淹水胁迫对红椿家系幼苗几种生理生化指标的影响

以TC3、TC5、TC9、TC16和TC20等5个1年生红椿家系幼苗为试验材料，研究淹水胁迫对红椿幼苗的生理影响。结果表明:在短期淹水胁迫下（3~6 d），TC9和TC3叶绿素含量有小幅度的上升，TC16、TC9和TC3的MDA含量增长较慢，质膜相对透性呈先增加后下降，抗氧化酶SOD和POD活性增长快、峰值高，TC16、TC9和TC3的SOD活性最高值为854.287、899.598 U·g^-1和734.619 U·g^-1，TC16、TC9和TC3的POD活性最高值为33 463.156、37 573.641 U·g^-1·min^-1和31 786.820 U·g^-1·min^-1。在长期淹水胁迫下，5个红椿家系幼苗的叶绿素含量呈下降趋势，在淹水胁迫第21天，TC5和TC20的叶绿素含量最低为0.548 mg·g^-1和0.756 mg·g^-1，叶片几乎全部变黄；MDA含量增加，在淹水胁迫第21天，TC5和TC20MDA含量达到21.399 μmol·g^-1和17.019 μmol·g^-1；质膜相对透性增大，TC5和TC20相对电导率达到76.3%和74.3%；抗氧化酶SOD和POD活性呈下降趋势。可见，长期淹水对5个红椿家系幼苗影响大；TC9、TC3和TC16在短期淹水胁迫下具一定的适应性，在育苗造林中可优先选用。

Effects of Waterlogging Stress on Lipid Peroxidation and Antioxidant System in Leaves of Toona ciliate Seedlings

One-year-old seedlings of 5 Toona ciliate families,including TC3,TC5,TC9,TC16,and TC20 were used as materials to examine their physiological responses under waterlogging stress.Under the short-term (3-6 d) waterflooding stress,the chlorophyll content of TC9 and TC3 had a slight increase;the MDA content of TC16,TC9 and TC3 increased slowly;the relative cell membrane permeability increased first and then decreased;the content of the SOD and POD climbed up quickly and achieved the highest peaks,the highest SOD activity of TC16,TC9 and TC3 were 854.287,899.598,and 734.619 U·g^-1,respectively;the highest POD activity of TC16,TC9 and TC3 were 33 463.156,37 573.641,and 31 786.820 U·g^-1·min^-1,respectively.Under the long-term waterflooding stress,the content of chlorophyll of 5 T.ciliate families all decreased;the lowest chlorophyll content of TC5 (0.548 mg ·g^-1) and TC20 (0.756 mg ·g^-1) occurred on the 21 d with almost all yellowed leaves;the relative cell membrane permeability increased and the relative electric conductivity of TC5 and TC20 reached to 76.3% and 74.3%;the SOD activity and POD activity declined.The figures indicated that long-term waterlogging had a huge bad influence on the seedlings.It was concluded that TC9,TC3 and TC16 demonstrated certain adaptability to short-term waterlogging,which could be considered as the first choice in afforestation.