The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species (Hymenaea courbaril and H. Stigonocarpa) in the Amazon. We adopted a 2 9 5 9 5 factorial system, referring to 2 species (H. courbaril and H. stigonocarpa) and 5 stages of hydration and rehydration. The five hydration and rehydration stages were established in: (1) Control treatment E0; (2) Plants with 13 days of stress after incubation-E13; (3) Plants with 26 days of stress E26; (4) The plants that were established after 26 days after incubation and rehydrated for two days (RD2); (5) rehydrated for two days (RD4). The plants that were established after 26 days after incubation and rehydrated for four days. The experiment totaled fifty young plants with five replicates. Biochemical measurements were performed at the beginning of the experiment (E0) at 13 (E13) and 26 (E26) days after the water stress, in which the plants were rehydrated, repeating the analyses after two (RD2) and four (RD4) days. Both species increased the sucrose concentration by 18%, with a decrease of 52% in starch content. The RD4 time presented the highest mean starch concentration (0.19 mmol g -1 of the residue for H. courbaril and 0.27 mmol g -1 of residue for H. stigonocarpa). Increased proline concentrations were recorded for controls until RD2 for both species. For glycine betaine, the highest increases in treatments E26 and RD2 were observed for the H. courbaril species. Our rehydration period was not sufficient for total recovery of pre-stress concentrations of all studied solutes.

The physico-chemical and microstructural changes of “Rojo Brillante” persimmons in two maturity stages (S1 and S2) were evaluated during air drying. The maturity stage influences moisture loss. A Moisture level of approximately 50%, a limit at which persimmons are considered semidried, was reached after 21 and 28 days for S1 and S2, respectively. Shrinkage resulting from water removal led to secondary epidermis formation concomitantly to internal flesh gelling, which was related to moisture loss and water activity changes of each fruit part. The thicker epidermis and the lower volume of gelled area inside the S1 fruits led to harder fruit compared to the S2 fruits. The microstructural study revealed parenchyma degradation during drying in both the outermost area (secondary epidermis) and internal flesh, and this process was faster in S1 than in S2. The second peel presented hollows, generated by water outflow, which were bigger in S1 and explained the faster internal dehydration in S1. During drying, slight browning occurred, as reflected in the declining color parameters (L*, h* and C*). Water removal led to soluble solids tannin reduction to non-astringency values on day 28.

No abstract

This study investigated the effect of preharvest 1-MCP treatment on maintaining ‘Rojo Brillante’ persimmon firmness. Early in the season, preharvest 1-MCP was applied 1, 7 and 10 days after ethephon treatment. The fruit firmness was evaluated during three different harvests and after the commercialization period of 3 d at 3 °C, plus 6 d at 20 °C. Late in the season, 1-MCP was applied 3 days before harvest in the fruit treated with gibberellic acid (GA) and then cold-stored for up to 60 days, plus a 6-day shelf life at 20 °C. The results showed that preharvest 1-MCP delayed the fruit softening induced by ethephon during the harvest period, and was the most effective treatment when performed 1 day after ethephon application. Therefore, preharvest 1-MCP extended the harvest period of ethephon-treated fruit. At the end of the season, preharvest 1-MCP had the same effect on maintaining the fruit firmness as the commercial postharvest application.

This study aimed to evaluate the concentrations of the main macroelements in leaves and fruit grown following organic and conventional practices, and to relate them to physico-chemical parameters during commercial fruit harvests. Three samplings were carried out during fruit maturation. Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) were determined in leaves and in two fruit flesh areas: basal and apical. Weight, color, firmness, soluble tannins (ST), and total soluble solids (TSS) were also evaluated in fruit. During the study period, the lowering leaf N concentration was accompanied by its increment in flesh. Leaf P and K lowered but did not imply changes in these concentrations in fruit. N, P, and K concentrations were higher in the apical area than in the basal flesh. No changes in Ca concentration occurred in leaf, but Ca translocation from the basal to the apical area was detected in fruit. Management affected the concentrations of leaf K and Mg and the fruit N, P and Ca. The agronomic efficiency of the macronutrients in the organic crops was superior to that in the conventional crops. The Ca and Mg and the N/Ca and Ca/(K+Mg) ratios were closely related to color, firmness, TSS, and ST content.