Common features: Fertilization (Syngamy) is absent in both apomixis and parthenocarpy.
Contrast features: Parthenocarpic fruits does not develop seeds, whereas in apomixis seeds are developed.

Microspores are formed by the process of microsporogenesis. The cells of microspore tetrad are haploid(n).

(a) A - Bud from eye
(b) Tuber
(c) Solanum tuberosum

Helobial endosperm: Primary Endosperm Nucleus moves towards the base of embryo sac and divides into two nuclei. Cell wall formation takes place leading to the formation of a large micropylar and small chalazal chamber. The nucleus of the micropylar chamber undergoes several free nuclear division whereas that of chalazal chamber may or may not divide. Examples: Hydril/a and Vallisneria.

The receptive surface of the stigma receives the pollen. If the pollen is compatible with the stigma it germinates to form a tube. This is facilitated by the stigmatic fluid in wet stigma and pellicle in dry stigma. These two also decide the incompatibility and compatibility of the pollen through recognition-rejection protein reaction between the pollen and stigma surface.

The maize is monoecious and unisexual. The male inflorescence (tassel) is borne terminally and female inflorescence (cob) laterally at lower levels. Maize pollens are large and heavy and cannot be carried by a light breeze. However, the mild wind shakes the male inflorescence to release the pollen which falls vertically below. The female inflorescence has a long stigma (silk) measuring up to 23 mm in length, which projects beyond leaves. The pollens drop from the tassel is caught by the stigma.

There are two types of tapetum based on their behavior. They are: 
Secretory tapetum (parietal/glandular/ cellular): The tapetum retains the original position and cellular integrity and nourishes the developing microspores.
Invasive tapetum (periplasmodial): The cells lose their inner tangential and radial walls and the protoplast of all tapetal cells coalesces to form a periplasmodium.

Occurrence of more than one embryo in a seed is called polyembryony.
The seedlings formed from the nucellar tissue in citrus are found better clones for orchards. Embryos derived through polyembryony are found virus free.

In Bryophyllum, the leaf is succulent and notched on its margin. Adventitious buds (epiphyllous buds) develop at these notches. They develop into new plants forming a root system. They become independent plants when the leaf gets decayed.

The term Apomixis was introduced by Winkler in the year 1908. It is defined as the substitution of the usual sexual system (Amphimixis) by a form of reproduction which does not involve meiosis and syngamy.

(a) Ovary ⟶ Fruit
(b) Secondary nucleus ⟶ Endosperm
(c) Outer integument of ovule ⟶ Outer seed coat (Testa)
(d) Funicle ⟶ Stalk of the seed

(a) Winds
(b) Birds.
(c) Bats
(d) Snails and slugs

Pollination in gymnosperms is said to be direct as the pollens are deposited directly on the exposed ovules.

(a) Cactaceae - Circinotropous ovule
(b) Leguminosae - Campylotropous ovule
(c) Polygonaceae Orthotropous ovule
(d) Primulaceae - Hemianatropous ovule

Pectin, cellulose, hemicellulose, callose, sporopollenin, pollenkitt and other proteins

(a) Androecium is the male part of a flower
(b) It is made up of stamens
(c) Each stamen possess anther and a filament
(d) Anthers bear pollen grains (male gametophyte)

The genetic ability of a plant cell to produce the entire plant under suitable conditions is said to be totipotency.

(a) Budding - Hydra
(b) Fragmentation - Spirogyra
(c) Regeneration - Planaria
(d) Gemma cup formation - Marchantia

Gymnosperms - Pollination is said to be direct as the pollen are deposited directly on the exposed ovules  Angiosperms - Pollination is said to be indirect as the pollen are deposited on the stigma of the pistil.

Dichogamy stamens and stigmas mature at different times (protandry, Protogyny) Herkogamy - Stamens and stigmas are arranged in such a way, self pollination become impossible.

(i) Structure of a Cicer seed as an example for Dicot seed The mature seeds are attached to the fruit wall by a stalk called funiculus.
(ii) The funiculus disappears leaving a scar called hilum. Below the hilum a small pore called micropyle is present.
(iii) It facilitates entry of oxygen and water into the seeds during germination.
(iv) Each seed has a thick outer covering called seed coat.
(v) The seed coat is developed from integuments of the ovule.
(vi) The outer coat is called testa and is hard whereas the inner coat is thin, membranous and is called tegmen.
(vii) In Pea plant the tegmen and testa are fused. Two cotyledons laterally attached to the embryonic axis are present.
(viii) It stores the food materials in pea whereas in other seeds like castor the endosperm contains reserve food and the cotyledons are thin.
(xi) The portion of embryonal axis projecting beyond the cotyledons is called radicle or embryonic root.
(x) The other end of the axis called embryonic shoot is the plumule.
(xi) Embryonal axis above the level of cotyledon is called epicotyl whereas the cylindrical region between the level of cotyledon is called hypocotyl.
(xii) The epicotyl terminates in plumule whereas the hypocotyl ends in radicle.

There are 5 types of ovules.
1. Orthotropous: 
Micropyle is at the distal end and the micropyle, the funicle and the chalaza lie in one straight vertical line. 
2. Anatropous:
The body of the ovule becomes completely inverted so that the micropyle and funiculus come to lie very close to each other. 
E.g: Dicots, Monocots (Common)

3. Hemianatropous:
The body of the ovule is placed transversely and at right angles to the funicle.
E.g: Primulaceae.
4. Campylotropous:
(i) The body of the ovule at the micropylar end is curved and more or less bean shaped. The embryo sac is slightly curved.
(ii)  All the three, hilum, micropyle and chalaza are adjacent to one another, with the micropyle oriented towards the placenta.
E.g: Leguminosae.
5. a) Amphitropous:
The distance between hilum and chalaza is less. The curvature of the ovule leads to horse shoe shaped nucellus.
E.g: Alismataceae.
b) Circinotropous:
Funiculus is very long and surrounds the ovule.
E.g: Cactaceae

Anther wall: The mature anther wall consists of the following layers a. Epidermis
b. Endothecium
c. Middle layers
d. Tapetum.
a. Epidermis: It is single layered and protective in function. The cells undergo repeated anticlinal divisions to cope up with the rapidly enlarging internal tissues.
b. Endothecium: It is generally a single layer of radially elongated cells found below the epidermis. The inner tangential wall develops bands (sometimes radial walls also) of cellulose (sometimes also slightly lignified). The cells are hygroscopic. In the anthers of aquatic plants, saprophytes, cleistogamous flowers, and extreme parasites endothelial differentiation is absent. The cells along the junction of the two sporangia of an anther lobe lack these thickenings. This region is called stomium. This region along with the hygroscopic nature of endothecium helps in the dehiscence of anther at maturity.
c. Middle layers: Two to three layers of cells next to endothecium constitute middle layers. They are generally ephemeral. They disintegrate or get crushed during maturity.
d. Tapetum: It is the innermost layer of the anther wall and attains its maximum development at the tetrad stage of microsporogenesis. It is derived partly from the peripheral wall layer and partly from the connective tissue of the anther lining the anther locule. Thus, the tapetum is dual in origin. It nourishes the developing sporogenous tissue, microspore mother cells, and microspores. The cells of the tapetum may remain uninucleate or may contain more than one nucleus or the nucleus may become polyploid. It also contributes to the wall materials, sporopollenin, pollenkitt, tryphine, and a number of proteins that control incompatibility reaction. Tapetum also controls the fertility or sterility of the microspores or pollen grains.

(i) The production and development of seedless fruit is called parthenocarpy.
(ii) Fruit like structures may develop from the ovary without the act of fertilization. Such fruits are called parthenocarpic fruits
Examples: Seedless-Banana, Grapes, Papaya
(i) Parthenocarpy is of three types
1) Genetic Parthenocarpy
(i) Arises due to hybridization or mutation. 
2) Environmental Parthenocarpy
Environmental conditions like frost, fog, low or high temperature induce Parthenocarpy.
Example - low temperature for 3-19 hours induces parthenocarpy in Pear.
3) Chemically induced Parthenocarpy
(i) By the application of growth promoting hormones like auxins and gibberellins.
Significance:
(i) Seedless fruits - Significance in Horticulture have commercial value useful for the preparation of jarns, jellies, sauces, fruit drinks,
(ii) High proportion of edible part is available

(i) The primary endosperm nucleus divides immediately after fertilization and develops into an endosperm.
(ii) It is a nutritive tissue, and regulatory structure by undergoing repeated mitosis to form triploid (3n) endosperm that nourishes the developing embryo. Depending upon the mode of development three types of endosperm are recognized.
1) Nuclear endosperm:
(i) Primary endosperm, (PEN) nucleus undergoes several mitotic divisions. There is no cell wall formation So free nuclear condition exists in the endosperm.
Example:
Coccinia, Capsella, Arachis
2) Cellular endosperm:
(i) Primary endosperm nucleus divides into two nuclei There is cell wall formation.
(ii) Subsequent division also follows cell wall formation. It is said to be cellular endosperm
Example:
Adoxa, Helianthus, Scoparia.
3) Helobial endosperm:
(i) Primary Endosperm Nucleus moves towards the base of embryo sac.
(ii) Divides into two nuclei cell wall formation occurs forming a large micropylar chamber and a small chalazal chamber.
(iii) The nucleus of micropylar chamber further undergoes several free nuclear divisions. The nucleus of the chalazal chamber may or may not divide.
Example:
Hydrilla, Vallisneria.

(i) A mature ovule (megasporangium) consist of a stalk and a body
(ii) Funicle - The stalk of the ovule by which it attaches the ovule to the placenta.
(iii) Integuments - one or two protective covering around the nucellus
(iv) Micropyle - Pore present at the tip of the ovule where the integument is absent
(v) Chalaza - The basal region of the body of the ovule where the nucellus, the integument and funicle meet or merge
(vi) Embryosac- The female gametophyte oval sac like structure in the nucellus, toward the micropylar end.