Q.6. Name two such thalloid Bryophytes which lacks tiberculate rhizoids, scales and the thallus is not differentiated into photosynthetic and storage regions. (2005)
Ans. The two Bryophytes are as follows -
(1) Pellia (2) Anthoceros.
Q.7. Give economic importance of Bryophytes. (2005)
Related Question-
Q. Give an account of economic importance of Bryophytes. (2006)
Ans. Economic Importance of Bryophytes: -
The members of Bryophyta are not much economically important. Some economic aspects are as follows :
1. The pieces of dead vegetable matter partially decomposed by water in the bog and gradually compressed and carbonized is called the peat. Peat is used as a fuel.
2. By the chemical treatment cellulose in peat is broken down into sugar which through fermnetation is converted into alcohol.
3. The dried plants of mosses are used as packing material for glass materials, toys and fruits.
4. In some countries, lawns are made up of mosses for beautification.
5. The Bryophytes are most important for checking soil erosion in bills.
6. Some members are medicinally important.
7. The moss of sphagnum is used in grafting or in making nursery beds for raising seedlings.
8. Sphagnum can retain large quality of water, hence used as packing material in the transport of seedings or Vegetative propagates.
9. Sphagnum is having antiseptic property. So, it is used for healing the wounds.
10. Some mosses serve as food for animals and birds.
Q.8. Why Bryophytes are known as the amphibians group of plant kingdom? (2005,10)
Ans. Bryophyta is a small group, include liverworts, hornworts and mosses. They prefer to grow on moist and shady places. Plants of this group are small and inconspicuous and cosmopolitan. Most of the species of Bryophytes are terrestrial. Some Bryophytes like Riccia fluitans, Ricciocarpus, Rellia are aquatic and other remainings are terrestrial which grow predominantly in amphibious environment. These are able to live on land as well as in water. Thus, some scientist called this group as “Amphibians of Plant Kingdom.”
Q.9. Write short notes on Rhizoids in bryophytes. (1997, 99)
Related Question -
Q. Difference between smooth walled and tuberculate rhizoids. (2006)
Ans. Rhizoids in Bryophytes: -
In bryophytes thallus attached to the substratum by unicellular, cyllinderical structures, these are called rhizoids. The rhizoidal system help in absorption and anchorage.
It is closed contact to the substratum. Rhizoids are two types- smooth walled rhizoids and tuberculated rhizoids.
The smooth walled rhizoids are broad, thin walled colourless contents. Their outer as well as inner walls are streched and smooth. They are first to be formed on germination on the ventral surface of the thallus besides the rhizoids the scales are present they are purpolish flattened. The arrangement of rhizoids may be two to four row on either side of the midrib.
The tuberculated rhizoids narrow with locking protoplasm at maturity. The inner walls of these rhizoids grows into peg like or plate like in growth.
The pegged and sinuos rhizoids are importing in forming a capillary conducting system. The rhizoids in form in and function some what resemble the root hair. They function as organs of attachment and also absorbs water on selutes Tuberculatd rhizoids arise from beneath the scales.
Bryopsida
Sphagnum
Q.10. Write the classification and characters of sphagnum. (2012)
Ans.
Division - Bryophyta
Class - Bryopsida
Sub-Class - Sphagnidae
Order - Sphagnales
Family - Sphagnaceae
Genus - Sphagnum
Characters: -
1. It is a perennial bryophyte and its growth continueus after year.
2. The increasing mass of dead remains accumulate year after year and form a compact dark coloured mass rich in carbon. It is known as peat and hence Sphagnum is called peat moss.
3. The plant body consists of upright stem, leaves and lateral leafy branches. The adul plant lacks rhizoids.
4. The branches at the apex of stem are short, stumpy, of limited growth and clustered into a compact conspicuous head called comma.
5. The plant growing in semi-aquatic habitat have two kinds of branches arising from the axil of every fourth leaf.
6. Sphagnum reproduces both by negative and sexual methods.