Changes of CFIN parameters of TER (full symbols) and END (open symbols) pea cultivars measured during the 21 days of cold acclimation. Changes in A) the maximal quantum yield of PSII photochemistry for a dark-adapted state (ΦPo); B) the maximal and the actual quantum yield of photosystem II photochemistry for a light-adapted state (ΦPSII, ΦP respectively), the coefficient of photochemical quenching (qP); C) the quantum yield of constitutive non-light induced dissipation processes (Φf, D); D) the quantum yield of regulatory light-induced heat dissipation (ΦNPQ); are shown. The values represent medians from 15 measurements. The error bars represent quartiles. The medians of all the TER and END parameters at the end of measurements were statistically significant (p value < 0.05), except of qp and ΦNPQ.