Tag: pictorial feature of plant kingdom

Conifers are a magnificent group of gymnosperm plants that produce seeds without fruit or flowers. They include some incredible trees, such as the 'Giant Sequoias' of North America, that can grow over 110 m tall.

The conifers are by far the largest group of gymnosperms with around 630 species worldwide of a total approximation of around 860 species. The word 'conifer' is Latin for 'cone bearing', because conifers produce cones within which they produce pollen (male cone) and grow seeds (female cone).

Conifers are all woody plants, mostly trees and a few shrubby species, they have either needle-like or scale-like leaves and most species are evergreen. They include the economically important pines and many other timber species that are exploited for use in construction and paper.

Gymnosperms have archegonia but no antheridia. The plants of this division are heterosporous. While the microspores or pollen grains produce the male gametophyte, the single megaspore within megasporangium (nucellus) develops into a female gametophyte, that bears two or more archegonia or female sex-organs. Also, there is no antheridium in which the sperm are produced.

• Ferns, algae, and bryophytes find water as an essential element for fertilisation to take place. Because they are in need of water for the movement of sperms, etc. Whereas the condition is not similar in the case of Cycas.

Fertilization in Cycas;

• The pollen tube grows towards the archegonium of the female gametophyte. There, the end of the pollen tube bursts and discharges its contents into the archegonia chamber.
• The spermatozoids are set free in the archegonia chamber. They swim towards the neck of the archegonium and make their way down to the egg cell. One of the spermatozoids fuses with the egg uncles i.e. oosphere.

Fertilization is thus effected. 

Casuarina is a xerophyte whereas Pistia, Hydrilla and Vallisneria are hydrophytes.

Peat, also known as turf, is an accumulation of partially decayed vegetaation or organic matter.Sphagnum "moss", also called peat moss, is one of the most common components in peat, although many other plants can contribute.

Sphagnum is one of the most important plant genera in the world. Sphagnum is one of the few bryophyte genera able to dominate an ecosystem. A healing ointment prepared by Sphagnum leaves mixed with grease is used in the treatment of cuts and wounds. The decoction prepared by boiling dried Sphagnum in water, is used in the treatment of acute haemorrhage. This decoction is used to cure diseases of eyes. The lakes where sphagnum grows are called as Sphagnum bogs. These are well known to produce peat in acidic water. The bog water is antiseptic and has astringent properties. Sphagnum exhibit strong antibacterial properties against Gaffkeya tetragena and Staphylococcus aureus. Sphagnum peat is suitable for production of low and intermediate BTU gas as well as hydrogen , ethylene , natural gas , methanol and gasoline. Sphagnum is used as an effective filtering and absorption agent for the treatment of waste water and effluent of factories with acid and toxic discharge consisting of heavy metals particularly Ag, Pb, Cu , Hg, Fe , Sb and organic substances like detergents, dyes, microorganisms and soils.