Fig. 1

Photosynthetic pigment content in sugarcane leaves cv. RB867515. A Representative scheme of a sugarcane plant depicting the leaf senescence gradient. Leaves were numbered according to the system proposed by Kuijper [26]. B Non-senescent (+1) and senescent (+8) leaves of 8-month-old sugarcane cv. RB867515. C Three-dimensional plot of the SPAD index changes in the ‘between-leaves’ gradient and the ‘in-leaf’ gradient (n = 5; read per position/leaf = 3); Statistical analysis: leaf refers to statistics applied to different leaves (from +1 to +8); leaf position refers to statistics applied to the same leaf (base, middle and tip portions) and leaf *position refers to statistics applied to the whole data set (‘between-leaves’ and ‘in-leaf’ gradients); asterisk indicates statistical difference: **p ≤ 0.01, *p ≤ 0.05, and ns non-significant; The ANOVA and significant p values are available in the Additional file 2. D Chlorophyll a/b ratio and E carotenoids content in sugarcane leaves; Statistical differences (p ≤ 0.05) were obtained with ANOVA followed by Tukey’s test; Different letters indicate statistical significance at p ≤ 0.05. FM fresh mass. Vertical bars show ± S.E. for n = 3