Pak. J. Bot., 37(3): 601-611, 2005. DEVIATIONS OF SOME NUTRIENT CONCENTRATIONS IN DIFFERENT PARTS OF SAFFLOWER CULTIVARS DURING GROWTH STAGES İBRAHİM ERDAL 1 AND HASAN BAYDAR 2 1 Department of Soil Science, 2 Department of Field Crops Faculty of Agriculture, Süleyman Demirel University, 32260 Isparta, Turkey Abstract The objective of this research was to examine the concentrations of P, K, Fe, Zn and Mn during growth and development in different parts of 4 safflower varieties. The nutrient concentrations of safflower showed variations depending on the varieties and plant parts at different stages of growth and development. Both phosphorus and potassium concentrations in all plant parts (except P concentration in head) decreased from shooting to maturity. Phosphorus concentrations in heads were higher than other parts at every stage of the growth and development in all varieties. Iron concentrations in the roots, stems and leaves showed quite deviations during the periods. Zinc levels in all parts of varieties showed the similar tendency without big deviations until the first blooming. After this stage concentration of Zn showed irregular increases and decreased at harvest again (except root zinc concentration). Mn levels of the root, stem and head in all varieties decreased through the end of the period. But in leaf, Mn concentrations increased through the harvest generally. Introduction Nutrient concentration of a plant changes depending on mineral mobility and mineral functions during growing period. The nutrients with high metabolic activity such as potassium, phosphorus or nitrogen moves easily from older tissue to newly growing part of the plant. Therefore, concentrations of highly phloem-mobile elements decrease throughout the leaf development. Import and export of mineral nutrients occur simultaneously during life cycle of a plant. During the growing stage, as a rule, export of mineral nutrients increase and thus decrease in net concentration and decrease in amount per organ such as leaf (Smith, 1996; Beaufils, 1973). During vegetative growth, mineral supply to roots is often either permanently insufficient or temporarily interrupted. Remobilization of mineral nutrients from leaves to growing parts is vitally important for completion of life cycle of plants. Remobilization of mineral nutrients is particularly important during reproductive growth, when seeds, fruits and storage organs are formed. At this growth stage root activity and nutrient uptake generally decrease, therefore the mineral nutrient concentrations of vegetative parts quite often decline sharply at reproductive stage. Remobilization of highly phloem-mobile mineral nutrients can lead to rapid decline in their concentration in the vegetative shoots. From experiments with different vegetables, decrease of mobile mineral nutrient in leaf related to senescence can easily be seen (Wood et al., 1986; Mauk & Nooden, 1992). In a study conducted by Garz (1966), with pea plant, changes of some nutrients concentration were examined from flowering to harvest and it was seen that nitrogen, phosphorus and potassium levels increased first and decreased continuously until ripening time. Similarly, potassium concentration of tomato varieties decreased from full bloom to ripening time and leaves showed severe potassium deficiency. Corresponding Author: E-mail: ierdal@ziraat.sdu.edu.tr tel:90 246 2113874, fax: 90 246 2371693