Abstract: The effects of increasing levels(0,0.1,1.0,10 and 20 μmol/L)of sorbitol-boric acid(SB)and boric acid(BA)on the boron concentrations,the activities of major antioxidant enzymes(superoxide dismutase,SOD;peroxidase,POD,and polyphenoloxidase,PPO),soluble protein content and chlorophyll fluorescence parameters(Fo,Fm,Fv,Fo',Fm',Fv',qP,ΦPSII,ETR and NPQ)of wheat(Triticum aestivum L Huaimai 19)seedlings were investigated.The results showed that B content in roots,vagina and leaves of wheat seedlings increased significantly with the increasing concentrations of B in culture solution.B content in roots and leaves treated with SB increased more than that treated with BA.And B deficiency resulted in the increase of SOD,POD and PPO activity.The two kinds of B could significantly reduce their activities.And the reduction was significant in treatments with lower concentrations(0.1,1.0 μmol/L)of SB.When the concentration of B in culture solution was less than 20 μmol/L,the quantum yield of electron transfer at PSII(ΦPSII),photochemical quenching coefficient(qP)and electron transfer rate(ETR)values increased with the increase of it.These parameters increased more significantly in the treatment with SB.But at 20 μmol/L,they declined perhaps due to B excess.So we speculated that compared to BA,SB was more advantageous to the absorption and utilization by wheat seedlings and translocation in body more easily.

Key words: Sorbito-l boric acid comp lexes, Boric acid, Antiox idant enzymes, Ch lorophyll fluorescence, Wheat seed lings

CLC Number: 

• S512.01