3 uniform-sized seedlings(10-12 cm height) were transplanted into each pot from the soyth china botanical garden. All pots were watered each day in order to keep soil moisture at 70-85%. After 90 days of cultivation, the physiological indicators were determined. After that, the shoots were cut and weighed immediately, washed with tap water and then washed with deionized water. Meanwhile, the roots were dug up and washed thoroughly. Then all the samples were dried at 75 C until completely dry, weighed, ground to