(i) Tissue culture can be carried out in any season to produce plants.
(ii) Plants which do not produce viable seeds and seeds that are difficult to germinate can he propagated by tissue culture.
(iii) Cells can be genetically modified and transformed using tissue culture.

Tongue grafting	Wedge grafting
In tongue grafting A scion and stock having the same thickness is cut obliquely and the scion is fit into the stock and bound with tape.	In wedge grafting a slit is made in the stock or the bark is cut A twig of the scion is inserted and tightly bound so that the cambium of the two is joined

Endothecium is a single layer of radially elongated cells, The inner tangential wall of this cell develops bands of a cellulose, The cells are hygroscopic. The stomium of anther lobe lack these thickenings. Stomium along with the hygroscopic nature of endothecium helps in the dehiscence of anther

The primary endosperm nucleus divides immediately after fertilization. It develops into an endosperm which is a nutritive tissue and a regulatory structure. The zygote divides only after that to form an embryo so that it can get nourishment from the endosperm that has formed earlier.

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.

In Grafting, parts of two different plants are joined so that they continue to grow as one plant. Of the two plants, the plant which is in contact with the soil is called stock and the plant used for grafting is called Scion.

(a) Cutting
(b) Grafting

(a) Only one parent is required.
(b) New individuals are genetically similar
(c) Rapid spreading
(d) Large scale production

Pollination by bees is called mellitophily.

A single cell from a rare and endangered plant can be grown into a an entire plant. So it is considered as the best method.

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

(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.