Posted by: Krishna | October 17, 2009

GREEN.WORLD

WONDER WORLD OF PLANTS

This is an attempt to create and improve awareness about the role of plants for the very existence of life on earth. It is an attempt to create awareness for the need to protect and promote the Green World.

This is a compilation of facts and information from various sources for spreading the above objectives.

Plants play a very significant role in human life and life of other living beings.

One way or the other we are dependent on plants in most of our activities and for fulfilling our needs including  basic needs- Food , Clothing and shelter.

Plants are the only living beings that make their own food and also surplus food over their own requirements. Food produced by / derived from plants is the real source and origin of food for all other living beings.

Even those who eat only “Meat” depend indirectly on plants because the animals which are the source for meat ultimately depend for their food only on plants.

WHAT ARE PLANTS

Any living organisms that make food to survive using sun light and by a process called photosynthesis  are plants.

There are other  plants which do not produce food by photosynthesis and live as parasites on other living plants.

There are also  plants which do not make food by photosynthesis and live on dead organic matter. These are called saprophytic.

Believe it or not, some plants  are carnivorous  which have modified leaves to trap animals , usually insects and small invertebrates , which get dissolved and digested by the secretions of the plant. These plants are also called insectivorous plants. These plants simultaneously  produce food in the normal process of photosynthesis.

HISTORY OF PLANTS

There are varying views about the origin and evolution of plants.

It is considered  that the earliest fossils of plants are 3500 millions of years old. Algae are the earliest form of life and it is generally believed  that other  plants evolved from the  Algae.

Let us see the primary characteristics of  early forms of plants.

ALGAE.

They grow in wide range of media and strata – water / snow / decaying material. They do not have roots, stems, leaves or flowers. They absorb nutrients directly from surrounding water. Algae also have green colored matter called Chlorophyll which makes food from Carbon dioxide and water by a process called photosynthesis using energy from sunlight.

Algae are used in preparation of various food products [ice creams , bakery items,  and even directly as food ] and cosmetics.

Over time by adoption, modification & migration to land,  some of Algae are believed to have evolved in to other early forms – MOSSES & FERNS

Also there are other type of organisms – FUNGI.  Opinion is divided about their origin, whether they are evolved from Algae or evolved independent of both animals and plants.

FUNGI

Fungi DO NOT HAVE CHLOROPHYLL. They do not produce their own food, they absorb food from other plants or feed as scavengers on dead and decaying matter. They thrive in forests, and grow in dark places.

MUSHROOMS WHICH WE ENJOY AS FOOD COME UNDER THIS GROUP.

By penetrating in to trees for feeding Fungi kill more trees in forests than any thing else.

MOSSES

MOSSES are small 1-10 cm tall and grow so close to each other and form  a layer  over land looking like a carpet. Roots are not well-developed and water and nutrients are absorbed by the whole surface of the plant from the soil.  Mosses appeared about 350 million years ago.

FERNS

Ferns also appeared  over 350 million years ago. They may be as  small as 2 Cm or  as tall as 20 mts and are spread across world. They do not have flowers and reproduce by spores.

CONIFERS

Conifers are about 300 million years old and do not have flowers. They bear seeds in “CONES”

Ferns, Mosses and Conifers are non-flowering plants. Ferns and Mosses propagate through Spores fallen on the ground. In case of Conifers  seeds develop inside a protective cone which when mature opens and the seeds spread by wind.

 

GROUPING OF PLANTS

Plant Kingdom is so large with countless varieties, sizes, life styles, and usefulness to other living beings  they  are divided in to different groups based on distinct characteristics for understanding their nature and take care of them.

 

Based on Physiological properties.

Non-Vascular >

Plants which cannot take / circulate [conduct] rain water through stems and leaves,  but only absorb from surrounding environment. They do not have roots, stems or leaves. Have tissues for internal transportation of water.

Vascular >>

Rest of the plants which have a system [xylem & Phloem] to take /circulate [conduct]  rain water & fluids and have  photosynthetic material.

  • Vascular plants are further divided in to two groups based on the process of propagation. One group reproduces from seeds and the other by means of minute cells called SPORES.

 

Based on Duration of life cycle

Plants are also grouped based on their life span in to >>

ANNUALS / BIENNIALS / PERENNIALS

Plants which complete the life cycle in less than one year [a few weeks to one year ] are  called ANNUALS. An annual plant is one that usually germinates, flowers, and dies in a year or season.

Those that live for two years are BIENNIALS.  A biennial plant is a  plant that takes two years to complete its biological life cycle. Flowering and  seeds are produced in the second year.

The ones that live for more than two years are called PERENNIALS. A perennial plant is one that lives for more than two years, producing flowers and seeds year after year,  generally from second year.

Based on the structure and size

Based on the structure and size of the plants are grouped in to >>>

HERBS / SHRUBS / TREES

HERBS

A herb is a plant that is valued for flavor, aroma, or other qualities. Herbs are used in cooking, as medicines, and for spiritual purposes. HERBS are generally non-woody plants and are more fragrant when fresh.

A herb is a plant or plant extract, including leaves, bark, berries, roots, gums, seeds, stems and flowers which is bestowed with nourishing and healing elements. Herbs are the endowment of Mother Nature which has been used for healthcare through out different ages and cultures of human history.

SHRUBS

Shrubs are woody, perennial, with a number of stems usually produced from near the soil, giving bushy look, generally less than 10 mts high with some exceptions growing up to 20 mts.

A shrub or bush is a horticultural rather than a strict botanical category of woody plant, distinguished from a tree by its multiple stems and lower height.

TREES

Trees are woody, perennial plants with a central stem bearing branches, generally more than 10 mts high, normally with a distinct head.

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk.  en.wikipedia.org/wiki/Trees

 

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