Plants Hormones - Biology

Plants produce different kinds of chemical substances, which increase the growth and development these chemicals are called plant hormone.

    They effect the gene expression, activities or inhibit enzymes and changes the properties of membrane. These are in very less concentration.

     There are five kinds of plants hormones.

Auxins: Auxin is class of chemicals, which are both natural and synthetic. The most important natural auxin in Acetic Acid (l.A.A), which is found in higher plants. It is synthesised at tips of stem and roots (apical meristem), young leaves and in young embryo within seed. The synthetic aux ins are in dole butyric and naphthalene acetic acid.

Cell Division and Cell Enlargement: The auxin stimulate cell division and cell enlargement, increase the plant in length. It also initiate cell division in the  cambium as a result more xylem and phloem are found, which increase the trans location and thickness of plants.

Initiation of roots: Auxin initiates the development of adventitious roots when applied at the cut base of stem.

Abscission: In mature leaves and fruits less amount of auxin is present, so a abscission layer is formed at the base of petiol and stalk of fruit, this layer consists of thin walled cells.

Growth of Fruit: Auxin produces in young embryo promotes the growth of fruit.

Parthenogenesis: Auxin helps in producing parthenocarpy as seedless fruits, these fruits are formed without fertilisation. 

Apical Dominance: Growth of apical bud inhibits growth of lateral buds below the stem. This is called apical Dominance. So auxin inhibits the growth of lateral buds. If apical bud is cut then lateral buds starts to increase in size.

Weedieide: Auxin's also acts as weeds killer, they kill the broad leaves and seeds. 2-4 dichlarophenoxy acetic acid is to kill weeds in cereal crops.

Gibberellins: Gibberellins are plant hormones that increase cell division and cell enlargement Gibberellins was is covered in fungus gibberella fujikuroi fungus. This fungus cause bakanae disease in rice seeding. 
     The infected seeding elongated and falls. T-Vabuta and T-Hayashi. Isolated a chemical from the fungus and was as gibberellins. Now there are more then seven types of gibberellins.
       They are produced in roots, stem and leaves.
Role of Gibberellins: 
They promote cell division and cell elongation.
They prevent genital and physiological dwarfism.
They promote leaves and fruit growth.
They break bud and seed dormancy.
In some plants they delay senescence in leaves.
They also help to transport food from endosperm to developing embryo.

Cytokinins: These are groups of both natural and synthetic substances, which act as plant hormone. First they were obtaining from coconut milk, now other sources are herring sperm DNA and yeast extract is natural cytokinins which is obtaining from immature corn grains.

Role of Cytokinins: 
They promote rapid cell division in the presence of auxin.
They promote lateral root growth and initiated primary root growth.
They break seed dormancy.
They promote fruit develop.
They promote opening of stomata.

Abscisic acid: Abscisic acid is growth inhibitor and are produced by plant during adverse condition. e.g. Drought Condition.

1. It causes dormancy in buds and seeds.
2. It causes stomata to close.
3. They inhibit stem and root growth waste logging.
4. It promotes leaves senescence.
5. It promotes abscission.

Ethene: It is gas which act as plant hormone. It has many functions.

1. It promotes ripening of fruits.
2. It inhibits stem and roots growth.
3. It breaks dormancy of buds and seeds.
4. It promotes flowering in pineapple.
5. It contributes to leaf abscission.

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Rupert of Hentzall - Character of The Novel ( The Prisoner of Zenda )

Rupert of Hentzall

Introduction: 

   Rupert of Henzall is an important character of the novel. He is one of the six hirelings of the Duke-Michael. He is the most ferocious, reckless and dangerous of them all. He is a rider and an expert swordsman.

Physical Appearance: 

    Rupert is a young man of about twenty five years old. He is very handsome person.

A Very Talkative Fellow: 

     Rupert is a man of very sharp tongue. He knows well how to hurt the feelings of others by his talk. He humiliates lady Mauban severely while talking about woman. When Russendyll challenges him to fight in the forest, he points to a peasant girl and refuses of fight in her presence. In this way the teases Rassendyll. Again, when the Duke Michael finds him alone in Mauban's room and asks him the reason, he promptly replies that he is apologizing to the lady for his long absence. And when Madam De Mauban shoots at him, he replies that he cannot fire at a lady when he has Kissed. 
A Bad Character Fellow: 
      Rupert is a treacherous person. He disrespects his mother by bringing a mistress into her house. He is a flirt and has deceived many woman. He is rough through and through and deceives even his master. He is so vulgar that he always talks nonsense. He knows that Michael wants to become a king and to marry Fla via. But he is also ready to get Michael Killed for his own purposes. Thus he meets Rassendyll in a street of Zenda and suggests that they should kill the king and Michael. He thinks that he can get De Mauban in this way. Thus he opposes his own master. On the other hand he satisfies Michael and tires to kill Rassendyll on different occasions. At last for his own benefit he kills his own master, Michael.
Brave And Daring: 
        Rupert is a dare devil. He is not afraid of any danger and nothing can frighten him. Among the Duke's cut-throats, he is the only great and constant threat to Rassendyll's life. He is an excellent swordsman and saves himself in the encounter with Rassendyll. He is very much reckless and quite  careless about the consequences. Once he tries to kill Rassendyll in bright day light and manages to escape unhunt. Having Murdered Michael, he comes to draw bridge with blood stained sword and stands in the middle of the bridge, fearlessly and bravely. Madam Mauban shoots at him but does not respond to the bullet of Mauban because it was below his dignity to shoot at a woman when he had kissed.
Conclusion: 
            From the study of Rupert's character we come to know that he is a stranger mixture of contradictions. He is grateful and graceless at the some time. His manners make him a detestable character and he plays the role of a villain in the novel to Black Michael.

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