DMTU对香石竹切花花瓣水分胁迫的抗氧化效应

以香石竹切花马斯特品种为试材,以0、5 mmol/L、10 mmol/L三种浓度的二甲基硫脲(DMTU)作为瓶插液,对不同瓶插时期的香石竹切花花瓣细胞保护酶活性进行测定,以期从细胞膜保护酶水平上明确H2O2外源抑制剂DMTU改善香石竹切花应对水分胁迫能力的机理。实验结果显示:在瓶插前期用DMTU处理的超氧化物歧化酶(SOD)活性变化平稳,过氧化物酶(POD)活性显著高于对照,瓶插后期用DMTU处理的SOD活性、过氧化氢酶(CAT)活性均显著高于对照,POD活性低于对照,说明DMTU在瓶插早期主要对POD起到了保护作用,而瓶插后期主要对SOD和CAT起到了保护作用。对不同DMTU的浓度而言,浓度为10 mmol/L清除活性氧、维持保护酶活性的作用更强,但是10 mmol/L处理的瓶插寿命短于5 mmol/L处理,5 mmol/L处理的瓶插寿命长于对照,因此DMTU的处理浓度以5 mmol/L为宜。由此可见DMTU在香石竹切花衰老时可清除活性氧,提高保护酶活性,从而缓解水分胁迫带来的膜脂过氧化,延缓花瓣衰老进程,延长其瓶插寿命。

Antioxidant Effect of DMTU on the Petal of Cut Carnation during Water Stress

The activity of cells protective enzymes in the cut flowers of Dianthus caryophyllus were measured with various periods of bottle-cutting and concentrations of 0,5 mmol/L and 10 mmol/L of the bottle-cutting solutions by N,N'-dimethylthiourea(DMTU)respectively in order to definite the mechanisms for DMTU,the exogenous inhibitor of H2O2 would improve the coping capacity of cut carnation cells protective enzymes during water stress.The activity of superoxide dismutase(SOD)was stable while that of peroxidase(POD)was higher than CK remarkable by treatment with DMTU at early stage of bottle-cutting.And the activity of both SOD and catalase(CAT)was higher than CKremarkable while that of PODwas lower than CK by treatment with DMTU at later stage of bottlecutting.The results showed that DMTU protects POD in the early stage while does both of SOD and CAT in the later stage,mainly.10 mmol/L of DMTU was eliminate active oxygen and more effective in maintaining protective enzyme activity,but vase life treated by 10 mmol/L of DMTU was shorter than that of 5 mmol/L while which have a longer one than CK,so we suggest taking the forms of treat with 5 mmol/L of DMTU to the study.As results,DMTU would eliminate active oxygen,enhance the protective enzyme activity and relieve the peroxidation of lipid membrane induced by water stress,as to delaying the senescence process in flower petals of cut carnation and extend the stage of bottle-cutting.