涝渍胁迫对桢楠幼树不同功能根系生理生化特性的影响

Effects of waterlogging stress on physiological and biochemical characteristics of different functional root systems of Phoebe zhennan saplings

【目的】探讨不同程度涝渍胁迫对桢楠幼树不同功能根系生理生化特性的影响,为桢楠苗圃水分管理及造林地的选择提供理论依据。【方法】以3年生桢楠幼树为研究对象,进行盆栽渍水处理,试验设对照(CK,不进行水淹)、轻度渍水(H5,淹水深5 cm)、中度渍水(H10,淹水深10 cm)、重度渍水(H15,淹水深15 cm)和完全渍水(H20,淹水深25 cm)5个处理,在处理第51天(H20处理叶片出现萎蔫)时,测定桢楠幼树吸收根和运输根的生长及生理生化指标。【结果】(1)除对照(CK)和完全渍水(H20)处理外,涝渍胁迫均可使桢楠幼树产生不定根,且胁迫程度越重新生不定根越少。(2)相较于CK,运输根根系活力在渍水胁迫下显著降低(P<0.05), H5、H10、H15和H20处理分别降低45.77%,74.58%,75.67%和90.72%;而吸收根则在胁迫程度重于中度渍水后才出现显著降低的趋势(P<0.05),在H20处理下降幅最大,相较于CK降低89.63%。(3)桢楠幼树运输根与吸收根H2O2、SP、SS含量及POD活性变化趋势基本一致,均随渍水强度的增加呈现先升高后降低的趋势;MDA含量呈降-升-降的变化趋势;随着渍水强度的增加,桢楠幼树吸收根SOD活性整体呈降低趋势,而运输根的SOD活性则呈先升高后降低的趋势,在H15处理下达最大值,且H5、H10、H15和H20处理分别比CK处理增加9.07%,9.81%,17.89%和8.66%。【结论】轻度渍水能促使桢楠幼树产生大量不定根,在一定程度上抵抗涝渍胁迫对根系的伤害;重度渍水处理后桢楠幼树根系表现出明显的受害症状。受到渍水胁迫时,桢楠幼树运输根表现出更强的抗氧化能力,而吸收根则表现出更强的敏感性和更快的更新能力。

【Objective】 The effects of waterlogging stress on physiological and biochemical characteristics of different functional root systems of Phoebe zhennan saplings were investigated to provide basis for water management in P. zhennan nursery and site selection in afforestation.【Method】 Three-year-old Phoebe zhennan saplings were treated with potted waterlogging.Five treatments including CK,H5,H10,H15 and H20 were set up with watering depths in the basin of 0,5,10,15 and 25 cm,respectively.The growth as well as physiological and biochemical characteristics of absorbing and transporting roots of P. Zhennan saplings were measured on day 51 of treatment, when plant leaves in treatment H20 withered.【Result】(1) Except H20 and CK,waterlogging stress caused adventitious roots of P. Zhennan saplings,and greater stress led to fewer new adventitious roots.(2) The activity of transporting roots decreased significantly under waterlogging stress(P<0.05) compared with CK,and it was decreased by 45.77%,74.58%,75.67% and 90.72% in the treatments of H5,H10,H15 and H20,respectively.The significant decrease of absorbing root activity emerged in treatments H10-H20,with the largest decrease of 89.63% in H20 treatment.(3) With the increase of waterlogging intensity,the change trends of contents of H2O2,SP and SS and POD activity in absorbing roots were same of increasing first followed by decrease,while MDA content showed decreasing-increasing-decreasing trend.With the increase of waterlogging intensity,SOD activity of absorbing roots decreased,while that of transporting roots increased first before decrease.The maximum was in H15 treatment,and that of H5,H10,H15 and H20 treatments were increased by 9.07%,9.81%,17.89% and 8.66%,respectively.【Conclusion】 Mild waterlogging induced a large number of new adventitious roots in P. Zhennan saplings,which can resist the damage of waterlogging stress.After severe waterlogging treatment,roots showed damage symptoms.With waterlogging stress,absorbing root systems showed stronger sensitivity and faster renewal ability,while transporting root systems showed stronger antioxidant capacity.