Sexual Reproduction in Flowering Plants

In seed plants, Ovule is the part of the female reproductive organ. It consists of three parts; Integument ( forming its outer layer) Embryo sac ( female gametophyte) and a Nucellus that is the central and largest part of the ovule as a source of nutrients for the embryo and its ploidy is diploid i.e 2n
Nucellus is derived from the apical portion of the ovule primordium of the ovule primordium and function as a megasporangium i.e, the nucellus produces the megasporocyte, which will undergo meiosis to form megaspores that is the reason that nucellus of the ovule is diploid in nature.
So, the nucellus of ovule is diploid.

So, the correct answer is 'Megasporangium'

The
ovule of flowering plants are located inside the gynoecium and are connected to
the placenta which is a parenchymatous tissue via a stalk-like structure called
the funiculus.

A. Female gametes are also called eggs or ovum. They are created during the cellular reproduction process known as meiosis. The resulting gamete cell is a haploid cell.

When in a flower, the internode between the corolla and the androecium is lengthened so as to raise the androecium high up in the air then that internode is called Androphore. It is an extension of the receptacle carrying the androecium and the gynoecium, typical of the caper family. In Passiflora, androphore is lightly differentiated.

When pollen tube enters through the micropyle, the phenomenon is known as porogamy. When pollen tube enters to the embryo sac through the tissue of the chalaza, the phenomenon is known as chalazogamy. When pollen tube enters through the base of a funiculus or the integument, the phenomenon is known as mesogamy. Isogamy is a form of sexual reproduction that involves fusion of gametes of similar size and structure. 

Ovule means 'small egg'. In seed plants, the ovule is the surface that gives rise to and contains the female reproductive cells. It consists of three parts: the integuments form its outer layers, the nucellus and female gametophyte in its center. The female gametophyte specifically termed as megagametophyte is also called the embryo sac in angiosperms.

The mature ovule contains in its central part a region called the nucellus that in turn contains an embryo sac with eight nuclei, each with one set of chromosomes. The two nuclei near the centre are referred to as polar nuclei. In the pines, the female gametophyte develops within the tissues of the nucellus and acquires abundant food reserves. The proembryo forms after a period of free-nuclear division in the zygote, and the tier of cells above the basal four then elongates to form a suspensor which pushes the embryonic group deep into the gametophyte.

Endothecium is defined as the lining of the inner cavity of the anther. It is present as a middle layer. 

In monocotyledonous plants, the single cotyledon is known as the scutellum. It is situated at the terminal end of the embryonic axis.

The pollen tube ultimately enters an ovule through the micropyle and penetrates one of the sterile cells on either side of the egg ( synergids). These synergids begin to degenerate immediately after pollination. 
Synergids are haploid in nature. Thus, if root cell has 2n = 42, synergids will have n = 21.

The hilum is the point of attachment of funicle with the chalazal end. It is the point where ovule attaches to the base. It is generally present as an eye of the seed as it is present as a scar.

The ovules where micropyle come to lie close to the funiculus due to unilateral growth of the ovule are called anatropous. This is the most common type of ovule in angiosperms where the curvature of the ovule also affects the nucellus so that the later becomes horse shoe-shaped. The ovule is called amphitropous.

When funicle lies at right angle to body of ovule and micropyle, the ovule is called hemianatropous or body of ovule has rotated by $90^{o}$.

The nucellus is a part of the inner structure of the ovule, forming a layer of diploid (sporophytic) cells inside the integuments. It is structurally and functionally equivalent to the megasporangium. In some plants, the diploid tissue of the nucellus gives rise to a seed through a mechanism of asexual reproduction called nucellar embryony.

An ovule is a structure in seed plants that develops into a seed after fertilization. Botanically, it is defined as an integumented megasporangium.

Synergid is one of two small, short-lived nuclei lying near the egg in the mature embryo sac of a flowering plant. The synergids are part of the egg apparatus and are thought to help the pollen nucleus reach the egg cell for fertilization. 

• Campylotropous ovule- This type of ovule is similar to Anatropous ovule but the curvature is less than that of an anatropous ovule. Micropyle is near to the funiculus. Chalaza and micropyle lie in the straight line but hilum is at 90° to the micropyle.

In the ovule or megasporangium, during the process of megasporogenesis, a hypodermal cell functions as a archesporium cell and becomes more prominent because of large size, denser cytoplasm and large nucleus. In tenuinucellate ovules, archesporial cell directly functions as megaspore mother cell while in crassinucellate ovules, archesporial cell divides periclinally to form an outer parietal cell and inner primary sporogenous cell that functions as megaspore mother cell.

•Hemianatropous ovule- The body of ovule is turned through 90° and micropyle and chalaza lie in a straight line but funiculus is at right angle or 90° with both these two.

•Orthotropous ovule is the simplest and primitive type of ovule. In this type of ovule, micropyle, chalaza and funiculus lie in one vertical plane.

The placentas consists an enlarged basal portion which is called as ovary bearing one or more ovules also called as integumented megasporangium.

• Orthotropous ovule - The simplest and primitive type of ovule. In this type of ovule, micropyle, chalaza, and funiculus lie in one vertical plane. Examples: all gymnosperms, Polygonum.

The placenta is attached to the developing seed near hilum. It is the scar located nearthe edge where seed breaks from stalk of funiculus, i.e., connecting the seed with fruitwall and placenta. 

Ovule- The ovule is the structure that gives rise to and contains the female reproductive cells. The ovule is located inside the portion of the flower called the gynoecium.

In flowering plants, the functional megaspore undergoes mitotic divisions to form the female gametophyte, which is known as the embryo sac. The megaspore mother cell and pollen mother cell are earlier precursor stages, not the developmental product of the functional megaspore.

The ovule  develops into seed and ovary develops into fruit and seeds are enclosed within the fruit. Both are result of fertilisation in angiosperm plant. 

In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument(s), forming its outer layer(s), the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its centre.

Those ovules in which the funicle, chalaza and micropyle lie in one straight line are called orthotropous ovules. Example, Urticaceae.

Egg cell is inside the embryo sac in the ovule. The embryo sac is further enclosed by the parenchymatous tissue, nucellus, which provides nutrition to developing embryo. Nucellus is ultimately surrounded by integuments.

Spores are haploid (n=10, DNA=20pg). The spore mother cell (SMC) is diploid (2n=20, DNA=40pg). During the S-phase, DNA replicates, doubling the DNA content to 80pg, while the chromosome number remains 20.

In seed plants, the ovule ("small egg") is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument(s) form its outer layer(s), the nucellus (or remnant of the megasporangium), and female gametophyte (formed from haploid megaspore) in its centre. Mature ovules i.e. megasporangia in angiosperms are mainly of five types. The principle of classification is based on the position of the micropyle, chalaza and hilum with regard to one another and also to the placenta.

The ovule is the structure that gives rise to and contains the female reproductive cells. The megaspore is produced inside the nucleus of the ovule. During megasporogenesis, the megasporocyte or megaspore mother cell, undergoes meiosis to produce initially four haploid cells (the megaspores). After megasporogenesis, the megaspore develops into the female gametophyte (the embryo sac) in a process called megasporogenesis

The carpel is one of the leaflike, seed-bearing structures that constitute the innermost whorl of a flower. The seeds of flowering plants are enclosed inside an ovary which contains ovule. The ovary is part of a flower's female reproductive structure called a carpel. A flower can have one or more carpels. If there are many carpels, they can be separate or fused together. Together, all the carpels are called a gynoecium, or a pistil.

The synergid cell wall forming an extremely thick structure at the micropylar end is called the filiform apparatus. It bears several finger-like projections into the structure of synergid cytoplasm. The function of filiform apparatus is to guide entry of pollen tube and release of sperm cells. 

Pomology (from Latin pomum (fruit) + logy) is a branch of botany that studies and cultivates fruit.

Plant fertilization is a process in which a male gamete, pollen, is transferred to the female reproductive organ to fuse with an ovule, as a part of the sexual reproduction. After fertilization, the ovule develops into a seed and the ovary develops into the fruit. 

A drupe typically develops from a superior or inferior ovary, but the key characteristic is a fleshy fruit with a stony endocarp (pit). The statement about it being exclusively from an inferior ovary is incorrect, as many drupes (like peaches or plums) develop from superior ovaries.

Integument is an envelope of one or more layers, each of two or more cell layers, covering the ovule, leaving only a pore, the micropyle, through which the pollen tube can enter. It may develop into the testa or seed coat. Seed coat is the outer protective covering of a seed.

The event of double fertilization and subsequent growth and development results in the development of ovule into the seed. Each seed contains a young plant embryo and nutritive tissue (the endosperm), both of which are surrounded by a protective seed coat (derived from integument). Monocots have persistent endosperm that serves as amain source of food in the mature seed. Eudicots endosperm nourishes the developing embryo and subsequently stores food in its cotyledons. During development of seed from an ovule following fertilization, the ovary wall surrounding it enlarges and develops into a fruit wall while ovary makes fruit. Thus, the correct answer is D

The event of double fertilization and subsequent growth and development results in the development of ovule into the seed. Each seed contains a young plant embryo and nutritive tissue (the endosperm), both of which are surrounded by a protective seed coat (derived from integument). Monocots have persistent endosperm that serves as a main source of food in the mature seed. Eudicots endosperm nourishes the developing embryo and subsequently stores food in its cotyledons. During development of seed from an ovule following fertilization, the ovary wall surrounding it enlarges and develops into a fruit wall while ovary makes fruit. Thus, the correct answer is D

The endosperm is the tissue produced inside the seeds of the flowering plants by triple fusion of two central nuclei and one male nuclei in embryo sac. This tissue  surrounds the embryo and provides nutrition to it in the form of starch while in some seeds these are completely absorbed by the time they mature, in others, the endosperm is present till the seeds germinate.

The scutellum is referred to the eqivalence of a thin cotyledon in monocots. It is very thin with high surface area, and serves to absorb nutrients from the endosperm during germination.

Study of seed is part of reproductive morphology because during study of seed, we observe the processes occuring after the sexual reproduction of plants and its growing into a plant. 
 The correct option is 'Reproductive morphology'.

National fruit of India is Mango (Mangifera indica).

The nucellus is generally used up during the development of embryo but in some cases it remains outside the endosperm in the form of a thin layer, called perisperm.

A. Endospermic seed- Reserve food material present in endosperm.

The outer most layer of the fleshy fruits is called as pericarp developed from the ovary wall of the flower and surrounds the seeds. Fruits are the mature ovaries of one or more flowers.

In pea, the gene which controls starch synthesis also controls the shape of the seed.

In the pea plant with wrinkled seeds, this gene is not involved in the synthesis of starch due to the absence of enzyme starch synthase. It is a branched enzyme.

So, the correct option is ‘Branching enzyme’.

Fruits are produced only by flowering plants (angiosperms). Following pollination of the flower, the fertilized ovules develop into seeds while the surrounding ovary wall forms the fruit tissue, or pericarp.

A seed is an embryonic plant enclosed in a protective outer covering. Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. The embryo is developed from the zygote and the seed coat from the integuments of the ovule. Seed has endosperm that stores food to provide nutrition to the embryo. The formation of the seed is part of the process of reproduction in seed plants

Plant part having two ages, one inside the other is seed. Seed is a develop ovule comprising of the embryonic plant along with the putaway nourishment material.

The main photoreceptor for photoperiodism and many other light-initiated plant responses is phytochrome, a family of about five blue-green pigment proteins, each of which is coded for by a different gene. Phytochrome is involved in the light requirement that some seeds have for germination. Seeds with a light requirement must be exposed to light containing red wavelengths. Exposure to red light converts $P _r$ to $P _{fr}$ and germination occurs. When $P _{fr}$ absorbs far-red light it is converted back to $P _r$. Hence, red light makes $P _{fr}$, far-red light makes $P _r$. In plants at least $P _{fr}$ is the physiologically active or "signalling" state.

 Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. The embryo is developed from the zygote and the seed coat from the integuments of the ovule. 

As the ovules develop into seeds, the ovary begins to ripen and the ovary wall becomes fleshy and forms a hard outer covering to protect the fruit. Fruit is also called as ripened ovary. So the given statement is true.

A seed develops from an ovule after fertilisation. It consists of a tough coat called testa enclosing an embryo which is made up of plumule, radicle or cotyledons. It is produced from an outer integument of the ovule. 

Pollen grains to be carried by wind as well as by insects will not be heavy in weight or showy. This is because it causes the wind as well as insects tough to perform pollination. They prefer light weight as well as winged ones.

Wind pollinated plants will have light weight pollens which are mostly winged and are thus easy to be carried away by wind. Whereas the plants where the pollinating agents are insects, the petals will be bright and scented so that the insects get attracted to it and acts as pollinator.

A very close relationship between flower and pollinating agent is best exhibited by Yucca as there is a mutually rewarding relationship between Yucca plant and species of moth. They cannot complete their life cycle without each other. The moth lays egg in the locules of the ovary. The larva uses some of the seeds as food. In turn, the flowers are pollinated by the moth. 

Nectar is produced in saliva to lure pollinators such as insects and the process of pollination continues from one flower to the other flower and so on.