Question

In anatropous ovule, micropyle lies
A. Side by Side with funicle
B. At 45° funicle
C. At 90° funicle
D. In straight line with funicle

Answer 1

The ovule in seed plants is the structure that gives rise to the female reproductive cells and contains them. It consists of three parts which includes the nucellus (or megasporangium remnant) and the female gametophyte (formed from a haploid megaspore) in the centre of the integument, which forms its outer layer. The female gametophyte in angiosperms is also called the embryo sac, specifically referred to as a megagametophyte. For the purpose of fertilisation, the megagametophyte forms an egg cell.

Complete Answer:
The orientation of the ovule can be anatrophic, such that the micropyle faces the placenta when inverted (this is the most common ovule orientation in flowering plants), amphitropic, campylotropous, or orthotrope (the anthropic is common and the micropyle is downward and the chalazal ends up in the upper position, such that the anatrophic configuration is tilted 90 degrees in the amphitropic and orthotrope.

Initially, ovules consist of diploid maternal tissue, which contains a megasporocyte (a cell that undergoes meiosis in order to create megaspores). To create the haploid female gametophyte or megagametophyte, which also remains inside the ovule, megaspores remain inside the ovule and divide by mitosis. The megagametophyte is surrounded by the remains of the megasporangium tissue (the nucellus). Mega Gametophytes produce archegonia, which produces egg cells (lost in certain groups, such as flowering plants).

Anatropous ovules are the most common type of ovules, which occur in more than 80 percent of angiosperm families. The body of the ovule is rotated 180 ° and the micropyle reaches the funiculus. In the straight line, Chalaza and micropyle lie, but hilum is the micropyle at 90 °. Thus, the micropyle is similar to the funiculus. There is also a ridge in the ovule, as the body of the ovule is fused with the funiculus. In this case, during development, the ovules become completely inverted so that the micropyle lies close to the hilum. The hilum is a scar that marks the point where the funicle connects the seed to the fruit wall.

The correct Answer is option (D) In straight line with the funicle.

Note: In sexual reproduction, the ovula plays a critical role. Once a pollen grain lands on the stigma of a flower of the same genus, via the style, it sends a pollen tube down. Then this tube joins the ovary and meets the plant's ovule. Fertilization will occur if that happens, as the nucleus of the pollen grain is sent down the tube to combine in the embryo sac with the nucleus. Remember that pollen, which includes the male gametophytes, is the male alternative to the ovule.