Caracterização fisiológica e produção de metabólitos secundários em Achillea millefolium L. após aplicação de quitosana

Elicitation with chitosan is a tool used to improve the responses of plant defense by inducing secondary metabolism routs. In addition, the adequate application of this elicitor on medicinal plants can promote the increase of major components in the composition of the oil. However, we lack information concerning which are the main physiological processes responsible for the changes in the composition of the oil. Thus, we aimed at evaluating the action of chitosan and determine an ideal concentration for optimizing the production of essential oil in Achillea millefolium L. and the changes in the physiological processes responsible for this increase. The research was conducted in greenhouse of the Plant Physiology sector of the Universidade Federal de Lavras (UFLA) with A. millefolium plants. The treatments consisted of control (water); acetic acid solvent (with no elicitor); and chitosan in the concentrations of 2, 4 and 6 g L -1 . The measurements of growth, gas exchange, enzyme activity of the antioxidant system and phenylalanine ammonia lyase (PAL), in addition to the production and composition of the essential oil. We verified that the application of chitosan promoted decrease in plant growth. However, the concentration of 4 g L -1 of chitosan induced an increase in the content and yield of the essential oil. In the oil, there was predominance of sesquiterpenic compounds, including the major compounds borneol, β-caryophyllene, β-cubebene, α-farnesene and chamazulene. The elicitation with chitosan at 4 g L -1 promoted an increase of the photosynthetic rate, activity of the antioxidant system and of PAL, however, this increase occurred in short-term, only in the first days after elicitation.

Estudos químicos e anatômicos de cascas de clones de Eucalyptus

The barks generated from the wood processing industries are wastes generated in significant quantities, becoming interesting to have basic studies of their anatomical and chemical properties in order to make better use of this material. This study aimed to carry out anatomical studies, chemical and tannins from the barks of commercial clones of Eucalyptus. For this, permanent histological slides for anatomical characterization and percentage of cellular elements were prepared; and cellular elements were dissociated for biometry of the elements. The analyses were related to chemical extractives, ash, lignin, suberin, sugars, phenols, tannins, flavonoids and antioxidant activity of the extracts. The tannins were extracted in pure water and with water mixed with sodium sulfite, and were subsequently evaluated the properties by FT-IR. It was verified by the anatomical characterization and chemical quantification, the similarity between the clones. Regarding the biometrics of cellular elements, statistically significant differences were not observed for the following parameters: length and diameter of sieve tube, axial parenchyma diameter, and rays hight. The yield of condensed tannins and Stiasny index for studied clones are low, showing the infeasibility of using bark for the extraction of tannins to produce adhesives, however tannins and other bioactive phenolic compounds can be used in the pharmaceutical and cosmetics sectors due to its antioxidant potential. The spectrum of tannins is the same as the one found the literature. Due to the high yield of verified sugar, (around 46,68%) sugars are potencial products, with a high yield of glucose , it is interesting for application in biorefinery.

Caracterização fisiológica de genótipos de soja submetidos ao estresse salino

Salinity, ever present in agricultural soils, affects plant productivity. However, there are species more tolerant than others, and the study of response mechanisms to salinity is necessary in order to elucidate which responses are correlated with tolerance to salinity. Thus, we aimed at physiologically characterizing two Glycine max L. genotypes concerning saline stress, and identify which variables are more correlated with tolerance to salinity. For this, plants of cultivars AS 3730 and M 8372 were submitted to three saline concentrations (0, 50 and 100 mM), having sampled 0, 8 and 16 days. We conducted analysis for growth, enzymatic and non-enzymatic antioxidant metabolism, photosynthesis beyond the content of chlorophyll a and b, carotenoids, total soluble sugars, reducing sugars, proteins and proline. A results, cultivar M 8372 presented better growth, higher antioxidant enzyme activity and higher content of antioxidants such as ascorbate and carotenoids, when compared to cultivar AS 3730. In addition, cultivar M 8372 also presented lower levels of lipid peroxidation. However, cultivar AS 3730 obtained higher contents of proline, an osmoprotector and lower growth compromise when compared to its control. In conclusion, there is a differential response of the cultivars to salinity.