干旱胁迫对红花玉兰幼苗生长和生理特性的影响

Growth and Physiological Characteristics of Magnolia wufengensis Seedlings under Drought Stress

以1年生红花玉兰幼苗为试验材料,采用称重控制土壤含水量的方法,设置对照(CK)、轻度干旱胁迫(T1)、中度干旱胁迫(T2)和重度干旱胁迫(T3)4个水分处理水平,研究了干旱胁迫对红花玉兰幼苗生长过程中的生长和生理生化指标的影响.结果显示:(1)随着干旱胁迫的加剧,红花玉兰幼苗株高、地径和生物量逐渐降低,可溶性蛋白含量逐渐升高,叶绿素a、叶绿素b和总叶绿素含量在T1处理略有升高,在T2和T3处理明显降低.(2)随着胁迫时间的延长,红花玉兰幼苗叶片组织相对含水量降低,丙二醛含量先升后降再升,脯氨酸含量逐渐升高,保护酶SOD、POD、CAT和APX活性均呈先增加而后降低的变化趋势.研究表明,在不同程度的干旱胁迫条件下,红花玉兰幼苗的生长受到一定程度的抑制,但能够通过调节自身的保护酶系统活性和渗透调节物质含量来减轻干旱伤害,维持植物体的正常生理代谢功能,从而表现出一定的抗旱耐旱潜力.

To study the growth and physiological characteristics under drought stress,1-year-old Magnolia wufengensis seedlings were potted under four different soil content levels：optimal water content（CK）,mild drought stress（T1）,moderate drought stress（T2） and severe drought stress（T3）,which were controlled by weighing the soil and pots.The result showed that：（1） with drought stress became more and more serious,the heights,base diameters and biomass of the seedlings decreased significantly;Chl a,Chl b and total Chl contents increased in treatment T1,decreased in treatments T2 and T3;and the contents of soluble protein increased observably.（2）Along with the period of drought stress continued,the RWC in seedlings＇ leaves decreased,the MDA content showed a trend of increasing firstly,decreasing then,and increasing at last,and proline content increased continuously,the variation trend in SOD,POD,CAT and APX activities was increase firstly and decreased then.We can concluded that the growth of Magnolia wufengensis seedlings were negatively influenced by different degree of drought stress,but the protective enzyme system and osmatic adjustment substance could adjust themselves to avoid water drought harms,which led to some tolerant ability of Magnolia wufengensis to drought conditions.