Resumo

GIL, SP; SEISDEDOS, L; REYNA, ME  e  CERANA, MM. Leaf epidermis in three Asteraceae native species of Argentina with ornamental potential. Phyton (B. Aires) [online]. 2012, vol.81, n.2, pp.205-210. ISSN 1851-5657.

The goals of this study were (1) to make a careful study of the foliar epidermis of Grindelia cabrerae var. cabrerae, Solidago chilensis y Wedelia buphthalmiflora, native Asteraceae from Argentina which have ornamental potential, and (2) to determine variables that indicate adaptation to xeromorphic environments. Five adult leaves from five plants were selected from each population. All the material was fixed in FAA. Te epidermis of both foliar sides were macerated in hypochlorite of sodium, and obtained by scraping. Tey were stained with safranine and mounted in water-glycerine (1:1). From each slide, five fields were chosen and frequency of the epidermal cells, stomata (SF) and trichomes, length of the stomatal complex, and stomatal index (SI) were studied. Te cuticle was analyzed in foliar cross sections. Statistical tests were performed. From an ecological point of view, the three species showed epidermal characters related to xeric habitats: thick cuticles, pubescence and great stomatal number. Grindelia had straight epidermal cell walls and glandular trichomes which produce resinous substances. Solidago showed the smallest ordinary epidermal cells and stomata, and a new (unmentioned to date) type of uniseriate hair. Wedelia had a lot of glandular and non-glandular hairs, some of them were big and very ornamented. It also showed a type of uniseriate hair with 2 or 3 cells, with smooth ornamented walls in the basal cells, unknown to date. Te three species had a greater (1) number of stomata and (2) SI at the lower leaf side. Solidago showed significant diferences in SF, and Wedelia in SI and SF. Also, the study species had non-glandular trichomes at both leaf sides, but Grindelia and Wedelia showed also glandular trichomes. Grindelia and Wedelia difered in the greater trichome density at the upper or lower leaf side, respectively. Trichome densities were diferent at the upper or lower leaf sides in Wedelia.

Palavras-chave : Leaf epidermis; Native Asteraceae; Xeromorfism; Argentina; Ornamental plants.

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