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Анатомическое исследование ареольного комплекса у представителей Mammillarieae (Cactaceae) в связи с формированием в этой трибе подобия типичной побеговой организациистатья
- Авторы: Озерова Л.В., Тимонин А.К.
- Сборник: Приношение Людмиле Ивановне Лотовой / Анатомия растений: традиции и перспективы. Материалы Международного симпозиума, посвященного 90-летию профессора Людмилы Ивановны Лотовой. 16–22 сентября 2019 г
- Редактор: Тимонин Александр Константинович
- Том: 2
- Год издания: 2019
- Издательство: ООО "МАКС Пресс"
- Местоположение издательства: Москва
- Первая страница: 207
- Последняя страница: 223
- DOI: 10.29003/m665.conf-lotova2019_part2
- Аннотация: TUBERCLE ANATOMY IN THE SERIES OF MEMBERS OF MAMMILLARIEAE (CACTACEAE) WHITH INCREASING SECONDARY SHOOT-LIKE BAUPLAN. The tubercles become more like the leaves in the series Mammillaria vetula ssp. gracilis – M. decipiens ssp. albescens – M. longimamma to culminate in Leuchtenbergia principis whose the longest triquetrous tubercles resemble the leaves of co-inhabiting Agave species (the plant resultantly simulates small agave). All these tubercles are of the same anatomical type, but those of L. principis have hypodermis of small cells with thickened pitted walls. The cortex highly exceeds the stele. The outer cortical chlorenchyma consists of oblique outward ascending rows of 3–8 short palisade cells. It is discontinuous in the tubercle tip. Larger longitudinally elongate cells with chloroplasts constitute the inner cortical parenchyma. Vascular plexus of thin bundles is in between these cortical tissues. The cortex is poorly delimited from the narrower stele whose parenchyma is hardly distinguishable from the inner cortical counterpart. The xylem of the stellar bundles is accompanied by the wide-band tracheids in the distal part of the tubercle. Number of these tracheids increases acropetally to give rise to terminal hydrocytic body which substitutes the stelar bundles. Mammillaria vetula has the largest specific obconic hydrocytic body in its ordinary small firm tubercles. Such a body takes up to distal third of the tubercle and makes it rigid. The cortical bundles mostly branch off the stelar ones in the basal part of tubercle and merge with the hydrocytic body in its tip. Leaf-like transformation of the tubercles is associated with reduction of specific size of the hydrocytic body therein up to the discontinuous mass in L. principis. Deeply reduced hydrocytic body makes the tubercles flexible in Mammillaria species, but they remain firm in L. principis due to rigid hypodermis. The more leaf-like is the tubercle, the more water-consuming are its tissues. Highly reduced hydrocytic body in the leaf-like tubercles shows that the wide-band tracheids it consists of are unimportant for water-supplying of the chlorenchyma and inner parenchyma of the tubercle cortex. The wide-band tracheids in mammillarias seem to load xylem with condensed water which is absorbed by the spines clustered on the tubercle tip. The concerned tubercles resemble the genuine terete leaves of Austrocylindropuntia subulata. Whether this similarity results from the complex nature of the tubercle derived from congenitally fused areola and the base of its subtending leaf, is to be explored. Anyway, the tubercle anatomy evolved allows the tubercle to transform into the leaf-like organ while keeping its anatomy nearly unaltered.
- Добавил в систему: Тимонин Александр Константинович