| Heavy metals can seriously affect the quality and safety of maize and pose a threat to the health of people and animals.Soil physical and chemical properties,fertilization methods,growth stages and rotation all affect the transportation and transportation of heavy metals in maize.This is mainly because the above factors can lead to the change of maize rhizosphere environment.Soil physical and chemical properties will be affected by fertilization methods and intercropping rotation.Meanwhile,some environmental protection materials can be applied to reduce the content of active heavy metals in soil and reduce the sources of heavy metals.The rational adjustment of fertilization methods should take into account the relationship between accumulation of heavy metals and yield.The characteristics of heavy metal absorption and transportation during different growth stages should be based on the characteristics of transportation and transportation of heavy metals in this growth period,and the methods of fertilization and cultivation should be adopted accordingly.The crop rotation between maize and other crops should pay attention to the reasonable collocation of intercropping crop rotation,and find the best intercropping rotation scheme according to the synergy or antagonism between species in heavy metal absorption.The accumulation ability of heavy metals in different organs of maize showed a certain regularity.In general,the roots and leaves were the strongest,followed by stems,and the weakest was grain.There are also differences in heavy metal accumulation ability of different species in various organs of maize,such as Cd,Cr,the enrichment ability of root of Hg,As,Ni and other heavy metals are strong,and the leaves of As,Cu,Zn,Mn,Hg and other heavy metals enrichment ability is the strongest,Pb in stems enrichment ability,enrichment all kinds of heavy metal elements in grains are relatively weak.These features can on a specific region of heavy metal pollution production has certain guiding function,easy to use in the actual production of corn of different organs on the enrichment ability of specific heavy metals,control of soil heavy metal pollution in the region,while the heavymetal content in maize organs within the scope of security for food and feed processing and other purposes,the largest play economic benefits.Effects of heavy metals on the growth and yield of Maize in different periods is two,showing the overall promotion of low concentration and high concentrations inhibited,low concentrations of heavy metals stress to a certain extent will stimulate the growth of maize,and at a critical value of this role will peak,but in general,in addition to some the necessary nutrition elements such as Ni,Cu,Zn,generally do not bring significant differences in biological characters and yield of maize,while high concentrations of heavy metals stress can cause toxic effects,inhibition of maize growth process.Under heavy metal stress,many physiological and biochemical processes of maize are affected,including,but not limited to,effects of carbon and nitrogen metabolism,enzyme activities,and metabolism of nucleic acids.The effects of heavy metals on carbon and nitrogen metabolism can lead to the reduction of accumulation of corn matter,while some intermediate metabolites also affect other physiological and biochemical processes.Heavy metals change the environment in which all enzymes work in maize,thus affecting the activity of enzymes.Heavy metals lead to destruction of nucleic acid structures and apoptosis in Maize cells.In the case of heavy metal stress,corn will produce some response mechanism,the mechanism of tolerance to deal with heavy metal stress cell walls of heavy metal sedimentation,induced heavy metal binding protein,enzyme system response mechanism and transcriptome response mechanisms,in addition,the leaves will have corresponding change according to the spectral characteristics,the spectral changes can be monitored for heavy metals type and degree of pollution. |
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