Effects of iso-osmotic Ca(NO_3)_2 and NaCl stress on root morphology and activity of cucumber seedlings

In order to investigate the effects of iso-osmotic Ca(NO3)2 and NaCl stress on the morphology,the activity of root and growth of cucumber seedlings,cucumber cultivar'Jinchun 2'(with less salt resistance)was used to carry out the experiment by nutrient solution culture.The results showed that both of salt stress significantly inhibited root growth,and decreased the root surface area and root volume obviously.Under 56 mmol·L-1 Ca(NO3)2 stress the total root biomass declined by 29.23% and the root length decreased significantly,but the lateral root density and average root diameter increased obviously.Root tips became short but swollen,and the whole root grew like clusters and the root activity increased significantly.Meanwhile,under 84 mmol·L-1 NaCl stress the total root biomass significantly decreased by 43.08% and the decline in total root length was less than the isotonic Ca(NO3)2 stress,but the lateral roots density and average root diameter decreased obviously,the root became slender,and the root activity decreased significantly.In conclusion,both salt stress inhibited the root growth and changed the root architecture,and the inhibition of NaCl on root was greater than that of isotonic Ca(NO3)2.