Summary
In recent years, the popularity of X-ray computed tomography (CT), as a non-destructive imaging technique, has continued to expand in various research domains. In wood research, X-ray CT has proven to be useful for three-dimensional (3D) structural studies investigating the complex tissues of trees. Wood formation (i.e., xylogenesis) initiates in the cambium and a narrow zone of subsequent differentiation, both of which play key roles in plant growth and development. However, the dynamics of xylogenesis in eucalypts remain relatively poorly understood, in large part due to challenges in sampling, imaging, and characterizing the cambium. Therefore, the aim of this study was to present a workflow to evaluate the feasibility of using X-ray CT to characterize and quantify the structural properties of the cambium in eucalypts. The growth responses of Corymbia hybrid seedlings, exposed to either irrigated or droughted conditions, was investigated by monitoring the structural development of the cambium. To track microstructural changes in the cambium, the same seedlings were imaged with X-ray micro-CT (μCT) one day before the treatments and again six days after the respective treatments. After the last X-ray μCT scan, X-ray nano-CT was also applied. Using image analysis techniques, the morphological characteristics of the cambium could be determined. X-ray μCT displayed a larger, thicker cambial zone in irrigated plants, while a much thinner cambium was visible in droughted seedlings. X-ray nano-CT revealed that droughted plants were associated with a significantly (
Summary
Studying biochemical variation in reaction wood is needed to understand the nature of reaction wood formation and the physiology of trees. The activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX)) was studied in normal wood (NW) and reaction wood (RW) (opposite wood (OW) and tension wood (TW)) in the bole of poplar trees (Populus alba L.). Four-year-old trees were induced to produce reaction wood by forced bending. The activity of antioxidant enzymes was studied with repeated sampling during a growing season. The results showed that total protein content and antioxidant enzymes are sensitive to mechanically induced stress. TW and OW showed higher activity of enzymes than NW as well as higher amounts of total protein. OW showed a higher concentration of CAT and SOD than TW. APX was more active than GPX in both TW and OW. In addition to mechanical stress, the effect of other climate factors was observed in the reactive oxygen species accumulation.