ASSAY OF NUTRIENT ELEMENTS IN TNE TOMATO PLANT AT DIFFERENT GROWTH STAGES BY ATOMIC ABSORPTION SPECTROMETRY

Some nutrient elements in tomato plants at different growing stages were assayedby atomic absorption spectrometry. It was found that the levels of 4 microelements,namelyFe,Zn,Cu and Mn were higher in the root than the corresponding levels in the stem and leafat the seedling,vegetative growth and reproductive stages. The weighted average of Fe con-centration at the seedling stage was far above those for the vegetative growth and reproduc-tive stages. At the vegetative growth stage the weighted average levels of Zn and Cu wererather high whereas that of Mn was the lowest. The levels for the macroelements Mg,Ca,Kand Na were as follows:At all three stages of growth the Ca level of the leaf was higher thanthose of the stem and root,whereas the K level in the stem was higher than those of the rootand leaf. During growth of the tomato plant,the weighted average level of Ca showedgradual incremental increase whereas that of K exhibited incremental decrease. As toMg,for the seedling stage the content was highest in the root,for the vegetative growthstage highest in the stem,and for the reproductive stage highest in the leaf. A certain amountof Na was present also in the plant.