Biomass Partitioning and Morphoanatomical Traits of Six Gymnocalycium (Cactaceae) Species Occurring along a Precipitation Gradient

PEROTTI, SB; PEREA, M; DELBÓN, NE; GURVICH, DE; ALISCIONI, NL; HAMMANN, A

Diversity

MDPI

Año: 2022

As a group, cacti are regarded as plants that tolerate water scarcity, since they present anumber of adaptations. However, little is known about how species of the family varied theirmorphoanatomical characteristics along environmental gradients. The aim of this study was toanalyze how six Gymnocalycium species occurring in three sites along a precipitation gradient (aridsite: G. pugionacanthum, G. marianae; semiarid site: G. hybopleurum, G. stellatum; subhumid site: G.oenanthenum, G. baldianum) differ in their biomass partitioning and morphoanatomicalcharacteristics. We collected mature individuals of each species and analyzed their biomasspartitioning (to spines, aboveground stem, underground stem, main root, and lateral and thinroots), morphological characteristics (such as size ratios, spine length and width, and areole density)and anatomical characteristics (stoma number, and cuticle, epidermis, and hypodermis width).Species differed, both qualitatively and quantitatively, in most of the analyzed variables. Forexample, biomass allocated to spines was highest in G. pugionacanthum, lowest in G. baldianum, andintermediate in the remaining species. However, these variations were not clearly associated witharidity, but were related to the subgenus of the species. These patterns were clearly observed in thePCA. Phylogenetic relatedness is the main factor associated with morphoanatomical characteristics.