Genotypic And Environmental Effect On Heavy Metal Uptake And Accumulation Of Potato(Solanum Tuberosm L.)

Heavy metal contamination has become a vital environmental factor that constrains agricultural productivity and threatens the safety of agricultural products.As the fourth important staple food in the world,the poistion of potato as a food crop is steadily rising.So far,there are relatively few researches on heavy metal uptake and accumulation in potato,and very fewer studies covered the genotype and environmental variation in heavy metal contents of the different potato organs.In this study,five potato cultivars were used and planted at 5 locations in Zhejiang province.The relationships between soil physical and chemical characteristics,and heavy metal and mineral element contents of potato organs were analyseds to determine the genotype and environmental variation in heavy metal contents of the different potato organs.so as to provide a theoretical guidance to the breeding and production of potato cultivars with low heavy metal accumulation.The major results are summarized as follows:1.Effects of organic matter,available phosphorus and potassium contents in soil on heavy metal bio-availability and their uptake by potatoDTPA-extractable contents of Fe.Cu.Zn were positively correlated with organic matter,available P and K contents,and there was a significantly positive correlation bewteen DTPA-extractable Zn content and organic matter content.However,a significantly negative correlation was found between DTPA-extractable Pb content and contents of organic matter,available P and K.In addition,a significantly positive correlation was found between DTPA-extractable Cd content and organic matter content,while a significantly negative correlation was found between DTPA-extractable Cd content and the contents of available P and K.Meanwhile,a significantly negative correlation was found between DTPA-extractable Mn content and organic matter content,while a positively correlation was found between DTPA-extractable Mn content and contents of available P and K.Stepwise multiple linear regression analysis indicated that although the regression model couldn't predict Cd and Pb contents in peeled-tuber,but it worked well on Cd and Cu content of leaf,Cd and Mn content of stem,and Mn content of peeled-tuber.2.Genotypic and environmental variation on cadmium,chromium and lead contents in peeled-tuberIn this study,genotypic and environmental variation of Cd,Cr and Pb contents in different organs of the five potato cultivars planted in the 5 locations were evaluated.The results showed that Cd,Cr and Pb contents in peeled-tuber were significantly affected by genotype,environment and their interaction.Eighty percentage and all tuber samples of MG56 and AG616 harvested from the 5 locations exceeded the maximum allowable value(MAV)of Cd content,respectively.Besides,20%of Zhongshu 3 tubers exceeded MAV of Pb content,while other cultivars had the heavy metal contents smaller than MAV.These results revealed that caution should be paid to cultivars MG 5 6 and AG616 for Cd,and Zhongshu 3 for Pb if they are planted in the slightly or moderately contaminated soils.The ANOVA analysis showed that Cd and Cr contents in peeled-tubers were significantly affected by genotype,while Pb was significantly affected by environment and the interaction.3.The properties of heavy metals uptake and accumulation in potatoThere is a large difference in heavy metal content and accumulation among the different potato organs.The contents of Cd,Cr,Fe and Mn were in the order of leaf>stem>peel>peeled-tuber,while Cu was peel>stem?leaf>peeled-tuber,and Pb and Zn were stem>leaf>peel>peeled-tuber.Meanwhile,the contents of Cd,Cr,Pb,Fe and Mn in leaf and stem were significantly higher than those in peeled-tuber.Otherwise,Cu was mainly found in peel,and Zn in stem.These results indicates the less transference of Cd,Cr,Pb,Fe,Mn and Zn from vegetative tissues to tuber.It is quite interesting to find that peeled tubers have very low Cd content in comparison with the un-peeled tubers.4.The relationship between heavy metal and mineral element in potato plantsFirstly,Cd content of peeled-tuber was positively correlated with Mn and Na contents in leaf,P content in peel and Zn content in peeled-tuber significantly,but significantly and negatively correlated with Cu content in leaf,Fe,Cu and B contents in stem,Fe and Mn contents in peel.Additionally,Cr content in peeled-tuber is positively correlated with Si and Mn contents in leaf,Mn content in stem,P,Cu and B contents in peel,Si and Fe contents in peeled-tuber significantly,but significantly and negatively correlated with Fe and Cu contents in leaf,Cu and B contents in stem,Fe and Na contents in peel,Cu and B contents in peeled-tuber.Finally,Pb content in peeled-tuber is positively correlated with A1 and Fe contents in leaf,Si,Al and Fe contents in stem,Fe content in peel,A1 and Na contents in peeled-tuber significantly,but significantly and negatively correlated with P,Si and B contents in leaf,P and B contents in stem,P,Si and Cu contents in peel,P and Mn contents in peeled-tuber.The current results suggest that antagonism or synergistic effects between heavy metal and mineral elements exist,which could be useful for directing fertilizer application in potato production in order to reduce uptake and accumulation of heavy metals in tubers.