Leaf
Leaf is a lateral dissimilar appendage of a plant body which arises on the node of stem and bears axillary bud on its axil. . This note contains detail information about types and venation of a leaf.
Summary
Leaf is a lateral dissimilar appendage of a plant body which arises on the node of stem and bears axillary bud on its axil. . This note contains detail information about types and venation of a leaf.
Things to Remember
- Leaf is a lateral dissimilar appendage of a plant body which arises in the node of stem and bears axillary bud in its axil.
- It is thin flattened expanded portion considered as the site of photosynthesis.
- Leaf with stipules is known as stipulate leaf and without stipules is known as an exstipulate leaf.
- Sometimes in monocotyledons, the leaf base becomes expanded and winged which partially or completely covers the internode and is known as sheathing leaf base or leaf sheath.
- Leaf with petiole is known as petiolate leaf and without petiole is known as a sessile leaf.
MCQs
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Subjective Questions
Q1:
Define population in your own words..
Type: Short Difficulty: Easy
Q2:
What is population education?
Type: Very_short Difficulty: Easy
Q3:
Write a short note on origination of population education.
Type: Short Difficulty: Easy
Q4:
Mention some of the significances of population education.
Type: Short Difficulty: Easy
<ul>
<li>Population education encourages couple to have less number of children and maintain small family.</li>
<li>It has developed as an important discipline in most of the developing countries.</li>
<li>It also provide information needed to formulate government population policies.</li>
</ul>
<p> </p>
Q5:
What are the major scopes of population education?
Type: Long Difficulty: Easy
<p><strong>Demography:</strong></p>
<p>Demography is the science of populations. Demographers deals by investigating three main demographic processes: birth, migration, and death. All three of these processes contribute to changes in populations, including how people inhabit the earth, form nations and societies, and develop culture.</p>
<p><strong>Population Change:</strong></p>
<p>Population change is the difference between the size of the population to the end and the beginning of a period. Population keeps changing in course of time. Birth, death, and migration are the determinates of population change. Population education deals with all these socio-economic factors such as culture, norms, values and biological aspects.</p>
<p><strong>Future Planning:</strong></p>
<p>Population Education suggests the government to plan for better future. It helps to formulate policies and programs which help for solutions. It helps to maintain a quality of life. It provides knowledge about the sanitation of population, problems faced by population and solutions of them.</p>
<p><strong>Reproductive Health:</strong></p>
<p>Reproductive health implies that people are able to have a satisfying and safe sex life. It is the capability to reproduce, and the freedom to decide if, when, and how often to do so. It also studies about the sexual behaviours, reproductive system, reproductive process, STDs and their prevention.</p>
<p><strong>Significance</strong>:</p>
<p>Rapid population growth is a major issue in today's world. Birth is the most important parameter deciding population growth, as it indicates how many new children are added every year to the existing population.The death rate can also lead to conclusions about population growth rate of a country.</p>
Q6:
How is population education useful in controlling population?
Type: Short Difficulty: Easy
<p> </p>
Q7:
When was Population Education initiated in Nepal?
Type: Short Difficulty: Easy
Q8:
How does population education help in future planning?
Type: Short Difficulty: Easy
Q9:
When was Ministry of Population and Environment established in Nepal?
Type: Short Difficulty: Easy
Q10:
What is demography?
Type: Short Difficulty: Easy
Q11:
What is population change?
Type: Short Difficulty: Easy
Q12:
When was Population Education coined?
Type: Short Difficulty: Easy
Q13:
When was International Conference on Population held in Romania?
Type: Short Difficulty: Easy
Q14:
What is the most important parameter deciding population growth?
Type: Short Difficulty: Easy
Q15:
When was National Population Commission established in Nepal?
Type: Short Difficulty: Easy
Videos
Population Education
Population Education
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Leaf
Leaf is a lateral dissimilar appendage of a plant body which arises on the node of stem and bears axillary bud on its axil. It is thin flattened expanded portion considered as the site of photosynthesis. In angiosperm different types of leaves are present such as; cotyledonary leaves, bract leaves, scale leaves etc. The common type of green leaf is known as foliage leaf which consists of three major parts:
- Leaf base
- Leaf stalk or petiole
- Leaf lamina or leaf blade
Leaf base
The point of attachment of leaf with the node of the stem is known as leaf base. Sometimes the leaf base may become swollen and is known as pulvinus leaf base. Eg; Mimosa pudica(Touch me not). Sometimes in monocotyledons, the leaf base becomes expanded and winged which partially or completely covers the internode and is known as sheathing leaf base or leaf sheath.
A pair of small leaf-like structures are known as stipules may occur on either side of leaf base. Leaf with stipules is known as stipulate leaf and without stipules is known as the ex-stipulate leaf. Stipules may be of different types such as;
- linear stipules
- Ochreate
- Foliaceous
Leaf stalk or petiole
The petiole is cylindrical or subcylindrical solid or hollow stalk of the leaf which joins leaf base with the leaf lamina. Leaf with petiole is known as petiolate leaf and without petiole is known as a sessile leaf.
Leaf lamina or leaf blade
The expanded green portion of the leaf is known as leaf lamina or leaf blade which bears midrib, veins, and veinlets. Mid-rib is the main vein arising from the tip of petiole which is known as costus and its number may vary in different cases. If the upper or ventral surface of leaf differs from the lower or dorsal surface than the leaf is known as a dorsiventral leaf which is present in dicots. If the two surfaces are almost same then it is known as an oblilateral leaf which is present in monocots.
Venation of leaf
Lesson
Angiosperm
Subject
Biology
Grade
Grade 11
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