20 research outputs found
Teor e composição quÃmica do óleo essencial e crescimento vegetativo de Aloysia triphylla em diferentes espaçamentos e épocas de colheita
How to construct and use a simple device to prevent the formation of precipitates when using Sudan Black B for histology
What is the influence of ordinary epidermal cells and stomata on the leaf plasticity of coffee plants grown under full-sun and shady conditions?
What is the influence of ordinary epidermal cells and stomata on the leaf plasticity of coffee plants grown under full-sun and shady conditions?
Stomata are crucial in land plant productivity and survival. In general, with lower irradiance, stomatal and epidermal cell frequency per unit leaf area decreases, whereas guard-cell length or width increases. Nevertheless, the stomatal index is accepted as remaining constant. The aim of this paper to study the influence of ordinary epidermal cells and stomata on leaf plasticity and the influence of these characteristics on stomata density, index, and sizes, in the total number of stomata, as well as the detailed distribution of stomata on a leaf blade. As a result, a highly significant positive correlation (R²a = 0.767 p < 0.001) between stomatal index and stomatal density, and with ordinary epidermal cell density (R²a = 0.500 p < 0.05), and a highly negative correlation between stomatal index and ordinary epidermal cell area (R²a = -0.571 p < 0.001), were obtained. However in no instance was the correlation between stomatal index or stomatal density and stomatal dimensions taken into consideration. The study also indicated that in coffee, the stomatal index was 19.09% in shaded leaves and 20.08% in full-sun leaves. In this sense, variations in the stomatal index by irradiance, its causes and the consequences on plant physiology were discussed
What is the influence of ordinary epidermal cells and stomata on the leaf plasticity of coffee plants grown under full-sun and shady conditions?
Stomata are crucial in land plant productivity and survival. In general, with lower irradiance, stomatal and epidermal cell frequency per unit leaf area decreases, whereas guard-cell length or width increases. Nevertheless, the stomatal index is accepted as remaining constant. The aim of this paper to study the influence of ordinary epidermal cells and stomata on leaf plasticity and the influence of these characteristics on stomata density, index, and sizes, in the total number of stomata, as well as the detailed distribution of stomata on a leaf blade. As a result, a highly significant positive correlation (R²a = 0.767 p < 0.001) between stomatal index and stomatal density, and with ordinary epidermal cell density (R²a = 0.500 p < 0.05), and a highly negative correlation between stomatal index and ordinary epidermal cell area (R²a = -0.571 p < 0.001), were obtained. However in no instance was the correlation between stomatal index or stomatal density and stomatal dimensions taken into consideration. The study also indicated that in coffee, the stomatal index was 19.09% in shaded leaves and 20.08% in full-sun leaves. In this sense, variations in the stomatal index by irradiance, its causes and the consequences on plant physiology were discussed
The problem of borderline hemoglobin A2 levels in the Screening for β-thalassemia carriers in Sardinia.
Background: The increase in HbA2 is the most important parameter for the identification of thalassemia carriers. However, in routine screening for hemoglobinopathies, some cases are difficult to classify because the level of HbA2 is not typically elevated. In this work, we report the results of a molecular investigation on a cohort of subjects with borderline HbA2. Methods: All subjects with a beta-thalassemia carrier partner and a borderline percentage level of HbA2 were investigated for the presence of a pathological mutation in the beta-globin gene. All negative subjects were screened for both the KLF1 mutation and the presence of alpha alpha alpha/ or alpha alpha alpha alpha/ alleles. The subjects with reduced MCV and/or MCH were also screened for deletional and nondeletional alpha-globin gene defects. Results: Various beta-globin mutations and KLF1 gene defects are the most common genetic determinants responsible for this phenotype in our population. Conclusion: KLF1 mutations are important in a screening program for hemoglobinopathies. An increase in HbF in association with borderline HbA2 levels is a useful but not exclusive marker that suggests the investigation of this gene. On the basis of our findings, we are able to suggest the molecular procedure to use in a population characterized by a high prevalence of thalassemia carriers