风吹时间和强度对玉米幼苗膜透性影响及其膜保护系统响应

Effects of Wind Blowing Time and Intensity on Membrane Permeability and Its Protection System of Corn Seedling

在我国东北西部半干旱风沙区,春季玉米幼苗经常受到大风危害。为了解玉米幼苗对风吹危害的生理响应特征,2013年春季在内蒙古东部科尔沁沙地研究了10 min和20 min两个风吹时间,0(CK)、6、9、12、15 m·s^(-1)和18 m·s^(-1)等6个风速水平下,其幼苗丙二醛含量、膜透性、保护酶活性和渗透调节物质含量的变化。结果表明:10min风吹下,随着风速增强,玉米幼苗的丙二醛(MDA)含量略有增加,其膜透性趋于下降,但大多数处理的MDA和膜透性与CK差异不显著;其超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均呈波动式变化,可溶性糖和脯氨酸含量趋于增加,其中15 m·s^(-1)和18 m·s^(-1)处理的SOD和POD活性显著高于CK,CAT活性低于CK,大多数处理的可溶性糖和脯氨酸含量与CK差异未达到显著水平。20 min风吹下,各处理MDA均较CK没有明显变化,但膜透性随风速增强大幅度增加,同时其SOD、POD和CAT活性及可溶性糖含量也大幅度增加,而脯氨酸含量呈波动式下降。说明10 min风吹对于玉米幼苗细胞膜危害不明显,除个别处理外,其保护酶系统未发挥明显作用,也未见明显渗透调节作用。20 min风吹对膜透性有显著影响,其危害程度随风速增强而增加,其SOD、POD、CAT和可溶性糖对减轻其膜系统受损发挥了协调保护作用。

In order to understand wind damage to corn seedlings and their physiological response mechanism,an experiment with two periods of wind blowing time（ 10 and 20 minutes） and six wind speeds〔0（ CK）,6,9,12,15 and 18 m·s^（-1）〕was conducted in the Herqin Sand Land in west Inner Mongolia in spring 2013. The results showed that,under the 10-minute wind blowing,the MDA content was slightly increased and the membrane permeability tended to decrease with the increase of wind speed,but the differences of MDA and membrane permeability between the most treatments and the CK were not significant; SOD,POD and CAT activities changed in a fluctuation way,of which the SOD and POD activities were significantly higher and the CAT activity was lower under the wind speeds of 15 m·s^（-1）and 18 m·s^（-1）than those under the CK; soluble sugar and proline contents tended to increase,but their differences were not significant under the most treatments compared with those under the CK. Under the 20-minute wind blowing,the change of MDA contents under these treatments was not significant,but membrane permeability was significantly increased with the increase of wind speed. Moreover,SOD,POD and CAT activities and soluble sugar content were all increased considerably and the proline content tended to decreased. The results suggested that the damage of 10-minute wind blowing to the cell membrane of corn seedlings was not significant,and their membrane protective system did not play an effective action except for SOD and POD under the wind speed treatments of 15 m·s^（-1）and 18 m·s^（-1）. The damage of 20-minute wind blowing to the membrane permeability was significant,and the damage degree was increased with the increase of wind speed. In the process,SOD,POD,CAT and soluble sugar played a protective role to alleviate the injury of membrane.