N-苯基-2-萘胺和邻苯二甲酸对生菜抗氧化系统及矿质养分吸收的影响

Effect of N-phenyl-2-naphthylamine and phthalic acid on antioxidant system and mineral nutrient uptake of lettuce

为明确辣椒(Capsicum annuum L.)根系分泌的潜在化感物质对生菜幼苗抗氧化特性及矿质养分吸收的影响,分别采用5、10、15、20和25μg·m L^(-1)的N-苯基-2-萘胺(P2NA)和邻苯二甲酸(PA)与Hoagland营养液混合胁迫处理生菜幼苗,测定抗氧化酶活性、渗透调节物质浓度和矿质养分含量,以期丰富辣椒根系分泌物化感机制研究。结果表明:与营养液对照比较,P2NA、PA,以及两者的混合处理在0~15μg·m L^(-1)浓度范围内,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性增强,谷胱甘肽(GSH)和游离脯氨酸(Fpro)含量增加,活性氧自由基(ROS)和丙二醛(MDA)含量降低;处理浓度达到20μg·m L^(-1)以上,ROS含量增加,抗氧化酶系活性和GSH含量显著降低,膜脂过氧化程度提高;潜在化感物质作用下,生菜幼苗的抗坏血酸氧化酶(AAO)活性降低,氮、磷、钾大量元素积累量均不同程度降低,钙和镁含量随着处理浓度增加先升后降,峰值处理浓度分别为10和15μg·m L^(-1)。10μg·m L^(-1)的P2NA和PA处理最适于生菜幼苗抗逆能力的提高,浓度>15μg·m L^(-1)则因ROS积累,尤其是过氧化氢(H_2O_2)积累,造成膜脂过氧化程度加强,细胞渗透调节能力和矿质营养吸收能力降低,且P2NA的潜在化感作用强于PA,可能两者具有一定的互作效应。

To evaluate effects of potential allelochemicals from hot pepper（Capsicum annuum L.） root exudates on antioxidant ability and mineral nutrient uptake of lettuce,N-phenyl-2-naphthylamine（P2NA） and phthalic acid（PA） were mixed to Hoagland nutrient solution with 5,10,15,20 and 25 μg·mL-1 for growth of lettuce under stress. Leaves of lettuce were sampled and determined about activities of antioxidant enzyme system,concentrations of osmotic regulation substances,and contents of mineral nutrient elements in order to explore allelopathic mechanism of root exudates of hot pepper. The results of present study showed that P2 NA,PA and mixture solution with 0–15 μg·mL-1 enhanced activities of superoxide dismutase（SOD）,catalase（CAT） and peroxidase（POD） compared to control,increased contents of glutathione（GSH） and free proline（Fpro）,which reduced contents of reactive oxygen species（ROS） and methane dicarboxylic aldehyde（MDA）. The levels of membrane lipid peroxide of lettuce were improved by high concentration（〉20 μg·mL-1） because of increasing of ROS content,which were caused by decreasing of activities of anti-oxidative enzymes and GSH content. Phenomenon was observed which lettuce seedlings exposed to potential allelochemicals had lower activity of ascorbic acid oxidase（AAO）,lower content of nitrogen,phosphorus and potassium,and abundance content of calcium and magnesium. The distribution of calcium and magnesium contents appeared single peak curve with peak value of 10 or 15 μg·mL-1. As optimum concentration of P2 NA or PA,10 μg·mL-1 was recommended to apply to lettuce for enhancing adversity ability. However,the high concentration exceeded 15 μg·mL-1 of P2 NA or PA resulted in the accumulation of ROS,especially the accumulation of hydrogen peroxide（H2O2）,thus cased membrane lipid peroxide,osmotic loss and nutrition absorption barrier. P2 NA was inconclusively deduced have better potential allelopathy than PA,and allelopathic interaction could be showed between P2 NA and PA.