Resumo A Myrciaria floribunda é uma espécie nativa das áreas de restinga da mata atlântica que apresenta grande variação fenotípica nos frutos, possui grande importância socioeconômica nas regiões de ocorrência natural e alto potencial produtivo. A caracterização de populações heterogêneas é determinante para um programa de seleção e de melhoramento de plantas, pois permite a distinção de indivíduos superiores. O objetivo deste estudo foi caracterizar a estrutura reprodutiva de acessos de M. floribunda e observar a influência das condições climáticas e do ambiente sobre o processo reprodutivo, por meio da biologia floral, da morfoanatomia floral e da fenologia reprodutiva. A Apis melífera e Trigona spinipes são os principais visitantes florais do cambuí. A receptividade do estigma tem duração de até 5 horas após a abertura da flor, e a viabilidade polínica esteve acima de 90%. Em relação à estrutura da flor, possui órgão sexual feminino monocárpico, ovário ínfero, bilocular, com dois óvulos por lóculo, apresenta inflorescência do tipo fascículo, constituída por pequenas flores de coloração branca, simetria actinomorfa, heteroclamídeas e monoclinas. As plantas floresceram de forma irregular praticamente o ano inteiro, concentrando a floração em duas épocas do ano com maiores picos em março e agosto, enquanto os maiores picos de frutificação foram observados em abril e setembro.

Abstract Myrciaria floribunda is a species native to the restinga areas of the Atlantic Forest that presents great phenotypic variation in fruits, great socioeconomic importance in regions of natural occurrence and high productive potential. The characterization of heterogeneous populations is crucial for plant selection and breeding programs, since it allows the distinction of superior individuals. The aim of this study was to characterize the reproductive structure of M. floribunda accessions, and to observe the influence of climate and environment on its reproductive process, through floral biology, floral morphoanatomy and reproductive phenology. Apis mellifera and Trigona spinipes are the main floral visitors of cambuí. Stigma receptivity lasts up to 5 hours after flower opening and pollen viability was above 90%. Regarding the flower structure, the female sexual organ is monocarpic, the ovary is efferent, bilocular, with two ovules per locule, the inflorescence is fascicle-like and consists of small white flowers, actinomorph symmetry, heteroclamid and monoclines. Plants bloomed irregularly throughout the year, concentrating flowering in two periods of the year with the greatest peaks in March and August, while the greatest fruiting peaks were observed in April and September.

ABSTRACT The aim of this research was to evaluate the physiological and productive aspects of irrigated cassava crop. The statistical design used was randomised blocks, with six treatments and four replications. The used treatments were irrigation levels, based on the crop evapotranspiration – ETC – (L0 = 0% [rainfed], L1 = 40%, L2 = 80%, L3 = 120%, L4 = 160% and L5 = 200% of the ETC) and the analysed physiological variables were: gas exchange, the quantum efficiency of photosystem II (PSII) and the soil plant analysis development (SPAD) index. The growth and crop productivity were also evaluated through of the leaf area index (LAI), the number and productivity of commercial roots and total biomass. In this research, the total irrigation depth was defined as the irrigation depth plus the effective rainfall. The estimated ETC was 1,030 mm over the 12-month production cycle and the greatest value for LAI and SPAD were 7.6 and 57.4, respectively, obtained in irrigated areas with the level of 80% of the ETC. While, in the areas irrigated with 120% of the ETC, were obtained the highest values of root productivity (93 Mg·ha–1), total biomass yield (149 Mg·ha–1) and photosynthetic rate (22.4 μmol CO2·m–2·s–1). On the other hand, with irrigation equivalent at 200% of the ETC were obtained the greatest values of internal CO2 concentration (245 μmol CO2·m–2·s–1), stomatal conductance (0.35 μmol H2O·m–2·s–1) and effective quantum efficiency (0.68).

RESUMO Esse trabalho teve como objetivo avaliar dois acessos de anona, cv. Crioula (com camada espessa de cera nas folhas) e cv. Verdinha (sem deposição de cera aparente nas folhas) durante o crescimento inicial sob condições de stresse hídrico em duas épocas: época chuvosa, compreendida entre julho e agosto de 2017 e época seca, avaliada em janeiro de 2018. O trabalho foi desenvolvido, com um esquema fatorial 2 x 4, sendo dois acessos de pinheira e quatro tempos de stresse após suspensão da irrigação, em delineamento experimental em blocos casualizados com 6 repetições. Foram avaliadas as variavéis fisiológicas. Os resultados mostraram que durante a época chuvosa houve maior taxa fotossintética (35,44 mol de CO2 m-2 s-1) nos dois acessos, independente do nível de stresse. O valor máximo de condutância estomática (0,69 mol m-2 s-1) e mínimo (0,02 mol m-2 s-1) foram observados em mudas avaliadas na época seca. A cv. Verdinha apresentou maior taxa transpiratória (5,49 mmol H2O m-2 s-1) na época seca. As plantas avaliadas na época chuvosa apresentaram maior potencial hídrico foliar. As alterações fisiológicas evidenciaram que os dois acessos de A. squamosa possuem alta capacidade de adaptabilidade em condições de stresse hídrico, independente da deposição de cera nas folhas.

ABSTRACT The objective of this work was to evaluate two accessions of sugar apple, cv. Crioula (with thick wax layer in the leaves) and cv. Verdinha (no wax deposition in the leaves) during initial growth under water stress conditions in two seasons: rainy season (July and August 2017) and dry season (January 2018). The work was carried out in a greenhouse, in a 2 x 4 factorial scheme, with two accessions of sugar apple and four stress times after irrigation suspension in a completely randomized design with 6 replicates. Were evaluated the physiological variables. The results showed that during the rainy season there was a higher photosynthetic rate (35,44 mol de CO2 m-2 s-1). in the two accessions, regardless of the level of stress. The maximum value of stomatal conductance (0.69 mol m-2 s-1) and minimum (0.02 mol m-2 s-1) were observed in seedlings evaluated in the dry season. The cv. Verdinha presented higher transpiration rate (5,49 mmol H2O m-2) in dry season. The plants evaluated in the rainy season presented greater leaf water potential. The physiological changes evidenced that the two accessions of A. squamosa have high adaptability capacity under conditions of water stress, independent of the wax deposition in the leaves.