134 Ruminations (0) absent, (1) testal, (2) tegminal and/or
chalazal.
The megaspore tetrads are arranged linearly, and the megaspore at the
chalazal end is functional.
Occurring at the
chalazal end of the ovule there is a cup-shaped region of thick-walled cells (see Figure 4G).
Detail of
chalazal and micropylar region of the ovule in longitudinal section.
Seed length was measured from hilar to
chalazal end; seed width and thicknesses were taken at the mid portion and the widest part, respectively, of the seed.
Se realizo un corte con bisturi en el extremo
chalazal bajo microscopio estereoscopico con aumento de 5X (Severin et al., 2004).
Seeds 4 per fruit, compressed, more or less cuadrangular in outline with a micropilar neck and a
chalazal beak, 9-10 mm long, 5-6 mm wide and 1 mm thick.
0,7 mm wide, flattened, not thickened towards the apex, yellowish; anthers linear, subdorsifixed, slightly sagittate, with a thick green connective and dark brown to blackish thecae, pollen yellow; ovary conical, the lower 1/3 (= nectary tissue) sunk into the receptacle, yellowish, nectary tissue orange, the superior part 7 mm long; ovules white, the flat
chalazal appendage about half as long as the ovule proper; style ca.
Changes in
chalazal cell walls and in the peroxidase enzymes of the crease region during grain development in barley.
We've all heard of physical dormancy, but the discussion in Chapter 3, along with information in a table and a figure, brings all the information together and helps to explain (and us to remember) differences between strophioles or
chalazal plugs.
Each megaspore initiates a pattern of free nuclear development, but only the gametophyte located in the most
chalazal (basal) position will continue to develop and eventually participate in fertilization [ILLUSTRATION FOR FIGURE 3C OMITTED].