Cold-acclimation and root temperature protection from chilling injury in chilling-sensitive mungbean (Vigna radiata L.) seedlings

Abstract

Exposure of mungbean seedlings to 4℃ for 2 days induced irreversible chilling injury. The major cation in the leakage from tissues of unacclimated seedlings was K(superscript +), the loss of which was 7 to 10-fold greater than that of Ca(superscript ++) or Mg(superscript ++). Acclimation of seedlings at 10℃ protected them from the injuries caused by the 4℃ treatment. Acclimation of seedlings at 10℃ for 2 to 3 days, significantly decreased the conductivity and the concentration of soluble sugars, free amino acids, and cations (K(superscript +), Mg(superscript ++) and Ca(superscript ++)) in the leakage. Compared to the 28℃-root/28℃-shoot control seedlings, those in the 28℃-root/4℃-shoot treatment did not suffer noticeable injury, but seedlings in the 4℃-rootl4℃-shoot treatment did. The solute potential, water potential, and the concentration of free amino acids and cations (K(superscript +), Mg(superscript ++), and Ca(superscript ++)) in the cell sap of the 28℃-root/4℃-shoot seedlings were similar to those of the control seedlings.