Hyperspectral images of Marchantia polymorpha under nutrient stress

Plant material and growth condition – M. polymorpha gemma (Accession: Tak-1) was spread on ½ x B-5 medium (PhytoTechnology Laboratories) with 1% agar and grown at 22oC under continuous light (50–60 µmol m−2 s−1). Seven-day old gemmalings were then transferred to full-strength Yamagami (cntl) medium 12 or the same medium with the reduced concentration of 0 or 3 mM potassium nitrate and 0 or 2mM sodium nitrate (0xN or 0.05xN), 0 or 1 mM potassium phosphate (0xP or 0.05xP) , 0.1 or 0.2 mM calcium chloride (0.05xCa or 0.1xCa), 0 or 0.43 µM iron sulfate (0xFe or 0.05xFe) and 0 mM magnesium sulfate (0xMg). The gemmalings were grown at 22oC under a 24-hr continuous light during nutrient deficiency treatment. RGB and hyperspectral images were captured on the 14th day of treatment. Full strength Yamagami nutrient medium contained 2 mM magnesium sulfate, 2 mM potassium dihydrogen phosphate, 6 mM potassium nitrate, 1 mM ammonium chloride, 2 mM calcium chloride, 4 mM sodium nitrate, 8.6 µM iron (II) sulfate, 10.3 µM manganese (II) sulfate, 30 µM boric acid, 1 µM zinc sulfate, 1 µM cupric sulfate, 130 nM cobalt sulphate, 24 nM sodium molybdate. Hyperspectral imaging - Hyperspectral images of M. polymorpha plants were captured using the Specim IQ camera (SPECIM) with halogen lamps as the light source. The hyperspectral image contains 512 x 512 pixels (x, y) and 204 spectral bands (λ) from 400 to 1000 nm with a spectral resolution of 7 nm. The white balance was set according to the manufacturer protocol with the interrogation time 35 s. The interrogation time for the samples was set to 40 s and the working distance was set to 23 cm.