Figure 3.

Time course of the relative changes in leaf SPAD values in peach tree (A) and sugar beet leaves (B). The treatment was carried out with a solution containing 2 mM FeSO₄ and 0.1% surfactant. In peach leaves, foliar treatments were made at weeks 0 and 4, and the SPAD index was measured each week. In sugar beet leaves, the treatment was made at days 0 and 2 and the SPAD index was measured daily. Peach tree data are means ± SE (n = 11 trees: 3 in 2009, 4 in 2010, and 4 in 2011; each sample was composed of 20 leaves, each from a different shoot from the same tree; two measurements were taken per half-leaf). Initial SPAD values in chlorotic peach tree leaves were 18 ± 2. Sugar beet data are means ± SE (n = 8 plants, 4 in each of two different batches; each sample was composed of four leaves from the same plant; four measurements were taken per half-leaf). Initial SPAD values in sugar beet chlorotic leaves were 11.5 ± 1.5.