Physiological Response of Medicago polymorpha L. ‘Chuxiong’ under Aluminum Stress

PurposeTo explore the physiological response of Medicago polymorpha L. ‘Chuxiong’ under aluminum stress.

MethodsUnder acidic conditions (pH=5), the seeds of M. polymorpha L. ‘Chuxiong’ were cultured in Hogland nutrient solution with different aluminum ion (Al³⁺) mass concentrations, and the seed germination, root growth, seedling osmotic regulation system, malondialdehyde content and reactive oxygen species system were measured after 15 days.

ResultsWith the increase of mass concentration of Al³⁺, the germination rate, germination vigor, root volume and catalase (CAT) activity of alfalfa gradually decreased; the root fresh weight, root length, root water content, and superoxide dismutase (SOD) and peroxidase (POD) activities were increased first and then decreased. When the mass concentration of Al³⁺ was 500 mg/L, the root water content of alfalfa and the SOD and POD activities in seedling leaves reached the maximum. When the mass concentration of Al³⁺ reached 700 mg/L, it could seriously inhibit the growth, seed germination, SOD and POD activities of M. polymorpha L. ‘Chuxiong’, and accumulate a large amount of malondialdehyde, soluble sugar and proline.

ConclusionM. polymorpha L. ‘Chuxiong’ has strong resistance to aluminum toxicity and can be popularized and planted in acidic soil with Al³⁺ mass concentration less than 700 mg/L.