and photographed. The number of the first- and second-order lateral
roots was counted and recorded, and the length of the primary stem
was measured. The leaves were separated from the plant for
photographing, and the surface area of each leaf was measured using
the ImageJ® software. The roots (washed 10 times with 1 L of sterile
water each time), stems, and leaves were collected separately, and airdried
at room temperature for 2 days followed by oven drying at
50 °C for 2 days before element analysis with inductively coupled plasma
optical emission spectrometry (ICP-OES). The remaining volume of
the nutrient solution was measured and recorded initially on the 20th
day.