根皮苷对平邑甜茶根系TGA循环酶的影响

摘要

[目的]研究平邑甜茶根系TCA循环对根皮苷的响应,为深入探讨根皮苷等酚酸类物质在苹果连作障碍中造成的伤害机理提供参考.[方法]以根皮苷和根皮苷+ KMnO4(两者摩尔浓度比4∶1)处理盆栽平邑甜茶植株,测定根系呼吸速率、TCA循环相关的9种酶活性、根皮苷的含量.[结果]4 mmol·L-1根皮苷处理抑制了根系基础呼吸速率,显著抑制了柠檬酸合酶(CS)、顺乌头酸酶、异柠檬酸脱氢酶(ICDH)、琥珀酸硫激酶(SCS)、琥珀酸脱氢酶(SDH)、延胡索酸酶(FUM)、苹果酸脱氢酶(MDH)的活性.根皮苷+KMnO4处理显著提高了CS、顺乌头酸酶、MDH活性,分别是对照的3.79倍、1.27倍、1.11倍；也不同程度地提高了SCS、ICDH、SDH和FUM活性.4mmol·L-1根皮苷处理显著提高了α-酮戊二酸脱氢酶系(α-KGDH)和丙酮酸脱氢酶系(PDH)的活性,而根皮苷+KMnO4处理明显降低了α-KGDH和PDH的活性但仍明显高于对照水平.根皮苷+KMnO4处理土壤中根皮苷的含量显著低于根皮苷处理.[结论]4 mmol·L-1根皮苷抑制平邑甜茶根系呼吸速率,降低根系TCA循环7种酶活性,1 mmol·L-1KMnO4能缓解上述不利影响.%[Objective] A pot experiment was conducted to study the effects of phloridzin on the tricarboxylic acid cycle (TCA) of roots of Malus hupehensis Rehd. Which is used widely as apple common stocks. The mechanisms were discussed so as to provide a basis for further study on the cause of apple continuous cropping diseases. [Method] Phloridzin of 4 mmol·L-1 and KMnO4 of 1 mmol·L-1 were used in the pretreatment. Malus hupehensis Rehd. Were planted in pots and treated with phloridzin of 4 mmol·L-1 (T1) and phloridzin of 4 mmol·L-1 added with KMnO4 of 1 mmol·L-1 (T2). The content of phloridzin in the soil and respiratory rate of roots were determined. Activities of enzymes related to TCA including citrate synthase (CS), aconitase, isocitrate dehydrogenase (ICDH), α-ketoglutarate dehydrogenase (α-KGDH), succinate thiokinase (SCS), succinate dehydrogenase (SDH), malic dehydrogenase (MDH), fumarase (FUM) and pyruvate dehydrogenase (PDH) were also determined. [Result] Treatments with T1 inhibited the respiratory rate of roots of Malus hupehensis Rehd., decreased obviously enzyme activities for the most part including CS, aconitase, ICDH, SCS, SDH, FUM, MDH only except for a-KGDH and PDH that their enzymes activities were improved. However, treatments with T2 had a critical difference from T1, it significantly enhanced the activities of CS, aconitase and MDH even over the control level, increased obviously the activity of SCS close to the control level, and to some degree improved the activities of ICDH, SDH and FUM. Besides, the activities of α-KGDH and PDH of T2 treatments were assayed to be a lower level than T1 but higher than the control level. Furthermore, the content of phloridzin in soil of T2 was less than T1. [Conclusion] The results showed that phloridzin at the concentration of 4 mmol·L-1 could inhibit the respiratory rate and the enzyme activities (7 of 9) related to TCA of roots of Malus hupehensis Rehd. With the treatments time following. The treatment of 1 mmol·L-1 KMnO4 could ease the above-mentioned adverse impact.