Leaf, stem and root content of proline in Atriplex canescens and Suaeda nigra

Abstract

Water deficit and salinity are the sources of abiotic stress that impose more limits on the utilization of plant resources. In the Chenopodiaceae family, the species of the genus Atriplex possess adaptations that provide them with advantages in saline environments. In Mexico, this genus is considered an important ecological resource; however, there is little information on its physiology. With the aim of contributing to the knowledge of the adaptations of this genus, 30-day seedlings of A. canescens were subjected to salinity for 12, 24 and 48 hours, and analyzed by scanning electron microscopy and energy dispersive X-ray spectrometry (SEM-EDS). The images showed that the surface of the leaves had abundant trichomes with vacuoles of 10-70 µm, which both promote and delimit the formation of crystals. Microanalysis suggests that these vacuoles store water and ions in an orderly fashion; the most abundant ions are Cl-, Na+ and K+. Magnesium was the only element present at all exposure times, suggesting its importance for the function of the gland. Cl- and K+ were detected after 12 hours of exposure; however, the concentration of K+ decreased after 48 hours and was gradually replaced by Na+.