Abstract Detail



Ecophysiology

Cruz , Marilyn Vásquez [1], Loera, Israel [2], NAKAMURA, MIGUEL [3], DEL ANGEL, MELINA N  [3], HERNANDEZ-HERNANDEZ, TANIA [4].

Succulents don’t like it that dry: Climatic niche evolution within the Core Caryophyllales reveals no trend of succulent lineages towards the driest and hottest conditions.

Succulent plants are strongly associated with arid regions across the world. They possess a vast array of morphological, anatomical, and metabolic modifications that increase their water use efficiency, such as water storage tissues and the Crassulacean Acid Metabolism (CAM). Although significant efforts have been made to understand the biochemistry, physiology and evolution of the molecular bases of CAM, their ecology remains largely unexplored. It is a common belief that environments with low precipitation, high temperatures, and pronounced seasonality confer the adaptive pressure under which succulent CAM plants evolved their strategies to survive water scarcity. However, the relationship between succulence (and associated traits) and climatic variables has never been explicitly tested. Here we study the climatic niche evolution of succulents and non-succulent relatives in the core Caryophyllales, a taxonomic group that includes some of the richest succulent families (i.e. Cactaceae, Aizoaceae). We use a carefully curated world scale dataset of ca. 5063 species included in 28 families distributed around the globe. We characterize and compare the climatic niche and habitat of succulents and non-succulents. We use a phylogenetic framework to understand the evolution of succulent’s climatic niche trajectories on a temporal scale. Each succulent lineage originates and diversifies at different times, under already arid conditions.  By implementing phylogenetic statistical regression, we found there is no relationship between succulence or degree of succulence and habitat or climatic traits related to aridity. Similarly to what happens with the C4 strategy, statistical analyses show that although the climatic niche of highly succulent plants is narrower than the niche of their non-succulent relatives, it is contained within the latter, and is not positioned in the hottest and driest portion of the niche space. They maintain the ability to exist in more humid or mesic environments; however freezing temperatures seem to pose a strong limit to their distribution. Our results show non-succulent lineages within the Core Caryophyllales show higher preferences towards extremely arid or arid environments, challenging the common belief of a super specialization of succulents towards these conditions. Our results support the idea that succulent lineages diversify in response to different factors rather to aridification by itself.


1 - UGA-Langebio Cinvestav, Biologia Evolutiva, Cerrada Del Bosque 222 Fraccionamiento Punto Verde, Irapuato, GUA, 36821, Mexico
2 - Instituto De Ecologia A.c., Apdo Postal 63, XALAPA, Veracruz, 91000, Mexico
3 - CIMAT, Guanajuato, Gto
4 - CINVESTAV IRAPUATO, LANGEBIO-UGA, Libramiento N Carretera A León Km 9.6, Irapuato, GUA, 36821, Mexico

Keywords:
CAM photosynthesis
Succulent
Caryophyllales.

Presentation Type: Oral Paper
Number: 0004
Abstract ID:641
Candidate for Awards:None


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