cultivares de melão conduzidas com um e dois frutos por planta. O experimento foi conduzido de setembro a dezembro de 2013. Utilizouse o delineamento de blocos ao acaso, em esquema fatorial 3 x 2, com seis repetições. No primeiro fator foram alocadas as cultivares de melão pertencentes aos tipos amarelo, rendilhado e pele de sapo e no segundo fator, a condução das plantas com um e dois frutos por planta. Foram utilizadas três cultivares de melão para cada tipo. As avaliações foram realizadas aos 40 e aos 56 dias após o transplantio. As características avaliadas foram: taxa de assimilação líquida de CO 2 (A), transpiração foliar (E), condutância estomática (g s ) e concentração interna de CO 2 (C i ). A partir dessas medidas foi calculada a eficiência no uso da água (WUE). O teor de sólidos solúveis foi determinado por leitura direta, enquanto que a massa média dos frutos foi mensurada no momento da colheita, estimando-se a produtividade. Diante dos resultados, pode-se concluir que as diferenças nos índices de trocas gasosas para as cultivares de melão do tipo pele de sapo não influenciaram na produtividade e no teor de sólidos solúveis. Como melão do tipo amarelo e do tipo rendilhado recomendam-se as cultivares Goldex e Louis, respectivamente. Independente da cultivar, recomenda-se o cultivo de melão com dois frutos por planta, por assim as plantas apresentarem maior produtividade sem alterar de forma expressiva os índices de trocas gasosas delas.Palavras-chave: Cucumis melo L., taxa assimilatória líquida de CO 2 , transpiração, condutância estomática, eficiência no uso da água.Gas exchange and productivity from three cultivars of melon conduced with one and two fruit per plant AbstractThe objective of the present work was to evaluate gas exchange and its influence on productivity and quality of melon cultivars conducted with one and two fruits per plant. The experiment was conducted from September to December, 2013. The experimental design was of randomized blocks in factorial design 3 x 2 with six replications. In the first factor were allocated the melon cultivars, belonging to types canary melon, net melon and frog skin melon; and the second factor was the conduction of plants with one and two fruits per plant. Three melon cultivars were used for each type. The evaluations were performed at 40 and 56 days after transplanting. The characteristics evaluated were: CO 2 assimilation rate (A), transpiration (E), stomatic conductance (gs), the internal CO 2 concentration (Ci). From these measurements was calculated water use efficiency (EUA). The soluble solids content was determined by direct reading, while the average fruit weight was measured at harvest, estimating productivity. With the results, it can be concluded that differences in gas exchange indexes to cultivars of frog skin melon type have no influence on productivity and soluble solids content. To cultivars of canary melon and net melon ...

Physiological and agronomic traits of cabbage plants hybrid Fuyutoyo ® sprayed with plant growth regulators

“…Lower Ci in plants tends to stimulate the stomatal opening, allowing greater input of CO 2 to the stomatal spaces and, which, consequently, promotes higher photosynthetic yield, as the authors observed for the treatment with 200 mL p.c./100 L H 2 O. Dalastra et al (2014), evaluating gas exchange indexes of melon cultivars conducted with one and two fruits, verified results similar to the ones found in this work for cultivar Sancho, 'Piel del Sapo', occurring simultaneously increase of A and reduction of Ci, when the plants were evaluated 56 days after transplanting.…”

Physiological behavior of melon cultivars submitted to soil salinity1

“…These authors denote that all the photosynthetic pigments decreased with the increase of electrical conductivity, with chlorophyll being more sensitive to salinity. Dalastra et al (2014) evaluated the gas exchange in three melon cultivars, conducted with one and two fruits, and found that the cultivars differed significantly, being Sancho superior to Medellin and Grand Prix, with 9.23 % and 11.30 %, respectively. That is, there is diversity in the physiology of plants of the same species.…”

“…However, the Natal and Goldex cultivars exceed the intercellular CO 2 concentration, with an increase up to 0.66 dS m -1 and 2.01 dS m -1 , respectively, declining sharply from these levels. Higher CO 2 concentrations support high photosynthetic rates, while, at very low intercellular CO 2 concentrations, photosynthesis is limited (Dalastra et al 2014). This photosynthetic variable is crucial for yield.…”

Biological Fertilization as an Attenuation of Salinity Water on Beetroot (Beta vulgaris)

“…As a means of alleviating the stress effect, the plant can close its stomata, reducing water absorption and consequently the entrance of toxic salts. Closure of the stomata may result in a decreased transpiration, and internal CO 2 concentration in leaves (Dalastra et al, 2014). Therefore, plant diminishes its photosynthetic processes, the fixation of CO 2 and the production of photoassimilates.…”