Study On The Accumulation Ability Of Soil Lead By Different Indica Rice Cultivars

The accumulation ability of lead by main indica rice cultivars in Fujian Province and the transfer characteristics of Pb from soil to rice grains of the rice were studied in order to provide scientific basis for safety cultivation of indica rice on Pb-polluted soils.1.The grains of 20 main indica rice cultivars(269 samples in total)and the corresponding surface soils were collected from Long yan,Nan an,Long hai,Fu qing and Tai ning of Fujian Province.The total soil Pb,DTPA-extractable soil Pb,Pb concentration of rice grains(brown rice)were determined.The main results were as follows:(1)The total soil Pb of the soils ranged from 19.14 mg·kg-1 to 992.3 mg·kg-1 with an average of 83.32 mg·kg-1.The DTPA-extractable Pb were between 1.93 mg·kg-1 and 289.1 mg·kg-1 with a mean of 12.61 mg·kg-1.The Pb concentration of rice grains(brown rice)varied from 0.026 mg·kg-1 to 0.383 mg·kg-1 with an average of 0.066 mg·kg-1.(2)The transfer factors(TFs)based on available soil Pb between soil and rice grain of the cultivars decreased with the increase in available soil Pb.A regression method was adopted to calculate the representative soil-to-grain transfer factors of Pb for each cultivar.The calculated soil-to-grain transfer factors at 5 mg·kg-1 available soil Pb(TF5)of the rice cultivars increased in the order of Te-you 009<Yang-liang-you 6<Shen-liang-you 5814<?-you 673<Nei-?-you 6<Yue-you 9113<Na-ke 1<Jia-fu-zhan<Yi-you 99<?-you 3301<Te-you 627<Quan-zhen 10<Jia-you 948<Yi-you 673<Yi-you 115<Feng-?-you 1<Tian-you 998<Pei-za-tai-feng<Yi-xiang 2292<Dong-lian 5.The difference in Pb accumulation among the rice cultivars was mainly attributed to the difference in varieties.2.Four rice cultivars,Te-you 009,Yi-you 673,Jia-fu-zhan and Dong-lian 5 were chosen to study the transfer characteristics.56 sets of samples,including the grains,roots,leaves and stems of rice,and the corresponding surface soils were collected from Longyan?Minhou?Nanan?Longhai of Fujian Province.The main results were as follows:(1)The total soil Pb ranged from 29.61 mg·kg-1 to 271.1 mg·kg-1 with an average of 97.02 mg·kg-1.The DTPA-extractable soil Pb were between 5.14 mg·kg-1 and 73.58 mg·kg-1 with a mean of 17.84 mg·kg-1.The Pb concentration of root was 18.27 mg·kg-1-106.4 mg·kg-1 with an average of 48.00 mg·kg-1.The Pb concentration of stem varied from 0.38 mg·kg-1 to 10.32 mg·kg-1 with an average of 2.02 mg·kg-1.The Pb concentration of leaf were between 0.61 mg·kg-1 and 4.59 mg·kg-1 with a mean of 1.91 mg·kg-1.The Pb concentration of rice grains(brown rice)was 0.057 mg·kg-1-0.431 mg·kg-1 with an average of 0.124 mg·kg-1.(2)The Pb concentration in the roots varied with rice cultivars,and was significantly correlated with both the total and DTPA-extractable soil Pb.For Jia-fu-zhan,Te-you 009 and Yi-you 673,the Pb contents of the organs decreased in order of root>stem>leaf>grain.For Dong-lian 5,the contents of Pb decreased in order of root>leaf>stem>grain.(3)The soil-to-stem and soil-to-leaf transfer factors based on available soil Pb(TFsoil-stem,TFsoil-leaf)were different between conventional rice and hybrid rice.The TFsoil-stem of conventional rice was larger than the TFsoil-leaf while the TFsoil-leaf of hybrid rice was larger than the TFsoil-stem.The TFsoil-grain of the conventional rice(Dong-lian 5>Jia-fu-zhan)was larger than the hybrid rice(Te-you 009>Yi-you 673).The transfer factors between different parts of four indica rice varieties showed as foll owed:for Jia-fu-zhan?Te-you-009 and Yi-you-673:TFstem-leaf>TFstem-grain>TFleaf-grain>TFroot-leaf>TFroot-stem>TFroot-grain;for Dong-lian-5:TFstem-leaf>TFleaf-grain>TFroot-stem>TFstem-grain>TFroot-leaf TFroot-grain.The effects of other transfer factors on the grain lead contents were mainly expressed as the difference between varieties.