【摘要】 测定了荒漠地区超旱生小灌木红砂在3种生境(山前荒漠、山前戈壁和中游戈壁)下的叶片水分状态、抗氧化酶活性及渗透调节物质含量,以探讨荒漠植物在不同生境下的生理生化特征及对荒漠极端环境的适应机制。结果表明:在3种生境下,红砂叶片相对含水量和叶片水势随着土壤含水量的下降而下降,叶绿素含量随着土壤含水量的下降而升高。随着生境土壤干旱的加剧,超氧化物歧化酶(SOD)及过氧化物酶(POD)活性逐渐升高,而过氧化氢酶活性下降。在土壤含水量较少的戈壁生境,渗透调节物质含量上升。SOD和POD活性的升高是红砂抵御干旱环境的主要抗氧化保护机制;渗透调节在红砂叶片适应干旱胁迫的过程中发挥着重要作用,高的渗透调节能力使红砂在水分不足的条件下维持较低的渗透势,有利于植物吸水,从而增强其耐旱性。更多还原

【Abstract】 Reaumuria soongorica,an extreme xeric subshrubs in desert areas,was used to quantified the water status,chlorophyll contents,antioxidant enzymes activities and osmotic adjustment solute contents in three habitats(piedmont of desert,piedmont of Gobi and the middle reaches of the Gobi),and to investigate the adaptive mechanism of physiological and biochemical response to desert condition.The results showed that in different habitats,the relative water content and leaf water potential of R.soongorica decreased with the soil moisture content decreasing,while the chlorophyll contents rose.Meanwhile,with the soil drought intensified,superoxide dismutase(SOD)and peroxidase(POD)activities increased.In gobi desert with lesser soil moisture content,the osmotic adjustment substances were increasing.It could be concluded that the in different habitats,increasing SOD and POD activities of R.soongorica was one of the major antioxidant protection mechanism to resist drought environments.Osmotic adjustment played an important role in water shortage conditions to maintain a lower osmotic potential,and is more conducive to plant water uptake and enhancing its drought tolerance.更多还原