Plant Biology and Genetics Basics

  Mendel is known for pea-plant experiments and subsequent theories on genetics. During a seven year period, Mendel experimented with pea plants in the garden owned in his monastery.

In mulberry (Morus), the inflorescence is a catkin, which is a pendulous spike of unisexual flowers.

The peduncle is the stalk of an inflorescence, which serves as the axis bearing the flowers. Pedicels are the stalks of individual flowers, while the petiole is the stalk of a leaf.

Apocarpous condition refers to a gynoecium where the carpels are free, as seen in Ranunculus and Lotus. In contrast, Datura and Cotton exhibit syncarpous (fused) ovaries.

Perianth is the term used when the calyx (sepals) and corolla (petals) are not distinct or are similar in appearance, often found in monocots like lilies.

A complete flower is defined by the presence of all four whorls: calyx, corolla, androecium, and gynoecium. If any of these are missing, the flower is considered incomplete.

Bulbs like onion and garlic are modified shoots where the stem is highly reduced to a disc-like structure. The fleshy leaves attached to this reduced stem store food.

Heterophylly is the phenomenon where a single plant exhibits different leaf shapes or sizes, often due to environmental factors or developmental stages. Venation refers to the pattern of veins, while vernation is leaf arrangement in the bud.

Velamen is a specialized hygroscopic tissue found in the aerial roots of epiphytes, such as orchids, which helps them absorb moisture from the atmosphere.

A flower is considered a modified shoot because it consists of a condensed axis (thalamus) bearing floral appendages (sepals, petals, stamens, carpels) which are homologous to leaves.

Pneumatophores are specialized roots found in mangroves that grow upwards out of the waterlogged soil to facilitate gas exchange (respiration) in oxygen-deficient environments.

While parallel venation is a characteristic of monocots, Smilax is a notable exception among dicots that exhibits parallel venation.

In Nepenthes (pitcher plant), the pitcher is a modification of the leaf lamina, while the lid is formed by the leaf apex and the tendril by the midrib.

Prop roots grow downwards from branches into the soil to provide structural support. Because they grow in the direction of gravity, they are positively geotropic.

The eyes of a potato are axillary buds located on the tuber. These buds can sprout to form new plants, serving as a primary method of vegetative reproduction.

Ginger is classified as a stem (rhizome) because it possesses distinct nodes and internodes, which are characteristic features of stems, not roots.

Phyllotaxy refers to the pattern or mode of arrangement of leaves on the stem or branch, such as alternate, opposite, or whorled.

Root hairs are unicellular extensions of the epidermal cells found specifically in the region of maturation, where they are responsible for water and mineral absorption.

In a standard dihybrid cross, the F2 generation has 16 possible genotype combinations represented in a 4x4 Punnett square. Among these, homozygous offspring for both traits make up 4 out of the 16 combinations, which simplifies to 1/4.

The capitulum (or head) inflorescence is considered the most highly evolved because it condenses many small flowers into a single structure that mimics a single flower, optimizing pollination efficiency.

In an ovule, the seed coat consists of two layers: the outer testa (from the outer integument) and the inner tegmen (from the inner integument).

After fertilization, the ovary of the flower matures into a fruit, while the ovules inside the ovary develop into seeds.

Random union of equal numbers of R and r gametes produced an F2 generation with 25% RR and 50% Rr and 25% rr.

The aerial part of the banana plant is not a true stem but a pseudostem formed by the tightly overlapping, rolled leaf sheaths.

A mulberry fruit develops from an entire inflorescence where the flowers fuse together along with the inflorescence axis and perianth, making it a classic example of a composite (or sorosis) fruit.

Law of independent assortment can be explained with the help of (or proved by) dihybrid (or trihybrid) cross.

Potato belongs to the family Solanaceae.The potato belongs to the Solanaceae or nightshade family whose other members include tomatoes, eggplants, peppers, and tomatillos. They are the swollen portion of the underground stem which is called a tuber and is designed to provide food for the green leafy portion of the plant. If allowed to flower and fruit, the potato plant will bear an inedible fruit resembling a tomato.

Cyathium inflorescence is characteristic of family Euphorbiaceae.The flower-like characteristics of the cyathia are underlined by brightly coloured nectar glands and often by petal-like appendages to the nectar glands, or brightly coloured, petal-like bracts positioned under the cyathia.

The new name of the family compositae is Asteraceae.Most members of Asteraceae are herbaceous, but a significant number are also shrubs, vines, or trees.

Non-endospermic (exalbuminous) seeds are those where the endosperm is consumed during development, as seen in most dicots like peas and beans. Maize, wheat, and rice are monocots with endospermic seeds.

Aleurone is a protein found in protein granules of maturing seeds and tubers. The term also describes one of the two major cell types of the endosperm, the aleurone layer. The aleurone layer is the outermost layer of the endosperm, followed by the inner starchy endosperm.

Micropyle in seed helps the entry of water during germination.The entry of water activates the embryo cells.

A collective fleshy fruit, in which the ovaries are hidden within a hollow receptacle, as in the fig.

Marginal placentation is found in most of the members of the family Leguminosae.he ovary in which the placenta forms a ridge along the ventral suture of the ovary and the ovules develop on two separate rows is known to have marginal placentation.

In apple, major part of fruit is formed from thalamus not from ovary. So, it is known as false fruit.