Abstract
Main conclusion Stump overgrowth may serve as a unique model for studying cellular reorganization and mechanisms responsible for cell polarity changes during the process of vascular tissue differentiation from initially unorganized parenchymatous cells. Cellular ordering and tissue reorganization during the overgrowth process of the transverse surfaces of Douglas fir stumps in forest stand was studied. At the beginning of stump overgrowth, the produced parenchymatous cells form an unorganized tissue. Particular parenchyma cells start arranging into more ordered structures which resemble rays. Application of digital image analysis software based on structure tensor was used. The analysis showed that at this stage of tissue development, cellular elements display a wide range of angular orientation values and attain very low coherency coefficients. The progress of the tissue differentiation process is associated with the formation of local regions with tracheids oriented circularly around the rays. This coincides with an increase in the range of angular orientations and greater values of coherency coefficients. At the most advanced stage of tissue development, with tracheids arranged parallelly in longitudinal strands, the degree of cell ordering is the highest what is manifested by the greatest values attained by coherency coefficients, and the narrow range of angular orientations. It is suggested that the ray-like structures could act as organizing centers in the morphogenetic field responsible for differentiation of the overgrowth tissue. The circular pattern of tracheids around rays in the initial phase of tissue development can be interpreted in terms of local rotation of the morphogenetic field which afterward is transformed into irrotational field. This transformation is noted by the presence of tracheids arranged parallelly in longitudinal strands. The possible involvement of a mechanism controlling cell polarity with respect to auxin transport is discussed.
Highlights
Plant morphogenesis includes all the processes involved in the development of an organism into its eventual form and structure (Wardlaw 1952)
The present studies showed that at the beginning of stump overgrowth the produced parenchymatous cells form an unorganized, irregular tissue, including particular parenchyma cells starting to arrange into more ordered structures resembling rays
The circular shape of tracheid-like cells, which were differentiated around the rays, may suggest that these cells can be considered as organizing centers responsible for the development of cambiallike cells in the morphogenetic field
Summary
Plant morphogenesis includes all the processes involved in the development of an organism into its eventual form and structure (Wardlaw 1952). Explaining the mechanisms responsible for the coordinated growth and differentiation at the various levels of organization, and enabling the development of an integrated form and structure characteristic for a given organism, are presently main aims of biological studies. Comprehensive investigations in this field involve various morphological, anatomical, cytological, physiological, molecular, and biophysical techniques as well as mathematical modeling (Gamborg et al 1973; Vasil and Vasil 1981; Murata and Orton 1987; Sujatha and Mukta 1996). Standard methods that are frequently used include analyses of cytodifferentiation and organogenesis in callus tissues, wounded organs, or tissues isolated in sterile cultures
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
