A look into the past, present and future potential distributions of Talinopsis frutescens, a North American endemic lineage closely related to Cactaceae

Talinopsis frutescens(Anacampserotaceae,a family that is close related to Cactaceae)is a succulent species endemic to North America.The aim of this study was to explore,using Ecological Niche Modeling(ENM),changes in potential distribution ranges considering different climate scenarios:past conditions during the Last Inter Glacial(LIG)and the Last Glacial Maximum(LGM),the present and projections for 2070(RCP 2.6 to 8.5).A pattern of contraction is observed during the LIG,which agrees with other studies focused in species from arid environments.This pattern was followed by a migration towards the south during the LGM and a possible recent expansion to the north as is observed in the present scenario.All future projections show the same contraction and fragmentation patterns,resulting in three discontinuous areas:the northern part of the Chihuahuan Desert,the southern-central part of the Mexican Plateau,and the smallest one in the Tehuacán-Cuicatlán Valley.Our projections for future scenarios agree with other studies and support that global climate change tends to alter the current distribution of arid environment species.

Effect of light on seed germination and seedling shape of succulent species from mexico

Aims Light requirements for cactus seed germination have been considered to be associated with their adult plant height and seed mass,but this has not been thoroughly studied for other succulent species.In order to understand seed photosensitivity from desert species belonging to Asparagaceae(subfamily Agavoideae)and Cactaceae,we performed a germination experiment with and without light for 12 species and 2 varieties from 1 species from the Southern Chihuahuan Desert.We also determined if adult growth is totally determined by seedling‘growth form’in cacti.Methods We performed a germination experiment using light and darkness for 13 species from Southern Chihuahuan Desert:10 rosette species(Asparagaceae),as well as 1 globose,1 columnar and 2 varieties from 1 depressed-globose species(Cactaceae).The response variables were seed germination percentage and relative light germination(RLG).In addition,in order to determine if adult-globose cacti could have cylindrical seedlings,we calculated the shape index(height/width ratio)for Coryphanta clavata and Mammillaria compressa.Important Findings All species were considered neutral photoblastic.Eleven species had similar seed germination in both light and dark conditions,and three taxa(M.compressa and the two varieties of Ferocactus latispinus)showed higher germination with light than without it.Agave salmiana,M.compressa and the two varieties of F.latispinus had higher RLG than the other species.Seed mass was an important factor because with higher seed mass there was lower dependence to light.These findings support the hypothesis that small seed mass and light requirements have coevolved as an adaptation to ensure germination.One adult-globose cactus species,M.compressa,and one adult-columnar species,C.clavata,had small seeds and neutral fotoblasticism.Seedlings from these two species exposed to light were cylindrical and those under darkness conditions were columnar.Perhaps seeds from this species are able to germinate in the dark because they produce columnar seedlings with the ability to emerge from greater soil depths where sunlight cannot penetrate.