Monoecious, biologicaltermThe flower of a plant has both pistils and stamens.There are two kinds of flowers: first, the pistil and stamen are divided into two kinds of flowers, which are called unisexual flowers, just like corn;Second, the pistil and stamen are separated in one flower, which is calledBisexual flower, just like peach blossom.MonoeciousDioeciousThe equivalent ofUnisexual flowerOfseed plantIts male flowers and female flowers are born on the same plant.Male flowers and female peanuts are on the same plant.In 1906, the first edition of Natural History Textbook: "One tree has female flowers or one tree has male flowers, so this plant is called dioecious. Conversely, such as pine, it is called monoecious." In 1913, the first chapter of the New Textbook of the Republic of China Botany: "If male flowers and female flowers are born on one plant, it is called monoecious."
Androgynous means that its pistil and stamen are divided into two kinds of flowers, which are called unisexual flowers, just like corn.asPumpkin(Cucurbitaspp.), cucumber (Cucumis sativa), watermelon (watermelon), etc.In the same inflorescence, those with female flowers and male flowers mixed together are called androgynous flowers, and those with female flowers at the top are called gynogenetic flowers.Ferns refer tomale and femaleThe bisexual reproductive organs are formed on the same individual and areHomosporeGerminationSpermatozoonandArchegonial apparatusOfProthallus。
History of botany
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Angiosperms are also known as flowering plants. Mammals, including humans, prospered with the rise of angiosperms, and evolved to an advanced stage.Therefore, the origin and early evolution of angiosperms have always beenPaleobotanistResearch focus.Named "Dummy Fruit", it is the first specimen directly connected with male organs, female organs, stems and dicotyledonous leaves, which grew 125 million years ago.Previously found in the local Early Cretaceous strataAncient Chinese FruitEarly quilts such as ancient fruit, cross Chinese fruit, and Delali flowerPlant fossil。The difference between "Dummy Fruit" and other early angiosperms is that the pistil and stamen are very close, and the pistil is in the center, similar to the state of flowers in modern angiosperms. The leaves connected to the reproductive organs have dicotyledonous feathery netted veins.Most importantly, the seeds grow on the midrib of the fruit.
The Cretaceous (Early Cretaceous) is the last period of the Mesozoic, lasting for 80 million years. It is located after the Jurassic and before the Cenozoic, both inorganic and organic communities have undergone important changes in the Cretaceous.The chalk layer is a kind of very fine and pure powdery limestone, which is the marine sediment of biological origin, mainly composed of a kind of algae called coccolithcalcareous nannoplankton And planktonic foraminifera fossils.[1]
Reproductive methods
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FirstSex chromosomeThere is no direct logical relationship between male gametes and female gametes.Sex chromosomes control whether life is male or female, and sex is our name for different individuals of the same species with obvious differences in traits, so it can be said that sex chromosomes control the male and female of life.ForHermaphroditeThere is no sex chromosome difference between the two plants, so we can say that they are sexless.But all this does not affect the existence of gender gametes.Gamete individuals with completely different characters can be called by different genders, that is, male and female gametes, but this has nothing to do with whether they carry sex chromosomes.A simple example is that sperm and egg can carry the same genes, but they are still completely different.In androgynous plants, their gametes are bred in completely different environments, that is, pistils and stamens. Mature gametes have different characters, so they can be called gametes of different sexes, and pistils and stamens are also the names of the parts where gametes of different sexes are bred.
Further, we can look at this matter from the perspective of evolution.Generally speaking, allogamy is better than homogamy.In general, animals tend to be hermaphrodite, while plants tend to be hermaphrodite, which is mainly due to their living behaviors.Animals have a great chance of meeting the opposite sex when they migrate throughout their lives. It is also very convenient to mate with the opposite sex. If they are hermaphrodite, the extra genitals of the other sex will be a burden for biology, because the development of genitals requires a lot of resources;But plants are different. They take root all their lives, and the difficulty of hybridization is greater than that of animals. If there is another hermaphrodite, the two male trees growing in the desert will only have a lifetime of tragedy.Therefore, in the evolution of hermaphrodite plants, there are gametes of different sexes, which enable them to complete heterosexual mating and retain the hermaphrodite, ensuring that heterosexual mating will not be affected by the sex of the zygote, which can be said to be a very clever compromise.[2]
Species classification
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Most plants are monoecious, such as the following:
（1） Corn, rice, wheat, sorghum, sesame, rape, legumes, etc.
