Changes in Mineral Element Contents in Pomelo and Citrus Seedlings under Salt Stress

Abstract:

Changes in mineral element contents in young seedlings of Citrus maxima cv. Pingshanyou and C. reticulata cv. Fuju cultured in plastic pots and treated with various salt concentrations were studied. Na⁺ and CIcontents in roots and shoots of Pingshanyou and Fuju seedlings increased with the increase of NaCl concentration. The contents of Na⁺ and Cl in roots and shoots of Fuju seedlings were higher than those of Pingshanyou under the same salinity. 40 mmol/L of NaCl significantly decreased Ca²⁺, Mg⁺ and Zn contents in roots and K⁺ and Fe contents in shoots of Pingshanyou and Fuju seedlings, whereas markedly increased the contents of Fe in roots and Zn in shoots. As salt concentration increased, K⁺ in roots and Ca²⁺, Mg²⁺ in shoots of Pingshanyou seedlings exhibited little change, but the above-mentioned mineral ions in Fuju seedlings significantly decreased when the salinity was higher than 160 mmol/L. It was shown that the contents of K⁺ in roots and Ca²⁺, Mg²⁺ in shoots were related to citrus varieties, which might be used as indices for evaluating the salt tolerance. Under salt stress, P, Mn in roots and shoots of Pingshanyou and Fuju seedlings decreased, but Cu increased obviously at high salt concentration. The value of K⁺/Na⁺, Ca²⁺/Na⁺ and Mg²⁺/Na⁺ decreased significantly in shoots of Pingshanyou and Fuju seedlings under NaC1 stress, of which the value of K⁺/Na⁺ could be considered as an index for evaluating the salt tolerance of citrus seedlings.