Category: Biology Second Paper

A third layer is formed when the ovule develops into a seed. It’s called Ariel. Such as litchi, kathlichu, nutmeg, betel nut etc.

1. In the process of fertilization, the sperm of the stamen unites with the egg of the female. Because the sperm and egg have different characteristics, there is a possibility of creating a new species. The new variety is different from the parent plant.
2. Iri-8 rice was developed in the Philippines by crossbreeding Indonesia’s Peta rice and Taiwan’s Dee-gee-woo-gen rice. The yield of this rice is 90-100 maunds per acre.
3. Erichile rice was developed by breeding Peta rice from Indonesia, TKM-6 rice from India and Taichu-1 rice from Taiwan. The yield of this rice is 70-75 maunds per acre. The yield of Iri-5 rice is 70-75 maunds per acre. High yielding Eri rice is Eri-20, Eri-28, Eri-29 etc.
4. Bangladesh Rice Research Center developed Birishail rice by crossbreeding BR-20 and BR-3. The four Ufshi rice varieties developed by the Bangladesh Rice Research Center are Chandina (BR-1), Mala (BR-2), Shahi Balam (BR-15) and Shrabni (BR-26).
5. Bangladesh Agricultural Research Institute (BRRI) has developed 17 Ufshi varieties of wheat through hybridization. High yielding wheat varieties are Balaka, Akbar, Kanchan, Barkat and Saugat. Besides, Ez-27 and Ez-28 wheat are more improved.
6. Disease-resistant varieties are developed by breeding cultivated disease-causing crops with wild disease-resistant crops. Mukta (BR-11), Ghazi (BR-14), Mohini (BR-15) etc. disease resistant varieties of rice.
7. Artificial breeding has created varieties of plants that can grow in adverse environments. All these varieties can tolerate drought, flood, salinity etc. due to different characteristics.
8. The characteristics of grain size, color, smell, taste etc. have been improved through artificial breeding.
9. Through artificial hybridization it has been possible to reduce the cultivation period of the crop to 20-30 days. This new variety yields before the onset of unfavorable conditions.

1. Fertilization involves the union of sperm and egg with different characteristics. The new plant thus created is different and diverse in size, shape and structure.
2. Fertilization results in the development of disease-resistant plants from susceptible plants. Disease resistant plants are of different characteristics and varieties.
3. Mating of two different plants through fertilization results in varieties that are antagonistic. All these plants have a collection of various adverse resistance properties. These diverse plants can easily tolerate drought, flood, salinity, heavy rain, no rain etc.
4. Fertilization process produces various traits in crop plants. The grain size, color, smell, taste etc. of these plants are different.

1. Embryo Development: Fertilization results in the formation of a zygote. The zygote divides to form the pro-embryo. The embryo divides to become a complete embryo. The primordial embryo divides to form the complete embryo through cotyledons, embryos and root formations.
2. Origin of seeds: The main source of food in the living world is seeds. The sperm unites with the secondary nucleus to form the endosperm or seed.
3. Seed production: Zygote is formed by the union of sperm and egg. After the zygote is formed, the ovum develops into a seed.
4. Fruit formation: After fertilization, the ovary of the flower gradually turns into fruit and the skin of the ovary turns into fruit.
5. Reproduction: After the union of sperm and egg, the ovule of the flower turns into a seed. Most plants on Earth reproduce by seeds.
6. Formation of new species: Zygote is formed by the union of two different cells sperm and egg. It gives rise to new species with new characteristics.
7. Creation of Biodiversity: Zygote is created by the union of sperm and egg. New species are formed from the zygote. Biodiversity is created through new species.
8. Fulfillment of food needs: Seeds and fruits are created through fertilization. Seeds and fruits fulfill the food needs of living organisms. Mango, yam, jackfruit, litchi, papaya, bell, palm, paddy, wheat, bhutra, barley, cown etc. meet the food needs.
9. Creation of disease-resistant varieties: Through fertilization, disease-resistant varieties of plants can be created.
10. Development of desired characteristics: Development of desired characteristics of plants can be done through fertilization.
11. Evolution: Neshik plays an important role in describing the course of evolution.
12. Chromosome balance: In the process of fertilization, a diploid zygote is formed by the union of sperm and egg. It keeps the number of chromosomes of the organism constant.

When the pollen tube enters the ovule through the ovary, it is called mesogamy.

When the pollen tube enters the ovule through the ovule, it is called calazogamy. Like- gourd, pumpkin etc.

Porogamy is when the pollen tube enters the ovule through the ovary. For example, Zhou.

The process by which female gamete and male gamete are sexually united is called fertilization or fertilization. Sexual reproduction of herbaceous plants is ugamous in nature. The stages of fertilization process are described as-

1. Pollen Germination: Inside the anther, the pollen nucleus divides to form two nuclei. Tubular nucleus and gonial nucleus. In the binucleate state, the pollen grains fall into the female endosperm through pollination. Pollen is trapped in the endosperm by the sticky sap secreted by the endosperm or with appendages. Pollen enlarges by absorbing fluid. This condition is called hydration. The anther is energized and pressure builds up inside it. Due to this pressure, the integument of the pollen tube is extruded through the reproductive pore. It is called pollen tube. Pollen does not germinate without its own species.
2. Pollen tube travel to the uterus and sperm production: Cutinase enzyme degrades the cutin of the uterus and the pollen tube enters the uterus. Enzymes like pectinase, cellulase etc. are secreted from the tip of the pollen tube and dissolve the pistil cells to form the tube. The pollen tube continues towards the ovary under the influence of calcium (Ca++) ions released from the ovary and ovary. The tube nucleus enters the pollen tube first and the generative nucleus later. The germ nucleus divides to form two spermatozoa.
3. Entry of the pollen tube into the embryo sac: The pollen tube enlarges and reaches the uterus. Penetrates the lining of the uterus and enters the ovum. The membrane of the ovary dissolves and the anther approaches the ovule. In most plants the pollen tube enters the ovary through the ovule.
4. Ejection of sperm into the ovary: After the pollen tube enters the ovary, its tip bursts. Through the slit, the sperm enters the two follicles.
5. Union of sperm and egg: In the embryo sac, one of the sperm moves towards the egg and the other towards the secondary nucleus like an amoeba. One of the two sperm fuses with the egg and the other fuses with the secondary nucleus. The union of sperm and ovum is called fertilization or syngamy and the union of sperm and secondary nucleus is termed triunion. Nishek and Trimilan together are called Bi-Nishek.

The process by which female gamete and male gamete are sexually united is called fertilization or fertilization. Sexual reproduction of herbaceous plants is ugamous in nature. The stages of fertilization process are described as-

1. Pollen Germination: Inside the anther, the pollen nucleus divides to form two nuclei. Tubular nucleus and gonial nucleus. In the binucleate state, the pollen grains fall into the female endosperm through pollination. Pollen is trapped in the endosperm by the sticky sap secreted by the endosperm or with appendages. Pollen enlarges by absorbing fluid. This condition is called hydration. The anther is energized and pressure builds up inside it. Due to this pressure, the integument of the pollen tube is extruded through the reproductive pore. It is called pollen tube. Pollen does not germinate without its own species.
2. Pollen tube travel to the uterus and sperm production: Cutinase enzyme degrades the cutin of the uterus and the pollen tube enters the uterus. Enzymes like pectinase, cellulase etc. are secreted from the tip of the pollen tube and dissolve the pistil cells to form the tube. The pollen tube continues towards the ovary under the influence of calcium (Ca++) ions released from the ovary and ovary. The tube nucleus enters the pollen tube first and the generative nucleus later. The germ nucleus divides to form two spermatozoa.
3. Entry of the pollen tube into the embryo sac: The pollen tube enlarges and reaches the uterus. Penetrates the lining of the uterus and enters the ovum. The membrane of the ovary dissolves and the anther approaches the ovule. In most plants the pollen tube enters the ovary through the ovule.
4. Ejection of sperm into the ovary: After the pollen tube enters the ovary, its tip bursts. Through the slit, the sperm enters the two follicles.
5. Union of sperm and egg: In the embryo sac, one of the sperm moves towards the egg and the other towards the secondary nucleus like an amoeba. One of the two sperm fuses with the egg and the other fuses with the secondary nucleus. The union of sperm and ovum is called fertilization or syngamy and the union of sperm and secondary nucleus is termed triunion. Nishek and Trimilan together are called Bi-Nishek.

The pollination that occurs between two flowers of different species or different plants is called cross pollination. The purity of the species is not intact in the cross-pollination process. Such as shimul, papaya etc