VASCULARIZACIÓN DEL PEDICELO Y CRECIMIENTO DEL FRUTO DE Citrus sinensis var. Salustiana Y SU RELACIÓN CON EL CONTENIDO DE ÁCIDO INDOLACÉTICO

Pedicel development and fruit growth in Citrus sinensis ‘Salustiana’ and their relation with indol-acetic acid content Experiments were performed in fruits collected from Citrus sinensis (L.) Osbeck var. Salustiana with the objective to establish the relationship between indol-acetic acid content and, fruit and pedicel development during the initial growth stage. Reproductive structures of different trees from an orchard in Museros (Valencia, Spain) were collected periodically, from anthesis to 118 days after anthesis and used to determine cross-sectional area of pedicel, anatomical changes, dry mass of fruit, and indol-acetic acid (IAA) content using HPLC. The increase in cross-sectional area of pedicel was related to the increase in cross-sectional area of xylem and phloem, with greater rate from the 62 dda, due to the activity of the vascular cambium. Xylem and phloem continued developing until the end of the study (118 dda), but from the 76 dda the active phloem area remained constant due to the development of internal fiber layers. During the period of study the concentration of AIA in the pedicel as in the fruit was noticeably superior during postanthesis, and soon it diminished sharply. The maximum levels of IAA fitted with processes of cellular division and differentiation in pedicel and with the slow phase of growth of the fruit. Growth kinetic of pedicel and fruit were noticeably similar, being observed a greater rate of increase in fruit dry mass during the period of greater development of the secondary vascular tissue, mainly of xylem. Additional key words: Orange, AIA, anatomy of pedicel