Differential Responses of Anti-Oxidative Enzymes to Aluminum Stress in Tolerant and Sensitive Soybean Genotypes

ABSTRACT

Seedlings of two soybean genotypes, BX10 [aluminum (Al)-tolerant] and BD2 (Al-sensitive), were treated with Al to evaluate the relative root growth (RRG), callose content, Al-sensitive zone, lipid peroxidation, and the anti-oxidative enzyme activities by histochemical and biochemical assays. Under Al toxicity, the RRG reduction of BD2 was more significant than that of BX10, while callose content displayed a contrary trend. The 2–5 mm zone of root apex was the main Al-sensitive zone for soybeans. The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were found to be higher in the two genotypes under Al toxicity than that of the controls. The SOD, POD, and CAT activities of BX10; however, were significantly lower than those of BD2. These results implied that producing low quantity of ROS may be one aspect of the Al-tolerant mechanism for soybeans, which in turn helps them adapt to Al stress.

Keywords:

• soybean
• Al toxicity
• oxidative stress
• anti-oxidative enzymes
• Al-sensitive zone

ACKNOWLEDGMENTS

This research was supported by a grant (No. 40771107) from the Natural Science Foundation of China (NSFC), the Project of New Century Excellent Talents in University (NCET-05-0448), the Cultivation Fund of the Key Scientific and Technical Innovation Project (N0. 707027), Ministry of Education of China, the Foundation for Natural Science of the Jiangsu Bureau of Science and Technology (Nos. BK2007140 and BK2008265), and the Funds for the University Ph.D. Programs from the Ministry of Education of China (Nos. 20070284037 and 20070284061).