Physiological and Biochemical Responses of Ulva prolifera and Ulva linza to Cadmium Stress

Abstract EN

Responses of Ulva prolifera and Ulva linza to Cd2+ stress were studied.

We found that the relative growth rate (RGR), Fv/Fm, and actual photochemical efficiency of PSII (Yield) of two Ulvaspecies were decreased under Cd2+ treatments, and these reductions were greater in U.

prolifera than in U.

linza.

U.

prolifera accumulated more cadmium than U.

linza under Cd2+ stress.

While U.

linza showed positive osmotic adjustment ability (OAA) at a wider Cd2+ range than U.

prolifera.

U.

linza had greater contents of N, P, Na+, K+, and amino acids than U.

prolifera.

A range of parameters (concentrations of cadmium, Ca2+, N, P, K+, Cl−, free amino acids (FAAs), proline, organic acids and soluble protein, Fv/Fm, Yield, OAA, and K+/Na+) could be used to evaluate cadmium resistance in Ulva by correlation analysis.

In accordance with the order of the absolute values of correlation coefficient, contents of Cd2+ and K+, Yield, proline content, Fv/Fm, FAA content, and OAA value of Ulva were more highly related to their adaptation to Cd2+ than the other eight indices.

Thus, U.

linza has a better adaptation to Cd2+ than U.

prolifera, which was due mainly to higher nutrient content and stronger OAA and photosynthesis in U.

linza.