Metal Elements Absorption And Distribution Characteristics And Stress Physiology In Wheat

Iron(Fe), zinc(Zn), copper (Cu), lead (Pb) and cadmium (Cd) accumulation and distribution c haracteristics in different wheat genotypes, and the effects of Pb,and Cd stress on photosynthesis, flag leaf senescence, starch biosynthesis, NPK absorption, grain yield formation and processing quality were studied at Crop Cultivation and Physiology Key Laboratory of Jiangsu Province, Yangzhou University from 2001-2003. The main results were as follows:1. Genotypic difference and characteristics of Fe, Zn, Cu accumulation and distribution in wheatField experiments were carried out in Yangzhou University from 2001-2003 to study Fe ,Zn,Cu accumulation and distribution characteristics in wheat for different end uses. The results showed that genotypic differences of Fe, Zn and Cu contents in grains existed among 35 different wheat varieties. The variance range of Cu content in grains among different wheat varieties was smaller than that of Fe and Zn. Fe, Zn, Cu contents in roots were higher than those in sterns, 1eaves, grains. Fe and Zn contents in 1eaves ate arly growth stage were higher than at other stages. Cu Fe and Zn contents in leaves changed differently. There was significant difference among Fe, Zn, Cu contents in the same organ of different varieties at the same stage. Fe, Zn, Cu contents in grains were not significantly correlated with those in stems and leaves. Zn, Cu accumulation amount of organs above ground increased along with the growth of wheat, reached to the peak tillharvest. While accumulated Fe amount reached its peak at booting stage. A large quantity of Zn, Cu was absorbed during the period from jointing to harvest while that of Fe from jointing to booting stage. The percentage of Fe, Zn, Cu accumulated in different organs fluctuated during the growth of wheat. Cultural techniques affected Fe, Zn, Cu contents in grains. Increasing plant density and N application amount could promote the rise of Fe, Zn& Cu contents in grains. While increasing P application amount decreased Fe, Zn&Cu contents in grains, increasing top dressing P percentage raised them. Spraying FeSO4and ZnSO4 at booting stage could increase Fe, Zn&Cu contents in grains.2. Genorypic difference and characteristics of Pb&Cd accumulation and distribution in wheatThirty eight d ifferent genotypes w ere p lanted i n P b and C d contaminated s oil by adding Pb (OAQs and CdCk to study the difference of Pb and Cd contents in grains among genotypes. The results showed that the difference was significant. 38 different genotypes could be divided into three types according to Pb, Cd contents in grains by SAS cluster analysis, ie. high, low and medium contents.Medium gluten wheat Yangmai 12 was planted in soil contaminated with different concentrations of Pb and Cd to study Pb, Cd uptake and accumulation characteristics. The results showed that Pb and Cd contents in leaves, stems and grains increased with the increment of Pb, Cd treatment concentration. The order of Pb & Cd contents in organs was roots>stems&sheathes>Ieaves>grains, and Pb and Cd contents in grains were significantly lower than that in other organs. Significantly positive correlation between Pb,Cd contents in grains and Pb,Cd concentrations in soil was found. Pb and Cd contents in leaves and stems&sheathes at 5-leaf stage were high, then declined at elongation stage, after that began to increase till harvest at which the contents were the highest during the whole growth stage. Pb and Cd accumulated in different organs increased with the rise of concentrations in soil while would decline when Pb, Cd concentrations exceeded 3000mg/kg, 200mg/kg respectively. Pb and Cd accumulated in stems&sheathes were higher than those in leaves at different growth stages except at 5-leaf stage. Pb and Cd were mainly accumulated from elongation stage to maturity, the percentage was about90%. The percentage of Pb and Cd in stems&sheathes to the whole plant increased with the growth and development of wheat while that in leaves was opposite. The percentage of Pb in grains to the whole plant...