Evolutive morphology of the red garlic clove protetive leaf (Allium sativum L.).

PELLEGRINI, C.N.; ORIOLI, G.A.

Buenos Aires

Congreso; X Argentine Congress of Morphological Sciences; 2006

Facultad de Ciencias Veterinarias.Univ.Nac.del Centro

EVOLUTIVE MORPHOLOGY OF THE RED GARLIC CLOVE PROTECTIVE LEAF (Allium sativum L.) Pellegrini CN, Orioli GA. Depto. Agronom.a, UNSur. (8000) Bah.a Blanca, Argentina. E-mail: pellegri@criba.edu.ar Literature shows references on the anatomy of the garlic clove protective leaf but descriptions are based on recently harvested material. During storage, developing garlic bulbs loose water and some structures become differentiated until the physiological maturity is reached. This work shows the morphological changes that take place in the red garlic clove protective leaf from harvest (inmaturo stage) to physiological maturity. Observations were made using light and electron microscopy. The protective leaf consists of a single layer of straight elongated cells in the clove main axis, with sharp edges, primary cell walls and wide lumen with a visible nucleus. As maturation progresses it becomes dry and hard, the epidermal cells deposit lignified secondary walls so their lumen mostly reduces and pits can be noted. This process is delayed in the upper third of the leaf where stomata are under differentiation. At early stages, the mesophyll consists of several layers of turgid parenchymatic cells and, closer to the outer epidermis, there is a single layer of square cells containing a homogeneous solution of anthocyanic pigment, responsible of the red colour of this leaf. As the leaf undergoes maturation, the mesophyll layers compress and obliterate, with the exception of the outer layer. Inside those uncollapsed cells, no reported before calcium oxalate crystals are formed while the pigment solution migrates towards the outer epidermal cells. Finally, it is found precipitated in the narrow lumen of those cells as dense clots. Those structures stand for the protective nature of this leaf