Research On Response Of Different Waxy Corn Varieties To The Difference Of Selenium Spraying On Leaves

Selenium is one of the essential trace elements for the human body and is associated with heavy metals such as cadmium,chromium,lead and arsenic.Waxy corn is a popular fresh food crop.Research on the safe production of selenium-rich waxy corn is an effective way to eliminate selenium deficiency and antagonize heavy metals.In order to screen varieties that efficiently absorb and utilize selenium,antagonize heavy metals and high yields,explore the physiological mechanism of selenium spraying on waxy corn,determine the optimal dosage and the optimal spraying times under the same dosage of selenium spraying on leaves,the method of two-factor split plot design was adopted in this study.Agronomic characters,yield,physiological indexes,selenium and four other toxic heavy metal elements contents in the grains of four waxy corn varieties promoted in Shanxi province at five different selenium supply levels were compared and studied.The main research results are as follows:（1）Under Se60 treatment,the population leaf area of JN20 was 33.1841% higher than that of CK,and the fresh ear yield increased 16.42% than CK.The selenium spraying at this dosage had a certain promotion effect on the increase of the population’s fresh biomass and seedling rate.（2）Compared with CK,Se60 treatment not only significantly increased the POD activity,GSH content,reduce MDA content,but also effectively increased the chlorophyll content of waxy corn leaves.Under this dosage,the physiological characteristics of JN20 and CTN1965 were the best.（3）There was a very significant positive correlation between the selenium dosage in leaf spraying and the selenium content in waxy corn grain,and the correlation coefficient was 0.951.The safety thresholds of JN18,JN20,CTN1965 and JDN41 were 90.8924,78.8770,61.5529 and 112.1874 g·hm^-2 respectively.The average content of selenium in four cultivars’ grains could reach the upper limit of 300μg·kg^-1 at that selenium spraying dosage.The sequence of selenium-enriching ability of four waxy maize varieties was JN20> CTN1965 >JN18 >JDN41.（4）There was a significant negative correlation between selenium dosage in leaf spraying and cadmium and lead content in grains.The increase of selenium content in the grain had a significant antagonistic effect on cadmium and lead.Low dosage of Se15 was beneficial to decrease the content of chromium in waxy corn grains and thus antagonized and weakened the toxicity of chromium in waxy corn grains,but high dosage of Se60 could also antagonize the accumulation of chromium in CTN1965 and JN20 grains.Under the experimental conditions,Se30 treatment of CTN1965 had the highest inhibition rate on arsenic,the highest inhibition rate of Se60 was JN20.Based on the above characters,JN20 is the best choice for high yield,selenium-enriched and safe waxy corn production.Three foliar spraying treatments were carried out at the jointing stage-bell stage,bell stage-tasseling stage and the early filling stage.Total amount of 60g· hm^-2 pure selenium was suitable for spraying selenium.