干旱胁迫对黄檀幼苗生长及生理特性的影响

Effects of Drought Stress on Growth and Physiological Characteristics of Dalbergia hupeana Seedlings

以人工栽培的黄檀实生苗为试验材料,采用盆栽控水法,研究不同干旱胁迫程度对黄檀幼苗生长及生理特性的影响。结果表明:正常浇水处理(CK)下,黄檀幼苗的各项指标大多无显著性差异变化,且生长良好;其他处理组则随干旱胁迫程度和时间的增加,黄檀叶片相对含水量、叶绿素a质量分数、叶绿素b质量分数、株高和地径相对生长量逐渐降低,类胡萝卜素、可溶性糖和可溶性蛋白质量分数以及SOD、POD活性在胁迫初期时呈上升趋势,但随胁迫时间的延长呈先上升后下降的趋势,SOD活性在胁迫7 d时达到最大值,可溶性糖和可溶性蛋白质量分数则在胁迫14 d时达到最大值;轻度和中度干旱胁迫下,黄檀幼苗通过提高SOD、POD活性、积累渗透调节物质来提高细胞的保水性,维持正常的光合作用和植物生长;重度和极度干旱胁迫下,黄檀幼苗叶片的相对含水量、光合色素和可溶性蛋白质量分数、SOD和POD活性显著下降,并随胁迫时间的延长,显著抑制黄檀幼苗的生长,且叶片出现萎蔫下垂现象,极度干旱胁迫28 d时黄檀叶片全部枯落。综合可知,黄檀幼苗具有较强的抗旱性和适应能力,能通过自身调节适应轻度和中度干旱胁迫。

Using cultivated artificially Dalbergia hupeana seedlings as experimental materials,pot method was conducted to study the effects of different drought stress levels on the growth and physiological characteristics of D.hupeana seedlings.Under normal watering treatment(CK),most of the indicators of D.hupeana seedlings showed no significant difference and grew well.With the increase of drought stress degree and time,the relative water content,chl a,chl b,plant height and stem diameter of D.hupeana decreased gradually in other treatment groups.The contents of carotenoid,soluble sugar,soluble protein,and the activity of SOD and POD showed an upward trend at the early stage of drought stress,but increased first and then decreased with the prolongation of stress time.The activity of SOD reached the maximum value at 7 th day of stress,the contents of soluble sugar and soluble protein reached the maximum value at 14 th day of stress.Under mild and moderate drought stress,the D.hupeana seedlings can improve the water holding capacity of cells,maintain normal photosynthesis and plant growth by increasing SOD and POD activities and accumulating osmoregulation substances.Under severe and extreme drought stress,the relative water content,photosynthetic pigment and soluble protein contents,SOD and POD activities of leaves of D.hupeana seedlings decreased significantly,and with the extension of stress time,significantly inhibit the growth,then the wilting and drooping phenomenon appeared,and the leaves of D.hupeana all withered after 28 d under extreme drought stress.Thereofore,D.hupeana seedlings have strong drought resistance and adaptability,and can adapt to mild and moderate drought stress through self-regulation.