Botany and Plant Science

Sclereids are responsible for grittiness of a pear. Sclereids are extremely thick-walled stone cells.

Plastids are organelles found in plant cells and algae, but they are not present in animal cells.

Mature RBC of mammal and seive tube of phloem lacks nucleus. Both options are correct

Photoperiodism was first discovered by Garner and Allard in 1920 using a variety of tobacco called Maryland Mammoth.

Meiosis occurs in the megaspore mother cell (MMC) within the nucellus to produce haploid megaspores. The nucellus is the tissue containing the MMC, but the division itself happens specifically in the MMC.

Since the pollen comes from the same plant, the genetic makeup is identical, making it genetically self-pollination. However, because it involves the transfer of pollen between two different flowers, it is ecologically cross-pollination (geitonogamy).

Synergids are part of the egg apparatus within the embryo sac. Like all cells in the mature embryo sac, they are haploid.

Xenia refers to the effect of foreign pollen on the tissues of the seed, specifically the endosperm, resulting in changes to its color or composition.

Vallisneria is a classic example of hydrophily (pollination by water). The male flowers are released into the water and float to reach the female flowers.

Salvia flowers have a specialized lever mechanism where an insect entering the flower pushes a sterile stamen arm, causing the fertile anther to deposit pollen on its back.

Parthenocarpy is the development of fruit without fertilization, resulting in seedless fruits. Parthenogenesis refers to embryo development without fertilization.

The growth of the pollen tube toward the ovule is directed by chemical signals released by the synergids, a process known as chemotropism.

The aleurone layer is the proteinaceous outer layer of the endosperm in seeds like maize.

In angiosperms, pollen grains are typically released at either the 2-celled or 3-celled stage of development.

A caruncle is a fleshy, outgrowth-like structure found on the seed coat, which is derived from the integuments of the ovule. It is commonly seen in seeds like castor.