Botany and Plant Science

The protonema is the juvenile, filamentous stage of the gametophyte in mosses like Funaria, which develops from the spore before the leafy gametophore is formed.

Intercalary meristem is involved in primary growth.

Chlorenchyma is a modification of parenchyma.

Sclerenchyma is present in the husk of coconut.

In angiosperms, double fertilization occurs where one male gamete fuses with the egg to form a zygote, and the other fuses with the two polar nuclei to form the primary endosperm nucleus (triploid).

Meiosis occurs in the megaspore mother cell (MMC) within the nucellus to produce four haploid megaspores.

Xenia is the effect of foreign pollen on the endosperm tissue, which can influence its color or texture due to the genetic contribution of the male gamete.

Each microspore mother cell undergoes meiosis to produce 4 microspores. Therefore, 256 / 4 = 64 microspore mother cells are required.

Synergids are part of the embryo sac (female gametophyte) and are haploid, having been formed from the mitotic division of the functional megaspore.

Each megaspore mother cell undergoes meiosis to produce 4 megaspores, but typically only one is functional. Thus, 20 functional megaspores require 20 megaspore mother cells.

Tapetal cells often become polyploid due to endomitosis or nuclear fusion, which helps them provide nutrients to the developing pollen grains.

A typical angiosperm embryo sac (Polygonum type) consists of 7 cells: 3 antipodal cells, 2 synergids, 1 egg cell, and 1 central cell with 2 polar nuclei.

A typical angiosperm anther is dithecous, meaning it has two lobes, each containing two pollen sacs (microsporangia), totaling four sporangia.

Each microspore mother cell undergoes meiosis to produce 4 pollen grains. Therefore, 10 mother cells produce 10 * 4 = 40 pollen grains.

The hilum is the scar on the seed coat that marks the point of attachment of the ovule to the funicle. Chalaza is the base of the ovule, while the micropyle is the small opening for the pollen tube.