Evaluation Of Low Accumulation Of Heavy Metals In Weedy Rice And The Law Of Cadmium Absorption And Its Effect On The Absorption Of Other Elements

Heavy metal pollution,especially cadmium,is becoming more and more serious in some rice-producing areas in China,which has adverse effects on people's health.It is an important task to evaluate and screen rice materials with low accumulation of heavy metals,especially cadmium.Weedy rice is a kind of rice germplasm resources that can be used,which has strong resistance to stress and potential breeding value.There are few studies on the low accumulation of heavy metals in weedy rice.In this study,the low accumulation of heavy metals in weedy rice was preliminarily evaluated by using the collected weedy rice resources.Cadmium concentrations were set at 0.5mg/L,1.0mg/L,1.5mg/L,2.0mg/L,2.5mg/L,and different selected materials were sprayed to preliminarily study the change law of cadmium absorption in weedgrass rice,and analyze the accumulation of cadmium in different organs such as root,stem,leaf and grain in different growth periods.The effects of cadmium accumulation on the absorption of magnesium,potassium and iron were studied.The main research results are as follows:1.Among the test materials,the low cadmium accumulation materials were preliminarily screened as WR05-18,WR05-19,WR05-28,WR5-22-1 and WR 07-133,and the low chromium absorption materials were screened as WR05-18,WR05-19,WR07-3,WR05-28 and WR05-12.The low lead absorption materials were selected as WR05-19,WR05-15,WR WR05-18,WR07-135 and WR07-140.The low copper absorption materials were selected as WR07-6,Shennong265,WR05-18,WR05-19 and WR07-140.Compared with the high cadmium accumulation materials,the cadmium absorption of weed rice WR05-18 and WR05-19,which were screened as low cadmium accumulation materials,was significantly lower than that of the high cadmium accumulation materials in both grains and roots.The absorption of heavy metals such as chromium,copper and lead from WR05-8 and WR05-19 was also relatively low.2.With the increase of cadmium concentration treatment gradient,the cadmium content absorbed by different parts of rice showed an increasing trend,which also indicated that the more serious the cadmium pollution was,the higher the cadmium content absorbed and accumulated in the plant.The cadmium content absorbed by different materials at tillering stage and jointing stage was root > leaf > stem and root > seed > leaf > stem.Cadmium absorption of high cadmium accumulation materials was significantly higher than that of lowCadmium accumulation materials at different concentrations and at different periods.The cadmium content absorbed in stem and leaves was Qishanzhan>LN-L-26 >WR05-18>WR05-19,and the cadmium content absorbed in roots and seeds was LN-L-26>Qishanzhan>WR05-18>WR05-19.Under the high cadmium concentration of2.5mg/L,the cadmium content absorbed by low-cadmium accumulation materials WR05-18 and WR05-19 was the most different in different periods from that of high-cadmium accumulation materials Qishanzhan and LN-L-26.At the high cadmium concentration of2.5mg/L,with the development of different growth periods,the cadmium content absorbed by the roots of the low-cadmium accumulation material WR05-18 and WR05-19 gradually decreased with the difference between the high-cadmium accumulation material Qishanzhan and LN-L-26,and the grain part of the low-cadmium accumulation material was less affected by the cadmium concentration than the high-cadmium accumulation material.3.Cadmium at different concentrations promoted the absorption of the three elements compared with the control.With the increase of cadmium treatment concentration,the absorption of magnesium and potassium in the four materials showed a trend of increasing first and then decreasing,while the absorption of iron showed a trend of decreasing gradually.The absorption of magnesium and potassium reached the highest when the cadmium concentration was 1.5mg/L and 2.0mg/L respectively.Iron was highest at 0.5mg/L cadmium and lowest at 2.5mg/L.From the point of view of different materials,magnesium and potassium in stems and leaves of low-cadmium accumulation materials WR05-18 and WR05-19 were significantly lower than those in LN-L-26 of high-cadmium accumulation materials at tillering stage,jointing stage and maturation stage.At the concentration of1.5mg/L~2.5mg/L,the low cadmium accumulation materials WR05-18 and WR05-19 were significantly higher than that of the high cadmium accumulation materials Ln-L-26.In terms of iron absorption,the low-cadmium accumulation materials WR05-18 and WR05-19 were significantly higher than the high-cadmium accumulation materials LN-L-26 in different parts in different periods.