22 Biology -- Gymnosperm

define Pinus and briefly explain its distribution

1 Answers

Pinus are evergreen, coniferous resinous trees growing three to eighty meters tall. It comprises about 90 species that are worldwide in distribution.

Pinus is found in arid places, slope of hills. Pinus is xerophytic plant. In Nepal, two species of Pinus are found.

1. Pinus roxburghii

They are found on the outer ranges and main valleys of the Himalayas. They are most abundant in south facing sunny slope hills of central and eastern Nepal. They are abundant in altitude between 1200m to 2100m above sea level.

2. Pinus wallichiana

It is extensively found in Karnali region and extends to central Nepal in Kali Gandaki region. In Nepal, vertical distribution ranges from 1800m to 3300m above sea level.

define gymnosperms and give two examples of it

Gymnosperms are sporophyte, evergreen, perennial, seed-producing woody plants which may be monoecious or dioecious.

Examples: Cycas, Pinus

mention any five general characterstics of gymnosperms

The five general characteristics of gymnosperms are as follows:

1. The dominant plant body s sporophyte, which may be monoecious or dioecious. Gametophytes are inconspicuous and endosporic.

2. The plant body is differentiated into roots, stems, and leaves.

3. Fruit is not formed due to lack of ovary.

4. Vascular bundle is conjoint, collateral, and open.

5. Leaf of gymnosperm does not have lateral vein and instead of it, transfusion tissue is present for lateral translocation.

explain in detail about the morpholgical structure of Pinus

what is the botanical name of pine

The botanical name of pine is Pinus.

define microsporophyll and megasporophyll

In gymnosperms, if the sporophyll bears megasporangia, they are called megasporophylls. Megasporophyll leads to the development of female gametophytes of seed.

If the sporophyll bears microsporangia, then it is called microsporophyll. Microsporophyll leads to development of male gametophytes.

name the native species of Pinus found in nepal .

The native species of Pinus found in Nepal are Pinus wallichiana and Pinus roxburghii.

explain about sexual reproduction in pinus

mention any five economic importance of gymnosperms

The five economic importance of gymnosperms are as follows:

1. Deodar is obtained from Cedrus deodara.

2. Cedar oil is obtained from juniperus virgiana.

3. Turpentine oil is obtained from the resin of pinus species.

4. Sago, a carbohydrate is produced from Cycas which has food value.

5. Many plants are used as ornamental plants eg. Ginkgo, Pinus, and Cycas.

mention any six similarities between pteridophytes and gymnosperms

Differentiate between Cycas and Pinus.

Cycas	Pinus
Dioecious i.e. male and female cone in different plant.	Monoecious i.e. male and female cone on same plant.
Root is dimorphic with tap root and coralloid root.	Root is dimorphic with tap root and mycorhizal root.
Microsporangium is grouped to form sori.	Sori is absent.
Pollen tube act as haustorium as male gamete is motile.	Pollen tube act as pollen carrier as male gamete is non motile.
Dehiscence of pollen grain occurs by pollen drop mechanism.	Dehiscence of pollen...

Differentiate between Gymnosperms and Angiosperms.

Gymnosperms	Angiosperms
Gymnosperms are not herbaceous.	Majority of angiosperms are herbaceous.
Leaves are usually pinnately compound.	Leaves may be simple or compound.
Microsporophyll and megasporophyll are present.	They are absent.
Ovules are naked.	Ovules are protected by carpels.
Double fertilization and triple fusion are absent.	Double fertilization and triple fusion are common.

ask mattrab