Biology

Plant Transport and Physiology

1,834 Questions

Access a comprehensive set of questions on plant transport mechanisms and physiological adaptations. Topics include water movement, translocation of food, and plant responses to external stimuli. These biology questions are essential for medical entrance exams and other science competitive tests.

Xylem and phloem transportTranspiration and evaporationPlant adaptationsGeotropic and phototropic responsesWater absorption by rootsRespiration in roots

Plant Transport and Physiology Questions

Multiple choice blackman's principle of limiting factors photosynthesis in higher plants biology

According to Lloyd, the opening and closing of stomata is governed by

  1. $ K^+ $ ion influx and efflux

  2. Change in pH

  3. Interconversion of starch and sugar

  4. Photosynthetic activity of guard cell chloroplasts
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Botanist Lloyd gave the theory of opening and closing of stomata is governed by starch sugar interconversion.
During the day, plants photosynthesize. Carbon dioxide is utilized during photosynthesis, therefore, less Carbon dioxide accumulates inside the guard cells leading to increased PH. High pH favours conversion of starch to sugar. 

Sugar is osmotically active and therefore water will move into the guard cells from the nearby cells through osmosis. Guard cells gain turgidity and they bulge outwards hence stomata opens.

At night photosynthesis does not occur therefore there is a high accumulation of unused Carbon dioxide inside guard cells. The low PH favours conversion of sugar to starch which is osmotically inactive. Guard cells lose water and become flaccid hence stomata close.

So the correct answer is 'Interconversion of starch and sugar'.
Multiple choice blackman's principle of limiting factors photosynthesis in higher plants biology

In guard cells, when sugar is converted into starch, the stomatal pore 

  1. Closes completely

  2. Opens partially

  3. Opens fully

  4. Remains unchanged
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
According to Lloyd stomatal movement occurs due to interconversion of starch and sugar, in the condition of water stress or during the absence of sunlight, sugar is converted into starch in the presence of some enzymes. Due to loss of starch from guard cells, these cells become shrink results into the closing of stomata.
So the correct answer is 'Closes completely'.
Multiple choice blackman's principle of limiting factors photosynthesis in higher plants biology

Select the correct events leading to the stomatal opening.
(a) The decline in guard cell solutes.
(b) Lowering of osmotic potential of guard cells. 
(c) Rise in K ions in guard cells.
(d) Movement of water from neighboring cells into guard cells.
(e) Guard cells become flaccid.

  1. a, e

  2. b, c, d

  3. a, c, d

  4. b, d, e
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The stomatal opening follows when solutes from near epidermal and mesophyll cell enter the guard cell lowering its osmotic potential and water potential. Also rising in K ions in guard cell allows movement of water into the guard cell from neighbouring cells and makes the guard cell swollen due to water accumulation which results in the opening of stomata. 

So, the answer is, "b,c,d".

Multiple choice biology respiration in organism human respiration the mechanism of breathing breathing and its movements

Microscopic pores in plants through which they expire air are called

  1. Stigma

  2. Thalamus

  3. Gills

  4. Stomata
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A.Stigma - the terminal part of the gynoecium is called stigma.
B.Thalamus - The upper exapanded structure present at the tip of the pedicle.
C.Gills - the paired respiratory organ of fish and some amphibians, by which oxygen in extracted from water flowing over surfaces within or attached to the walls of the pharynx.
 D.stomata - minute pores present on the epidermis of aerial organs meant for transpiration
So, the correct option is 'stomata'.
Multiple choice botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

In plants, hill reaction occurs

  1. All the time

  2. Only in day time

  3. Only when the plants are grown in cold climate of hills

  4. When the plant carries out up hill task of slat absorption and food translocation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Experiments with isolates chloroplasts, in presence of oxidants like ferricyanides and benzoquinone (Hill reagents) were conducted by Hill in 1937 and 1939. By placing the isolated chloroplasts in sunlight, he notices evolution of oxygen from water. Hill concluded that if there was suitable hydrogen acceptor in the medium it would have been reduced. In absence of light Hill reaction can not be possible. So, it can say it occurs only in day time.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

The process of the escape of liquid from the tip of uninjured leaf is called as

  1. Evaporation

  2. Transpiration

  3. Guttation

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Guttation is loss of water in liquid form as a dilute solution from uninjured leaf tips. The uninjured leaf tips have hydathodes or water stomata. Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

The presence of fluid on the edges of leaves in early morning is due to

  1. Transpiration

  2. Guttation

  3. Exudation of water

  4. Condensation of moisture
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Guttation is the excretion of drops of xylem sap on the tips or edges of leaves of some vascular plants through hydathode, such as grasses. It occurs in the absence of light i.e., at night and thus it is present on the edge of leaves in the early morning.

So, the correct answer is option B.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Which of the following is not a controlled process?

  1. Transpiration

  2. Guttation

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transpiration is the loss of water through stomata in vapour form. Transpiration is regulated through guard cells. Guttation is the loss of water in liquid form through hydathodes. Hydathodes are free ends of vascular supply of leaves. Hydathodes are always open and not regulated by any cells.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

The process of water exudation through the hydathode is called as

  1. Guttation

  2. Transpiration

  3. Excretion

  4. Hydrolysis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Guttation is the loss of water in  the form of liquid through hydathodes or water stomata. It occurs due to positive root pressure and serves to remove excess water from the plant. As xylem sap is having dissolved minerals, water droplets that ooze out from them contain solution of water and minerals. 

Multiple choice transpiration guttation excretion in plants long distance transport of water

If the absorption is more and transpiration is less then process affected will be

  1. Root pressure

  2. Guttation

  3. Bleeding

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Transpiration is defined as loss of water as gas or vapour from leaves through the stomatal pore. If there is less transpiration due to high atmospheric humidity and the soil is well watered; there will be an increase in root pressure. The increased root pressure leads to oozing out of the solution of minerals from hydathodes (called as guttation) and other openings (called as bleeding). Thus, the correct answer is option D.

Multiple choice transpiration guttation excretion in plants long distance transport of water

The process involved in the formation of toddy is

  1. Guttation

  2. Transpiration

  3. Bleeding

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Toddy refers to fermented palm wine. It is prepared by fermentation of sap obtained from palm trees. The process of obtaining sap from trees is through bleeding of plant. The sap is extracted and collected by a tapper. Typically the sap is collected from the cut flower of the palm tree. A container is fastened to the flower stump to collect the sap. The white liquid, that initially collects tends to be very sweet and non-alcoholic before it is fermented.

Multiple choice transpiration guttation excretion in plants long distance transport of water

Which one is not related to transpiration?

  1. Regulation of plant body temperature

  2. Absorption and distribution of mineral salts

  3. Circulation of water

  4. Bleeding
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Bleeding takes place through injured organs of the plant. It usually describes fluid oozing from injured plant parts. Transpiration describes the loss of water in vapour form and helps in cooling of leaf surface as well as the movement of mineral ions in transpiration stream. Transpiration is primarily responsible for uptake of water circulating in plant's xylem vessels and tracheids.

Multiple choice transpiration guttation excretion in plants long distance transport of water

Oozing out of water drops from injured edges or tips is

  1. Bleeding

  2. Guttation

  3. Transpiration

  4. Oozation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Oozing out of water drops from injured edges or tips in plants is called bleeding. Bleeding usually develops because of the pressure of sap inside of the tissues which conducts water and sugars around the plant. If any positive pressure exist in the xylem due to any cut or opening results in the exudation or bleeding of the solution from the trachery elements.

So, the correct answer is option A.

Multiple choice transpiration guttation excretion in plants long distance transport of water

Oozing of water drops from injured leaf edges is

  1. Bleeding

  2. Guttation

  3. Transpiration

  4. Translocation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When water oozes out from the pores of the plants known as Hydathodes then it is known as Guttation.

When water vapour is released from the stomata then the process is known as transpiration .
When the water oozes out from injured leaf edges then it is known as bleeding. 
So the correct answer is 'Bleeding'. 

Multiple choice botany adaptation plant adaptation adaptation in plants plant habitat importance and classification of angiosperms aquatic plant adaptations pollination through water life in water

Plants adapted to grow in shade are

  1. Psammophytes

  2. Sciophytes

  3. Mesophytes

  4. Xerophytes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plants growing in bright light are called as sun plants or heliophytes, while plants growing in partial shade or low light intensity are called as shade plants or sciophytes. 

In sciophytes the stems are soft, slender with large internodes. Leaves are thin and large sized. The have bright green colour. Leaf cells are large. Cuticle is thin. Stomata are in level with surface. Palisade parenchyma is less developed. There is more vegetative growth as compared to flowering and fruiting
So, the correct answer is 'Sciophytes'