Question

Phyto hormones and thier functions

Why pancreas are both endocrine and exocrine system .exp

Answer 1

Plant hormones are known asphytohormonesin botanical terms. They are chemicals just like animal hormones that help in the growth, development, and functioning of plants. Like animals, plants too are living organisms that function as a unit. They carry out vital biochemical reactions that are required to survive.

There are five major hormones which are auxin, cytokinin, gibberellin, abscisic acid, and ethylene.

1)Auxin

This hormone is present in the seed embryo, young leaves, and apical buds' meristem.

Functions of Auxins

• Stimulation of cell elongation, cell division in cambium, differentiation of phloem and xylem, root initiation on stem cuttings, lateral root development in tissue culture
• Delaying leaf senescence
• Suppression of lateral bud growth when supplied from apical buds
• Inhibition or promotion of fruit and leaf abscission through ethylene stimulation
• Fruit setting and growth induced through auxin in some plants
• Auxin can delay fruit ripening
• In Bromeliads, the auxin hormone promotes flowering
• Stimulation of flower parts, femaleness of dioecious flowers, and production of high concentration of ethylene in flowering plants
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2) Cytokinin

They are synthesized in roots and then transported to other parts of the plant.

Functions of Cytokinins

• Stimulation of cell division, growth of lateral buds, and apical dominance
• Stimulation of shoot initiation and bud formation in tissue culture
• Leaf cell enlargement that stimulates leaf expansion
• Enhancement of stomatal opening in some plant species
• Etioplasts converted into chloroplasts through stimulation of chlorophyll synthesis.

3) Ethylene

Ethylene is present in the tissues of ripening fruits, nodes of stems, senescent leaves, and flowers.

Functions of Ethylene

• Leads to release of dormancy state
• Stimulates shoot and root growth along with differentiation
• Leaf and fruit abscission
• Flower induction in Bromeliad
• Stimulation of femaleness of dioecious flowers
• Flower opening is stimulated
• Flower and leaf senescence stimulation
• Stimulation of Fruit rripen

• 4)Abcisic acid
• Abcisic acid is found mostly near leaves, stems, and unripe fruit.

Functions of Abscisic Acid

• Stimulation of closing of stomata
• Inhibition of shoot growth
• Inducing seeds for synthesizing storage of proteins

5) Gibberellins

Gibberellins are present in the meristems of apical buds and roots, young leaves, and embryo.

Functions of Gibberellins

• Stimulates stem elongation
• Leads to development of seedless fruits
• Delays senescence in leaves and citrus fruits
• Ends seed dormancy in plants that require light for induction of germination

Functioning as an exocrine gland, thepancreas excretes enzymes to break down the proteins, lipids, carbohydrates, and nucleic acids in food. Functioning as an endocrine gland, the pancreas secretes the hormones insulin and glucagon to control blood sugar levels throughout the day.
So pancreas is both endocrine and exocrine.