Am 300

Chlorosis scoring was conducted using a visual scale according to Wang et al. (2008) (link): (1) no chlorosis, plants normal and green; (2) slight yellowing of the upper leaves, no differentiation in color between the leaf veins and interveinal areas; (3) interveinal chlorosis (green veins and chlorotic interveinal areas) in the upper leaves, but no obvious stunting of growth or death of leaf tissue (necrosis); (4) interveinal chlorosis of the upper leaves with some apparent stunting of growth or necrosis of plant tissue; and (5) severe chlorosis with stunted growth and necrosis in the youngest leaves. Also, Soil and Plant Analyzer Development (SPAD) readings were conducted with a portable chlorophyll meter (Konica Minolta SPAD-502Plus; Minolta, Osaka, Japan) at the end of 10 days, using the first expanded trifoliate leaf from the top of the plant.
Sampled roots, stems and leaves were separated, weighed, and measured for length. The material was then dried at 70°C until constant weight and stored for ICP-OES analysis. Foliar area of the trifoliate leaves was measured using a leaf area meter AM300 (ADC BioScientific Ltd., UK).

Trichome number was measured upon the appearance of the first true fully expanded rosette leaf produced by treated and untreated plants (after 9 days of co-cultivation). The target leaf was first removed from the plant and traced. The leaf area was measured using a leaf area meter (AM 300, ADC BioScientific, Hoddesdon Herts, UK) and the adaxial trichome number was determined under a dissecting microscope. The trichome density was calculated as trichome number per leaf area (number/cm²).

The whole seedlings were collected and rinsed with deionized water, surface dried and separated into roots, stems and leaves. The area of the fresh leaves was measured with a meter (AM 300, ADC Bio-scientific Ltd., UK). All parts were subsequently dried at 80 °C for 48 h to obtain dry mass. Plant root ratio (%) was calculated as [dry mass (root) / dry mass (root + shoot)] × 100. Measurements were replicated three times with 5 plants per replicate.