ABSTRACT:
Drought stress is one of the most important
factors limiting the survival and growth of
plants in different habitats of Egypt. This
study was carried out to investigate the effect
of drought stress on growth and some
metabolic activities of sunflower seedlings
under treatments with ascorbic acid (AsA) or
CaCl2. Drought stress showed a marked
reduction in shoot length, leaf area, shoot
fresh and dry weight, photosynthetic
pigments, soluble sugar , and amylase activity.
On the other hand, root length, soluble
proteins, protease activity, proline content ,
soluble phenolics and flavonoid contents,
phenylalanine ammonia lyase (PAL) ,
peroxidase (POX) , polyphenol oxidase (PPO)
activities, H2O2 and Malondialdehyde (MDA)
contents, and total antioxidant capacity were
induced compared with normal plant. The
application of AsA or CaCl 2 mitigated the
drought stress throughout the increase of
growth criteria, antioxidant enzymes and
photosynthetic pigments and decreased of
H2O2, Malondialdehyde (MDA) , soluble
phenolics and flavonoid contents. |
