Proximate causes - The subject of cell biology, neurobiology, and many other biological disciplines.

Ultimate causes - Their historical causes, especially the action of natural selection.

#Id: 10711

#XL - R Botany

#Id: 10712

#XL - R Botany

In elongation zone, cells elongate rapidly and undergo a final round of divisions to produce a central ring of cells called the endodermis

#Id: 10713

#XL - R Botany

Feature of root

Most Vascular plants has two types of roots;

I. Primary Roots (Tap root) that grow downward

II. Secondary Roots that branch out to the side

#Id: 10714

#XL - R Botany

I. Tap root system

A single, thick Primary root, called Taproot, with smaller Secondary Roots going out from the sides

#Id: 10715

#XL - R Botany

I. Tap root system

Tap root system found in Dicot Plants.

e.g., Mustard, Pulses, Fiscus, Mango tree, Banyan

Families- Brassicaceae, Lamiaceae, Rutaceae, Fabaceae, Moraceae, Malvaceae, Apocynaceae, Compositae, Rosaceae, Cucurbitaceae, Leguminosae, Solanaceae etc.

#Id: 10716

#XL - R Botany

In monocotyledonous plants, the primary root is short lived and is replaced by a large number of roots called “Fibrous root system”

II.Fibrous root System

It develop from other than radicles

Many Small branching Roots, called fibrous root, but no large Primary root

The huge number of thread like roots increases the surface area for absorption of water and minerals

Fibrous root anchor the plant less securely

Fibrous root system

Fibrous root system found in Monocot Plants.

e.g., Maize, Paddy, Wheat, Grass, Onion

Families- Liliaceae, Poaceae etc.