Introduction: Toxic soil concentrations of the essential micronutrient boron (B) represent major
limitations to crop production worldwide. Plants have a range of defense systems that might be
involved in their affinity to resist and tolerate nutrients stress.
Materials and methods: The experiments were carried out to study the differential responses in five
wheat cultivars to boron toxicity.
Results: The fresh and dry matter yield of the test wheat cultivars showed marked decrease as the
concentration of boron was increased. Elevated concentration of boron had a notable inhibitory effect
on the biosynthesis of pigments fractions in the test wheat cultivars as severely as dry matter gain.
The adverse concentration effects of boron on some metabolic responses were clearly displayed by
shoot and root systems, exhibited in the elevated rates of proline, hydrogen peroxide and
malondialdehyde formation. Potassium leakage was severely affected by boron-stress in some
cultivars at all tested concentrations, while in some others a moderate damage was manifested only
at the higher boron concentrations.
Conclusions: Sakha 93 out of all the different cultivars investigated was found to display the lowest
sensitivity to boron-stress, while Gemmeza 9 was the most sensitive one.