Botany and Plant Science

Double fertilisation is a complex fertilisation mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). It occurs in angiosperms.

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Potatoes are underground stem tubers. Underground stems are modified plant structures that derive from stem tissue but exist under the soil surface.

Each androcyte metamorphoses into a coiled (2-3), multi-flagellate and multiciliate antherozoid or spermatozoid.

In open vascular bundles, a layer of cambium will be present between the xylem and phloem. This enables secondary growth in it.

It is characterised by morphologically dissimilar spores that are produced from two types of sporangia. These are microspores or male spores and megaspores (macrospores) or female spores. The arrangement of the young leaves within a bud is vernation. In cycas, circinate vernation is there.

The sporogonium of Funaria is photosynthetic. It has stomata present on its seta part. Seta is a long stalk with a pear-shaped capsule by its tip.

During its transit inside the pollen tube, the generative cell divides to form two male gametes. The third cell is the pollen tube cell.

In Polygonum type of development, the functional megaspore passes through three mitotic divisions to produce a seven-celled embryo sac.

A bract is a modified or specialised leaf, especially the one associated with a reproductive structure such as a flower.

Thigmotropism is the directional response of a plant organ to touch or physical contact with a solid object. It is best seen in leaves or tendrils.

It is completely inverted so that the micropyle is facing downwards and situated near the base of the funiculus. It is the most common type of ovule found in angiosperm (all plants of gamopetalae).

Wolffia, a hydrophyte, is the smallest angiospermic flower known.

In gymnosperms, female meiocyte undergoes meiosis and four unequal megaspores are formed in a linear tetrad.