The objective of this study was to evaluate the effect of the hydrogel on the planting of clonal Eucalyptus urograndis seedlings in pots, related to different water management, to provide information about the hydrogel use efficiency. The experiment was carried out in a forest nursery in a factorial scheme, as factor "A" referred to the absence and presence of hydrogel and factor "B" to water management (0 - irrigation only at planting, 1 - daily, 4 - every 4 days, and 8 - every 8 days). Evaluations of the water stress symptomatology, morphological characteristics, chlorophyll content, soil water content, gas exchange, increase in diameter and height, and dry biomass were performed. The hydrogel provided an increase in water content in the soil and a delay in the symptoms of water stress, increasing the survival rate. Water stress was a limiting factor for stomatal opening, contributing to the decrease in carbon assimilation by photosynthesis.

The objective of this paper was to test the effects of water deficit, saturation and salinity in individuals of Toona ciliata. Seven treatments were tested: the control group, the complete suspension of irrigation, the permanent saturation of the pot soil and four doses of NaCl (50, 100, 200 and 400 µmol). The experimental design was completely randomized, with 8 repetitions in each treatment. Physiologic evaluations were carried out during the experiment, and morphologic evaluations at the end. The plants were responsive to the applied stresses comparatively to the control group. Reductions were observed in morphological and physiological variables in all treatments under stress. All individuals under stress recovered slightly in the end of the experiment, and began to sprout again, representing a probable adaptation to the conditions.

Sequoia sempervirens (sequoia) é uma espécie conhecida pela qualidade superior de sua madeira, sendo a produção de mudas por miniestaquia uma alternativa viável. O objetivo do trabalho foi avaliar a posição de coleta, presença ou ausência de folhas aciculares em miniestacas e a produção de mudas cultivadas em diferentes substratos e utilização de AIB. Foram utilizadas miniestacas de diferentes clones, oriundas de minijardim clonal. Para o padrão de miniestacas utilizou-se a porção lignificada, com média lignificação e pouca lignificação, na presença ou ausência de folhas aciculares, avaliando-se um clone. Em relação aos substratos, observou-se o comportamento de três clones e quatro substratos de marcas comerciais. Para o emprego de regulador de crescimento utilizou-se um clone e diferentes concentrações de AIB (0,0 a 5000 mg L-1). As miniestacas foram colocadas para enraizar em estufim e avaliadas aos 90 dias. Todos os experimentos foram instalados em delineamento inteiramente casualizado, com posterior avaliação da porcentagem de sobrevivência; porcentagem de miniestacas com calos; porcentagem de miniestacas enraizadas e número de raízes emitidas por miniestaca enraizada. Miniestacas pouco lignificadas (ápice) com folhas aciculares apresentaram os melhores resultados para sobrevivência (96%) e enraizamento (94%); miniestacas muito lignificadas sem folhas aciculares obtiveram baixo enraizamento (10%). Houve considerável variação de enraizamento entre os substratos (66 a 100%) e o número de raízes foi mais influenciado pelo clone utilizado. Os melhores resultados foram observados naqueles com componentes mais orgânicos. O emprego de AIB na miniestaquia não foi significativo para nenhuma das variáveis analisadas. Miniestacas coletadas em porções apicais e com presença de folhas aciculares mostraram-se mais indicadas para trabalhos com a espécie. Para a seleção do melhor substrato deve-se observar o efeito clonal, priorizando-se substratos com composição mais orgânica. A utilização de AIB não influenciou positivamente o enraizamento de miniestacas, não sendo recomendado o seu uso.

Eucalyptus cultivation in Brazil benefits from techniques such as mini cutting; however, adverse climatic conditions in the southern region of the country limit seedling production. This study evaluated the effects of LED lighting (blue, red, combined, and natural) and cultivation environments (greenhouse with and without heating, and conventional nursery) on the propagation of Eucalyptus dunnii. The experiment, conducted in Otacílio Costa, SC, followed a two-factor (4 × 4) design with biweekly data collection from March to September 2024. Variables analyzed included sprout productivity, rooting performance, phytosanitary status (powdery mildew incidence), physiological parameters (photosynthetic rate, stomatal conductance, transpiration), and nutritional content. The results showed that LED lighting and cultivation environments did not affect the incidence of powdery mildew. Rooting was enhanced during winter in the heated mini-tunnel system. Sprout productivity was highest in the mini tunnel (~360 sprouts/m² under red light in winter), while heated environments led to a reduction in sprout production. Physiological variables such as photosynthetic rate and stomatal conductance were improved in the heated mini-tunnel, and transpiration responded to the interaction between light spectrum and environment. The evaluated factors did not cause significant changes in the nutritional profile of the mini stumps. It is concluded that the mini tunnel, particularly when heated during winter, enhances rooting and physiological responses, while red LED light increases sprout productivity. Supplemental LED lighting proved to be a strategic tool for overcoming seasonal limitations in Eucalyptus propagation.

The objective of the study was the evaluation of survival and productivity indicators in different species/hybrids of Eucalyptus in the adult stage, as well as the vegetative rescue of adult trees ...

Plants use light as a source of energy in the process of photosynthesis. Different levels of luminosity cause physiological and morphological changes in the plant, and its success depends on its adaptation to these different levels. Light emitting diodes (LED) have been proposed as a light source in controlled environments. The present research evaluated physiological and morphological aspects in Eucalyptus benthamii (Myrtaceae) seedlings kept under different colors of LED lamps and submitted to water stress. The experiment was carried out in a completely randomized design, in which the treatments were defined as: T1 (control, with white light); T2 (blue light); T3 (red light) and T4 (mixed blue and red light). Red light resulted in the best response to most morphological variables in plant growth. In response to water stress, blue light LEDs resulted in a better seedling response, with slower reduction of photosynthetic rate and other variables. This may indicate the possibility of reducing water deficit damage in seedlings acclimated to blue light prior to field planting.