DCPTA对干旱胁迫下玉米幼苗生长和抗氧化酶系统的影响

Effect of DCPTA on the Growth and Antioxidant Enzyme Systems of Maize Seedlings under Drought Stress

以玉米自交系‘昌7-2’幼苗为材料,采用水培方式研究了模拟不同干旱胁迫程度(10%、12.5%、15%、17.5%、20%、22.5%、25%PEG-6000)及15%PEG-6000干旱胁迫下不同浓度(5、10、15、20、25、30mg/L)植物生长调节剂2-(3,4-二氯苯氧基)三乙胺(DCPTA)对玉米幼苗生长和抗氧化酶系统的影响,以筛选出玉米苗期抗旱性鉴定的适宜PEG-6000浓度,为玉米自交系苗期的抗旱性鉴定提供依据。结果表明:不同浓度PEG-6000处理后,玉米幼苗地上部和根部的干重、鲜重、叶片相对含水量及叶绿素(SPAD)含量均下降,叶片抗氧化酶SOD、POD、CAT的活性增强,丙二醛(MDA)含量升高,渗透调节物质可溶性蛋白、脯氨酸的积累量增加。且当PEG-6000浓度达15%时,以上各指标变化均与清水对照差异显著;在15%PEG-6000浓度模拟干旱胁迫下,不同浓度DCPTA处理均使玉米幼苗上述抗氧化酶活性增强,渗透调节物质含量增加,叶片相对含水量、叶绿素(SPAD)含量和生物量提高,而MDA含量降低,并以15和20mg/L浓度效果较佳。研究认为,室内水培条件下采用PEG-6000模拟干旱鉴定玉米苗期抗旱性的适宜浓度可初步确定为15%;DCPTA处理可促进干旱胁迫下玉米幼苗的生长,并通过提高抗氧化酶活性和渗透调节物质含量来增强其抗旱性,其适宜浓度为15和20mg/L。

Under hydroponic conditions,Chang7-2 were used to study the effect of different PEG-6000 con-centrations（10%,12.5% ,15%,17.5% ,20% ,22.5%,25%）and different concentrations （5,10,15,20,25, 30 mg / L） plant growth regulator 2-（3,4-dichlorophenoxyl）-triethylamino（DCPTA）under 15.0%PEG- 6000 simulated drought stress on maize seedling growth and antioxidant enzyme systems. The results showed that, hiomass index（dry and fresh weight of shoot and root）, leaf relative water content（RWC） and SPAD value decreased after the PEG-f000 treatment, antioxidant enzyme （SOD, POD, CAT） activi ties ,malondialdehyde （MDA） content and osmotic adjustment substance （soluble protein, proline） accu- mulation increased,when PEG-6000 concentration reached 15 ~. The indices significantly different from control; The treatment by addition of DCPTA to the hydroponic solution induced an increase in drought tolerance during subsequent exposure to 15~ PEG-6000 water stress. This was evidenced by the indices （biomass, RWC, SPAD, antioxidant enzyme activities, MDA content and osmotic adjustment substances） of maize seedling. We can concluded preliminarily that the appropriate PEG-6000 concentration for the i dentification of maize drought tolerance in seedling stage was 15% ; DCPTA could enhance drought toler- ance of maize seedling by modulating growth, increasing osmotic adjustment substance accumulation and antioxidant enzyme activities. The appropriate concentration was 15 and 20mg/L.