Arsenic (As) upward transport from roots was limited by its high toxic
ity for the radicular and transporter cells. Tomato plants caused an i
ncreasing accumulation of arsenic in roots as a strategy for increasin
g plant tolerance to arsenic; the ratio As in root/As in the aerial pa
rt was 69/1. However, bean plants limited the absorption of arsenic by
roots, but there was not a limited transport of the absorbed arsenic;
the ratio As in roots/As in shoots is 1/1.