The strobiles, also known as cones, are structures commonly confused with flowers, but they should not be so named. Mainly found in gymnosperms, strobiles are responsible for the formation of gametes.
→ What is a strobile like?
The strobiles, found in many lycophytes and most gymnosperms, are structures formed by groups of sporophiles. (modified leaves that have sporangia) or egg-bearing scales. The sporangia responsible for pollen production are called microsporangia, and the leaves that support them are called microsporophils. The sporangia that produce eggs, in turn, are called megasporangia, and the leaves that support them are called megasporophiles.
→ Strobiles of pine
The strobiles have different characteristics, depending on the species studied. In pine, you male strobiles, or microsporangia (produce pollen), are small, about 1 cm to 2 cm in length, and present membranous microsporophiles spirally arranged in the cone.
You female strobiles, or megasporangiados (ovulated), of pine they are larger and more complex and have scales with ova, arranged spirally around the axis of the strobile. At the time of reproduction, the scales of this strobile are well separated, ensuring that the pollen grains reach the proximity of the eggs, germinate and produce the pollen tube, which is responsible for carrying the male gamete to the feminine.
It is these strobiles that will house the seed after fertilization.The strobiles are located in the final portion of stem branches.When we observe the arrangement of strobiles in pine, we found that the male strobiles are located in the lower branches of the tree, and the female strobiles are present in the upper branches. In some pines, we can see that male and female strobiles are on the same branch, with the females positioned closer to the apex.
This differentiated location of strobiles in the plant prevents self-fertilization. This is because the wind does not usually carry the pollen directly to this structure, so the fertilization of the ovulated strobiles is done by pollen from other trees.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-estrobilo.htm
