[Endogenous NO and ROS generation in grape roots and leaves under CdCl2 stress]

Taking the cutting seedlings of grape variety 'Ze-xiang' as test materials, a hydroponic experiment was conducted to study the generation patterns of endogenous nitric oxide (NO) and reactive oxygen species (ROS) in their roots and leaves, and the changes of root MDA content and root activity under the stress of cadmium chloride (CdCl2). In the treatments 0-1 mmol x L(-1) of CdCl2, the NO content and NOS activity in roots and leaves and the root activity all presented a tendency of increasing first and decreasing afterwards with increasing CdCl2. At 0.01 mmol L(-1) of CdCl2, the NO content and NOS activity in roots increased by 51% and 63%, respectively; but at >0.1 mmol L(-1) of CdCl2, they decreased significantly. At 0.01 and 0.05 mmol x L(-1) of CdCl2, the leaf NO content and NOS activity had the greatest increase; at 0.5 and 1.0 mmol x L(-1) of CdCl2, the root O2 generation rate and H2O2 and MDA contents increased significantly. At the same concentrations of CdCl2, the O2 generation rate in leaves was much lower while the H2O2 content was much higher, compared with those in roots.