肉桂酸对平邑甜茶幼苗根系呼吸速率及相关酶活性的影响

Effects of Cinnamon Acid on Respiratory Rate and Its Related Enzymes Activity in Roots of Seedlings of Malus hupehensis Rehd

【目的】探讨外源肉桂酸对平邑甜茶幼苗根系呼吸速率和相关酶活性的影响,为深入研究肉桂酸等酚酸类物质在苹果连作障碍中造成伤害的机理提供参考。【方法】将20ml不同浓度的肉桂酸溶液浇至栽植平邑甜茶幼苗的营养钵中,处理后定期取样,在恒温(25℃)条件下用液相Oxy-Lab氧电极测定根系呼吸速率,用冻样测定相关酶活性。【结果】测定期内,5mg·kg-1土、25mg·kg-1土浓度处理使基础呼吸速率和三羧酸循环(TCA)、磷酸戊糖(PPP)途径的呼吸速率均表现初期上升随后(第3天)下降但末期有所恢复的趋势,而糖酵解途径(EMP)的呼吸速率则持续下降在末期小幅回升;125mg·kg-1土浓度处理后基础呼吸速率及3条途径呼吸速率均呈下降趋势;磷酸果糖激酶(PFK)、苹果酸脱氢酶(MDH)和葡萄糖-6-磷酸脱氢酶(G-6-PDH)活性变化趋势分别与其对应途径呼吸速率变化相似。【结论】一定浓度的肉桂酸可抑制平邑甜茶幼苗根系基础呼吸速率以及EMP、TCA、PPP途径的呼吸速率,其中,高浓度下TCA途径呼吸速率下降更为显著。各途径对应相关酶活性与其呼吸速率变化相一致,随处理浓度的升高各酶活性均降低。

【Objective】 The objectives of this research were to study the effect of different concentrations of cinnamon acid application on respiratory rate and its key enzymes activity in roots of seedlings of Malus hupehensis Rehd.The mechanisms were discussed so as to provide a basis for further study on the cause of diseases in apple continuous cultivation.【Method】 Twenty milliliters of different concentrations of cinnamon acid were added to the containers,and the respiratory rate of roots was measured by solution OXY-LAB oxygen electrodes under 25℃ and the key enzymes＇ activity was also determined.【Result】 At 5 and 25 mg·kg^-1（soil）,the total respiratory rate had a similar trend with tricarboxylic acid cycle（TCA） and pentose phosphate pathway（PPP）,T1,and T2 were higher than the control on the 1st day and then declined three days late but they had a recover on the last day.Embden-Meyer-hot-Parnas pathway（EMP） had a declined trend forever.The respiratory rate of the total and three pathways were decreased under 125 mg·kg^-1（soil）.The enzyme activity of pyrophosphate-dependent phosphofructokinase（PFK）,glucose-6-phosphate dehydrogenase（G-6-PDH） and malate dehydrogenase（MDH） were similar to relative respiratory pathway.【Conclusion】 Cinnamon acid destroyed the respiratory mechanism of roots of seedlings of Malus hupehensis Rehd.,and reduced the respiratory rate of total,EMP,TCA and PPP,meanwhile,reduction of respiratory rate are increased with the improvement of concentration of cinnamon acid.Three enzymes have a similar trend with respiratory rate.