Pre-treatment

Each shoot sample (2.0 g) was ashed overnight in a crucible at 60 °C and 5 mL of 1:1 HCl added and left to stand in an oven overnight at 60 °C. The solution was filtered, and distilled water added to make it up to 40 mL. The samples were then analyzed for both major and trace elements using inductively coupled plasma-mass spectrometry (ICP-MS).