In order to reveal the correlation between Cd uptake and photosynthetic physiological characteristics of Solanum nigrum L.

pot experiments in greenhouse were conducted to investigate the Cd uptake and physiological response of Solanum nigrum

during its mature growth stage under five levels of Cd (0

2

5

10 and 20 mg/kg

denoted as Cd0

Cd2

Cd5

Cd10 and Cd20 respectively). The results showed that Solanum nigrum had a strong resistance to Cd

which could grow normally in 20 mg/kg Cd contaminated soil

and the Cd accumulation coefficient and translocation factor of Solanum nigrum in the Cd contaminated soil with ≤ 10 mg/kg were both larger than 1

however

when the soil was heavily polluted (20 mg/kg)

the Cd uptake and transfer ability of Solanum nigrum decreased significantly (p<0.05). In general

the Cd content in the overground of Solanum nigrum was larger than that in the underground of Solanum nigrum

and the Cd accumulation in oveground parts of Solanum nigrum in five Cd levels were all significantly (p<0.05) larger than that in underground parts

which was about 10~15 times more. At the same time

the increase of soil Cd concentration could cause not only the changes of Cd uptake and transfer of Solanum nigrum

but also cause the changes of its photosynthetic physiological characteristic. The photosynthetic rate (Pn)

transpiration rate (Tr) and stomatal conductance (Gs) of the flag leaf in Cd10 treatment were significantly higher ( 23.71%~79.80%) than those in Cd0

Cd2

Cd5 treatments（p<0.05）

while the photosynthetic intensity of Solanum nigrum was significantly decreased as Cd content of soil reaches 20 mg/kg. The results of correlation analysis showed that the Cd uptake by Solanum nigrum was mainly affected by soil Cd concentration (SCCD)

and had no significant correlation with the internal factors

such as Tr and Gs. Therefore

it is not a good choice to improve the uptake and accumulation of Cd in Solanum nigrum by the physiological regulation of Solanum nigrum; further researches need to be done to reveal the mechanism and regulation of Cd uptake in Solanum nigrum.