1Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta (Binzhou University). Binzhou, 256603, China
2Key Lab of ECORES, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, China
3Soil Fertilizer and Environment Resources Institute of Heilongjiang Academy of Agricultural Science, Harbin 150056, China
*Correspondence author, E. Mail: jinchuangwang@yahoo.com, wangjc@cib.ac.cn
The effects of coumarin application were investigated on growth, photosynthetic pigments, concentration of nitrate (NO3−), ammonium (NH4+), soluble proteins and Enzymes [nitrate reductase (NR), glutamine synthase (GS) and glutamate dehydrogenase (GDH)] activities in leaves of alfalfa (Medicago sativa). Five-day-old alfalfa seedlings were exposed to 0, 25 μM, 50 μM, 0.1 mM and 1 mM concentrations of coumarin. Up to 50 μM, coumarin did not affect the concentrations of N forms, key enzymes of nitrogen metabolism and plant growth. Above 0.1 mM concentrations, coumarin reduced the shoot and root fresh biomass, photosynthetic pigments, nitrate (NO3-), soluble proteins and NR activities and yet increased the ammonium (NH4+) concentration and GDH activities. Moreover, only 1 mM coumarin significantly reduced (32.64%) the activity of GS. Thus, it was concluded that coumarin at higher concentration adversely affects the plant growth and the key enzymes of nitrogen metabolism in alfalfa.
Alfalfa, coumarin, enzymes, Glutamate dehydrogenase (GDH), Glutamine synthase (GS), Nitrate reductase (NR), nitrogen metabolism, photosynthetic pigments, plant growth, soluble proteins
