Morpho-anatomy and histochemistry of vegetative organs of Lycium humile (Solanaceae): adaptative traits to high altitude saline wetlands MORFO-ANATOMÍA E HISTOQUÍMICA DE ÓRGANOS VEGETATIVOS DE LYCIUM HUMILE (SOLANACEAE): RASGOS ADAPTATIVOS A HUMEDALES SALINOS DE ALTURA

LEAL, MARIANA; MERCADO, M. INÉS; CUELLO, A. SOLEDAD; ZAMPINI, I. CATIANA; PONESSA, GRACIELA I.; ISLA, M. INÉS

DARWINIANA

INSTITUTO DE BOTÁNICA DARWINION

Año: 2023 vol. 11 p. 466 - 484

0011-6793

Lycium humile Phil., is an extreme halophyte plant, endemic to Argentina, Bolivia, and Chile, which grows between 2000 and 4000 m a.s.l. in saline wetlands environments. The aim of this work is to identify morpho-anatomical and histochemical adaptive characteristics of the vegetative organs of L. humile linked to its tolerance to extreme environments of high altitude saline wetlands, in order to evaluate its potential as source of metabolites with commercial value or as source of resistance genes related to abiotic stress tolerance. To carry out the analysis, during the period of February 2018, samples were obtained from plants belonging to 4 populations of the species (5 individuals per population) located at the departments of Antofagasta de la Sierra, Santa María and Ambato, province of Catamarca, Argentina. Leaf and stems were studied using histochemical tests, conventional histological preparations and optical microscopy. Different foliar tissues were analyzed by scanning electron microscopy coupled to elemental X-ray diffraction spectroscopy (EDS). The leaves and stems of the analyzed populations showed uniform anatomical and histochemical features. It was stated for the first time that the succulence of the leaf is reached by the folding of the tissues evidenced in a tridimensional venation pattern. The presence of isolateral-radial mesophyll and aquifer parenchyma is highlighted as a unique feature characteristic for the species. The glandular trichomes and palisade parenchyma revealed complex contents of phenols, flavonoids, proteins, lipids, terpenes, and alkaloids; while the outer layer of the cuticles presented phenolic, terpenic and lipidic deposits. The EDS analysis showed crystalliferous idioblasts with high contents of Ca2+ and Na+. The stems exhibited hypodermis and air chambers formed in the cortical and medullary layers. These anatomical and histochemical characteristics of L. humile represent adaptive traits to saline high-altitude wetland environments. Its functionality in relation to the environment and its potential as source of resistance genes and metabolites interesting for the cosmetic and pharmaceutical industries are discussed.