Anatomia comparada da madeira de Cordia trichotoma (Vell.) Arráb. ex Steud. (Boraginaceae) proveniente de sementes de duas procedências e análise dos anéis de crescimento

Abstract

Wood characteristics are directly influenced by environmental and genetic factors. However, some genetic features have high heritability, low phenotypic plasticity and are independent of the environmental conditions in which they operate. This study aimed to compare the wood anatomy of Cordia trichotoma that were planted in the same place, but with seeds of two provenances (Bauru e Piracicaba), and to correlate growth rings width with precipitation and temperature. Twelve discs were collected of this species in the Experimental Station of Luiz Antônio, SP, and six from each provenance (Bauru and Piracicaba). For microscopic analysis of the stem histological sections were made in the conventional three planes (cross, tangential longitudinal and radial longitudinal) were obtained and permanent histological slides were made according to standard techniques in wood anatomy. Woody fragments were dissociated and with it slides were made. We analyzed the qualitative and quantitative anatomical wood features. For analysis of growth rings, the twelve disks had their cross sections polished manually on a series of sandpaper and the growth rings were marked with the stereomicroscope. The measurement of the growth rings width was achieved using the image analysis software Image-Pro Plus. To check the quality and accuracy of the data held on the cross-dating measurements with the help of free software COFECHA and, the rings width was transformed into series allowing synchronization and better interpretation of the data. After synchronization, the data were analyzed with the use of free software ARSTAN for disposal of the growing trends and getting the residual chronology. Precipitation and temperature analyses were performed using Pearson's correlation in Microsoft Office Excel. Qualitatively, the wood anatomy was similar between the two provenances, and the only difference between then was the presence of geniculate vessel in Bauru. Quantitatively, there was significant difference in vessel diameter, fiber diameter, lumen diameter of fibers and parenchyma per mm2, and the averages were higher for provenance Piracicaba. The number of vessels per group was significantly higher in Bauru. The presence of geniculate vessels, smaller vessels diameter and larger number of vessels per group in the provenance of Bauru suggest greater water security in the wood of these trees, or possibly genetic information of the place of origin of the seed are related to these variations. Growth rings analysis, there was a significant positive correlation between the growth rings widths and the variable temperature in the months from August to October (winter and early spring), at which time the temperature is milder and a negative and significant correlation between the growth rings widths and variable rainfall in April, the month the levels of rainfall decreases sharply.