A cushion along an elevation gradient

Along the Talabre–Lejía transect, the species was studied at about 2800–3800 m above sea level. Its compact mass of segments creates spaces where other plants can root. In the associations observed, roots of Atriplex imbricata also developed in decomposing material within the cushion. [Díaz et al. 2024]

At each elevation, 20 pairs comprising a cactus and a similarly sized open surface were compared. Across the full dataset, 18 species were recorded with cushions at at least one elevation. The most consistent positive associations were found for A. imbricata and Baccharis tola. [Díaz et al. 2024, p. 1076–1078]

Temperature beneath the stems

Sensors were placed 5 cm deep under cacti and outside them. Measurements included four replicates of each position. In the field series, cushions reduced daytime heating and raised night-time minima. Recorded extreme differences reached about 20°C and 8°C, respectively. They concern soil temperatures during particular measurement periods. [Díaz et al. 2024]

On the transect studied, A. imbricata occurred with the cactus about 400 m higher than on open terrain. The model relating cover to temperature supported the importance of thermal protection. The physiological and spatial findings are developed in the article on the cactus as a nurse plant. [Díaz et al. 2024]

Pollen and microscopic identification

Miesen and coauthors described spherical pollen grains with pores distributed over the entire surface. In the sample studied, they were 85–110 µm in diameter and had about 12 sunken oval pores. The description was based on light microscopy after chemical preparation. These dimensions refer to the prepared pollen material. [Miesen et al. 2015, p. 260–261]

Metabolomic studies revealed a set of 93 chemical signals associated with the presence of A. imbricata inside the cushion. Some identified compounds were flavonoids, and many signals remained unidentified. The change in metabolite composition indicates a different physiological state of the associated plant in the sheltered microenvironment. [Díaz et al. 2024]

Synonyms and names in the literature

Opuntia camachoi · Tephrocactus camachoi [2-WWW]