Effects of Mn stress on seed germination and seedling physiological characteristics of Celosia argentea L.

Revealing the effects of heavy-metal stress on seed germination and seedling growth is the first step for effective controlling manganese（Mn） population by using these plants. In the present paper，we studied the relationship between Mn concentration and seed germination / and seedling growth of Celosia argentea by conducting seed germination experiments under different Mn concentrations（ 0.005，1.000，5.000， 8.000，12.000 and 15.000 mmol/L）. The results showed that seed germination rate，germination potential， germination index and vitality index all increased first and then decreased with Mn concentration increasing. The length of root（ r =-0.954，P =0.003） and shoot（ r =-0.957，P =0.003） of seedlings both decreased with Mn concentration rising when the Mn concentration ascended to a certain level. And the total biomass of seedling （r =-0.941，P =0.005） showed the same trend. Total amylase activity of seedlings（ r =-0.643，P =0.169） decreased with the increase of Mn concentration. And the soluble sugar content increased firstly and then decreased with Mn concentration rising. The results illustrated that the changes of amylase activity and soluble sugar content of seedlings under different Mn concentrations might be the most important reasons that causing the changes of seed germination and seedling growth.