Mix Examples- Transport in Plants Questions in English

(D) Water is the most important constituent of plant cells, typically comprising $70-90\%$ of their fresh weight.
It is essential for the translocation of solutes from the soil to various parts of the plant through the xylem.
Water is also crucial for the mobility of gametes in many lower plants, such as algae, bryophytes, and pteridophytes, which require a water medium for fertilization.
Furthermore, water provides buoyancy and structural support to aquatic plants, allowing them to remain upright.
Therefore, all the mentioned options are correct.

(B) Cells absorb water primarily through $Osmosis$,which is the movement of water molecules from a region of higher water potential to a region of lower water potential across a semi-permeable membrane.
$Imbibition$ is a special type of diffusion where water is absorbed by solids (colloids),causing them to increase in volume. Both processes are essential for the uptake and movement of water in plants.

(D) Osmosis is the spontaneous net movement or diffusion of solvent molecules through a selectively permeable membrane from a region of high water potential to a region of low water potential.
$A$. Cell to cell movement of water occurs via osmosis.
$B$. Movement of water through cortical cells in roots also occurs via osmosis.
$C$. While water absorption can be active,the primary mechanism of water movement across membranes is osmosis.
Since $A$ and $B$ are classic examples of osmosis in plants,and the context of plant water relations often groups these processes,the most appropriate answer is $D$.

(D) The absorption of water by roots is influenced by several environmental and soil-related factors.
$1$. Soil temperature: Low temperatures decrease the permeability of root membranes and increase the viscosity of water,thereby reducing absorption.
$2$. Soil aeration: Adequate oxygen is required for the metabolic activities of root cells,which facilitate active water absorption.
$3$. Relative Humidity $(RH)$ of the atmosphere: High humidity reduces the rate of transpiration,which indirectly affects the rate of water absorption from the soil.
$4$. Amount of soil water: The availability of water in the soil is the primary determinant for absorption.
Therefore,all the listed factors affect the process of water absorption by roots.

(D) Dew is formed when atmospheric water vapor condenses on cool surfaces,such as leaves,during the night or early morning.
This process is known as condensation of moisture.
It is distinct from guttation,which is the loss of water in liquid form from the tips of leaves through specialized structures called hydathodes.

(A) Guttation is the process of exudation of liquid water droplets from the margins of leaves through specialized pores called hydathodes.
It typically occurs when root pressure is high and transpiration is low.
This condition is favored when the plant is placed in a highly humid or saturated atmosphere,which prevents the evaporation of water from the leaf surface,thereby promoting the release of liquid water.

(A) Guttation is the process of exudation of liquid water droplets from the margins or tips of leaves through specialized pores called hydathodes. This phenomenon typically occurs in small herbaceous plants under conditions of high soil moisture and low evaporation (e.g.,at night or early morning). Unlike transpiration,which involves the loss of water in the form of vapor through stomata,guttation involves the loss of water in liquid form.

(C) The loss of water in its liquid form from the surface of leaves,typically through specialized structures called hydathodes,is known as Guttation.
In contrast,Transpiration involves the loss of water in the form of water vapor.
Evaporation is a physical process of liquid turning into vapor from any surface.
Therefore,the correct process is Guttation.

(A) Passive guttation occurs when the rate of water absorption is very high and the rate of transpiration is very low. This process is driven by the $Tension-cohesion$ force of water molecules,which pulls water through the xylem to the hydathodes. Unlike active guttation,which involves the metabolic activity of the $Epithem$ tissue,passive guttation is a physical process resulting from the water potential gradient created by high transpiration pull or high root pressure under conditions of low evaporation.

(D) The translocation of organic solutes through the phloem can be proven by several experimental evidences:
$1$. Girdling or Ringing Experiment: Removing a ring of bark (including phloem) from the stem causes accumulation of food above the ring,proving phloem is the pathway.
$2$. Structure of Phloem: The presence of sieve tubes with perforated end walls (sieve plates) is structurally adapted for the longitudinal transport of sap.
$3$. Chemical Analysis: Analysis of phloem sap (obtained via aphid stylets) shows a high concentration of sucrose and other organic nutrients,confirming its role in transport.

(C) The ringing experiment (or girdling experiment) involves removing a ring of bark (including the phloem) from the stem of a woody plant.
Since the phloem is responsible for the translocation of food (sucrose) from leaves to roots,the removal of this tissue causes food to accumulate above the ring,leading to swelling.
Simultaneously,the xylem remains intact,allowing the ascent of sap (water and minerals) to continue to the upper parts of the plant.
Therefore,this experiment demonstrates both the path of food translocation and the path of water transport.

(D) Phloem is the vascular tissue responsible for the translocation of organic nutrients,primarily sugars,from the source (leaves) to the sink (roots,fruits,and growing tissues).
When a ring of phloem is removed (a process known as girdling),the downward transport of sugars is blocked.
Since phloem also facilitates the movement of various signaling molecules and hormones,their distribution is also disrupted.
While the upward flow of water and salts occurs through the xylem,the disruption of the phloem affects the overall physiological health of the plant,including the supply of nutrients to the roots,which indirectly impacts the entire system.
Therefore,all the listed processes are affected.

(A) The process where leaf cells lose turgidity during the day due to high rates of transpiration exceeding water absorption, but regain it at night when transpiration rates drop, is known as $Temporary \ wilting$.
$Permanent \ wilting$ occurs when the plant cannot recover its turgidity even when placed in a saturated atmosphere, leading to the death of the plant.
$Guttation$ is the exudation of water droplets from the margins of leaves through specialized structures called $Hydathodes$.

(C) Guttation is the process of exudation of liquid water droplets from the margins or tips of leaves of plants.
It occurs through specialized pores called hydathodes.
The liquid released during guttation is not pure water but a dilute solution containing various dissolved organic and inorganic substances (salts,sugars,etc.).
Therefore,the correct answer is $C$.

(D) Membrane proteins are essential for the movement of hydrophilic substances across the lipid bilayer.
Facilitated diffusion involves the use of membrane proteins (channels or carriers) to move molecules along the concentration gradient without the expenditure of energy.
Active transport also utilizes membrane proteins (pumps) to move molecules against the concentration gradient,which requires energy in the form of $ATP$.
Therefore,both facilitated transport and active transport rely on membrane proteins.

(C) Physiological drought occurs when water is present in the soil,but plants are unable to absorb it. When the water content in the soil is excessively high,it displaces air from the soil pores,leading to a deficiency of oxygen. In this condition,root cells cannot perform respiration,resulting in a lack of $ATP$ production. Due to the lack of energy,active absorption of water stops. Additionally,excessive water reduces the capillary force,which is essential for the movement of water to the roots. Therefore,despite the availability of water,the plant cannot absorb it.

(C) The correct matches are as follows:
$1$. Polarity $(I)$: Due to its polar nature, water acts as an efficient solvent $(s)$ for various substances.
$2$. Viscosity $(II)$: The viscosity of water allows aquatic organisms to float or move through it $(p)$.
$3$. Latent heat $(III)$: High latent heat of fusion and vaporization helps in thermal regulation, ensuring lakes do not freeze completely in winter $(q)$.
$4$. Cohesive force $(IV)$: The strong cohesive forces between water molecules facilitate the ascent of sap against gravity in plants $(r)$.
Therefore, the correct sequence is $I-s, II-p, III-q, IV-r$.

(D) Water exhibits several unique properties due to its chemical structure.
$1$. $Planktons - Density$: Water is densest at $4^{\circ}C$, which allows ice to float and protects aquatic life, including planktons, in freezing conditions.
$2$. $Ascent of sap - Cohesion$: The high cohesive and adhesive forces of water molecules allow for the continuous column of water to rise in the xylem during the ascent of sap.
$3$. $Excellent solvent - Polarity$: Due to its polar nature, water acts as an excellent solvent for various polar and ionic substances.
$4$. $Mechanical shock - Latent heat$: This is mismatched. Water provides protection against mechanical shock due to its incompressibility and high surface tension, not latent heat. Latent heat is related to temperature regulation (thermoregulation) and phase changes.

(C) The correct matches are as follows:
$(1)$ High viscosity: Water provides protection against mechanical shocks,thus $(1 - c)$.
$(2)$ Cohesion: The force of attraction between water molecules is essential for the ascent of sap in plants,thus $(2 - d)$.
$(3)$ High specific heat: Water can absorb or release large amounts of heat without significant changes in its own temperature,protecting the environment,thus $(3 - a)$.
$(4)$ Polarity: Due to its polar nature,water acts as an efficient solvent for many substances,thus $(4 - b)$.
Therefore,the correct sequence is $(1 - c), (2 - d), (3 - a), (4 - b)$.

(D) : The transpiration process pulls water upwards with the help of cohesion and adhesion properties of water molecules. According to the transpiration pull theory,due to transpiration,the water column inside the plant comes under tension. This is called 'transpiration pull'. On account of this tension,the water column is pulled up passively from below to the top of the plant (almost like a rope).
Root pressure is the pressure that forces water,absorbed from the soil,to move through the roots and up ($i.e.$,pushes it up) the stem of a plant. It may be due to both the osmosis of water from the soil into the root cells,and the active pumping of salts into xylem tissue which maintains a concentration gradient along which the water moves.

(D) The correct matching is as follows:
$(P)$ Active absorption: This process involves the uptake of $(3)$ minerals against the concentration gradient,requiring energy.
$(Q)$ Osmotic pressure: This is directly related to $(4)$ solute concentration; higher solute concentration leads to higher osmotic pressure.
$(R)$ Stomata: These are pores on the leaf surface responsible for the $(1)$ loss of water in the form of water vapor (transpiration).
Therefore,the correct sequence is $P-3, Q-4, R-1$.

(A) $1.$ Diffusion is a passive process because it does not require metabolic energy. Hence, statement $1$ is $\text{True} (T)$.
$2.$ Solute potential $(\Psi_S)$ is always negative in a solution because the addition of solutes lowers the water potential. Hence, statement $2$ is $\text{True} (T)$.
$3.$ Osmosis is the movement of water across a semi-permeable membrane, which is driven by both concentration gradients and pressure gradients. Therefore, it does depend on pressure. Hence, statement $3$ is $\text{False} (F)$.
$4.$ Mycorrhiza is a symbiotic association between fungi and the roots of higher plants, not algae. The association between fungi and algae is called a Lichen. Hence, statement $4$ is $\text{False} (F)$.
Thus, the sequence is $T, T, F, F$.

(D) The magnitude of forces involved in water movement in plants varies significantly.
$1$. Imbibition is the strongest force,capable of exerting immense pressure (often hundreds of atmospheres) to initiate water uptake by dry seeds.
$2$. Transpiration pull is the primary force responsible for long-distance water transport in tall trees,capable of pulling water columns up to $100 \ m$ or more.
$3$. Root pressure is a positive pressure that can push water up to a limited height (usually a few meters) and is most effective in small herbaceous plants.
$4$. Adhesion forces (attraction between water and cell walls) are significant but generally weaker than the massive pull generated by transpiration.
Therefore,the correct order of magnitude is: Imbibition force > Transpiration pull > Root pressure > Adhesion force.

(A) Assertion $(A)$ is correct: Diffusion is a passive,random,and slow process that does not depend on a living system. It is effective only over short distances.
Reason $(R)$ is correct: In plants,long-distance transport of water,minerals,and food occurs through the vascular tissues ($xylem$ and $phloem$) using a mass or bulk flow system,which is driven by pressure differences.
Since both statements are scientifically accurate,the correct option is $A$.

(D) mustard plant absorbs water equal to its own weight in approximately $5$ hours. This high rate of water absorption is necessary to maintain the plant's turgidity and to support the continuous process of transpiration,which is essential for nutrient transport and temperature regulation.

(D) Statement $(1)$ is correct: The apoplastic pathway consists of non-living parts of the plant,i.e.,cell walls and intercellular spaces.
Statement $(2)$ is correct: The symplastic system is the system of interconnected protoplasts,which are connected through plasmodesmata.
Statement $(3)$ is incorrect: Casparian strips are made of suberin and are present in the endodermis,which blocks the apoplastic pathway,forcing water to enter the symplastic pathway.
Statement $(4)$ is incorrect: The symplastic movement is slower because it involves the movement of water through the cell membranes and cytoplasm,whereas the apoplastic movement is faster as it occurs through the cell walls and intercellular spaces without crossing membranes.

(D) Water potential $(\Psi_w)$ is defined as the sum of solute potential $(\Psi_s)$ and pressure potential $(\Psi_p)$.
In plant cells, $\Psi_w = \Psi_s + \Psi_p$.
Normally, the water potential of plant cells is negative due to the presence of solutes.
However, during the process of guttation, water is forced out of the hydathodes due to root pressure.
Root pressure creates a positive hydrostatic pressure $(\Psi_p > 0)$ in the xylem, which can lead to a positive water potential in the leaf tissues during this specific event.

(D) The phenomenon of loss of water in the form of droplets from the surface of plants is known as guttation. Guttation typically occurs through specialized pores called hydathodes,not lenticels. Lenticels are involved in gaseous exchange. Therefore,the Assertion is incorrect.
Root pressure is a positive pressure generated in the xylem due to the active absorption of minerals and subsequent osmotic influx of water. While root pressure is responsible for guttation,it does not regulate water loss from lenticels. Thus,the Reason is also incorrect.

(C) Soluble substances,such as minerals and organic nutrients,migrate through the plant body via the vascular tissues.
$1$. Minerals absorbed by the roots are transported upward through the $xylem$ along with water.
$2$. Organic nutrients,primarily synthesized in the leaves,are transported to other parts of the plant through the $phloem$.
Therefore,both $xylem$ and $phloem$ are involved in the migration of soluble substances.

(N/A) $(1)$ Differences between Diffusion and Osmosis:

Diffusion	Osmosis
$(1)$ Movement of molecules from a region of higher concentration to a region of lower concentration.	$(1)$ Movement of solvent molecules from a region of higher water potential to a region of lower water potential through a semi-permeable membrane.
$(2)$ It is a random activity.	$(2)$ It is a directed process.
$(3)$ It occurs in gases,liquids,and solids.	$(3)$ It occurs only in liquid solutions.
$(4)$ No semi-permeable membrane is required.	$(4)$ $A$ semi-permeable membrane is essential.

$(2)$ Differences between Transpiration and Evaporation:

Transpiration	Evaporation
$(1)$ Loss of water as vapour from aerial parts of living plants.	$(1)$ Loss of water as vapour from any free surface.
$(2)$ It is a physiological,controlled process.	$(2)$ It is a physical,uncontrolled process.
$(3)$ It occurs mainly during the day.	$(3)$ It occurs throughout the day and night.
$(4)$ It is regulated by stomatal activity.	$(4)$ It is not regulated by any biological structure.

(N/A) $(1)$ Osmotic Pressure vs Osmotic Potential:

Osmotic Pressure	Osmotic Potential
$(1)$ It is the pressure required to prevent the net movement of water into a solution across a semi-permeable membrane.	$(1)$ It is the decrease in the water potential of a solution due to the presence of solute particles.
$(2)$ It is always a positive pressure.	$(2)$ It is always a negative value.

$(2)$ Diffusion vs Imbibition:

Diffusion	Imbibition
$(1)$ Movement of particles from a region of higher concentration to a region of lower concentration.	$(1)$ $A$ special type of diffusion where water is absorbed by solid colloids, causing them to increase in volume.
$(2)$ It is a random movement of molecules.	$(2)$ It is a specific process involving adsorption of water by hydrophilic substances.
$(3)$ It occurs in gases, liquids, and solids.	$(3)$ It occurs specifically in solid substances (imbibants).

(N/A) $(1)$ Comparison between Apoplast and Symplast pathways:

Apoplast pathway	Symplast pathway
$(1)$ Movement occurs through cell walls and intercellular spaces.	$(1)$ Movement occurs through the cytoplasm and plasmodesmata.
$(2)$ Water does not cross any cell membrane.	$(2)$ Water crosses the cell membrane.
$(3)$ It is a faster process.	$(3)$ It is a slower process.
$(4)$ It is dependent on the gradient.	$(4)$ It is dependent on cytoplasmic streaming.

$(2)$ Comparison between Guttation and Transpiration:

Guttation	Transpiration
$(1)$ Occurs mainly in early morning or night.	$(1)$ Occurs mainly during the day.
$(2)$ Occurs through hydathodes.	$(2)$ Occurs through stomata,cuticle,or lenticels.
$(3)$ Water is lost as liquid droplets.	$(3)$ Water is lost as water vapour.
$(4)$ It is an uncontrolled process.	$(4)$ It is a controlled process regulated by stomata.

(N/A) $(1)$ The upward movement of water and dissolved mineral salts,absorbed by the root system,through the xylem tissue towards the stem and leaves against the force of gravity is called ascent of sap.
$(2)$ The transport of food (sucrose) prepared by photosynthesis from the leaves (source) to other parts of the plant,including the roots (sink),through the phloem tissue is called phloem transport.

(C) $\Rightarrow$ In a girdling (ring) experiment,the phloem is removed,which stops the downward translocation of food (sucrose) to the roots.
$\Rightarrow$ However,the xylem remains intact initially,allowing water to move upward to the leaves.
$\Rightarrow$ The leaves remain green for some time because they continue to perform photosynthesis using the supplied water.
$\Rightarrow$ Eventually,the roots die due to a lack of food supply (as phloem is blocked),which in turn stops the absorption of water and minerals.
$\Rightarrow$ Consequently,the entire plant,including the leaves above the girdle,eventually wilts and dies because the root system is no longer functional.

(N/A)

Diffusion	Translocation
$(1)$ It is the movement of molecules from a region of higher concentration to a region of lower concentration.	$(1)$ It is the transport of organic solutes (like sucrose) and mineral ions from source to sink in plants.
$(2)$ It is a passive process; no metabolic energy $(ATP)$ is required.	$(2)$ It is an active process; it requires metabolic energy $(ATP)$ to move substances against concentration gradients.

(N/A) Wilting is the loss of turgidity in plant leaves and stems, causing aerial organs to droop or fold. This occurs when the rate of transpiration exceeds the rate of water absorption.

Temporary Wilting	Permanent Wilting
$(i)$ Occurs during the afternoon when the rate of transpiration is high.	$(i)$ Occurs when the soil moisture content falls below the permanent wilting percentage.
$(ii)$ Caused by a temporary imbalance where transpiration exceeds absorption.	$(ii)$ Caused by a severe, prolonged water deficit in the soil.
$(iii)$ The plant recovers its turgidity when water is added to the soil or transpiration decreases (e.g., at night).	$(iii)$ The plant cannot recover its turgidity even if water is added to the soil.
$(iv)$ The plant continues its normal growth after recovery.	$(iv)$ The plant eventually dies due to severe dehydration.

(A) $(1)$ Guttation
$(2)$ Water and minerals
Explanation:
$(1)$ Stomata are the sites for transpiration (loss of water vapor). Similarly,hydathodes are the specialized pores through which guttation (loss of water in liquid form) occurs.
$(2)$ Phloem is responsible for the translocation of sugars (food) from source to sink. Xylem is responsible for the transport of water and dissolved minerals from roots to other parts of the plant.

(A) $(1)$ In xylem, water and minerals are transported from roots to the aerial parts of the plant, which is a $unidirectional$ process.
$(2)$ The loss of water in the form of water vapour from the aerial parts of the plant is known as $transpiration$.

(C) Bulk flow (or mass flow) is the movement of substances in bulk from one point to another as a result of pressure differences between the two points.
Bulk flow can be achieved through two types of pressure gradients:
$1$. Positive hydrostatic pressure gradient: This is created by applying pressure,such as water flowing out of a garden hose.
$2$. Negative hydrostatic pressure gradient: This is created by suction,such as drawing water through a straw.
Therefore,a garden hose represents a positive hydrostatic pressure gradient,and suction through a straw represents a negative hydrostatic pressure gradient.

(A) In plants,the transport of organic substances (photosynthates),hormones,and other solutes is multidirectional because these substances are transported from source to sink,and the source-sink relationship can change depending on the plant's needs. In contrast,the transport of water and minerals is generally unidirectional (upward from roots to leaves).

(C) $I$. Correct: Root pressure provides a positive pressure that acts as a light push in the overall process of water transport.
$II$. Incorrect: Root pressure is not sufficient to push water to the heights of tall trees,and transpiration pull is the primary driver for water movement.
$III$. Incorrect: The symplast pathway involves movement of water through the cytoplasm and plasmodesmata,not the cell wall. Movement through cell walls is the apoplast pathway.
$IV$. Incorrect: Guttation is a result of root pressure,not a cause of transpiration pull.
$V$. Correct: Transpiration pull is the primary force responsible for the ascent of sap in most plants.
Therefore,statements $I$ and $V$ are correct.

(B) When there is heavy rainfall and poor drainage,the soil becomes waterlogged. This leads to a lack of oxygen in the soil,which is known as poor aeration. Roots require oxygen for aerobic respiration to generate energy for the active absorption of water and minerals. Due to the lack of oxygen,the roots cannot function properly,leading to a reduction in water uptake,which causes the leaves to wilt.

(A, C) Statement $A$ is correct. The Casparian strip is a band of suberized cell wall material found in the endodermis of roots. It acts as a barrier,forcing water and solutes to pass through the plasma membrane,thereby allowing the plant to regulate the uptake of water and minerals.
Statement $B$ is incorrect. Guttation occurs when there is high soil moisture and low transpiration,typically during high atmospheric humidity (often at night or early morning),not low humidity.
Statement $C$ is correct. According to the active $K^{+}$ transport theory (Levitt's theory),the influx of $K^{+}$ ions into guard cells is the primary mechanism for stomatal opening.
Statement $D$ is incorrect. In $CAM$ plants,stomata remain open at night to take in $CO_{2}$ and remain closed during the day to prevent water loss.

(C) During the transport of water from the soil to the xylem, water moves through two main pathways: the symplastic pathway and the apoplastic pathway.
$1$. The symplastic pathway involves the movement of water through the cytoplasm of adjacent cells connected by plasmodesmata $(A)$.
$2$. In the root, water must pass through the endodermis $(B)$, which contains the Casparian strip $(C)$, a suberized layer that forces water to move symplastically.
$3$. The apoplast $(D)$ refers to the system of adjacent cell walls that is continuous throughout the plant, while the symplast $(E)$ refers to the system of interconnected protoplasts.

(C) $I.$ True: The association between $Pinus$ roots and fungi is an obligate mutualism.
$II.$ False: $Pinus$ and orchid seeds are dependent on mycorrhizal fungi for germination and development.
$III.$ False: Water absorption by root hairs involves both active and passive processes,not just diffusion.
$IV.$ True: The apoplast pathway involves movement through cell walls and intercellular spaces.
$V.$ False: Fungi receive sugars from the plant,while they provide water and minerals to the plant,not the other way around.
Therefore,statements $I$ and $IV$ are true.

(B) $I.$ True: Diffusion is the primary mechanism for gaseous exchange in plants.
$II.$ True: Active transport requires energy $(ATP)$ to move substances against the concentration gradient via protein pumps.
$III.$ True: Facilitated diffusion uses specific membrane proteins to transport hydrophilic molecules.
$IV.$ False: In diffusion,molecules move along the concentration gradient (from higher to lower concentration),not against it.
$V.$ False: Facilitated diffusion is generally slower than active transport because it relies on the concentration gradient and protein saturation,whereas active transport can move substances rapidly against the gradient using energy.
Therefore,statements $I, II,$ and $III$ are true,while $IV$ and $V$ are false.

(A) $I.$ True: The positive hydrostatic pressure that develops in a plant cell due to the entry of water is known as turgor pressure.
$II.$ True: Wall pressure is the pressure exerted by the cell wall against the expanding protoplast,which prevents the cell from bursting and limits the increase in protoplasm size.
$III.$ False: Diffusion is much more rapid in gases than in liquids because gas molecules have higher kinetic energy and move more freely.
$IV.$ False: The diffusion of water through a semi-permeable membrane is called osmosis,not imbibition. Imbibition is the special type of diffusion when water is absorbed by solids (colloids).
$V.$ False: Osmosis is the diffusion of water across a differentially or semi-permeable membrane,which is a specific type of movement,not just any substance moving along a diffusion gradient.

(C) Water moves from root hairs to the xylem through two main pathways: the Apoplast pathway and the Symplast pathway.
$1$. The Apoplast pathway involves the movement of water through the cell walls and intercellular spaces of the root cortex.
$2$. The Symplast pathway involves the movement of water through the cytoplasm and plasmodesmata,connecting the cells.
Since water utilizes both routes to reach the xylem,the correct answer is both $(A)$ and $(B)$.

(D) Xylem is primarily responsible for the conduction of water and dissolved mineral salts from the roots to the aerial parts of the plant.
Additionally,xylem sap also contains small amounts of organic nitrogen compounds such as amides and certain plant hormones (like cytokinins) that are transported from the roots to the shoot system.
Therefore,all the given options are correct,making the final answer 'More than one option is correct'.

(D) Root pressure is a positive hydrostatic pressure that develops in the xylem of roots due to the active absorption of mineral ions. It is responsible for phenomena like sap exudation,bleeding,and guttation. Transpiration,on the other hand,is the loss of water in the form of vapor from aerial parts of plants. It is driven by the cohesion-tension-transpiration pull mechanism,which is a negative pressure (suction) mechanism,not a positive pressure mechanism like root pressure.