Leila Cristina Rosa de Lins

THE LYCHEE TREE PROPAGATION BY LAYERING

The aim of the study was to assess the influence of season and different substrates on rooting of air layers of lychee (Litchi chinensisSonn.) for the production of seedlings to ensure the formation of uniform and productive orchards. Air layers were done in plants of the Bengal cultivar using leafy and healthy woody branches, with about 0.010 to 0.015 m in diameter, in which were performed complete girdling with 0.020 m wide at a distance of 0.30 to 0.40 m below the apex. Then the branches were wrapped in moistened substrate. The layering was made at six times of theyear (January, March, May, July, September and November) and two substrates were used (coconut fiber and sphagnum) in a 6 x 2 factorial design in a randomized block with ten replicates. After 90 days, layers were separated from the matrix plant and evaluated for rooting and callus formation, root number, considering only the primary roots, length, area and volume of the roots, beyond the dry weight of roots and calluses. The months of January, March, September and November showed the best results for all analyzed variables related to rooting. With respect to the substrates, the only difference was in January and March to the root number and dry weight of roots, where the sphagnum showed the best results. The month of July was more conducive to the formation of calluses. The period between September and March was more suitable to the propagation of lychee, when there were rooting percentages above 90%, in addition to the formation of large amount of roots.

Jabuticaba—Myrciaria spp.

Abstract The term “jabuticaba” refers to several species of Myrciaria genus, originating from the south and southeast regions of Brazil, and Myrciaria jaboticaba is the most cultivated. A peculiar feature of these species is the fruiting directly in the main trunk and branches of tree, which makes fruit harvest difficult in the highest branches. This factor, combined with the long juvenile period of the plant and the rapid deterioration of the fruit, limits the commercial expansion of culture. The fruit is a black color berry, whose development occurs in less than two months. The pulp is rich in sugars, especially fructose, and the peel is abundant in phenolic compounds, especially anthocyanins, which give high antioxidant capacity to the fruit. However, knowledge about the fruit physiology and biochemistry is still very limited. Besides fresh consumption, the fruit is utilized in the manufacture of wine, jellies, nectar, and flour, besides presenting phytotherapeutic indications.

CHEMICAL AND PHYSICAL CHARACTERISTICS OF ‘IMPROVED SUNRISE SOLO LINE 72-12’ PAPAYA FRUITS SUBMITTED TO DIFFERENT MECHANICAL DAMAGE

Objetivou-se avaliar algumas alteracoes no metabolismo dos frutos do mamoeiro submetidos aos danos de impacto, abrasao e compressao. Os danos foram provocados em duas areas de 15 cm2 cada, em posicoes diametralmente opostas, na regiao equatorial de mamoes ‘Improved Sunrise Solo Line 72/12’ no estadio 3 de amadurecimento (frutos com 25 a 40% da area superficial da casca amarela). Apos os danos, os frutos foram armazenados a 15 ± 1 oC e 85 ± 5% de UR, sendo as amostragens feitas em intervalos de dois dias para avaliacao de indice de cor da casca, incidencia de podridoes, perda de massa fresca, vazamento de solutos, firmeza da polpa, teor de solidos soluveis e atividade das enzimas pectinametilesterase e poligalacturonase. A taxa respiratoria foi avaliada nos intervalos de 4, 8, 12, 24, 48 e 72 horas apos os danos. Os resultados evidenciaram os efeitos depreciativos dos danos mecânicos na qualidade final e tambem no tempo de vida de prateleira dos mamoes. Os frutos mecanicamente danificados anteciparam o amadurecimento, apresentando indices de cor da casca maiores do que os dos frutos controle. O dano por abrasao foi o que provocou efeitos mais drasticos, por apresentar, no final do periodo avaliado, perda de massa media e vazamento de solutos 27% e 18,7%, respectivamente, maiores do que nos frutos controle. Alem disso, os frutos submetidos a esse dano apresentaram uma maior taxa respiratoria e tambem maior incidencia de podridoes. A atividade das enzimas pectinametilesterase e poligalacturonase nao foi alterada de forma consistente em funcao dos danos. Da mesma forma, nao se observou diferencas no teor de solidos soluveis.

COMPONENTS OF CELL WALL, ENZYME ACTIVITY IN PEDICEL AND SUSCEPTIBILITY OF BANANAS TO FINGER DROP

A major problem in post-harvest handling of bananas is the individual detachment of the fruit from the hands. This study aimed to establishing the relationship between carbohydrate concentration and enzyme activity in the pedicel region of three cultivars of bananas, resistant and susceptible to natural dropping, during post-harvest ripening, and the susceptibility of bananas to finger dropping. Cultivars ‘Terra’ (plantain, AAB group) and ‘Prata’ (banana, AAB group) triploids and the ‘Prata Grauda’ (banana, AAAB group) tetraploid were used. The experiment was distributed in split plots, with three plots (cultivars) and five subplots (peel color stages) in a completely randomized design with three replications and three fruits per sample unit. ‘Terra’ showed resistance to dropping, even though the fruit were ripe, unlike ‘Prata Grauda’, which, starting from the fifth stage (yellow fruit with green tips), exhibited high susceptibility to dropping. At all ripening stages, the ‘Terra’ had the highest dry mass levels. In turn, the ‘Prata Grauda’ always maintained the lowest levels. The ‘Terra’ showed decreasing levels of pectins during ripening, whereas starch remained high even in the ripe fruit. About the enzymes studied, the results confirmed the increased resistance of the ‘Terra’ to dropping, allowing to conclude that polygalacturonase (PG) and pectinametylesterase (PME) are the key enzymes for the solubilization of the cell wall that accompanies ripening, thus playing a critical role in inducing natural dropping. The high susceptibility of the ’Prata Grauda’ to dropping is associated with the high activity of PG and PME and the low levels of dry mass; the greater resistance of the ‘Terra’ to dropping is related to higher accumulation of dry mass and starch in the pedicel.

Torta de mamona no controle da broca-do-rizoma (Cosmopolites sordidus) em bananeira-Terra

The aim of this study was to evaluate the effects of castor bean pie on the infestation by Cosmopolites sordidus and on the development of banana plants cv. Terra. To observe the dose-response relationship, each treatment focused on a different dosage of castor bean pie (0 g, 12 g, 15 g, 18 g, 24 g) applied every two months to the banana plants, starting from the planting date. The experimental design was completely randomized with ten replicates. Plant vegetative growth was evaluated by measuring plant height, pseudostem diameter, and counting alive (or green) leaves. The infestation of plants was undertaken by using 25 adults of C. sordidus per plant. Six months after planting, the percentage of damage caused was scored on rhizomes and the number of adults (alive and died), larvae, and pupae was registered. Absorbance related to the leaf chlorophyll content was also determined by a chorophyllometer. In plants treated with castor bean pie there was a low infestation of the banana weevil borer. Vegetative growth and absorbance were also positively affected by applying castor bean pie. Therefore, castor bean pie reduces C. sordidus population in rhizomes of bananas cv. Terra, improving vegetative growth and chlorophyll content in leaves.

TRATAMENTO HIDROTÉRMICO PARA PREVENÇÃO DO ESCURECIMENTO DO PERICARPO DE LICHIA

The browning of litchi pericarp (Litchi chinensis Sonn.) occurs rapidly after harvest, limiting the marketing period of the fruits. The objective of this study was to evaluate the effect of hot water treatments in preventing browning of the pericarp and the maintenance of postharvest quality of litchi fruit. Fruits of litchi cv. Bengal uniformly red pericarp were submitted to immersion in water at tree temperature (45, 50 and 55°C) x five soaking times (0, 4, 8, 12 and 16 minutes) in a completely randomized design with tree replications and five fruit per replicate. After drying, the fruits were packed in polystyrene trays, covered with plastic wrap with 12 mm thick and stored in the lab benches at room temperature (19.0 ± 2.4°C and 75 ± 5% RH) to simulate the exposure conditions at supermarket counters. Every two days, during eight days, were evaluated the weight loss, color of the pericarp, soluble solids, titratable acidity of the pulp and ascorbic acid content of the pericarp and pulp. It was observed that the weight loss was higher in fruits that were not subjected to hydrothermal treatment. Fruits subjected to 50°C during 16 minutes and 55°C in all immersion times were evaluated only until the 4th day, thereafter, these fruits are not suitable for commercialization. Immersion at 45°C during four minutes was the most effective in maintaining the red color of the pericarp and did not affect the quality measured during the experimental period.