Tropical floriculture is an economically relevant activity, particularly for family farming, because of the high added value of cut flowers and the potential for rapid financial returns. Among tropical ornamentals, Heliconia species are valued for their diversity of colors and forms. However, cultivation under full-sun conditions in semi-arid regions exposes plants to high solar irradiance, which may constrain physiological performance and growth. This study evaluated the effects of foliar applications of salicylic acid (SA) and kaolin on the physiological responses, vegetative growth, and floral stem quality of Heliconia bihai cv. Lobster Claw Two, Heliconia rostrata, Heliconia psittacorum cv. Red Opal, and Heliconia psittacorum × Heliconia spathocircinata cv. Golden Torch grown under full-sun conditions in the Submiddle São Francisco Valley, Brazil. Treatments consisted of SA at 0, 100, 200, and 300 mg L-1 and kaolin at 50 g L-1, arranged in a randomized complete block design. Chlorophyll a fluorescence, photosynthetic pigments, membrane integrity, vegetative growth, and floral stem quality were evaluated. Foliar treatments modulated PSII photochemistry, photosynthetic pigment contents, and membrane integrity, with responses depending on species, treatment, and phenological phase. Among the evaluated species, H. rostrata showed the most consistent favorable physiological responses, particularly to kaolin and SA at 100 and 200 mg L-1 during the reproductive phase. However, these physiological and biochemical responses were not consistently translated into improved vegetative growth or floral stem quality compared with the water control, with these traits remaining predominantly species-dependent. Overall, SA and kaolin induced species-specific physiological adjustments in Heliconia under full-sun semi-arid conditions, but no generalized beneficial effect was observed across the evaluated species, highlighting the importance of species-specific management when considering these compounds as photoprotective strategies.
Saline stress affects the growth and development of crops worldwide. The use of hydrogels can alleviate the deleterious effects of salts on plants. Thus, the objective was to evaluate the use of hydrogels on the growth and biomass accumulation of sunflowers irrigated with brackish water. The experiment was conducted in a protected environment belonging to the Federal Institute of Education, Science, and Technology of Ceará – IFCE/Sobral Campus, located in the municipality of Sobral, Ceará State, Brazil. The experimental design was randomized blocks, in a factorial scheme (3 × 3), with one factor consisting of three levels of electrical conductivity of irrigation water (0.3, 1.0, and 2.0 dS m-1) and the second referring to the use of hydrogels: without the presence of hydrogel, synthetic hydrogel, and alternative hydrogel (acrylate-acrylamide polymer matrix incorporated with kaolin). Increased electrical conductivity of the irrigation water reduces the leaf growth rate, abundance, and biomass accumulation of ornamental sunflowers. The use of hydrogels does not attenuate the deleterious effects of salinity on plant height growth rate, or stem, root, and total dry mass accumulation under 2.0 dS m-1 irrigation. Conversely, synthetic hydrogel regarding stem diameter growth rate and both hydrogels regarding root growth partially reduce salt impacts, allowing greater expansion in stem diameter and root system length of ornamental sunflower. The use of the alternative hydrogel increases the outer capitulum diameter of ornamental sunflower, demonstrating superior performance compared to the synthetic hydrogel for this floral structure.
Aglaonema is a high-value ornamental foliage plant showing considerable variation in growth and physiological responses among cultivars. Silica is a beneficial element that enhances plant growth, strengthens tissues, improves photosynthetic efficiency, and increases resistance to biotic and abiotic stresses. The effects of foliar application of nanosilica (SiO2) on growth, leaf epidermal characteristics, and disease resistance of Aglaonema were evaluated. The experiment was conducted using a split-plot design arranged in a randomized complete block design, with four nanosilica concentrations (0, 0.3, 0.6 and 0.9 g L-1) as main plots and sixteen cultivars as subplots. Significant differences among cultivars were found in plant height, number of leaves, leaf length, chlorophyll a, chlorophyll b, total chlorophyll, chlorophyll a/b ratio, and carotenoid content. Nanosilica at 0.3 g L-1 produced the highest in plant height, stomatal density, chlorophyll a/b ratio, and carotenoids, while 0.6 g L-1 enhanced epidermal thickness and chlorophyll content. The highest concentration, 0.9 g L-1, increased leaf length and width, stomatal index, and reduced incidence and severity of Lepidosaphes beckii, Ceroplastes rubens, Pseudococcidae, anthracnose, and stem rot. Interactions between cultivars and nanosilica were significant for leaf width, epidermal thickness, stomatal index, and stomatal density. Correlation analysis showed positive relationships among leaf size, plant height, stomatal density, and chlorophyll content. Considering consumer preference for compact plants with broad leaves and high resistance to pests and diseases, the foliar application of nanosilica at 0.9 g L-1 is deemed the most suitable concentration.
Gerbera is a high-value cut flower whose commercial longevity is frequently compromised by microbial-induced vascular occlusion and oxidative stress-driven senescence. This study evaluated the efficacy of Derris elliptica leaf extract as a natural, eco-friendly biopreservative for extending the vase life of cut gerberas. Results demonstrated that D. elliptica extract significantly improved postharvest performance in a dose-dependent manner, with 175 mg L-1 identified as the optimal concentration. At this level, vase life was extended to 13.57 days, nearly double that of the distilled water control (6.93 days). The extract effectively suppressed microbial proliferation in the vase solution, maintaining a low optical density (0.15) compared to the control (0.72) at day 10. This reduction in bacterial load preserved xylem hydraulic conductivity, resulting in improved water balance, as reflected by relative fresh weight values exceeding 100%. Furthermore, the 175 mg L-1 treatment significantly alleviated oxidative damage by reducing malondialdehyde content and electrolyte leakage. This was associated with enhanced antioxidant defense along with higher total phenolic and flavonoid contents (2.6-4.7-fold over the control). However, higher concentrations (200–250 mg L-1) led to a decline in physiological performance, suggesting an optimal threshold at 175 mg L-1. Derris elliptica extract extended vase life through dual mechanisms involving microbial suppression and oxidative stress regulation.
To improve turfgrass development within the production system, it is essential to adopt sustainable alternatives that meet producers’ demands. These strategies should contribute to reducing production costs, improving product quality, and promoting crop sustainability. In this context, the use of sewage sludge compost and biostimulants has been widely studied for their application in agriculture. Thus, this study aims to evaluate the growth of Zoysiagrass cv. Esmeralda through the application of sewage sludge compost (SSC) combined with biostimulants as a nutrient source in the sod production in two cycles. The experiment was conducted under field conditions, in southwest of Brazil in February 2021, organized in a randomized block design with four repetitions. The treatments followed a 5 x 3 + 1 factorial scheme, consisting of five doses of SSC (0.0, 2.5, 5.0, 7.5, and 10.0 Mg ha-1) combined with the absence or presence of biostimulants: (i) the growth-promoting bacterium Azospirillum brasilense and (ii) seaweed extract from Ascophyllum nodosum, and a control. The evaluated parameters included leaf green color intensity, the normalized difference vegetation index, and the green cover rate on the soil. The growth and visual quality of the grass were significantly improved by the application of seaweed extract combined with higher doses of SSC during periods of lower rainfall
