TY - JOUR

T1 - Modular growth and functional heterophylly of the phreatophyte Ziziphus lotus

T2 - A trait-based study

AU - Torres-García, M. Trinidad

AU - Salinas-Bonillo, Maria Jacoba

AU - Pacheco-Romero, Manuel

AU - Cabello, Javier

N1 - Funding Information: We thank Mar?a Rodr?guez, Ester Mora and Alba Rodr?guez, from the University of Almer?a (UAL), who assisted with laboratory and field work. We also thank Emilio Gonz?lez Miras, from the Environment and Water Agency of Andalusia, for his technical support in the field. We acknowledge the advice and assistance of Esmeralda Urea (UAL) in the use of the SEM for stomata visualization. This research was carried out in the framework of the LTSER Platform ?The Arid Iberian South East LTSER Platform - Spain (LTER_EU_ES_027)? and supported by the European project LIFE Adaptamed (LIFE14349 CCA/ES/000612), the Spanish Ecological Transition Ministry (through Biodiversity Foundation) project CO-ADAPTA (CA_CC_2016), and the RTI2018-102030-B-I00 project of the University of Almer?a (PPUENTE2020/001). The Spanish government supported M.T.T. with an FPU predoctoral fellowship (16/02214). Publisher Copyright: © 2021 The Authors. Plant Species Biology published by John Wiley & Sons Australia, Ltd on behalf of Society for the Study of Species Biology

PY - 2021/10

Y1 - 2021/10

N2 - The variation of plant functional traits, from the cell to the whole-plant level, is a central question in trait-based ecology with regard to understanding ecological strategies and adaptations that result from environmental drivers. Here, we analyzed whole-plant and leaf traits of the phreatophyte Ziziphus lotus (L.) Lam., a long-lived shrub that dominates one of the few terrestrial groundwater-dependent ecosystems (GDEs) in Mediterranean Basin drylands. We (a) assessed architectural traits and growth patterns, (b) analyzed leaf morpho-functional traits (specific leaf area [SLA] and stomata pore index [SPI]) and physiological traits (gas exchange rates), as well as their variations within individuals, and (c) evaluated temporal variations in modular growth (i.e., sequential iteration of structural units) between growing seasons and in leaf traits within seasons. Z. lotus' growth pattern was based on the repetition of modules composed of shoots (short and long) and branches (flowering and plagiotropic) that promoted a functional differentiation between vegetative and reproductive structures, respectively. We identified morpho-functionally distinct leaves (i.e., heterophylly) borne on different types of branches. Leaves on flowering branches had higher SLA and water use efficiency (WUEi), but lower SPI and transpiration rates than leaves on vegetative ones. We also observed trade-offs in the elongation of vegetative and flowering structures between growing seasons: the shorter the long shoots, the larger the flowering branches. The modular differentiation and heterophylly of Z. lotus might contribute to prioritizing the investment of resources of this phreatophyte, either for growth or reproduction, and could improve the efficiency in uptake and conservation of resources in drylands.

AB - The variation of plant functional traits, from the cell to the whole-plant level, is a central question in trait-based ecology with regard to understanding ecological strategies and adaptations that result from environmental drivers. Here, we analyzed whole-plant and leaf traits of the phreatophyte Ziziphus lotus (L.) Lam., a long-lived shrub that dominates one of the few terrestrial groundwater-dependent ecosystems (GDEs) in Mediterranean Basin drylands. We (a) assessed architectural traits and growth patterns, (b) analyzed leaf morpho-functional traits (specific leaf area [SLA] and stomata pore index [SPI]) and physiological traits (gas exchange rates), as well as their variations within individuals, and (c) evaluated temporal variations in modular growth (i.e., sequential iteration of structural units) between growing seasons and in leaf traits within seasons. Z. lotus' growth pattern was based on the repetition of modules composed of shoots (short and long) and branches (flowering and plagiotropic) that promoted a functional differentiation between vegetative and reproductive structures, respectively. We identified morpho-functionally distinct leaves (i.e., heterophylly) borne on different types of branches. Leaves on flowering branches had higher SLA and water use efficiency (WUEi), but lower SPI and transpiration rates than leaves on vegetative ones. We also observed trade-offs in the elongation of vegetative and flowering structures between growing seasons: the shorter the long shoots, the larger the flowering branches. The modular differentiation and heterophylly of Z. lotus might contribute to prioritizing the investment of resources of this phreatophyte, either for growth or reproduction, and could improve the efficiency in uptake and conservation of resources in drylands.

KW - functional traits

KW - heteroblasty

KW - modular unit

KW - plant architecture

KW - Rhamnaceae

KW - Environmental planning

UR - http://www.scopus.com/inward/record.url?scp=85107316658&partnerID=8YFLogxK

U2 - 10.1111/1442-1984.12343

DO - 10.1111/1442-1984.12343

M3 - Journal articles

AN - SCOPUS:85107316658

VL - 36

SP - 554

EP - 566

JO - Plant Species Biology

JF - Plant Species Biology

SN - 0913-557X

IS - 4

ER -