Plants that have representatives of different sexes - male and female - this dioecious plants. Examples of such plants are dioica nettle, poplar, mulberry tree (mulberry), asparagus, spinach, willow, hemp, pistachio, podocarpus and others. But this is not a complete list.
And all dioecious plants have flowers, but some will have “male” flowers, while others will have “female” flowers. Such representatives of the flora are characterized by cross-pollination. Monoecious and dioecious plants differ in that the former have "male" and "female" flowers on the same plant.
Pollination of dioecious plants
Dioecious plants from the point of view of evolutionary development are considered more perfect. They are not capable of self-pollination, and this circumstance contributes to the strengthening of the species.
For some fruit trees, it is important to have both sexes. In the process of fertilization and production of seeds and fruits, stigmas of male flowers take pollen of stamen male flowers. Only in this case can one get the fruits. But this does not mean that for each "female" plant you need to have one tree of the opposite sex.
One male representative will serve for pollination of a number of female plants. The approximate amount varies depending on the type of plant. For example, to fertilize a whole grove of date palm trees, only a few "male" trees are planted. One male date palm tree is enough for pollination of 40-50 palm trees of the opposite sex. Often, to guarantee successful pollination, a branch of the male tree is grafted onto female trees.
Differences between representatives of different sexes of the same species
Very often, it is initially difficult to determine which house a plant belongs to. But this ceases to be a mystery when the time comes for the first harvest - the fruits will be on the female. At the same time, the difference in the structure of the male and female flower is noticeable. The male has little or no stigma, while the female flower may lack stamens. Stamens in female flowers almost do not produce pollen, while stamens of male flowers are abundantly dotted with it.
Practical application of knowledge about dioecious plants
For practical purposes, it is important not only to know which plants are dioecious, but also the ability to distinguish the gender of individuals of the same species. For example, if there is a mulberry tree on the plot that does not bear fruit, then most likely it is a male tree. And in order to enjoy tasty and healthy berries, you need to plant a pair for him - a female tree. Or at least plant a branch of a female tree. And vice versa: a female tree to plant a male branch.
At the same time, if you need to buy a mulberry tree for a personal garden exclusively for decorative purposes, so that you do not need to constantly remove overripe berries that have crashed to the ground, it is better to choose a male tree - it has a beautiful magnificent crown, but will never bear fruit.
Dioecious plants, in particular, representatives of their male part, produce a huge amount of pollen. This fact has a very simple and logical explanation: the female tree may not be near, so there should be a lot of pollen in order for it to reach the goal. Male trees produce more pollen, its particles are very light and have a shape that makes it easy to "travel" on air currents.
Figs - a special dioecious plant
Figs, also called fig trees or figs, are one of the most curious representatives of the dioecious. It is considered the oldest cultivated plant. The fig tree is even mentioned in the Bible.
Fig tree does not differ beautiful flowering - fig flowers are small and inconspicuous. But this disadvantage is more than compensated by juicy and honey-tasting fruits. True, only female plants bear fruit. Therefore, a fig tree grown from seeds can turn out to be, as the people say, a hollow, that is, a male tree. But without it there will be no fruit on female trees.
Pollination of figs is a very interesting topic for a separate study. The fact is that fig flowers are pollinated only with the help of wasp blastophages. A wingless male wasp awaits the female inside the male flower. A fertilized female blastophage collects pollen from a male flower on its body, getting out of it, and transfers pollen to female flowers in search of new male inflorescences.
Interesting Facts
Scientists have found that for the health of a person prone to allergies, dioecious plants are very dangerous. Among them, allergenic plants are more common. And those who have earned the fame of the most powerful allergens are also dioecious. But, choosing plants for landscaping, you can not refuse dioecious plants, you just need to give preference to females - they do not produce as much pollen as males, which means they have less effect on humans.
Under certain unfavorable conditions, dioecious plants, for example, hemp, can turn into monoecious. At the same time, male and female flowers will be presented on one plant.
In ancient times, knowledge about what is dioecious plants. Examples of this can be found even in the history of military confrontations. For example, troops during raids on foreign territories destroyed males in date groves - this is much easier than completely cutting down all plantings, but guarantees the absence of crops and will cause significant economic damage to the state.