At present, root length, shoot length and biomass are often
used to evaluate the tolerance of plants [28,29]. However, the
effects of heavy metals on leaf shape are ignored and leaf
length and width are seldom used to reflect the tolerance of
plants to heavy metals. In this study, leaves became shorter
and wider under Cd pollution, and the leaf shape (leaf length/
width) was first influenced by Cd (Table 1), which indicates
that leaf shape is more sensitive to Cd than other indicators.
Therefore, the ratio of leaf length to width may be an important
index for evaluating the metal tolerance of plants. The
reduction and enhancement of shoot water content may be
caused by heavy metal toxicity [30,31]. In this study, the shoot
water content under Cd pollution was significantly higher
than in the control, which agreed with previous studies [31].