Agrumi ornamentali

Somatic embryogenesis and plant regeneration from pistil thin cell layers of Citrus

Callus induction, somatic embryogenesis and plant regeneration were obtained in six different citrus species [Citrus deliciosa Ten. (cv 'Avana'), C.limon (L.) Burm. (cv 'Berna'), C.madurensis Lour. (cv 'CNR P9'), C.medica L. (cv 'Cedro di Trabia'), C.tardiva Hort. ex Tan. (cv 'CNR P6'), C.sinensis (L.) Osb. (cv 'Ugdulena 7')] from cultures of pistil transverse thin cell layer explants [(t)TCL]. Explants were cultured on three different media: the nutrients and vitamins of Murashige and Skoog medium alone (MS) or MS supplemented with either 500 mg l(-1) malt extract (MS I) or 500 mg l(-1) malt extract and 13.3 mu M 6-benzylaminopurine (MS II). Sucrose (146 mM) was used as the carbon source. …

Self-regulation mechanism of an ecosystem in a non-Gaussian fluctuation regime

We study a dynamical model for an ecological network of many interacting species. We consider a Malthus-Verhulst type of self-regulation mechanism. In the framework of the mean field theory we study the nonlinear relaxation in three different cases: (a) towards the equilibrium state, (b) towards the absorbing barrier, (c) at the critical point. We obtain asymptotic behavior in all different cases for the time average of the process. The dynamical behavior of the system, in the limit of infinitely many interacting species, is investigated in the stability and instability conditions and theoretical results are compared with numerical simulations. \textcopyright{} 1996 The American Physical So…

Kinetics of Ordered Phases in Finite Spin Systems

We study the growth of the ordered phase in a spin system of finite size suddenly brought below the transition temperature. Such a growth is driven by the instability of the mode corresponding to the largest eigenvalue of the interaction matrix. The relaxation occurs through different regimes according to whether the unstable mode has a negligible or macroscopic amplitude. One regime is characterised by dynamical scaling properties whereas in the other we can distinguish the growth to a macroscopic amplitude followed by rare transitions from one equilibrium amplitude to another. The analysis is carried out in the framework of a dynamical generalisation of the spherical model assuming non-ra…

Recupero, conservazione ed analisi della collezione di agrumi dell’Orto Botanico di Palermo

Characterization of five sour orange clones through molecular markers and leaf essential oils analysis.

Five clones of sour orange (Citrus aurantium L.) showing significant morphological differences were selected from our germplasm collection and characterized both by genetic and leaf volatiles analysis. The genetic studies were undertaken by the use of molecular markers developed by PCR-based techniques (ISSR and RAPD), while the leaf essential oil patterns were obtained by chromatographic and mass spectrometric determination. Data obtained suggest that reasonably similar information can be achieved from the two techniques, supporting each other in characterization studies.

In vitro rescue of zygotic embryos of sour orange, Citrus aurantium L., and their detection based on RFLP analysis

Embryo development in vivo has been studied in four Citrus aurantium L. polyembryonic genotypes. Seeds were collected 65, 85, 105, 125 and 220 days after pollination (DAP). None of the immature seeds harvested 65 and 85 DAP contained visible embryos. A single embryo at a more advanced developmental stage was observed in the central position at the micropylar apex of the embryo sac in about 74% of seeds harvested at 105 DAP, while at 125 and 220 DAP the majority of seeds had two or more embryos at the same developmental stage crowded together. Restriction fragment length polymorphism (RFLP) analysis of low- and high-copy-number nuclear DNA was used to distinguish zygotic from nucellar seedli…