Growth, leaf pigments and photosynthesis in boron-deficient turnip (Brassica rapa L.) plants under different light intensities

Effect of boron deficiency on growth, leaf pigments and photosynthesis was studied in turnip (Brassica rapa L.) plants grown under three different light conditions (50, 100 and 150 µmol m-2 s-1) in a hydroponic medium for one month under controlled environmental conditions. Two levels of B treatment including adequate (25 µM) and low (2.5 µM) boron supply were applied. Dry matter production of shoot and root was reduced under low boron supply up to 79% and 82% respectively. Re-supply of deficient plants by boron during the last week of growth period increased significantly plants dry matter production. Higher light conditions increased not only plants growth but also boron uptake. Plants susceptibility to low boron supply was higher under high compared with lower light conditions. Leaf chlorophyll and carotenoids decreased under boron deficiency conditions while leaf anthocyanins and free soluble phenolics in leaf and roots increased in low boron plants.