pot
The pot culture experiment was conducted in a greenhouse at
the South China Botanical Garden, Chinese Academy of Sciences
(2380 N, 113170E). Top soil (0e20 cm) was collected from
a local abandoned kaleyard, and soil properties were as follows:
soil texture of 70.5% sand, 12.2% silt, and 17.3% clay, soil
pH of 6.09, organic matter of 3.9%, cation exchange capacity
(CEC) of 79.7 mmol kg1, total Cd concentration of
1.35 mg kg1, and available Cd concentration of 0.17 mgkg1.
Six treatments (0, 8, 15, 30, 60 and 100 mg kg1 Cd) with 4
replicates were set up and designated as CK, Cd8, Cd15, Cd30,
Cd60 and Cd100, respectively. Dried soil (12.5 kg) sieved
through 1 cm mesh was put into each plastic pot (30 cm in
diameter and 25 cm in height), and then saturated with a
heavy metal solution containing the required amount of
CdCl2$2$5H2O. One month later, 3 uniform-sized plants were
planted into each plot. The plants were obtained by cutting
stem nodes of king grass from a king grass plantation in the
South China Botanical garden, Chinese Academy of Sciences
in 2009 March, and then were rooted in soil. Ten days later,
when the cuttings had grown to 10e12 cm height and were
used for transplanting. All pots were watered each day in
order to keep the soil moisture at 70e85%. After 90 days of
cultivation, the growth indicators, chlorophyll content and
photosynthetic rate were determined. After that, the shoot
was cut and weighed immediately, and then washed with tap
water, followed by deionized water. Meanwhile, the roots
were dug up, washed thoroughly, and then the root lengths
were measured. Then all the samples were dried at 75 C until
completely dry, weighed, ground to <0.5 mm, and sealed into
plastic bags for analyses.
2.2. Growth
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