Studies On The Tolerance Of Broussonetia Papyrifera To Cadmium And Manganese Under The Condition Of The Tissue Culture

In recent years,with the rapid development of economic construction,the demand for mineral resources is also increasing.However,the entire process from mining,transportation,smelting,processing to consumption of mineral resources may cause different degrees of heavy metal pollution.When the soil is contaminated with heavy metals,it will not only change the structure and physicochemical properties of the soil,reduce the quality and yield of crops,but also enter the human body through the food chain,seriously endangering human health.Phytoremediation is the technique that uses the properties of plants to reduce the heavy metal contents in the environment through the absorption,transportation and solidification of plants,taking into account the advantages of economic cost and ecological aesthetics.Broussonetia papyrifera is a multi-purpose native tree species with high medicinal value and ecological environmental value,and can be used as a pioneer tree species for mine vegetation restoration.Plant tissue culture can multiply a large number of plants in a short period of time,and the offspring can maintain the excellent characteristics of the parents.Studies have shown that the tissue culture technology can also screen certain plants with enhanced resistance.This experiment took Broussonetia papyrifera tissue-cultured seedlings as the research object,through adding different concentrations of cadmium or manganese-containing solutions to the medium,analyzed the effect of different heavy metal stresses on the growth of Broussonetia papyrifera tissue-cultured seedlings and explored the tolerance of Broussonetia papyrifera tissue-cultured seedlings to cadmium and manganese.The main results are summarized as follows:(1)The heavy metals cadmium and manganese had a certain "low promote and high suppression" effect on the plant height and chlorophyll content of tissue culture seedlings of Broussonetia papyrifera.(2)The heavy metals cadmium and manganese can significantly inhibit leaf differentiation,delay rooting time and inhibit root growth,and the greater the concentration,the more significant the inhibition.(3)The tissue culture seedlings of Broussonetiapapyrifera in the experiment could tolerate 200 umol/L cadmium stress and 5000 umol/L manganese stress for up to 60 days,although the growth of roots was completely suppressed,there were new leaves on the stems.(4)Tissue culture seedlings of Broussonetia papyrifera could cope with the damage caused by heavy metal stress by increasing the content of soluble protein and proline and increasing the activity of antioxidant enzymes.(5)The tissue cultured seedlings of Broussonetia papyrifera in the experiment had a certain ability to accumulate and transport cadmium and manganese.The transport coefficient of cadmium was less than 1,while the transport coefficient of manganese was greater than 1.(6)The regenerated plants of tissue culture seedlings after the heavy metal stress under tissue culture conditions showed a stronger metal tolerance.