Natália Pereira

Yield and Nutrient Uptake of Common Bean Cultivars as Affected by Plant Population and Growing Season

Brazil’s production of common bean is insufficient to supply the domestic market. Factors such as plant density, cultivar, growing season, and nutrient uptake affect bean yield, suggesting the need for more studies to optimize bean production. The objective of this work was to evaluate the effect of plant density on seed yield components and nutrient uptake of two common bean cultivars grown in two different seasons. Field experiments were carried out at the IAPAR experimental site in Santa Tereza do Oeste, Parana, Brazil in the wet and dry season using five planting densities: 6, 8, 10, 12, and 14 plants m-1. The experimental design was randomized blocks with four replications and two bean cultivars of different growth types. The cultivars used were ‘IPR Curio’ (type I) and ‘IPR Tangara’ (type II), both have erect plant architecture and belong to the Carioca group. Obtained data underwent analysis of variance and regression. Macronutrient uptake was not affected by crop density probably due to nutrient availability and compensatory growth of the crop. High crop density per linear meter decreased the number of seeds and pods per plant but did not affect the first pod height or yield in both cultivars and seasons.

Leaf anatomy and gas exchange of ornamental sunflower in response to silicon application

Silicon applied to substrate for greenhouse cultivation of ornamental pot plants can improve the yield and quality of the ornamental product; however, the possible anatomical and physiological changes caused by Si have to be assessed. Therefore, the objective of this study was to evaluate gas exchange rates and leaf anatomy of ornamental sunflower ‘Sunbright’ grown on a substrate amended with Si. The experiment was conducted in a greenhouse, and the treatments consisted of sunflower plants cultivated in pots containing 600 g substrate fertilized with Si at rates of 0, 0.25, 0.50, 0.75, and 1.00 g kg. The treatments were arranged in randomized complete block design and four replications. Samples from the middle region of leaf blades in the sixth pair from the apex were collected and analyzed morphometrically. Epidermal trichomes were analyzed using diaphanization and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The following traits were determined: leaf blade thickness, palisade and spongy parenchyma thickness, mesophyll thickness, and abaxial and adaxial epidermis thickness. Net photosynthesis, stomatal conductance and transpiration rates were determined in the fifth leaf at the beginning of the flowering stage by an infrared gas analyzer. The data were subjected to ANOVA and regression analyses. The results indicate that the ornamental sunflower ‘Sunbright’ accumulates Si in leaf trichomes, and that leaf thickness is not affected by Si application to the substrate; however, transpiration rates decrease while net photosynthesis rate and stomatal conductance increase in response to Si application.

Produção de gladíolo submetido a ácido giberélico em ambiente protegido

1. Manuscript received in Jul./2016 and accepted for publication in Dec./2016 (http://dx.doi.org/10.1590/1983-40632016v4642418). 2. Universidade Estadual do Oeste do Paraná, Centro de Ciências Agrárias, Marechal Cândido Rondon, PR, Brazil. E-mails: maristelacarvalho@gmail.com, fvilla2003@libero.it, claudiotsutsumi@unioeste.br. 3. Universidade Estadual do Oeste do Paraná, Centro de Ciências Exatas e Tecnologias, Cascavel, PR, Brazil. E-mail: pe.nataliaa@gmail.com. Gladiolus is an important cut flower commercialized in Brazil, and the use of gibberellic acid (GA3) to cultivate it in a protected environment may promote the production of high quality flower spikes. This study aimed at evaluating the production of flower spikes and corms of gladiolus (‘White Friendship’ cultivar) submitted to high concentrations and application methods of gibberellic acid, in a protected environment. The experimental design was randomized blocks, in a 2 x 4 factorial arrangement, being two application methods (foliar spraying and corm soaking) and four concentrations (0 mg L-1, 250 mg L-1, 500 mg L-1 and 1,000 mg L-1) of gibberellic acid, with six replications and two plants per experimental unit. The following traits were evaluated: plant height, number of leaves per plant, marketable harvest point of flower spikes, number of florets per flower spike, flower panicle length, stem and floret diameter, corm perimeter, number of cormels per plant and production of corm fresh matter and leaf dry matter, flower spikes, corms and cormels. High concentrations of GA3 are not recommended for the production of flower spikes and corms of the gladiolus ‘White Friendship’ cultivar. The corm soaking application method anticipates the harvest of flower spikes and produces a higher number of cormels per plant. Regardless of the application method, the concentration of 550 mg L-1 of GA3 increases the cormel yield of the ‘White Friendship’ cultivar.