Selective Transport Capacity for K<sup>+ </sup>and Ca<sup>2+</sup> over Na<sup>+</sup> of Leaf Sheath is Correlated with Salt Tolerance of Energy Plant Sweet Sorghum

Abstract

Two sweet sorghum varieties (salt tolerant Jitianza 2 and salt sensitive Lvneng 1) were used to investigate their adaptation to NaCl stress under different cultivation conditions of potted cultivation and field cultivation, and selective transport capacity for K+ over Na+, and Ca2+ over Na+ of leaf sheath. NaCl stress decreased Pn, Fv/Fm, fresh weight of leaf sheath and leaf blade, field yield in both varieties. NaCl stress induced Na+ accumulation while it decreased K+ and Ca2+ levels in leaf sheath and leaf blade of both varieties. The increase in Na+ of leaf blade and the decrease in K+ and Ca2+ of leaf blade were greater in Lvneng 1 than those in Jitianza 2. Furthermore, the Na+, K+ contents in leaf sheath of Jitianza 2 were significantly higher than those of Lvneng 1 under NaCl stress. The selective transport capacity for K+ over Na+, and Ca2+ over Na+ of leaf sheath in Jitianza 2 was significantly greater than that in Lvneng 1. Pn, Fv/Fm, stem stalk field, ear field, juice yield, stalk Brix, sugar content of Jitianza 2 were significantly higher than those of Lvneng 1, which was correlated with stronger selective transport capacity for K+ over Na+, Ca2+ over Na+ of Leaf Sheath of Jitianza 2.