Effects Of Soil PH On Cadmium Uptake And Growth In Rice Cultivars With Low Cadmium Accumulation

The pollution of heavy metal cadmium in farmland is becoming more and more serious,and have to be solved.A pot experiment,with 3 early-rice and 2 late-rice,carried out to investigate the cadmium uptake and growth in rice cultivars with low cadmium accumulation under different soil pH value.The effects of soil pH value on per plant yield and its components,agronomic traits,cadmium content of rice gain and different parts of rice during the key growth period were researched under the soil pH value range 4.0~8.0.The main results as follows:(1)In soils with a pH range of 4.0 to 8.0,the yield per plant of 5 rice cultivar increased first and then decreased,when the soil pH value greater than 7 or less than 5,the yield per plant was significantly decreased,because the number of panicles per plant,grains per panicle and seed setting rate decreased.The rule of yield components is different among different varieties.(2)In soils with a pH range of 4.0 to 8.0,the plant height of 5 rice cultivar increased first and then decreased.Panicle length increased first and then decreased in rice cultivar E06 and E07,and was decreased in rice cultivar L02 and L13.(3)As the increase of soil pH value ranging of 4.0 to 8.0,cadmium content in polished rice was linear downward trend,and the highest content was in soil pH 4.0 while the lowest was in soil pH 8.0.The cadmium content of 3 early-rice gain decreased by about 80% in soil pH 7.0 and decreased by about 90% in soil pH 8.0,while the cadmium content of 2 late-rice gain decreased by about 80% in soil pH 7.0 and decreased by about 85% in soil pH 8.0,compared with in soil pH 4.0.(4)In soils with a pH range of 4.0 to 8.0,with the increase of soil pH,cadmium content of root in rice cultivar E06,E07 and L02 increased at booting stage,and cadmium content of all parts in rice cultivar L13 decreased at booting stage.Cadmium content of root and panicle in rice cultivar E02 as well as all parts in rice cultivar E07 and L02 increased first and then decreased at heading stage.Cadmium content of stem and leaf in rice cultivar E02 decreased at heading stage,the same as all parts in rice cultivar E06.Cadmium content of all parts in rice cultivar E06,E07 and L13 decreased at maturation period,while cadmium content of all parts in rice cultivar L02 increased first and then decreased at maturation period.(5)The soil pH value can be adjusted to 7.0 by using amendments to treat cadmium contaminated soil,and the cadmium content and yield of rice can be taken into account.When breeding rice varieties with low cadmium accumulation,it is recommended to screen them under soil p H 5.0~6.0 conditions.The key factor of cadmium content in rice is not the difference of cadmium uptake by root,but the ability of rice to transfer cadmium to rice gain.