Tr Aditions and Perspec Tives Plant Anatomy

МОСКОВСКИЙ ГОСУДАРСТВЕННЫЙ УНИВЕРСИТЕТ ИМЕНИ М.В. ЛОМОНОСОВА БИОЛОГИЧЕСКИЙ ФАКУЛЬТЕТ PLANT ANATOMY: TRADITIONS AND PERSPECTIVES Международный симпозиум, АНАТОМИЯ РАСТЕНИЙ: посвященный 90-летию профессора PLANT ANATOMY: TRADITIONS AND PERSPECTIVES AND TRADITIONS ANATOMY: PLANT ТРАДИЦИИ И ПЕРСПЕКТИВЫ Людмилы Ивановны Лотовой 1 ЧАСТЬ 1 московский госУдАрствеННый УНиверситет имени м. в. ломоНосовА Биологический факультет АНАТОМИЯ РАСТЕНИЙ: ТРАДИЦИИ И ПЕРСПЕКТИВЫ Ìàòåðèàëû Ìåæäóíàðîäíîãî ñèìïîçèóìà, ïîñâÿùåííîãî 90-ëåòèþ ïðîôåññîðà ËÞÄÌÈËÛ ÈÂÀÍÎÂÍÛ ËÎÒÎÂÎÉ 16–22 ñåíòÿáðÿ 2019 ã. Â двуõ ÷àñòÿõ ×àñòü 1 МАТЕРИАЛЫ НА АНГЛИЙСКОМ ЯЗЫКЕ PLANT ANATOMY: ТRADITIONS AND PERSPECTIVES Materials of the International Symposium dedicated to the 90th anniversary of Prof. LUDMILA IVANOVNA LOTOVA September 16–22, Moscow In two parts Part 1 CONTRIBUTIONS IN ENGLISH москва – 2019 Удк 58 DOI 10.29003/m664.conf-lotova2019_part1 ББк 28.56 A64 Издание осуществлено при финансовой поддержке Российского фонда фундаментальных исследований по проекту 19-04-20097 Анатомия растений: традиции и перспективы. материалы международного A64 симпозиума, посвященного 90-летию профессора людмилы ивановны лотовой. 16–22 сентября 2019 г. в двух частях. – москва : мАкс пресс, 2019. ISBN 978-5-317-06198-2 Чaсть 1. материалы на английском языке / ред.: А. к. тимонин, д. д. соколов. – 308 с. ISBN 978-5-317-06174-6 Удк 58 ББк 28.56 Plant anatomy: traditions and perspectives. Materials of the International Symposium dedicated to the 90th anniversary of Prof. Ludmila Ivanovna Lotova. September 16–22, 2019. In two parts. – Moscow : MAKS Press, 2019. ISBN 978-5-317-06198-2 Part 1. Contributions in English / Ed. by A. C. Timonin, D. D. Sokoloff. – 308 p. ISBN 978-5-317-06174-6 Издание доступно на ресурсе E-library ISBN 978-5-317-06198-2 © Авторы статей, 2019 ISBN 978-5-317-06174-6 (Часть 1) © Биологический факультет мгУ имени м. в. ломоносова, 2019 © ооо «мАкс пресс», 2019 BASIC PRINCIPLES OF THE CONDUCTIVE APPARATUS STRUCTURE IN WOODY PLANTS1 L.I. LOTOVA † Prof. Sergey I. Vanin used to define the wood science as a science about the wood consumer properties and methods to study them. Vanin’s definition means that technological issues are the base for the wood science as determined by great economic importance of this tissue. However, I do believe that the principal aspect of the wood science is biological one, and wood investigations are just a constitu- ent part of the complex morphological and anatomical research of woody plants. Such a research should primarily involve studies of wood development, wood structure and aging, correlations of its physical and mechanical features with the forest type, environments etc. Every plant is a very complex integrated structural and functional system, whose all the organs and tissues are closely interrelated. The cambium governs the rate of wood formation and wood structural features which were fixed during the evolution. The wood and the bast jointly constitute the complete conductive apparatus to transport mineral and organic aqueous solutes through the plant body. The bast is a principal component of the bark. Therefore, I believe that modern wood science should not deal with only the wood. This science should cover the bark as well, especially since the latter is also quite usable. However, the bark is usually just a waste of the wood industry because of our squandering. It is almost never used in economics despite of some elaborated valuable technologies of bark processing. A need for bark investigations was emphasized by Karl Mercklin, the first Russian researcher of the bark. In his “Anatomy of the stem bark and wood of forest trees and shrubs of Russia” published in 1857 he wrote that “the wood alone is insufficient for distinguishing similar genera of trees and even less for distinguishing between their species… Not only the bark but the very elementary bodies, i.e. cells and vessels should be examined under the potent microscope to comprehend completely the inner structure and properties of the stems of forest trees”. When summarizing his scientific and educational activity, illustrious Prof. Ivan P. Borodin who taught botanical disciplines in full their entirety at the St. Petersburg Forestry Institute for many years, said that he could not vouch that progressing specialization in science would not cause the wood structure and the bark structure to be taught by different professors in 21st century. However, we are in opposite position by the end of 20th century. There is the wood that has grabbed all attention of plant anatomists, while the bark has still 1 A talk delivered at Ivanov Readings on late 1980s. Unpublished Russian manuscript trans- lated by A.C. Timonin. 3 been ignored. Only a few Russian botanists are interested in exploring bark. The situation is quite the same abroad. But why is bark investigation necessary within the framework of wood science? The main reason is that the bark greatly influences the wood development, but it also affects the wood structure. The bark is understood as a heterogeneous complex of tissues outside the cambium. Plant physiology data show that the inner bark accumulates hormones of auxin group in autumn to stimulate cambium activity next spring. Everton, Kozlowski & Davis conducted an interesting experiment in 1972. They made girdling of the trunks of maple trees and other tree species without damaging the cambium. Debarked areas of the trunks were waxed. The wood was then periodically sampled from both injured and intact areas of the trunks. If the girdling was made in win- ter when the cambium was dormant, it prevented spring resumption of cambium activity in 50% debarked areas of the trunks, though rare tangential divisions of the cambium fusiform initials were noted. The cambium functioned normally in the intact areas of the same trunks. If the girdling was made in summer in July and August when the conductive tissues were differentiating in the trunk, the wood cells were prevented from developing their secondary cell walls whereas the cambium fusiform initials were provoked to divide tangentially. Both results caused increased parenchymatization of the wood, i.e. significant changing of wood structure and consequently wood properties. Thus, the bark or rather its bast indirectly affects the wood structure through influencing cambium activity. Close physiological connection between the bark and the wood is caused not only by the hormones but also by the presence of radial communications in the stem in the form of the radial rays. The bark and the wood are rather similar in their topographic differentiation into functional zones. The bast zone adjacent to the cambium which corresponds to one growth ring is termed ‘conducting’. The sapwood is its counterpart in the wood. It is also adjacent to the cambium but usually includes several growth rings. The sapwood rarely consists of only one growth ring. The non-conducting bast zone is outside the conducting one and corresponds either to the heartwood or to the ripe wood, the latter one being less hydrated than the sapwood. My speculations on analogy of the topographic patterns of bark and wood could be considered superficial, especially as there are woody species that have neither heartwood nor ripe wood. However, this analogizing of the bark and wood topographies seems quite acceptable as it shows general principles of age changes of both tissues associated with loss of their conductivity. But such changes are amplified outwards in the bark and terminate with the rhytidome formation. The bark is more complex functionally than the wood. It maintains the de- scending transport and also accumulates waste metabolites and removes them out 4 of the plant body due to shedding off outer layers of the rhytidome. The bark is the first to react to the mechanical damages and pathogen invasions. The plant blocks damager intruding by means of additional cork development in the bark or in some other ways including bark cell sclerification and resin production (in conifers). Histological compositions of the bark and wood are quite similar as composed by 2 systems. The vertical (axial) system is represented by prosenchymatous cells; the transverse (radial) system is represented by the bast and wood rays. The com- ponents of the axial system originate from the cambium fusiform initials and those of the transverse system derive from the cambium ray initials. Constituents of the bast and wood are combined not only topographically but also functionally as they compose 3 systems. The conductive system of the wood includes solitary cells termed ‘tracheids’ and/or uniseriate longitudinal files of end-perforated cells termed ‘tracheas’ or ‘vessels’. The conductive system of the bast consists either of the sieve-cells, e.g. in conifers, or of the sieve-tubes; the former resemble the tracheids, and the latter are comparable with the vessels in the structure of the end walls of their segments. The supporting system of the coniferous woods consists of the late-wood (summer wood) tracheids, which are narrower and less-pitted than the early-wood (spring wood) tracheids. The most advanced supporting system is inherent in the hardwood species which have fiber tracheids and specific wood fibers also reported to as libriform fibers. There are also bast fibers, but only in some species. The sclereids very often develop in the bast; some of them look like the bast fibers, e.g. fiber sclereids of larch bast, but they differ from the genuine bast fibers in their origin. The bast fibers directly differentiate from the cambium derivatives and have few- layered walls, whereas the sclereids develop from the bast parenchyma cells via sclerification; they are varied in shape and have multilayered pitted walls. The woody species comprise three groups according to the type of supporting system of their bast, viz. 1) those with only bast fibers (e.g. linden, chestnut), 2) those with both bast fibers and sclereids (e.g.

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