Aerial Root Structure and Its Significance for Function in Dracaena draco
- PDF / 2,461,071 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 90 Downloads / 183 Views
Aerial Root Structure and Its Significance for Function in Dracaena draco Joanna Jura‑Morawiec1 · Pedro Monroy2 · Aguedo Marrero2 · Mirela Tulik3 Received: 26 June 2019 / Accepted: 8 May 2020 © The Author(s) 2020
Abstract The dragon tree, Dracaena draco, is a vulnerable species. In response to stress it forms aerial roots (AR). Although the exact function of these AR is unknown, it has been the subject of speculation on the basis of morphological observations. This study aims to investigate the structural organization of the D. draco AR compared to the background of the structure of its soil roots. The material was obtained from the collection of dragon trees growing at Jardín Botánico Canario "Viera y Clavijo" on Gran Canaria as well as from the plants obtained from the commercial nursery. Based on hand-cut sections and permanent preparations, we analysed (a) AR structure along its length encompassing the active and dormant state of the AR tip, as well as (b) the general structural organization of the soil roots (stem-borne, lateral and fine roots). We observed that AR are similar to the lateral soil roots in terms of the distribution of the primary and secondary tissues. AR are protected by rhizodermis and/or hypodermis which undergoes metacutization during the transition from the active to dormant state of the AR tip. Chloroplasts are present in cortical parenchyma cells along the entire length of the AR. The obtained anatomical findings are discussed in the context of the putative AR functions. Keywords Anatomy · Arborescent monocots · Primary growth · Secondary growth · Stress
Introduction Dracaena draco (Asparagaceae), a monocotyledonous dragon tree, is a vulnerable species (IUCN 2019) with very rare wild populations limited to the Canaries, Morocco, Cape Verde and Madeira (Marrero et al. 1998; Marrero and Almeida-Perez 2012). Studies regarding the structure of this plant date back the turn of the 19th and twentieth centuries (Scott and Brebner 1893; Cheadle 1937; Tomlinson and Zimmermann 1969) and have recently attracted the attention of scientists once again. New information has * Joanna Jura‑Morawiec [email protected] 1
Polish Academy of Sciences Botanical Garden–Centre for Biological Diversity Conservation in Powsin, Prawdziwka 2, 02‑973 Warsaw, Poland
2
Jardín Botánico Canario “Viera y Clavijo” – Unidad Asociada CSIC, Cabildo de Gran Canaria, Camino al palmeral 15, 35017 Las Palmas de Gran Canaria, Spain
3
Department of Forest Botany, Warsaw University of Life Sciences – WULS, Nowoursynowska 159, 02‑776 Warsaw, Poland
been gathered on the micromorphology and anatomy of its leaves (Klimko and Wiland-Szymańska 2008; Nadezhdina et al. 2015; Klimko et al 2018), leaf contribution to water collection (Nadezhdina and Nadezhdin 2017), intricacies of the stem vascular system (Carlquist 2012; Jura-Morawiec and Wiland-Szymańska 2014; Jura-Morawiec 2015, 2017) and secretion of a red resin named dragon’s blood (JuraMorawiec and Tulik 2015, 2016). Despite the progressive research, our current knowledg
Data Loading...
