Sodium and potassium allocation under drought stress in Atlas mastic tree (Pistacia atlantica subsp. mutica)

Abstract

© iForest -Biogeosciences and Forestry IntroductionAmong the many physiological features by which plants cope with water shortage, maintaining cation uptake and mobility in different tissues plays many crucial roles to deal with water deficit. Monitoring of cation changes under soil water shortage is so important that it was recently used as a drought tolerance index for selecting cultivars (Achakzai 2007(Achakzai , 2008. Nutrients uptake and consequent cation translocation highly depend on transpiration stream (Greenway & Kelpper 1969). Reduced root lateral growth can also restrict nutrient uptake. Potassium is the most abundant cation in higher plants and is involved primarily in osmotic-mediated cell expansion (Elumalai et al. 2002), protein synthesis, glycolytic enzyme activity, membrane permeability, photosynthesis, stomatal movement, drought resistance (Hopkins & Hüner 2004) and tropism (Philippar et al. 1999). In contrast, sodium at elevated concentrations -usually more than 100 mMhas toxic effects on plants. Sodium has lower replacing power than K + as revealed from Hofmeister's cation sequence, higher affinity with anionic groups as the carboxyl groups of proteins (Vrbka et al. 2006) and generally impairs the positive roles of K + in living cells. Because of high frequency, similar valence electron in outer shell, similar hydrated ion radius and deficiency of high performance discriminating antiporters (Maathuis & Amtmann 1999), Na + interferes in K + uptake and translocation. It can also enhance plant performance, being involved in osmotic regulation in vacuoles (Mengel & Kirkby 2001, Maathuis & Sanders 1993. This role of Na + is even more relevant under water deficit where total nutrient uptake is affected by decreasing soil water content and Na + toxicity is not an issue. Most of studies emphasize the necessity of reducing Na + under salt stress to maintain high K + /Na + ratio in the intracellular space (Maathuis & Amtmann 1999). Although changing K + /Na + ratio is not the main concern under drought stress, increasing of this ratio can facilitate plant survival and development under this condition. Exposing six cultivars of sorghum seedlings to progressive water deficit reduced the content of these univalent cations both in root and shoot, whereas the amount of sodium increased and potassium remained constant in the roots of a drought tolerance cultivar (Achakzai 2007). Plants that are able to take more K + and maintain higher K + /Na + ratio in the intracellular space, are able to ameliorate the negative effects of drought on water relations and organic and inorganic solute accumulation in different organs (Nandwal et al. 1998).The genus Pistacia (Anacardiaceae), commonly known for the edible nuts of P. vera, has at least 11 species worldwide. P. atlantica Desf. is a wild pistachio species which produces mastic (an edible resin) and small edible nuts with high content of valuable essential oils (Barrero et al. 2005, Tzakou et al. 2007, Gourine et al. 2009). As a xerophyte species, P. atlantica is ...

Potassium: a neglected nutrient in global change

“…However, the RE of K remains considerable and could be expected to be higher in dry ecosystems, compensating for the low capacity for K uptake in dry conditions (in comparison with plants at wetter sites as reported in some studies; see, e.g. Fayyaz et al, 2013;Tomlinson et al, 2013). Moreover, the capacity of plants to retain K in arid environments could be improved by lower leaching (Singer, 1989).…”

“…This effect is related to the role K plays in enhancing photosynthetic CO2 fixation, improving the transport of photosynthates into sink organs and inhibiting the transfer of photosynthetic electrons to O2, thereby reducing ROS production (Cakmak, 2005). Many field studies have thus observed correlations between K concentrations in plants and soils and mechanisms of drought avoidance (Nandwal et al, 1998;Arquero et al, 2006;Teixeira et al, 2008;Fayyaz et al, 2013;Tomlinson et al, 2013). Many physiological and metabolomic studies in garden and potted plants (Babita et al, 2010;Cuéllar et al, 2010) and in crops (Römheld & Kirkby, 2010;Waraich et al, 2011;Wang et al, 2013), and some studies across environmental gradients under field conditions (Kadar & Foldesi, 2001), have observed a strong link between K concentrations and the resistance and adaptation of plants to drought.…”

Determination of Root Structures and Element Contents of Two Pumpkins (Cucurbita pepo L.) Genotypes Under Drought Stress

“…Some studies have suggested that the K + content in roots and shoots is independent and shoot K + content is related to transpiration. In contrast, variations in root K + content are not related to leaf transpiration rate (Fayyaz et al, 2013). Therefore, plants with high K + can absorb more water under drought stress (El-Hadi et al, 1997).…”

Pengaruh Suhu, Pemupukan K dan N terhadap Pertumbuhan Tanaman Padi Inpari 30 (Oryza sativa L.)

“…Kalium berfungsi untuk menjaga tekanan osmotik serta keseimbangan cairan atau air di dalam sel. Sintesis dan akumulasi senyawa osmolit berperan dalam pengaturan tekanan osmotik sel serta melindungi sel-sel dengan cara mengikat spesies oksigen reaktif (ROS) (Fayyaz et al, 2013). Berdasarkan uraian diatas maka perlu dilakukan penelitian pengaruh suhu, pemupukan K dan N terhadap pertumbuhan tanaman padi.…”