1991, "Introduction to fish spermatozoa and the micropyle
," In: Fish evolution and systematic.
Microbes could bypass the tedious process of decomposing the seed coat if they could gain access directly via pre-designed weak spots, such as hilum, strophiole, chalaza, or micropyle
, or via entrances created by cracks, nicks or wrinkles in the seed coat.
The obpyramidal seeds are attached to a central placenta in rows, have a thick testa with rounded comers, a sub-basal micropyle
, spongy parenchyma within, and are 2-3 x 1.
The site of direct pollen reception itself in most gymno-ovulate plants is the pollination drop, a drop of fluid (mainly water) secreted through the micropyle
of the ovule.
Single polar granule occasionally present, attached either to oocyst residuum or sporocyst; micropyle
Winged fruits have many characters potentially useful for identification including size, number of wings, patterns of wing venation, wing shape and position, persistence of style(s) and pedicel, placentation type, seed number and orientation, position of micropyle
and raphe, and epidermal anatomy.
was reported to be present for a few of the oocysts, which we interpret here to represent the small bump observed on about 10 percent of the outer wall surfaces.
secretes a small droplet of mucilaginous fluid from its micropyle
and oocyst residuum absent, one to five polar granules present.
sections of the regions of the micropyle
and of the hilum.
The Cacteae dade is supported (b86/j83% and b70/ j67%) by various structural features, but only one of them, the occurrence of a disjunct hilum and micropyle
in their seeds (63), is a synapomorphy.
High temperatures induced germination of Rhus ovata seeds by rupturing the second seed-coat layer along the edge of the seed first above the micropyle