DCPTA对低温下玉米叶片抗氧化系统及渗透调节物质的影响

Effect of DCPTA on antioxidant system and osmotic adjustment substance in leaves of maize seedlings under low temperature stress

为研究2-(3,4-二氯苯氧基)三乙胺[2-(3,4-dichlorophenoxy)triethylamine,DCPTA]对低温胁迫下玉米(Zea mays)幼苗生长、光合特性、抗氧化系统及渗透调节物质的影响,以‘郑单958’(抗冷型)和‘丰禾1号’(冷敏感型)玉米为实验材料,盆栽培养至四叶一心时,利用人工气候箱进行低温模拟处理(14°C/5°C,昼/夜)48 h后,测定相关生理生化指标。结果表明,DCPTA处理能有效缓解低温胁迫对玉米幼苗的生长抑制作用,增加地上部鲜重、根系鲜重、叶面积和株高;DCPTA处理能够显著提高低温胁迫下玉米幼苗叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、叶绿素含量和光合系统II(PSII)最大光化学效率(Fv/Fm),降低胞间CO2浓度(Ci);同时DCPTA处理也能显著提高低温胁迫下玉米幼苗叶片超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)与抗坏血酸过氧化物酶(ascorbate peroxidase,APX)活性;DCPTA处理还能够调节活性氧代谢,降低超氧阴离子(O2ˉ·)产生速率、H2O2含量、丙二醛(malondialdehyde,MDA)含量和相对电导率,同时幼苗叶片脯氨酸、可溶性糖及可溶性蛋白含量增加。这些结果说明DCPTA处理能够通过增强低温下植株光合电子传递效率,促进叶片光合作用,改善植株抗氧化系统运行,从而有效缓解低温胁迫对玉米幼苗叶片细胞的伤害。上述研究结果可为DCPTA应用到东北春玉米苗期抗低温生产提供理论依据。

The pot-culture experiments were set to explore the response of maize seedling leaves to low temperature stress with 2-（3,4-dichlorophenoxy） triethylamine（DCPTA） application.Two different maize hybrid cultivars,‘Zhengdan 958＇（cold resistant） and ‘Fenghe 1＇（low temperature sensitive）,were chosen as the experimental materials.Fifty mg·L-1 DCPTA was sprayed on the maize leaf at four-leaf stage.The materials were subjected to low temperature treatment of（14/5）°C（day/night） in the artificial climate chamber.The results show that DCPTA treatment could significantly relieve growth inhibition by increasing maize seedling shoot fresh weight,root fresh weight,leaf area and plant height.The net photosynthetic rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr）,chlorophyll content and photochemical efficiency of photosystem II（Fv/Fm） significantly increased,and intercellular CO2 concentration（Ci） was reduced in maize leaves with DCPTA application.In addition,DCPTA alleviated the oxidative damage in maize leaves by reducing O2？- production rate,H2O2 content,lipid peroxidation and cell membrane permeability,and by increasing the activities of superoxide dismutase（SOD）,peroxidase（POD）,catalase（CAT） and ascorbate peroxidase（APX）.DCPTA could regulate metabolism penetration and enhance the contents of leaf proline,soluble sugar and soluble protein under low temperature stress.The research indicates that DCPTA alleviates low temperature stress induced cell damages through regulating the photosynthesis and antioxidant system of maize seedlings,which provides theoretical basis and experimental evidence to DCPTA application for low temperature resistant maize production.