摘要
绵刺(Potaninia mongolica)是西鄂尔多斯-东阿拉善地区特有的单种属残遗植物。选取内蒙古磴口县境内具有绵刺群落的草原化荒漠区为研究样区,于2002~2003年每年8月1~5日采集未劈裂、正在劈裂和已劈裂植株,运用PV技术对不同劈裂生长状态绵刺的多种水分关系参数(φssat、φstlp、ROWCtlp、RWCtlp、Δφ、εmax等)进行了测定,从绵刺保持膨压的能力和途径两方面进行了深入探讨;同时结合同一项目研究中绵刺劈裂生长过程中抗氧化酶系统和内源激素方面的研究成果,综合分析并探讨了绵刺劈裂生长的发生机理及其环境适应性。结果表明:1)未劈裂绵刺主要通过增加细胞内溶质(如脯氨酸),减少细胞内的水分丧失来进行渗透调节,从而在干旱胁迫下能够维持正常的膨压。2)已劈裂绵刺通过渗透调节和高的组织弹性两条途径来共同保持膨压,以抵抗不良的生存环境;同时对环境水分胁迫具有较高的敏感性。3)3种状态绵刺保持膨压的能力由强到弱依次为:未劈裂绵刺、正在劈裂绵刺、已劈裂绵刺。4)劈裂的发生导致绵刺保持膨压能力的降低,同时耐旱方式和途径发生了变化。
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 (φs^sat, φs^tlp, ROWC^tlp, RWC^tlp, △φ, ε^max 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 ε^max) 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.
出处
《植物生态学报》
CAS
CSCD
北大核心
2007年第3期476-483,共8页
Chinese Journal of Plant Ecology
基金
国家自然科学基金资助项目(30060006和30460033)
关键词
绵刺
劈裂生长
PV技术
水分参数
耐旱性
Potaninia mongolica, fissurate growth, PV technique, water parameters, drought tolerance