MOLYBDENUM DEFICIENCY IN WINTER WHEAT SEEDLINGS AS ENHANCED BY FREEZING TEMPERATURE

Abstract

Molybdenum (Mo) deficiency caused killing of winter wheat seedlings during winter season in southern China has become a problem limiting wheat yield. The effects of low temperature (−5°C–0°C) on Mo deficiency of winter wheat seedlings (Triticum aestivum L. var. “Lumai22”) were investigated in a pot experiment with an acid soil. After induction by low temperature, symptoms of Mo deficiency appeared quickly in whole plants of no Mo (−Mo) treatment, especially in lower leaves. Molybdenum deficiency increased the rate of K⁺ leakage at 9 h and 24 h after cold treatment in lower and upper leaves respectively. Nitrate reductase activity decreased with − Mo treatment under low temperature conditions, free amino acid content decreased corresponding to it. Total soluble sugar and sucrose contents in functional and primary leaves were raised in − Mo treatment as a whole. After low temperature treatment, total soluble sugar and sucrose content in functional leaves of Mo deficient plants dropped, while those in primary leaves increased, indicating sugar transported from old leaves to primary leaves where sugar is not enough. Mo deficiency had less influence on superoxide dismutase, and catalase activity, however peroxidase activity raised by − Mo treatment under low temperature. It is concluded that Mo deficiency has a close relationship with low temperature induction.

ACKNOWLEDGMENTS

We are grateful to Prof. Jeschke for reviewing the manuscript. This work was supported by the Major State Basic Research Development Programme of the People's Republic of China (Project No. G1999011707).