Phylogenetic signal and climatic niche of stem photosynthesis in the mediterranean and desert regions of California and Baja California Peninsula.

Autor: Ávila-Lovera E; Schimd College of Science and Technology, Chapman University. One University Drive, Orange, CA, 92866, USA., Garcillán PP; Centro de Investigaciones Biológicas del Noroeste, Av. Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita Sur, La Paz, B.C.S., 23096, México.
Jazyk: angličtina
Zdroj: American journal of botany [Am J Bot] 2021 Feb; Vol. 108 (2), pp. 334-345. Date of Electronic Publication: 2020 Dec 06.
DOI: 10.1002/ajb2.1572
Abstrakt: Premise: Woody plants with photosynthetic stems are common in the drylands of the world; however, we know little about the origin(s) and geographical distribution of photosynthetic stems. Therefore, we set to answer the following questions: (1) Is stem photosynthesis phylogenetically conserved? (2) Do green-stemmed and fleshy-stemmed species have identifiable climatic niches?
Methods: We mapped the photosynthetic stem trait onto a phylogeny of 228 mediterranean and desert species and calculated indices of phylogenetic signal and created climatic niche models of 28 species belonging to three groups: green, fleshy, and green-and-fleshy stemmed species.
Results: We found phylogenetic signal in the fleshy stem trait, but not in the green stem trait. Fleshy-stemmed species occupy areas associated with high isothermality, high precipitation seasonality, and high mean temperature of the wettest quarter, whereas green-stemmed species occupy areas associated with high precipitation of driest month, high precipitation of coldest quarter, high mean diurnal temperature range and high maximum temperature of the warmest month.
Conclusions: Despite the fact that both photosynthetic stem types help cope with water shortage, having fleshy stems allows plants to cope with greater precipitation seasonality than is possible with green stems. Green stems require a lot of water to be stored in the soil to maintain net photosynthesis during the dry season, so they inhabit areas with higher and more predictable precipitation.
(© 2020 Botanical Society of America.)
Databáze: MEDLINE
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