Sporopollenin an organic material is present in
The exine of the pollen grain is made of sporopollenin. Sporopollenin is one of the most resistant organic compounds. It can withstand high temperature, strong acids and alkalis and cannot be degraded by any of the known enzymes. Hence, it acts as a shield and protects the pollen grain from getting damaged.
The female gametophyte in angiosperm is
Embryo sac: The female gametophyte of flowering plants, which produces the two female gametes – the egg cell and central cell – for double-fertilization by the two sperm cells of the male gametophyte (pollen grain).
Which tissue is required to be present in between stock and scion during grafting?
Phloem, also called bast, tissues in plants that conduct foods made in the leaves to all other parts of the plant. Phloem is composed of various specialized cells called sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells. Primary phloem is formed by the apical meristems (zones of new cell production) of root and shoot tips; it may be either protophloem, the cells of which are matured before elongation (during growth) of the area in which it lies, or metaphloem, the cells of which mature after elongation. Sieve tubes of protophloem are unable to stretch with the elongating tissues and are torn and destroyed as the plant ages. The other cell types in the phloem may be converted to fibres. The later maturing metaphloem is not destroyed and may function during the rest of the plant’s life in plants such as palms but is replaced by secondary phloem in plants that have a cambium.
What is the function of germ pore?
The germ pores are apertures in the exine layer of the pollen grain where the sporopollenin is absent. The pollen grain a thin-walled area through which the germ tube (or) pollen tube emerges on germination. It helps to the formation of the pollen tube and releases the male gamete during fertilization.
Male gametes in angiosperms are formed by the division of
Generative cell which is a cell of the male gemetophyte or pollen grain in seed plants that divides to give rise directly or indirectly two sperms.
The embryo sac is also known as
The female gametophyte specifically termed a megagametophyte is also called the embryo sac in angiosperms. The megagametophyte produces an egg cell (or several in some groups) for the purpose of fertilization.
Starting from the innermost part, the correct sequence of parts in an ovule are
Starting from the innermost part, the correct sequence of parts in an ovule is egg, Embryosac, nucellus, integument. This sequence can be seen in following
A diagrammatic view of an ovule
In angiosperms, functional megaspore develops into
In angiosperms or flowering plants, the megasporocyte produces a megaspore that develops into an embryo sac through two distinct processes megasporogenesis (formation of the megaspore in the nucellus, or megasporangium), and megagametogenesis (development of the megaspore into the embryo sac, or megagametophyte).
Filiform apparatus is a characteristic feature of
A synergid cell wall forms a highly thickened structure called the filiform apparatus at the micropylar end consisting of numerous finger like projection into synergid cytoplasm. These synergid cells are necessary for pollen tube guidance in ovule.
From among the sets of terms given below, identify those that are associated with the gynoecium.
The gynoecium represents the female reproductive part of the flower and consists of pistil. Each pistil has three parts, i.e., stigma, style and ovary. Inside the ovarian cavity, the placenta is located. Arising from the placenta there are the mega sporangia, commonly called ovules. The functional megaspore undergoing the meiotic division develops into the female gametophyte or embryo sac. In option 'b' thalamus is not a part of gynoecium. Thalamus is the part of flower which form the base on which all the floral whorls rest upon, it is not associated with gynoecium. In option 'c' tapetum is not a part of gynoecium. Tapetum is the inner most nutritive layer or microsporangium and in option 'd' stamens not a part of gynoecium. Stamen is male reproductive part (androecium) of plant. Therefore, the other options are wrong.