Railway Science (Biology-Reproduction in Plant) (Part-II)

Dicotyledons (Dicot) is generally referred to the flowering plants or angiosperms in which the seeds typically contain two embryonic leaves or cotyledon. Examples : All legumes including beans, lentils, pea, and peanuts. Characteristics: Dicotyledonous plants give rise to tap roots, the stem is branched and underground stems arise, broad leaf blades, The embryo is relatively large.

Reproductive parts of the plant: Female - Pistil (located in the center of the flower) is made up of three parts Stigma (sticky knob at the top of the pistil), Style (leads to the ovary) and Ovary (contains the female egg cells called ovules). Male - Stamens (surrounding the pistil) is made up of two parts (anther and filament). The anther produces pollen (male reproductive cells). The filament holds the anther.

In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. Four primary steps of fertilization of plants: Pollination, Germination, Penetration of the Ovule, and Fertilization. After fertilization, the zygote develops into the embryo, the ovules develop into the seed and the ovary develops into the fruit.

A formative plant tissue usually made up of small cells capable of dividing indefinitely and giving rise to similar cells or to cells that differentiate to produce the definitive tissues and organs.
Sclerenchyma is formed mostly of dead cells and they provide structural support to plants. parenchyma is the simple permanent ground tissues that form the bulk of the plant tissues, such as the soft part of leaves, fruit pulp, and other plant organs.

Sepals (calyx) - outermost whorl of the flower, main function is to protect the flower before it blossoms (in the bud stage). Petals - lies above the sepal layer, main function is to attract pollinators such as insects, butterflies. Male parts : Stamens (surrounding the pistil) - made up of two parts (anther and filament). The anther produces pollen (male reproductive cells). The filament holds the anther.

Parthenocarpy - Production of fruits without the fertilisation of ovules. Example - Pineapple, banana grape, orange. These develop without fertilization and are often seedless.
Types : Vegetative and Stimulative both take place without pollination. Stenospermocarpy is a unique type of parthenocarpy where fertilization does take place and the seed begins to develop but it eventually aborts.

Bisexual Flower - The flower possessing both male (stamen made up of anther) and female (pistil or carpel) reproductive parts; Examples - Rose, Sunflower, Hibiscus, Lily. Unisexual Flower - The flower which includes either male or female reproductive parts; To reproduce they undergo cross -pollination; Examples - Papaya, White mulberry, Cucumber, Watermelon, Pumpkin.

Vegetative Propagation - A type of asexual reproduction in which new plants are produced by stem, leaves and buds. Type of Vegetative propagation : Natural Vegetation - Propagation occurs through vegetative parts of a plant such as stems, roots and leaves. Artificial Vegetation - Vegetative propagation occurs through cutting, layering, grafting and tissue culture or micropropagation.

Tissue culture is the growth of tissues or cells in an artificial medium separate from the parent organism, Also called micropropagation and discovered by Gottlieb Haberlandt; Types - Seed Culture, Embryo Culture, Callus Culture, Organ Culture, Protoplast Culture; Use - For genetic modification of a plant or simply increase its yield.

Pollen grain - Pollen grains are microscopic structures, which bear androecium (a male reproductive organ of a flower). The interior section of it contains cytoplasm along with the tube cell, which converts into a pollen tube and the generative cell releases the sperm nuclei.
Pollination - Transfer of Pollen Grains from Anther of a plant to a Stigma of a plant. Other parts of plant : Locule - Pollen containing cavity within an anther; Ovules - Part of the ovary of seed plants that contains the female germ cell; Stigma - Part of the pistil where pollen germinates.