Effects Of Different Pre-chilling Temperatures On Maize Seed Germination And Seedling Growth Under Heavy Metal Stress

With the development of industry and agriculture,the exploitation of mines,metal smelting and industrial sewage discharge,resulting in increasing heavy metal pollution,toxic effects of heavy metals on the plant in recent years have become a hot issue of ecology and environmental studies.The effects of different pretreatment temperature(20 ℃,-5 ℃,-10 ℃,-15 ℃)on maize seed germination and seedling growth under different concentrations(0,0.1 mmol/kg,0.2 mmol/kg,0.5 mmol/kg)zinc(Zn2+),copper(Cu2+),cadmium(Cd2+)stress were studied,which provides a basis for clarifying the mechanism of toxic effects of heavy metal to plants and a reference for soil-plant heavy metal pollution remediation.The main results of this study are as follows:1、Zn2+,Ce2+,Cd2+ in low concentration have a promoting effect on seed germination and seedling growth.When the concentrations of heavy metals are the same,the effect of Zn2+ is the biggest.Under the high concentration of Cu2+,Cd2+,the germination indexes of maize have a declining trend.And at the same concentration,the inhibitory effect of Cd2+ is more obvious.The germination indexes decreased significantly when the concentration of heavy metals is higher.The seed germination and seedling growth are still promoted under high concentration of Zn2+Stress.Therefore,among the three heavy metals,the tolerance of corn to Zn2+ is the strongest and the most toxic to maize is Cd2+.It is also found that under the same conditions,the effect of heavy metals on root is greater than the bud.2、-5 ℃ and-10 ℃ pretreatment can be able to promote seed germination and seedling growth,and promoting effect of-10 ℃ is more obvious.But when the temperature is-15 ℃,the germination indexes and growth indicators of mazie decreased significantly.And this trend has nothing to do with the concentrations of heavy metals.3、Under different low temperature pretreatment and heavy metals stress,-5 ℃ and-10 ℃pretreatment produced a certain relief effect for toxic effects of heavy metals to corn.And the concentration of heavy metal is higher,the effect is lower.-15 ℃ pretreatment exacerbated the toxic effects produced by heavy metals on the corn.And the concentration is higher,the toxic effect is more serious.