Growth, Water Relations, and Accumulation of Organic and Inorganic Solutes in Roots of Maize Seedlings during Salt Stress

Abstract

Seedlings of maize (Zea mays L. cv Pioneer 3906), hydroponically grown in the dark, were exposed to NaCl either gradually (salt acclimation) or in one step (salt shock). In the salt-acclimation treatment, root extension was indistinguishable from that of unsalinized controls for at least 6 d at concentrations up to 100 mM NaCI. By contrast, salt shock rapidly inhibited extension, followed by a gradual recovery, so that by 24 h extension rates were the same as for controls, even at 150 mM NaCI. Salt shock caused a rapid decrease in root water and solute potentials for the apical zones, and the estimated turgor potential showed only a small decline; similar but more gradual changes occurred with salt acclimation. The 5-bar decrease in root solute potential with salt shock (150 mM NaCI) during the initial 1 O min of exposure could not be accounted for by dehydration, indicating that substantial osmotic adjustment occurred rapidly. Changes in concentration of inorganic solutes (Na+, K+, and CI-) and organic solutes (proline, sucrose, fructose, and glucose) were measured during salt shock. The contribution of these solutes to changes in root solute potential with salinization was estimated.

Acclimation improves salt stress tolerance in Zea mays plants

“…The final salinity treatment was set at 100 mM to ensure a significant reduction of the growth as reported in previous experiments (e.g. Rodríguez et al, 1997).…”

Sugar Accumulation along the Seminal Root Axis, as Affected by Osmotic Stress in Maize: A Possible Physiological Basis for Plastic Lateral Root Development

“…In addition, under osmotic stress conditions, they are used as a compatible solute for osmotic adjustment in roots (Sharp et al, 1990;Rodrígues et al, 1997;Ogawa and Yamauchi, 1999). Although there are no studies about osmotic adjustment in lateral roots, Ogawa and Yamauchi (1999) investigated the transient changes in maize seminal root elongation and water relations after stress treatments, to evaluate the process of osmotic adjustment in roots.…”

Growth and Uptake of Sodium and Potassium in Broad Bean (Vicia fabaL.) under Salinity Stress

“…The available literature records that salt stress in various plants leads to reductions in growth parameters such as inhibition of plant height; reduction in number of leaves; inhibition of leaf extension and development (assimilation surface); thinner epidermal and mesophyll layers in leaves; decreased rate of CO 2 uptake; difficulties of stomatal regulation; reduction of transpiration rate, chlorophyll content, and cell division and development; reduction of internode numbers and internodal length; reduction of dry weights of plant organs, leaves, stems, and roots; and inhibition of lateral roots (Parida, Das, and Mittra 2004;Kaya, Erol, and David 2003;Singh et al 2003;Ramoliya and Pandey 2002;Sairam, Rao, and Srivastava 2002;Bolarin et al 2001;Katerji et al 2000;Carvajal et al 1998;Rodriguez et al 1997;Katerji et al 1994;Matsuda and Riazi 1981;Rizk and Normand 1969).…”

“…(4) Inhibition of water transportation to the stem because of reduction of water-transport capacity of the roots. (5) Decrease in synthesis of DNA, RNA, and protein, increase of ABA, followed by decreasing of gibberellic acid and cytokinin (Lorenzen, Aberle, and Plieth 2004;Kaya et al 2003;Adiku et al 2001;Katerji et al 2000;Khan, Ungar, and Showalter 2000;Rodriguez et al 1997;Marschner 1995;Botella, Cerda, and Lips 1994;Kuchenbuch, Claassen, and Jungk 1986;Kafkafi, Valoras, and Letey 1982;Tal 1977;Helal, Koach, and Mengel 1975).…”