The Living World of Plants Online Test 6th Science Lesson 4 Questions in English

The underground part of the main axis of a plant is known as root. Root has no nodes and internodes. It has a root cap at the tip.

A tuft of root hairs is found just above the root tip. Roots are positively geotropic in nature. Plants root system is classified into two types. 1. Tap root system 2. Fibrous root system

It consists of a single root, called taproot, which grows straight down into the ground. They are seen in dicotyledonous plants.

It consists of a single root, called taproot, which grows straight down into the ground. They are seen in dicotyledonous plants. Example: Bean, Mango, Neem.

Smaller roots, called lateral roots arise from the taproot. They are seen in dicotyledonous plants.

Fibrous root system consists of a cluster of roots arising from the base of the stem. They are thin and uniform in size.

Fibrous root system is generally seen in monocotyledonous plants. It consists of a cluster of roots arising from the base of the stem. They are thin and uniform in size.

Fibrous root system consists of a cluster of roots arising from the base of the stem. They are thin and uniform in size. It is generally seen in monocotyledonous plants. Example: Grass, Paddy, Maize.

Roots fixes the plant to the soil, absorbs water and minerals from the soil, Stores food in some plants like Carrot and beet root.

Main axis of the shoot system is called the stem. The shoot system consists of stem, leaves, flowers and fruits.

Shoot system has nodes and internodes. Nodes are the parts of stem, where leaf arises.

The part of the stem between two successive nodes is called internode. Shoot system has nodes and internodes.

The bud at the tip of the stem is known as apical or terminal bud, and the buds at the axils of the leaves are called auxiliary buds.

The stem transports the prepared food from leaves to other parts through stem and stores food as in the case of sugarcane.

The stem supports the branches, leaves, flowers and fruits and transports water and minerals from roots to upper aerial plant parts.

The leaf is a green, flat expanded structure borne on the stem at the node. A leaf has a stalk called petiole.

The leaf is a green, flat expanded structure borne on the stem at the node. The flat portion of the leaf is called leaf lamina or leaf blade.

The leaf is a green, flat expanded structure borne on the stem at the node. On the lamina, there is a main vein called midrib.

The portion of the leaf connected in the nodal region of the stem is known as the leaf base.

Leaves of some plants possess a pair of lateral out-growth on the base, on either side of auxiliary bud. These are called stipules. The green colour of the leaf is due to the presence of green coloured pigment called chlorophyll.

The green leaves • Prepare food by the process of photosynthesis. • Helps in respiration. • Carry out transpiration.

Victoria amazonica, the leaves of this plant grow up to 3 metres across.

A mature Victoria leaf can support an evenly distributed Load of 45 Kilograms or apparently young person.

Based on flower plants can be classified into two main groups. Flowering plants and Non-flowering plants.

Based on position of seed plants can be divided into two groups. Angiosperms. and Gymnosperms

Aquatic habitat includes areas that are permanently covered by water and surrounding areas that are occasionally covered by water. Nile is the longest river in the world. It is 6650 Km long.

Nile is the longest river in the world. It is 6650 Km long. The Longest river in India is Ganges River. It is 2525 Km long.

Rivers, lakes, ponds and pools are the fresh water habitat. Stem and leaves have air chambers that allow aquatic plants to float in water.

Rivers, lakes, ponds and pools are the fresh water habitat. Water hyacinth, water lily and lotus are seen in the fresh water habitat.

Air spaces in stems and petioles of lotus are useful for floating in water

Oceans also support the growth of plants. Marine plants perform about 40% of all photosynthesis that occurs on the planet.

Marine plants perform about 40% of all photosynthesis that occurs on the planet. Example: Marine Algae, Sea grasses, Marsh grass, Phytoplanktons.

Terrestrial habitat are the ones that are found on land like forest, grassland and desert. It also includes man-made habitats like farms, towns and cities. They can be as big as a continent or as small as an island. They make up about 28% of the entire world habitat.

The first land plants appeared around 470 million years ago. They were mosses and liverworts.

The Amazon Rain Forest in South America produces half of the world’s oxygen supply.

A habitat without much water is called deserts. Deserts are the driest place on earth, They get fewer than 25cm of rainfall annually.

A habitat without much water is called deserts. Deserts cover at least 20% of the earth. The plants which grows in this habitat have thick leaves that store water and minerals.

The plants like cactus store water in their stem and the leaves are reduced to spines. They have long roots that go very deep in the soil in the search of water.

A habitat without much water is called deserts. Deserts are the driest place on earth, They get fewer than 25cm of rainfall annually. Deserts cover atleast 20% of the earth. Example: Cactus, Agave, Aloe, Bryophyllum.

Types of desert habitat: (i) Hot dry deserts, (ii) Semi-arid deserts, (iii) Coastal deserts, (iv) Cold deserts.

Thar Desert, also called Great Indian Desert, is an arid region of rolling sand hills on the Indian subcontinent. It is located partly in Rajasthan state, north-western India, and partly in Punjab and Sindh (Sind) provinces, eastern Pakistan.

Grassland is an area where the Vegetation is dominated by grasses. Grasses ranges from short to tall. E.g. Savanna Grassland

Forest is a large area dominated by trees. Annual rainfall ranges from 25-200 cm

Forest is a large area dominated by trees. There are three types of forests and are:- tropical forests, temperate forests and mountain forest.

Adaptations are special features in plants which help them to survive in the habitats they live in over a long period. World habitat day is observed on 1st Monday of October.

Tendril is a twining climbing organ of some weak stemmed plants like peas and bitter gourd. Tendril coils round a support and help the plant to climb.

Bitter Gourd – Axillary buds are modified into tendril which helps the plant to climb.
Sweet Peas – Leaflets are modified into tendrils.

Bamboo is one of the fast- growing plants, during active growth phase.

Some plants have weak stems are Twiners. They cannot stand straight on their own. They must climb on any support to survive

Twiners: Some plants have weak stems. They cannot stand straight on their own. They must climb on any support to survive. Example: Clitoria and Jasmine

Leaves of some plants become wholly or partially modified into sharp pointed structures called “thorns or spines” for defensive purpose. Opuntia – the leaves are modified into spines.

In Agave the leaf apex and margins are modified into thorns. Leaves of some plants become wholly or partially modified into sharp pointed structures called “thorns or spines” for defensive purpose.

Leaves of some plants become wholly or partially modified into sharp pointed structures called “thorns or spines” for defensive purpose. bougainvillea – the stem has sharp thorns.