Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (2): 355-360.DOI: 10.3773/j.issn.1005-264x.2009.02.013

• Research Articles • Previous Articles     Next Articles

CHANGES OF PROTECTIVE ENZYME ACTIVITY IN PYROLA DAHURICA BEFORE AND AFTER SNOW COVER IN NORTHEASTERN CHINA

MA Yu-Xin(), CUI Da-Lian   

  1. Marine Science College, Zhejiang Ocean University, Zhoushan, Zhejiang 316004,China
  • Received:2008-05-13 Accepted:2008-07-12 Online:2009-05-13 Published:2009-03-31

Abstract:

Aims Pyrola dahurica, an indicator of mixed conifer-broadleaved forest, is an important medicinal species in northeastern China. Our objective is to explore the mechanism of cold hardiness for this evergreen species during winter seasons.

Methods We studied changes in Malondialdehyde (MDA), cell membrane relative conductivity and the activities of peroxidase (POD) and superoxide dismutase (SOD) in the leaves of P. dahurica during two periods (November to December 2005 and March to April 2006) in Maoershan, Harbin, China.

Important findings Safe hibernation of P. dahurica depends on two critical periods, early stage of snow cover (ESSC: November to December in 2005) and late stage of snow cover (LSSC: March to April in 2006). ESSC extends from the beginning of snow cover to the peak of snow cover, and LSSC extends from the early to late stage of snow thaw. MDA content, cell membrane relative conductivity, and SOD and POD activity increased during the period of snow accumulation. Entering the peak period of snow cover, these same factors decreased as the temperature became higher and more constant under the snow. In the early stage of snow thaw in spring (March 1 to 15), temperature decreased and the MDA content increased, cell membrane relative conductivity increased to a higher level than in the period of snow accumulation and SOD and POD activities increased but were lower than in the period of snow accumulation. During the late stage of snow thaw (middle March), MDA content, relative conductivity of cell membrane and SOD and POD activity decreased.

Key words: Pyrola dahurica, MDA, SOD, POD, cell membrane permeability, snow cover