不同遮阴环境对广西火桐幼苗生长及生理生化的影响

Effects of Different Shading Conditions on Growth,Physiological and Biochemical of Firmiana kwangsiensis Seedlings

为了解广西火桐幼苗在不同光照环境下的生长及生理响应机制,采用人工遮光方式设置4个不同光照度水平(7月晴朗天气13:00时光照度分别为5 362、2 413、584、183 Lux)开展广西火桐幼苗培育试验,5个月后测定其在不同光照环境下的生长和生理指标。结果显示:随着光照强度的减弱,广西火桐幼苗的株高、基径、叶片数、叶面积、主根长、根数、总生物量、地上部分生物量和根部生物量均呈现下降趋势,而叶长宽比则显著增大;随着光照强度的减弱,叶片的叶绿素含量呈现先上升后下降趋势;随着光照强度的减弱,叶片丙二醛(MDA)含量、可溶性蛋白含量和超氧化物歧化酶(SOD)活性呈现上升趋势,可溶性糖含量呈减少趋势,过氧化氢酶(CAT)活性呈现先增加后减小趋势,脯氨酸含量则呈现先减小后升高趋势,过氧化物酶(POD)活性呈现“降低-升高-降低”趋势。结果表明:广西火桐幼苗对弱光的适应性较弱,光照过弱不利于其生长发育。该结果可为广西火桐苗木繁育和野外种群复壮提供理论基础。

In order to understand the response mechanisms of growth and physiological of Firmiana kwangsiensis seedlings to different light environments.In this study,four different light treatments(the lux at 13:00 of clear weather in July was 5362,2413,584,183,respectively)were set up by using artificial shading method and used to cultivate the F.kwangsiensis seedings.After 5 mouths of treatment,the growth and physiological indicators of F.kwangsiensis seedlings were detected.The results showed that with decreasing of light intensity,the plant length,base diameter,leaf number,leaf area,main root length,root number,total biomass,biomass of over-ground parts,and biomass of root of F.kwangsiensis seedlings decreased,while the ratio of length and width of leaf increased.Chlorophyll content firstly increased and then decreased with decrease of light intensity.Moreover,with decreasing of light intensity,the MDA content,soluble protein content and SOD activity increased,while the soluble sugar content decreased.The CAT activity showed an initial increase before decreasing,while the proline content showed an initial decrease before increasing.The POD activity in leaves showed a trend of decreasing-increasing-decreasing with the decrease of light intensity.In summary,the weak light adaptation of seedings of F.kwangsiensis was weak,and weak light environment is unfavorable for growing of F.kwangsiensis seedings.This study provides theoretical basis for the cultivation of F.kwangsiensis,but also provides significant guidance for rejuvenation of its wild population.