Navegando por Autor "Kuki, Kacilda N."

Agora exibindo 1 - 6 de 6

Acclimation responses of macaw palm seedlings to contrasting light environments
(Scientific Reports, 2018) Dias, Adriel N.; Siqueira-Silva, Advanio I.; Souza, João P.; Kuki, Kacilda N.; Pereira, Eduardo G.
The photosynthetic adjustments of macaw palm (Acrocomia aculeata) were evaluated in 30-day- old seedlings exposed to high and low light environments, and sudden transference from low to high light and comparisons were made with the hardening protocol used in nurseries. Furthermore, we evaluated the responses to long-term exposure (265 days) to high and low light environments. Macaw palm seedlings exhibited an efficient mechanism that maximized light capture under scarce conditions, and dissipated excess energy to avoid damaging to the photosystem II under high light. The seedlings showed low saturation irradiance but no photoinhibition when exposed to excess light. When grown under low light intensities, seedlings presented higher photochemical efficiency and minimized the respiratory costs with positive carbon balance at lower irradiance than hardened seedlings did. The hardening procedure did not appear to be an advantageous method during seedling production. Long-term exposure to either low or high light did not cause significant leaf anatomical adjustments. However, the low light seedlings showed higher leaf area and chlorophyll content than those exposed to higher light intensity did, which enabled shaded seedlings to maximize the captured light. Furthermore, the high non-photochemical dissipation allowed rapid acclimation to excessive light exposure. These responses allow macaw palm cultivation and establishment in very different light environments.
Air-drying of eucalypts logs: Genetic variations along time and stem profile
(Industrial Crops and Products, 2018-11) Carneiro, Angélica de Cássia O.; Kuki, Kacilda N.; Leite, Helio G.; Resende, Marcos Deon V.; Resende, Rafael T.; Ferreira, Ricardo Augusto D. C.; Zaidan, Úrsula R.; Santos, Raul Duarte; Ferreira, Ricardo Augusto D. C.
Knowledge of wood drying potential is relevant in forestry and biomaterials technology field, being directly related with timber transport, lumber properties, charcoal yield and pulping process. Using mixed models approach by REML-BLUP procedure, we aimed to evaluate the moisture content loss potential among different eucalypt genotypes, by means of genetic correlations, heritabilities, coefficients of variation and determination of wood air-drying over 154 drying days and in five tree stem heights. Moreover, we tested three possible auxiliary traits (Heartwood/Sapwood ratio, Log Circumference, and Basic Wood Density) for indirect selection on wood air-drying rate. The highest air-drying heritabilities occurred at the two most basal stem heights and only after the 98th day. However, genetic correlations across the drying measurements were considerably high from day 42. The three auxiliary traits demonstrated potential for indirect selection, suggesting the possibility of integrating wood air-drying to future Eucalyptus sp. breeding programs. There is no need to wait for industrial moisture content to carry out genetic evaluation. Besides, perform selection at trees basal region is the safest way to improve the air-drying rate of genotypes.
High-performance prediction of macauba fruit biomass for agricultural and industrial purposes using artificial neural networks
(Industrial Crops and Products, 2017-12-01) Castro, Carla Aparecida de O.; Resende, Rafael T.; Kuki, Kacilda N.; Carneiro, Vinícius Q.; Marcatti, Gustavo E.; Cruz, Cosme Damião; Motoike, Sérgio Y.
Biomass estimation plays of crucial role in agriculture and agro-based industries. The macauba, Acrocomia aculeata (Jacq.) Lood., ex Mart., is a palm species that has been a focal point for research and development of an alternative biomass-bioenergy crop for the tropics. The macauba fruit components (exocarp, mesocarp, endocarp and seed/kernel) present different constitutional characteristics and their biomass determination, by traditional methods, is labor-consuming. Therefore, the validation of procedures that can streamline this process is relevant, since it can reduce costs and time for both breeding programs and industries. This study tested the efficacy of Artificial Neural Networks (ANN) on biomass prediction of the macauba fruit components by comparing it to the multiple linear regression method. The data used came from fruits collected in 18 localities, distributed throughout the state of Minas Gerais, Brazil. According to their provenance, the matrices were clustered into two groups with the k-means method for posterior ANN cross-validation. Each group was interchangeably used for both training and validation purposes. The ANN was more efficient than multivariate linear model in the predictions of dry weight of the fruit́s four components and oil content of the mesocarp and seed. As for variables related to dry weight, ANN reached 98% predictive accuracy (i.e., 98% accuracy of the value predicted by the network), and for variables related to oil contents, accuracy was around 90%. Additionally, non-invasive measurements of the fruit (i.e., low-cost and low-time measurement variables) were adequate enough to predict most of the variables of interest. These results show the ANN's prediction potential, saving time and efforts for the consolidation of macauba as a crop.
Iron ore industry emissions as a potential ecological risk factor for tropical coastal vegetation
(Environmental Management, 2008-03-05) Kuki, Kacilda N.; Oliva, Marco A.; Pereira, Eduardo G.
In the coastal zone of the Espírito Santo state, Brazil, fragments of restinga, which form a natural ecosystem, share their space with an increasing number of iron ore industries. The iron ore dust and SO2 originating from the industry processing activities can interfere with the vegetation of the adjacent ecosystems at various levels. This study was undertaken in order to evaluate the effects of industry emissions on representative members of the restinga flora, by measuring physiological and phenological parameters. Foliar samples of Ipomoea pes caprae, Canavalia rosea, Sophora tomentosa, and Schinus terebinthifolius were collected at three increasing distances from an ore industry (1.0, 5.0, and 15.0 km), and were assessed for their dust deposition, chlorophyll, and Fe content. Phenological monitoring was focused on the formation of shoots, flowers, and fruits and was also performed throughout the course of a year. The results showed that the edaphic characteristics and the mineral constitutions of the plants were affected by industry emissions. In addition, the chlorophyll content of the four species increased with proximity to the industry. Phenological data revealed that the reproductive effort, as measured by fruit production, was affected by emissions and S. tomentosa was the most affected species. The use of an integrative approach that combines biochemical and ecological data indicates that the restinga flora is under stress due to industry emissions, which on a long-term basis may put the ecosystem at risk.
Key leaf traits indicative of photosynthetic plasticity in tropical tree species
(Trees, 2015-02) Anjos, Letícia dos; Oliva, Marco A.; Kuki, Kacilda N.; Ventrella, Marília C.; Galvão, Mayra F.; Mielke, Marcelo S.; Pinto, Luiz R. M.
Information about light tolerance and photosynthetic plasticity of indigenous tropical tree species is still limited, particularly information of first years of plants’ development. In this study, we evaluated the adjustments in response to different light environments of 25 leaf traits most commonly assessed in studies on light acclimation of photosynthesis in current literature. This evaluation was used to investigate the photosynthetic plasticity on young plants of five tropical tree species belonged to different successional groups. All the species are commonly used in forest restoration programs in Brazil. Plants were grown for 6 months under different light conditions simulating environments that could exist due to variation in naturally occurring canopy openings of secondary tropical forests. The level of adjustment on leaf traits to environmental conditions was calculated via a plasticity index. The relation between leaf trait adjustments and species photosynthetic plasticity was investigated by multivariate Biplot analyses. We selected the seven most explicative leaf traits of the photosynthetic plasticity of the studied species in response to different light environments: dark respiration rate (R d), Rubisco carboxylation capacity (V cmax), total chlorophyll content (ChlT), contribution of spongy parenchyma (%SP), contribution of leaf collenchyma tissue (%C), chlorophyll parenchyma thickness (PP/SP) and specific leaf area (SLA). Based on the selected traits, we identified the traits most related to high plasticity (V cmax, PP/SP, %SP, %C and SLA) and low plasticity (V cmax, R d and ChlT) and grouped species into three different patterns of photosynthetic plasticity. Our plasticity grouping was not correlated with species successional classification, indicating the importance of including physiological features related to light tolerance in species successional classifications. This work provides complementing information to traditional species successional groupings and to our current ability to select species for enrichment planting on restoration efforts.
Mating system and genetic composition of the Macaw Palm (Acrocomia aculeata): implications for breeding and genetic conservation programs
(Journal of Heredity, 2016-11) Lanes, Éder C. M.; Motoike, Sérgio Y.; Kuki, Kacilda N.; Resende, Marcos D. V.; Caixeta, Eveline T.
Acrocomia aculeata (Arecaceae), a palm endemic to South and Central America, is a potential oil crop. Knowledge of the mating system of this species is limited to its reproductive biology and to studies using molecular markers. The present study analyzed genetic diversity between its developmental stages and determined its prevailing mating system in order to support genetic conservation and breeding programs. We tested 9 microsatellite markers in 27 mother trees (adult plants) and 157 offspring (juvenile plants) from the southeastern region of Brazil. Heterozygosity levels differed between the 2 studied life stages, as indicated by the fixation index of adult and juvenile trees, suggesting that selection against homozygotes occurs during the plant life cycle. The mating system parameters analyzed indicate that A. aculeata is predominantly outcrossing (allogamous). However, its low levels of selfing suggest that there is individual variation with regard to self-incompatibility, which can be a survival strategy in isolated or fragmented habitats. Deviations in variance effective size were detected because of high mating rates among relatives and correlated matings. These findings indicate that the main source of inbreeding results from biparental inbreeding in the population and that the progenies are predominantly composed of full-sibs. The information provided by this study on the ecology and reproduction dynamics of A. aculeata should be useful to both breeding and genetic conservation programs, allowing the development of more precise mathematical models and the estimation of the appropriate number of mother trees for seed collection.