Research Of The Effect Of Soil Copper On Plant Growth And Leaf Reflectance Spectra

Soil heavy metal pollution is a phenomenon that the contents of heavy metal elements in soil are significantly higher than those of their natural background,and the ecological damage and environmental quality deteriorated.In recent years,the problem of soil heavy metal pollution in China is becoming more and more serious,a large number of mining development,the rapid development of industrialization and urbanization,and the lag of environmental protection measures,which bring about that farmland soil pollution is becoming more and more serious in China,this is a serious threat to people's life safety and health.Copper is a kind of trace nutrients needed for plant growth and development,it plays an important role in the adjustment of protein composition,participation in photosynthesis,mitochondrial respiration and cell wall metabolism.Copper has accumulation and will accumulate in the plant,high copper content in plant will influence plant normal metabolic function,and harm the nutrient uptake,growth,yield and quality.In recent years,the development of remote sensing technology has provided a new way for the rapid and accurate extraction of heavy metal elements in soil.High spectrum feature recognition is based on the fingerprint effect of ground objects,which can be used to evaluate the difference of soil properties.This paper took experiment as an example,researched on the plant growth and the spectral variation law of plant leaf,and established fitting relationship between leaf measured elements content and leaf spectral characteristic parameters,and inverted the leaf metal elements contents through leaf spectra and their characteristic parameters.The results showed that:(1)Through the description of macroscopic characteristics about the water spinach,when the concentration of copper reached 1000 mg/kg,the water spinach appeared obvious Cu stress phenomena,and the growth inhibition effect was obvious;(2)Through the experiment of chlorophyll extraction,the volume ratio of 95% ethanol and pure acetone was 1:2,the extraction time was 18 h,then the extraction effect was satisfactory.In the fitting analysis of chlorophyll content and leaf copper content,the effect of chlorophyll a was the best,the correlation coefficient was 0.854 and 0.923.It could build composite,growth,exponential,logical function curve models;(3)The copper accumulation characteristics in different parts of water spinach was root>stem>leaf,the copper content in different parts gradually increased with the increase of copper concentration.The enrichment coefficient of two groups water spinach maximum reached 2.4859 and2.3342,minimum reached 0.2648 and 0.2595,about ten times distance,and the transfer coefficient of two groups basically was a downward trend;(4)Through analysis of FieldSpec data,it reached eight characteristic bands,the green edge,green peak,yellow edge,red valley,red edge,near infrared,valley 1 and valley 2.Through the correlation and displacement analysis,it was concluded that the correlation of red edge position Xi was the largest,the first GL water spinach got compound,power,S,growth,index,logic curves model,the goodness of fit was 0.901;the second DY water spinach got twice,three times curve model,the goodness of fit was 0.920;(5)Through analysis of object spectrum and TM remote sensing images about Hongtoushan mining,the “blue shift”phenomenon of red edge was more than 10 nm in the heavy metal stress area.The appropriate method could be used to distinguished the mineralization area and background area.That is the vegetation and heavy metal stress could be distinguish clearly by the interpretation of image data.