不同光照强度对格木苗木生长和生理生化特性的影响

Effects of Illumination Intensity on the Growth and Physiological Characteristics of Erythrophleum fordii Oliv Seedlings

[目的]研究不同光照强度下格木苗木生长和生理生化特性变化,探讨苗木对不同光照条件的响应特征。[方法]对1年生格木实生苗进行自然全光照(NS)、60%NS、30%NS和15%NS 4种不同光照处理,处理结束后测定苗木生长与生理生化指标。[结果]1苗高及地径的生长量和生物量,在不同的光照下呈现不同的变化,在30%NS处理下达到最大,与全光照相比差异显著。2叶绿素a、b和总含量随着光照强度的减弱呈逐渐上升的趋势,在15%NS处理下达到最大,叶绿素a/b的变化比较缓和,随着光照强度的减弱呈现均匀下降的趋势;3可溶性蛋白和可溶性糖的含量随着光照强度的减弱先上升后下降,在30%NS处理下达到最大值,而游离脯氨酸含量受遮光强度的影响不显著;4SOD活性、CAT活性以及MDA含量均随着光照强度的减弱呈上升的趋势,在15%NS处理时达到最大值,POD活性在30%NS处理下最大。[结论]格木幼龄期需要适度遮阴,光强在不超过30%NS时苗木生长较好。

[Objective] To study the growth and physiological changes of Erythrophl.eumfordii Oliv seedlings under the different light conditions and to discuss the responses of seedlings to these illumination intensities. [ Method] The 1-year-old Erythrophleumfordii Oliv seedlings were treated under the condition of different illumination intensities,such as nature sunlight （NS） ,60% NS,30% NS and 15% NS. After the end of the treatment,seedling growth and physiological index were detected. [ Result] （1） The seedling height,ground diameter growth and biomass showed different changes under different light intensities,and the maximum was achieved under 30% NS illumination. （2） With the decrease of light intensity,chlorophyll-a,chlorophyll-b and total chlorophyll increased gradually,and the maximum value were presented in 15% NS. The chlorophyll a/b declined gradually with the decrease of light intensity. （3） The content of sohible protein and soluble sugar increased firstly and then declined with the decrease of light intensity,and reached the maximum at 30% NS,while the free proline content was not significantly affected by the light intensity. （4） The SOD activity, CAT activity and MDA content increased with the decrease of light intensity,which were the highest in the treatment of 15% NS, and the activity of POD was the highest in 30% NS. [ Conclusion ] Moderate shade is needed for E.fordii at juvenility period, and the seedling grows better when the light intensity was 30% NS.