What are the conditions for Growth?

The conditions necessary for growth are 

i. Water - Water is required for the enlargement of the cells and various metabolic processes. Water also provides the medium for the enzymatic reactions necessary for the growth. Water imparts turgidity which helps in extension growth of the cells. 

ii. Oxygen - Oxygen helps in releasing the metabolic energy that is needed for growth activities. It is needed for the respiration of the cells. 

iii. Nutrients - are required by plants for the synthesis of protoplasm and act as source of energy.

iv Temperature - Optimum temperature is required the growth

v. Environmental signals - Light and gravity also affect certain phases/stages of growth

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Who coined the term gibberellin ?

Yabuta.
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Write an essay on characteristics of Plant growth regulators. 

Plant growth regulators are small, simple molecules having different compositions. Chemically they may be indole compounds (indole-3-acetic acid, IAA), adenine derivatives like N6- furfrylamino purine, kinetin), derivative of carotenoids (abscisssic acid, ABA), terpenes (giberellic acid, GA3) , gases (ethylene, C2H4). 

They can be divided into two main groups on the basis of the function they perform. 

i. One group is involved in growth promoting activities like cell division, cell enlargement, pattern formation, tropic growth, flowering, fruiting and seed formation etc. For example Auxin, cytokinin, gibberelins etc. 

ii. Hormones in the other group play an important role in plant responses to wounds and stresses of biotic and abiotic origin. They are also involved in various growth inhibiting activities such as dormancy and abscission. For example abscissic acid and ethylene. 

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 Is growth measureable ? What are its parameters ?

Yes growth is measureable.

Parameters for growth :
Growth is measured by a variety of parameters some of which are increase in fresh weight, dry weight, length, area, volume cell and growth in number of cells. For example

Growth by increase in the number of the cells : Maize root apical meristem can give rise to more than 17, 500 new cells per hour.

Growth in size : Cells of watermelon may increase in size by upto 3,50,000 times.

Growth in length : Growth of pollen tube is measured in terms of its length.

Growth in surface area : An increase in surface area denotes the growth in a dorsiventral leaf.

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 Term kinetinwas coined by whom ?


Skoog and Miller.
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