Micropyle is a pore like structure on one side of the ovule, where integuments are absent. First, there is a great variation in megasporogenesis itself. This compound provides spiny appearance to the exine. Two divisions are vertical and one division is transverse. Differentiate between a Hypocotyl and epicotyl b Coleoptile and coleorhiza c Integument and testa d Perisperm and pericarp Answer a Hypocotyl and epicotyl Hypocotyl Epicotyl The portion of the embryonal axis which lies below the cotyledon in a dicot embryo is known as the hypocotyl. Therefore, the nuclei are pushed to the periphery along the wall of the embryo sac. In certain cases otter parts of the flower such as calyx or thalamus may also take part in the formation of the fruit.
Triple fusion is a fertilisation that involves fusion of one male gamete and two polar nuclei or secondary nucleus; if the two have already fused in the central cell of embryo sac. The other two are present at each side of the embryo sac. Answer: Removal of anther from a bisexual flower is called as emasculation. The three chalazal nuclei fuse. It is the process of formation of megaspores from the megaspore mother cell.
The large central cell has 2-polar nuclei. However, for embryo to develop, it needs constant nourishment. Certain species of the following genera show different cases of apomixis Iris. Thus cellular tissues are formed. Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
The part of endosperm is starchy and part is sugary. The rest three nuclei degenerate. Answer: Self-incompatibility or self-sterility is the inability of the pollen grains of an anther to germinate on the stigma of the same flower. The first mitotic division in the megaspore forms two nuclei. In lower plants like Liverwort … s the main plant body is gametophytic in nature and sporopytes are dependent on gametophytes. The nucleus at the chalazal end gives rise to antipodal cells. One cell of the micropylar triad is the egg.
If such are diploid then the embryo and the resulting plant would also be diploid. Now cell walls start to build leading to the organisation of female gametophyte or embryo sac. In this case, first division of primary endosperm nucleus is followed by a transverse wall. This is known as monosporic development of the female gametophyte. When and why does a plant breeder employ this technique? The female gametophyte or the embryo sac develops from a single functional megaspore.
Arrange the following terms in the correct developmental sequence: pollen grain, sporogenous tissue, microspore tetrad, pollen mother cell, male gametes. And these are called as megasporangium. Example of cleistogamous flowers include commelina and groundnut, etc. Together they are known as the egg apparatus. This food is utilized by the embryo during the germination of the seed. Later, these cells divide by repeated divisions. In both events, meiosis cell division occurs.
Since, fertilisation does not take place; as a result no seeds are produced. The cell toward the microphyll end is called suspensor cell. What is meant by monosporic development of female gametophyte? The outer layer is called dermatogen, middle is called periblem and central one is called plerome. It means that God, the creator, made two different types of humans, male and female, to procreate and fill the earth with their descendants. Male sporophytes produce male spores and that of female produce … megaspores of female spores while male gametophytes produce male gametes while female gametophytes produce female gametes Gametophytes are haploid plants developing from the spores and giving rise to the sex organs on them.
In this technique, the breeder chooses two plant varieties, say one is pest resistant variety and the other with high yielding fruit variety. Answer: After entering one of the synergids, the pollen tube releases the two male gametes into the cytoplasm of the synergid. It undergoes meiosis to produce 4 microspores. Therefore, apple fruit is considered as false fruit. Explain the role of the tapetum in the formation of the pollen grain wall.