Various studies pointed out the effect of NPK mineral supply on the biology of sunflower leaf apparatus: form, structure, and activity of photosynthetic apparatus. Investigations have been conducted on five sunflower hybrids (P.I. 2001, Select, P.I. 2002, P.I. 2004, and Performer) with various degrees of precociousness, fertilized with different NPK rates (N 0 P 0 K 0 ; N 60 P 80 K 60 ; N 80 P 80 K 80 ), under pedoclimatic conditions of the Moldavian Plain. Leaf morphogenesis was analysed by determining the number of active leaves and leaf area per plant, as well as the anatomical structure of leaf, at limb and petiole level. The obtained results have demonstrated that leaf morphogenesis was differentiated according to studied hybrid and dose of applied fertilizers. Analyses concerning the anatomical structure of leaf have shown differences between experienced variants, which were found especially at the leading tissue and stomata apparatus. The differences were quantitatively: number of collenchyme layers, number of stomata per area unit, number of leading fascicles, and qualitatively: presence of concentric fascicles, presence of the cap of lignified cells in the phloem parenchyma, and the presence of two stomata types.

anatomical leaf; sunflower; hybrids; fertiliyation

Presentation: oral