狭叶坡垒幼苗对PEG模拟干旱胁迫的生理响应

Physiological Responses of Seedlings of Hopea chinensis to PEG Simulated Drought Stress

以1年生狭叶坡垒(Hopea chinensis)幼苗为试材,采用聚乙二醇PEG-6000模拟干旱胁迫的方法,设置轻度干旱胁迫(T1,100 g/L PEG)、中度干旱胁迫(T2,200 g/L PEG)和重度干旱胁迫(T3,300 g/L PEG)、对照(CK,未添加PEG)4个水分处理,研究了干旱胁迫对狭叶坡垒幼苗生理生化特性的影响。结果表明,随着干旱胁迫程度的加剧和胁迫时间的延长,狭叶坡垒幼苗叶片的相对含水量迅速降低,MDA含量逐渐升高;狭叶坡垒幼苗叶片叶绿素含量在T1处理下缓慢上升,T2、T3处理下先缓慢升高后降低;可溶性蛋白含量和可溶性糖含量的变化趋势相类似,均呈先升高后降低的趋势,但可溶性糖含量在前期(24 h)和中期(48 h)时增幅较大。说明在干旱胁迫下狭叶坡垒幼苗受到一定程度的伤害,但可以通过调节自身可溶性蛋白和可溶性糖等渗透调节物质的含量来提高其吸水和保水能力,可减轻干旱伤害。其中,可溶性糖可能是狭叶坡垒的重要渗透调节物质。

To study the physiological characteristics under the PEG-6000 simulated drought stress,one-year-old Hopea chinensis seedlings were planted under four different soil moisture levels including,mild drought stress （T1,100 g/L PEG）,moderate drought stress（T2,200 g/L PEG）,severe drought stress（T3,300 g/L PEG）,and clear water content（CK）.The results showed that with the increase of intensity and duration of drought stress,the relative water content of seedling rapidly decreased and MDA content increased consistently.Along with the time of drought stress the chlorophyll content of seedling slowly increased when treated with T1,but increased first and then decreased in treatments T2 and T3-.The soluble protein and soluble sugar contents increased firstly and then decreased.At the early and middle stage of drought stress（within 24 and 48 hours）,increment of soluble sugar content was larger than that of soluble protein content.The results indicated that the growth of Hopea chinensis seedlings were negatively influenced by drought stress.Osmatic adjustment substances （soluble protein and soluble sugar） could adjust themselves to avoid water drought harms.Soluble sugar was an important osmatic adjustment agents.