Tag: plant physiology

Questions Related to plant physiology

Mass flow hypothesis was first described by ___________.

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Swanson

  2. Buchman

  3. Kursanov

  4. Munch

Show answer
Correct Option: D
Explanation:

Mass flow or pressure flow hypothesis was put forward by Munch $(1927, 1930)$. According to this hypothesis, organic substances move from the region of higher osmotic pressure to the region of lower osmotic pressure in a mass flow due to the development of a gradient.

So, the correct answer is 'Munch'

Presence of bicollateral vascular bundle provides evidence that conduction of food takes place through the

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Phloem

  2. Xylem

  3. Both A and B

  4. None of the above

Show answer
Correct Option: A
Explanation:

Translocation of prepared food occurs through the phloem. Bicollateral vascular bundles have two patches of phloem. Bicollateral vascular bundles show following arrangement of vascular tissue, outer phloem, outer cambium, xylem, inner cambium, inner phloem. These vascular bundles can transport much more amount of sugars than collateral vascular bundles having only a single patch of phloem. Bicollateral vascular bundles are common in Family Cucurbitaceae with large leaves, large fruits called Pepo and thin weak stems. 

According to Dixon and Jolly, cohesive force of water molecules is of the magnitude of ...............

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. 1 - 10 atm

  2. 10 - 15 atm

  3. 45 - 200 atm

  4. 15 - 45 atm

Show answer
Correct Option: C
Explanation:

One atmospheric pressure of transpiration pull is enough to pull the water unto the height of 20 feet or so; but normally, the transpiration pull that develops runs to about 20-100 atm (it can be as high as 200 atms in case of rapidly transpiring tall trees in tropics), which is enough to pull the water to the height of 400 to 1000 ft and the tallest plant known to mankind is just about 400 ft. 

Which one is against the theory of ascent of sap by Dixon and Joly?

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Pores in tracheary elements

  2. Cohesion force of water molecules

  3. Adhesion force of water molecules

  4. Requirement of ATP

Show answer
Correct Option: D
Explanation:

Dixon and Joly gave the theory that ascent of water in the plant through pored tracheary elements of xylem which uses cohesion-tension, transpiration pull and suction pressure developed in the leaf cells.

According to this theory, there is no use of energy or ATP for the ascent of the sap.
So, the correct answer is 'Requirement of ATP'.

Which of the following is appropriate for mass flow hypothesis?

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Large amount of ions are also absorbed alongwith absorption of water.

  2. As suction pressure increases, absorption of water increases and along with water, absorption of ions also increases.

  3. Transpiration pull is responsible for absorption of ions.

  4. All the above.

Show answer
Correct Option: D
Explanation:
Mass flow hypothesis is also known as the pressure flow hypothesis. It was proposed by Ernst Munch in 1930. 
During this process, the large number of ions are absorbed along with the absorption of water. Due to an increase in suction pressure and transpiration pull, absorption of water and ions increases. 
So the correct answer is 'All of the above'.

Cohesion transpiration pull theory of ascent of sap was proposed by 

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Munch

  2. Stephen Hales

  3. Dixon and Joly

  4. Bose

Show answer
Correct Option: C
Explanation:

Cohesion transpiration pull theory was proposed by Dixon and Jolly. They proved that cohesion and adhesion support continuity of water columns and provide strength like a steel wire, transpiration pulls water columns towards leaves which causes ascent of sap.

So, the correct answer is 'Dixon and Jolly'.

Match the lists and find the correct option 


   LIST I    LIST II
 A.  Henry Dixon  1.   Bioelectric response
 B.  Slatyer and Taylor  2.  Cohesion tension theory
 C.  Levitt  3.  Active proton concept
 D.  J. C. Bose  4.  Water potential
     5.  Term physiology

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. A - 3, B - 4, C - 2, D - 1

  2. A - 1, B - 2, C - 4, D - 3

  3. A - 4, B - 1, C - 2, D - 3

  4. A - 2, B - 4, C - 3, D - 1

Show answer
Correct Option: D
Explanation:

Cohesion tension theory was proposed by John Joly and Henry Horatio Dixon in the year 1894. The theory has two fundamental features such as (i) cohesion of water and adhesion between water and xylem tiusses, (ii) Transpiration pull. This theory explains plants which is responsible for the movement of water column upward.

Water potential term was coined by Slatyer and Taylor in the year 1960. He proposed that chemical potential of water be used as a property of water in plant soil air system.
Levitt in 1974 gave a altered form of the mechanism of stomatal movement which was called the proton - potassium pump hypothesis. This hypothesis explains K+ ions are transported into the guard cells in the presence of light. This is termed as active proton concept.
J. C. Bose invented rare, elegant apparatus for together measuring bioelectric potentials and for computing very small movements in plants. Bose concluded that plants and animals have substantially the same essential physiological mechanisms. Based on electrical signalling all plants co-ordinate their movements and responses to the environment. 
So, the correct answer is option D.

Mass flow hypothesis was put forward by

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Swanson

  2. Munch

  3. Curtis

  4. De Vries.

Show answer
Correct Option: B
Explanation:

Mass flow hypothesis is also known as pressure flow hypothesis it is the best-supported theory to explain the movement of sap through the phloem. It was discovered by the scientist by Ernst Munch in 1930, He was the German plant physiologist. This creates the hydrostatic pressure in the phloem of the plant.

So, the correct option is B.

Choose the correct answers from the alternatives given.
An example of selectively permeable membrane is

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. Plasmalemma

  2. Cell wall

  3. Chloroplast membrane

  4. Mitochondrial membrane

Show answer
Correct Option: A
Explanation:

Cell membrane, also known as plasmalemma, is the innermost membrane of a plant cell. It is surrounded by a cell wall. The cell membrane is a selectively permeable membrane that allows only some type of compounds to pass through. The membrane has a phospholipid structure that contributes to this property.

Hence, the correct answer is 'Plasmalemma'.

According to mass flow hypothesis
(a) Sucrose is moved into the companion cells and then into the sieve tube by passive transport.
(b) Inside the phloem, an osmotic pressure gradient is generated that facilitates the mass movement in the phloem.
(c) Water in the adjacent xylem moves into the phloem by active process

botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

  1. (a) and (c) are correct

  2. (b) and (c) are incorrect

  3. (a) and (c) are incorrect

  4. (a) and (b) are correct

Show answer
Correct Option: A