| Arsenic pollution is serious in southern China,and arsenic in rice is generally higher than other crops.In this study,two kinds of upland rice with low（V1）and high（V2）absorption were used as experimental materials,and the typical arsenic-contaminated paddy soils in southern China were selected and tested by pot experiment.First studied in the effects on growth,As content in organs,root iron plaque of upland riceof the different concentration of As in soils(S1:24.8g·kg-1,S2:60.24g·kg-1),different Se valence:（S4:sodium selenite,S6:sodium selenate）,different ways to addition(CK,R1:Se with a soil in 1.0 mg kg-1,R2:Se with a soil in 5 mg·kg-1,L1:Se with leavesin 1 mg·L-1,L2:Se with leavesin 5 mg·L-1).And then studied theeffects on the uptake and transport of As ane Se,the correlation of As and Se content in different organs,chlorophyll content,photosynthesis,membrane lipid peroxidation and antioxidant enzymes system impact of upland rice in booting stage of no addition(Se:0mg·kg-1),root addition(R 1:1.0 mg·kg-1,R2:5.0mg·kg-1),leaves addition(L1:1.0 mg·L-1、L2:5.0 mg·L-1)with sodium selenite on soilsin different concentrations of As,(S1:20.1 mg·kg-1,S2:65.2 mg·kg-1,S3:83.9 mg·kg-1).The results show:a).In whole growth stage,soil arsenic increase will reduce the fresh straw weight and grain quality of two cultivar upland rice,and effect is greater on V2;Light pollution:two cultivar of fresh straw weight reduced by 30.39%and 48.03%,grain quality by 31.85%and 48.96%,respectively;In two soils,stalks fresh weight of V2 is lower than V1,respectively 3.39%and 27.88%,and grain quality is 25.78%and 44.71%lower;Selenium increased the fresh straw weight of V2 upland rice in light arsenic pollution soil,an increase of 22.35%～39.76%;selenium increased rice grain quality inlight arsenic pollutionsoil of two varieties,V1 increased 17.58%～47.79%,V2 increased 35.42%～71.79%;but effects of fresh straw weight and grain quality in S1 unsignificant.b).In whole growth stage,the As content of root,stem,leaf,unpolished rice and polished rice of V1 was lower than V2,and Ascontentin organs increase with the increase of arsenic content in soils significantly.The addition of sodium selenite and sodium selenate were reduced Ascontentin organsunder As stress.c).In whole growth stage,sodium selenite and sodium selenate reduced the root iron and Mn plaque and it’s As content.Root addition of sodium selenite and sodium selenateincreased the Se content the root iron plaque,while the leavesaddition of sodium selenite and sodium selenate did not significantly change the Se content in the root iron plaque.d).The growth of upland rice was inhibited by As stress,the biomass in booting stage was decreased by 54.72%～92.41%,and the plant height decreased by 19.36%～48.97%,root and leavesadditionof sodium selenite significantly promoted the growth of upland rice under As stress.The biomass of V1 increased by 1.43%～122.96%,V2 increased by 6.2%～59.81%The effects of sodium selenite on the plant height of upland rice was not significant.e).The effects of sodium selenite on the As content and the transport coefficient between the organs was significant in the booting stage under As stress.The high concentration of sodium selenite(5.0 mg·kg-1)could significantly increase the As content（12.71%～55.69%）in root,the As contents in thestem and leaf were decreased by 16.25～32.09%and 15.12%～43.13%of V1,and 7.32%～29.13%and 9.47%～43.27%of V2,The effects of Se addition of sodium selenite on leaves than root.The transfer coefficient of V2 is higher than V1,and the transfer coefficient of V1 is larger than that of V2.The effects of arsenic stress on the translocation coefficients SR and LS of upland rice were significantly decreased,the addition of sodium selenite under arsenic stress reduced the SR of V1 by 2.77%～47.90%,and the SR of V2 decreased by 3.57%-44.30%.Arsenic stress also significantly reduced the uptake of Se in the roots and leaves of upland rice,but increased the uptake of Se by stem.f).The contents of As and Se in booting stage of upland rice reached a very significant positive correlation.The contents of As of V1 in roots and stems,stems and leaves,roots and leaves were 0.88,0.90 and 0.88 respectively,the correlation of Se content was 0.79.0.82 and 0.94（P<0.01）.The content of As of V2in roots and stems,stems and leaves,root and leaf were 0.89,0.95 and 0.85 respectively,the correlation of Se content was 0.82,0.87 and 0.77（P<0.01）.There was a negative correlation between As content and Se content in the booting stage of upland rice,the correlation coefficient between As content and root Se content of V1 was-0.37,which was negatively correlated（P<0.05）.g).Under arsenic stress,the chlorophyll content of the two upland rice varieties and leaves decreased significantly.The addition of sodium selenite increased the chlorophyll content of upland rice under arsenic stress,（except in soil S1）.The photosynthesis rate（Pn）,stomatal conductance（Gs）and transpiration rate（Tr）of the two cultivars showed a decreasing trend with the increase of soil arsenic pollution concentration under arsenic stress,while theconcentration intercellular of CO2（Ci）showed an increasing trend.Addition of sodium selenite to alleviate the inhibition of arsenic stress on photosynthesis of upland rice leaves.The contents of malondialdehyde（MDA）in two upland rice cultivars under arsenic stress were significantly increased.Under arsenic stress,sodium selenium significantly reduced the content of malondialdehyde（MDA）,the decline of V1 and V2 was 9.29%-29.56%and 4.80%-30.79%,and the leaf addition decrease was higher than that root.The SOD activity of the two cultivars was numerically similar,however,the POD and CAT of the high arsenic absorption of V2 were significantly higher than those of V1.Under arsenic stress,the SOD of the V1 decreased gradually,POD increased gradually,while the CAT increased first and then decreased.The content of SOD and CAT of V2 increased gradually,while the POD content increased first and then decreased.The contents of SOD,POD and CAT in V1 increased with the increase of the content of sodium selenite.Sodium selenium addition make SOD and the content of CAT of V2 in soil S2 increased,POD and CAT in S3 soil content decreased.This study shows that in As-contaminated rice fields,it can reduce arsenic contamination by increasing the uptake of upland rice and applying Se,and improve the selenium content. |
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