Long-term in situ sap flow monitoring in a mature Dracaena cinnabari tree on Socotra
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Dracaena cinnabari is a relict of the remote Socotra Island (Yemen) where it grows at higher altitudes with the frequent occurrence of fogs. D. cinnabari as the only representative of the dragon tree group creates woodlands and forests on the Socotra Island. It is not clear what mechanisms allow this relict arborescent monocot to survive harsh climate and poor soil of karst rocks there. In this work, we conducted long-term sap flow monitoring in the stem and roots of the mature D. cinnabari plant during the driest period of year between two regular monsoons. We aimed to reveal plant responses to a range of environmental conditions and to understand mechanisms of drought survival by this woody monocot. Several following features of sap flow performance were found: high flow sectoriality in the stem and in roots corresponding to the intensity of insolation, free lateral flow, higher stem integrity compared to roots, internal storage replenishment from the fog followed by increased transpiration presumably from the refilled stem storage. Results indicate that in studying the sap flow dynamics in the mature D. cinnabari tree, plant water storage should be included in the analyses in addition to soil water availability and intensity of evaporating demands. The ability to replenish succulent woody organs from atmospheric water and to survive long periods of drought from the internal supply distinguishes the behavior of this short-rooted arborescent monocot from the known strategies of deep-rooted trees in arid areas.
KeywordsArborescent monocot Fog Heat field deformation Internal plant storage Multi-point sensor Lateral flow Radial and circumferential variations Transpiration
The authors are grateful to the local authority of Socotra for the permission to conduct sap flow measurements on the mature D. cinnabari tree, to local inhabitants for their general help during the long-term sap flow monitoring and to Zdenek Cermak and Petr Nemec for the occasional equipment control. We also thank the anonymous reviewers and the Associated Editor for their constructive and thoughtful comments and suggestions.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
- Adolt R, Maděra P, Abraham J, Čupa P, Svátek M, Matula R, Šebesta J, Čermák M, Volařík D, Koutecký T, Rejžek M, Šenfeldr M, Veska J, Habrová H, Čermák Z, Němec P (2013) Field survey of Dracaena cinnabari populations in Firmihin, Socotra Island: methodology and preliminary results. J Landsc Ecol 6:7–34. https://doi.org/10.2478/jlecol-2014-0001 CrossRefGoogle Scholar
- Attorre F, Francesconi F, Taleb N, Scholte P, Saed A, Alfo M, Bruno F (2007) Will dragonblood survive the next period of climate change? Current and future potential distribution of Dracaena cinnabari (Socotra, Yemen). Biol Conserv 138:430–439. https://doi.org/10.1016/j.biocon.2007.05.009 CrossRefGoogle Scholar
- Brown G, Mies BA (2012) Vegetation ecology of Socotra. Plant and Vegetation 7. Springers, Dordrecht, Heidelberg, New York, LondonGoogle Scholar
- Buček A, Habrová H, Maděra P, Král K, Modrý M, Lacina J, Pavliš J (2015) Application of the Czech methodology of biogeographical landscape differentiation in geobiocoenological concept – examples from Cuba, Tasmania and Yemen. J Landsc Ecol 8:51–67. https://doi.org/10.1515/jlecol-2015-0014 CrossRefGoogle Scholar
- Culek M, Král K, Habrová H, Adolt R, Pavliš J, Maděra P (2006) Socotra’s annual weather pattern. In: Cheung C, DeVantier L, Van Damme K (eds) Socotra - a natural history of the islands and their people. Odyssey books and guides, Airphoto international ltd, Hong Kong, pp 42–45Google Scholar
- Gentry HS (1982) Agaves of continental North America. In: Univ. Arizona Press, TucsonGoogle Scholar
- Habrová H (2004) Geobiocoenological differentiation as a tool for sustainable land-use of Socotra Island. Ekol Bratislava 23:47–57Google Scholar
- Habrová H, Čermák Z, Pavliš J (2009) Dragon’s blood tree – threatened by overmaturity, not by extinction: dynamics of a Dracaena cinnabari woodland in the mountains of Soqotra. Biol Conserv 142:772–778. https://doi.org/10.1016/j.biocon.2008.12.022
- Maděra P, Habrová H, Šenfeldr M, Kholová I, Lvončík S, Ehrenbergerová L, Roth M, Nadezhdina N, Němec P, Rosenthal J, Pavliš J (2018) Growth dynamics of endemic Dracaena cinnabari Balf. f. Seedlings in situ on Socotra Island suggest essential elements for a conservation strategy. Biologia https://doi.org/10.2478/s11756-018-0152-0
- Martorell C, Ezcurra E (2002) Rosette scrub occurrence and fog availability in arid mountains of Mexico. J Veg Sci 13:651–662. https://doi.org/10.1658/1100-9233(2002)013[0651:RSOAFA]2.0.CO;2Google Scholar
- Miller AG, Cope TA (1996) Flora of the Arabian peninsula and Socotra. University Press, EdinburghGoogle Scholar
- Monteith JL, Unsworth MH (1990) Principles of environmental physics. Edward Arnold, LondonGoogle Scholar
- Nadezhdina N, Nadezhdin V (2017) Are Dracaena nebulophytes able to drink atmospheric water? Environ Exp Bot 139:57–66. https://doi.org/10.1016/j.envexpbot.2017.04.005
- Nadezhdina N, Čermák J, Nadezhdin V (1998) Heat field deformation method for sap flow measurements. In: Čermák J, Nadezhdina N (eds) Proceedings of the 4th Int. workshop on measuring sap flow in intact plants. Publishing house of Mendel University, Brno, pp 72–92Google Scholar
- Udvardy MDF (1975) A classification of the biogeographical provinces of the world. IUCN Occasional Paper No. 18. Morges, SwitzerlandGoogle Scholar
- Zimmermann MH, Tomlinson PB (1970) The vascular system in the axis of Dracaena fragrans (Agavaceae) 2. Distribution and development of secondary tissue. J Arnold arboretum 51:478–491Google Scholar