水氮耦合对软籽石榴幼苗抗氧化生理特性的影响

Effects of Water and Nitrogen Coupling on Antioxidant Physiological Characteristics of Soft-seeded Pomegranate Seedlings

以‘突尼斯’软籽石榴幼苗为试材,设置3个灌水(W1:灌水上下限为田间持水量的35%~45%;W2:灌水上下限为田间持水量的55%~65%;W3:灌水上下限为田间持水量的75%~85%)与4个施氮(N0,0g·kg^(-1);N1,0.1g·kg^(-1);N2,0.2g·kg^(-1);N3,0.3g·kg^(-1))的耦合处理,采用盆栽种植方式,探究不同处理对叶片相对含水量(RWC)、光合色素含量(叶绿素与类胡萝卜素)、膜透性指标(相对电导率(REC)与丙二醛(MDA)含量)、过氧化氢(H2O2)含量、超氧阴离子(■)产生速率及抗氧化酶活性的影响,并对处理40d后各指标进行热图聚类与主成分分析,以期为软籽石榴生产栽培提供参考依据。结果表明:灌水量为田间持水量的35%~45%(W1)的灌水水平显著抑制了超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,降低了叶绿素总量、类胡萝卜素含量,但适宜施氮会缓解其抑制效应,高氮反而会加剧石榴受到的干旱胁迫程度;灌水量为田间持水量的55%~65%(W2)的灌水水平下具有相对较高的SOD、APX、POD和CAT活性与光合色素含量,较低的REC、MDA含量、■产生速率及H2O2含量;灌水量为田间持水量的75%~85%(W3)的条件下各指标与W2相比略有降低,且在W2、W3条件下均以N2、N3处理下石榴具有较高的光合色素含量、抗氧化酶活性。综上,经聚类与主成分分析发现,W2N2为该试验条件下的最佳水氮运筹模式。

Taking‘Tunis’soft-seeded pomegranate seedlings as the test material,three irrigation (W1,the upper and lower limits of irrigation were 35%-45%of the field water holding capacity;W2,the upper and lower limits of irrigation were 55%-65% of the field water holding capacity;W3,the upper and lower limits of irrigation were 75%-85% of the field water holding capacity) and four N application(N0,0g·kg^(-1);N1,0.1g·kg^(-1);N2,0.2g·kg^(-1);N3,0.3g·kg^(-1))treatments were set up.The effects of different treatments on the relative water content(RWC),photosynthetic pigment content(chlorophyll and carotenoids),membrane permeability indexes(relative electrical conductivity(REC)and malondialdehyde(MDA)content,hydrogen peroxide(H_(2)O_(2))content,superoxide anion(O_(2))production rate and antioxidant enzyme activity were investigated in pots,and heat map clustering and principal component analysis were performed for each index after 40days of treatment,in order to provide reference for cultivating of soft-seeded pomegranate.The results showed that the irrigation level of 35%-45%(W1)of field capacity significantly inhibited the activities of SOD,APX,POD and CAT,and decreased the total chlorophyll and carotenoid content.However,suitable nitrogen application could alleviate the inhibition effect,and high nitrogen application could aggravate the drought stress degree of pomegranate.The activities of SOD,APX,POD,CAT and photosynthetic pigment contents were relatively high,but the contents of REC,MDA,O_(2) and (H_(2)O_(2))were relatively low when the irrigation amount was 55%-65%of field capacity(W2).When the irrigation amount was 75%-85%of field capacity(W3),the indexes were slightly decreased compared with that of W2,and the pomegranate treated with N2 and N3 had higher photosynthetic pigment content and antioxidant enzyme activity under both W2and W3conditions.In conclusion,the clustering and principal component analysis showed that W2N2 was the best water and nitrogen operation mode under this experimental condition.