Chin J Plant Ecol ›› 2007, Vol. 31 ›› Issue (3): 476-483.DOI: 10.17521/cjpe.2007.0059

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WANG Ying-Chun, LI Xiao*()   

  1. College of Life Sciences, Inner Mongolia University, Huhhot 010021, China
  • Received:2006-03-16 Accepted:2006-11-14 Online:2007-03-16 Published:2007-05-30
  • Contact: LI Xiao


Aims Potaninia mongolica is a xerophytic shrublet in the East Alashan-West Erdos Region of Inner Mongolia. It is an ancient species in its own genus and well-adapted to drought environments with fissurate growth and summer dormancy.
Methods We selected Dengkou as our research site and collected three stages of P. mongolica (before, during and after fissuration) during August 1-5, 2002 and 2003. We used PV technique and measured several water relations parameters (${φ_{s}}^{sat}$、${φ_{s}}^{tlp}$, ROWC tlp, RWC tlp,Δφ, εmax etc.) in different stages of fissurate growth for comparison and analysis of drought tolerance and its mechanisms.
Important findings Different stages of P. mongolica had different abilities and pathways to maintain turgor pressure. Fissurate growth decreased the species' drought tolerance and involved multiple adaptations to drought. Before fissuration, osmotic adjustment occurred by the addition of solute to cells (such as, proline) and decreasing the loss of water in the body, so that it could maintain normal turgor pressure during drought. After fissurate growth, turgor pressure was maintained by higher cell and tissue elasticity (lower εmax) and by osmotic adjustment for normal plant development in dry conditions and to avoid dehydration under water stress during the drought period, but it also became more sensitive to water stress. The ability to maintain turgor pressure varied from strong to weak during the period before, during and after fissuration. Fissurate growth decreased the ability of P. mongolica to maintain turgor pressure and led to changes in walls related to drought tolerance.

Key words: Potaninia mongolica, fissurate growth, PV technique, water parameters, drought tolerance