Simultaneous Biochemical and Physiological Responses of the Roots and Leaves of Pancratium maritimum (Amaryllidaceae) to Mild Salt Stress

Abstract

Pancratium maritimum (Amaryllidaceae) is a bulbous geophyte growing on coastal sands. In this study, we investigated changes in concentrations of metabolites in the root and leaf tissue of P. maritimum in response to mild salt stress. Changes in concentrations of osmolytes, glutathione, sodium, mineral nutrients, enzymes, and other compounds in the leaves and roots were measured at 0, 3, and 10 days during a 10-day exposure to two levels of mild salt stress, 50 mM NaCl or 100 mM NaCl in sandy soil from where the plants were collected in dunes near Cuma, Italy. Sodium accumulated in the roots, and relatively little was translocated to the leaves. At both concentrations of NaCl, higher values of the concentrations of oxidized glutathione disulfide (GSSG), compared to reduced glutathione (GSH), in roots and leaves were associated with salt tolerance. The concentration of proline increased more in the leaves than in the roots, and glycine betaine increased in both roots and leaves. Differences in the accumulation of organic osmolytes and electron donors synthesized in both leaves and roots demonstrate that osmoregulatory and electrical responses occur in these organs of P. maritimum under mild salt stress.

The Influence of the Partitioning of Sugars, Starch, and Free Proline in Various Organs of Cyclamen graecum on the Biology of the Species and Its Resistance to Abiotic Stressors

“…Corroborating our results, a 60-fold higher proline concentration was detected in tomato flowers than in all the vegetative tissues [50]. Enhanced proline content was also documented in petals of P. maritimum and was attributed to a requirement for osmotic adjustment, because this geophyte is exposed to dry and saline ambient environmental conditions [26,46]. Multiple explanations of proline accumulation in flowers have been published.…”

“…Additionally, proline accumulation patterns may have implications on nitrogen storage and partitioning, especially under stress conditions [22,27,42]. Proline pool has been reported to expand during transition phase, i.e., from vegetative to reproductive growth [43][44][45][46].…”

Enhancement of Pigments Production by Nannochloropsis oculata Cells in Response to Bicarbonate Supply

“…an excess of NaHCO 3 caused salt stress, ROS (reactive oxygen species) production and a decline in photosynthetic efficiency due to a PSII complex damage. In general, in plant cell, salinity creates several physiological and molecular changes, such osmotic stress, oxidative damage and a decrease of photosynthetic activities [33,34].…”

Non-Protein Thiol Compounds and Antioxidant Responses Involved in Bryophyte Heavy-Metal Tolerance

“…In Arabidopsis leaf tissue, glutathione was measured in mitochondria (15 mM), nuclei (6.4 mM), cytosol (4.5 mM), peroxisomes (4.4 mM), chloroplasts (1.2 mM) and vacuole (0.08 mM) [ 107 ]. Glutathione exists either in a reduced form (i.e., GSH) with a free thiol group or in an oxidized form (i.e., GSSG) with a disulphide bond linking two glutathione molecules [ 105 , 109 ]. GSH plays an important role in the regulation of developmental processes such as cell division [ 110 , 111 ], flowering [ 110 , 112 ], and in protecting plants against abiotic stresses such as nutritional starvation, heavy metal exposure, drought, salinity, heat, cold, and certain exogenous and endogenous organic-chemical agents [ 16 , 110 , 113 , 114 ].…”