Abstract:

Abstract : Elements analysis of 8 species of Convolvulaceae in tropical and subtropical areas showed that the mean concentration of N, K and Ca were higher than 1%, S, Mg, P ranged between 0.2 and 0.5%, Fe, Mn ranged between 0.01 and 0.05%, Zn, B, Cu, Hg, Pb, As, Cr, Mo and Cd were less than 0.01%,　The mean element concentration of 18 plants followed an order asN> K> Ca> S> Mg> P> Fe> Mn > Zn> B> Cu> Hg> Pb> As> Cr> Mo> Cd; The variation coefficient of 6 major elements ranged between 0.30 to 0.60;in addition to B, Cu, with low variation coefficient of 0.40 and 0.48 respectively, the variation coefficient of the rest trace elements were higher than 0.70, in particular, the variation coefficient of Pb, Mo, Cd were higher than 1.00 (1.13,1.32,1.54 respectively); The correlation analysis of element concentration in plant revealed that N and P, Ca and S, Cr and Mo, Cd, Pb and Mo, Fe positively correlated at the level of 0.05, K and B, Pb and Cr, Mo positively correlated at the level of 0.01,while As and Cu, N and Mn, P and Cd, Mn negatively correlated at the level of 0.05;72% of the plants lacked B, Merremia boisiana and Merremia umbellata in Yunnan lacked Cu , Merremia vitifolia in Baise City of Guangxi lacked Mo (not detected), while Mn in 50% of 18 plants was overhigh; Defining the degree of pollution as the ratio of element concentration of test plants and the general scope, As concentration of Merremia umbellate in Yunnan, Ipomoea pes-caprae in Hainan and Ipomoea pes-tigridis,Cd concentration of 4 plants, Cr concentration of 61% of 18 plants,Zn concentration of Ipomoea aquatica, Pb concentration of Merremia vitifolia in Yunnan and Ipomoea cairica in Guangxi to which were higher than 1.