When they’ve finished their reproductive lifetime, pine cones (Pinus spp.) Become Christmas decorations, gas for fireplaces or craft objects. Pines are. They have both male and female cones, with the cones plant seeds. As with other gymnosperms, the seeds differ from flowering plants because they aren’t surrounded by an ovary that makes a fruit for seed dispersal. The seeds lie in the open, wedged between the scales of the cone. Pine cones require two years to develop, eventually become fertilized and produce seeds, and it’s a complex story.
Formation Begins
In spring, generally higher in the blossom, the hints of some pine tree branches, grow small, green, female cones. They are thought to be derived from branches that have modified scale-like constructions rather than leaves. Each scale has two ovules on its hand, and each ovule develops into a seed. Because the cone is tiny, everything is on a small scale in this stage. Within the ovule, cell division occurs at a technical structure toward the base of the ovule known as the nucellus. It divides to form the female sex cell or gamete.
Pollination Occurs
Cones type producing pollen. Pollen floats on fluid near the tip of this scale on the wind into the female cone and lands. The scale tip opens marginally to let the pollen. The pollen rests there for a year. The female cone expands into a hard structure using the scales. Changes are occurring in the pollen and the ovule, although fertilization will not happen until the spring. The cells are dividing to produce the gametes, semen that is known as, and female gametes, known as eggs, that will unite to produce the seeds.
Fertilization Follows
Throughout the spring of the next season of this cone, the male and female gametes are ready. The pollen develops a pollen tube, which enters just a little hole at the ovule’s skin near its basal end, known as the micropyle. The semen goes, and the tube enters the ovule down the tube and to the ovule. Fertilization occurs when egg and the sperm fuse and the seeds grow. Each seed includes food to nourish it, in addition to the embryo of a young pine tree.
Maturation and Seed Dispersal
The female cone develops as the seeds grow, getting browner and larger. If the seeds are mature, the scales of the cone start to separate from one another, becoming sterile, dry and brown. You can see two seeds resting at the top of each scale When you look between the scales. There’s enough space for the seeds to drop out. Depending upon the species seeds are light and winged and have carried by the wind, or they are heavy and nearly wingless and have dispersed by creatures. A good example of a walnut with winged seeds, Afghan pine (Pinus eldarica) is hardy in U.S. Department of Agriculture plant hardiness zones 6 through 11. The Italian stone pine (Pinus pinea), which develops in USDA zones 7 through 11, releases large seeds used as food. They are an important element in cooking.