| Corn is the main food crop in China and occupies an important position in China’s agricultural production.Waterlogging is one of the major meteorological disasters restricting agricultural production in China.Waterlogging is the most vulnerable in seedling stage of maize,which leads to corn yield reduction or even extinction.In order to alleviate the damage caused by waterlogging stress to maize at seedling stage,this study conducted a pot experiment to simulate waterlogging stress,and compared the effects of different dosage and application period of calcium peroxide on physiological and biochemical indexes of maize at seedling stage under waterlogging stress.Four calcium peroxide dosages were set in this experiment,which were 0 g kg-1,0.2 g kg-1,0.4 g kg-1 and 0.8 g kg-1,respectively.Three treatments were set at each level,which were conventional non-flooding fertilization,calcium peroxide is evenly distributed in the groove and covered with soil pre-flooding,fertilization and post-flooding fertilization,respectively.16 plants were sown in each treatment and repeated 3 times.These effects of calcium peroxide on the growth and physiological characteristics of maize seedling under waterlogging stress were studied.Main results are as follows:（1）The application of calcium peroxide is beneficial to the growth and development of maize in seedling stage.Under the condition of no flooding,plant height,stem diameter and leaf area increased gradually with the increase of calcium peroxide concentration,but the difference was not significant.Under the flooding condition,the plant height of maize with calcium peroxide was significantly increased compared with that of the control group,and the increase of maize aboveground part showed an upward trend,in which the increase of calcium peroxide at 0.4 g kg-1 level was the most significant.The root length,root surface area and root volume of maize decreased firstly and then increased with the increase of calcium peroxide concentration.Under the condition of flooding,the application of calcium peroxide at 0.4 g kg-1and 0.8 g kg-1levels had a significant effect on the root morphological indexes.（2）Under the flooding condition,the activity of antioxidant enzyme in maize leaves and roots decreased significantly,the production rate of superoxide anion increased,the content of malondialdehyde increased,and the osmotic regulatory substances decreased.The application of calcium peroxide can alleviate the damage of flooding stress on the growth of maize at seedling stage,which shows that the activity of antioxidant enzyme in maize leaves and roots increases,and the scavenging system capacity of reactive oxygen species is enhanced,especially at 0.4 g kg-1 and 0.8 g kg-1 levels.（3）Application of calcium peroxide improves photosynthetic performance of maize seedling leaves.Under the condition of flooding,the application of calcium peroxide could inhibit the degradation of chlorophyll and improve the photosynthetic performance of maize seedling leaves.After flooding,the photosynthetic performance showed a trend of returning to the normal level,especially at the level of 0.4 g kg-1 and 0.8 g kg-1.（4）The application of three amounts of calcium peroxide had no significant effect on soil p H value.Compared with the control treatment,the application of calcium peroxide increased soil enzyme activity,but there was no significant difference between different application rates.The soil enzyme activity was significantly increased by applying calcium peroxide after waterlogging compared with before waterlogging. |
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