Chin J Plant Ecol ›› 2007, Vol. 31 ›› Issue (1): 145-149.DOI: 10.17521/cjpe.2007.0018

• Research Articles • Previous Articles     Next Articles

ECOPHYSIOLOGICAL RESPONSE OF TAMARIX LAXA TO CADMIUM STRESS

DING Xiao-Dong, GAO Dong-Rui, FENG Gu()   

  1. College of Nature Resource and Environmental Science, China Agricultural University, Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing 100094, China
  • Received:2005-10-25 Accepted:2006-04-13 Online:2007-10-25 Published:2007-01-30
  • Contact: FENG Gu

Abstract:

Aims Excretion of salt by gland had been studied, but the response of salt glands to heavy metals was rarely explored. A hydroponic cultivation experiment was conducted in glasshouse with excretohalophyte to investigate: 1) if salt gland is able to excrete Cd2+ ions, 2) extent of Cd2+ tolerance for secretohalophyte, and 3) possible mechanisms by which the excretohalophyte is able to resist Cd2+ stress.

Methods Branches of Tamarix laxa plants were cut into 15 cm sections and propagated for 3 months. They were then transferred into hydroponic cultivation with a Hoagland's nutrient solution for 20 days and treated with 0, 10, 50, 200 and 500 μmol·L -1 Cd2+ for 2 weeks to determine the uptake and excretion of Cd2+.

Important findings There were no significant differences in the relative growth rate or water content of the plants between the treatment with 10 μmol·L -1 Cd2+ and the control. When Cd2+ levels exceeded 50 μmol·L -1, the shoots of T. laxa suffered toxicity. Cd2+ excretion through salt glands was detected in all Cd2+-added treatments, but the total amount was lower, although the amount of secreted Cd2+ from salt gland was increased with increasing of Cd2+ levels. Salt glands excreted Cd2+, but the secretion plays less important role in Cd2+ toxic resistance for excretohalophyte.

Key words: Tamarix laxa, cadmium, salt gland, excretion