What is the mechanism in trees/ plants to pump water/ manure from root to leaves?

Answer 1

Capillary Action
Osmosis
Water Potential
Transpiration

Answer 2

The problem was debated in the botanical circles for a long time and ultimately a theory advocated by Dixon has been accepted by and large. This will be a valid theory till some new and more satisfactory explanation is put forth by some one, as the science is always in the quest of eternal truth..


The theory is known as Dixon’s Theory of Ascent of Sap.
According to this theory not any single factor, but four factors in combination lift the water to great height.
These four factors are explained below in brief.


1) Osmosis Or Endosmosis – This factor is responsible for the lateral movement of water from the soil, across the cortical tissue in to the water conducting xylem elements.
a) Root hair are unicellular living cells, they absorb water from the soil by a process called osmosis and pass it on to the other living cells LATERALLY in the cortex or the middle zone of the root. All the cells involved are living as only a living cell with a cell membrane or plasma membrane can show osmosis.
b) The water thus absorbed, passes through the pericycle and enters the xylem element, which is a dead tissue.
c) No upward movement of water is involved in this phase.
d) The roots are spread far and wide below the soil surface always in the quest of water. This is more so in the case of trees. For any given plant the total surface area of the root system is far far greater than that of the shoot system and that is precisely for water absorption.


2) Transpiration Pull – This factor is responsible for the UPWARD movement of water in the direction of the leaves.
a) The loss of water from the surface area of the leaves is called transpiration.
b) As the leaves transpire water there is a water deficit in the leaves. To make good that deficit the water is pulled up from the adjoining tissue in to the leaves. This is precisely called transpiration pull.
c) If there is no enough water then the leaves begin to wilt and dry. And it is a matter of common observation. That is why the crop plants or pot plants require regular watering.


3) Cohesive Force of Water Molecules – The ability of water molecules to remain clinging together is due to the force of cohesion between them ( i.e. mutual attraction) .
a) When one opens a water tap, water comes in a form of a continuous stream and not in a form of a molecule after a molecule. This is precisely due to the force of adhesion. It is exhibited by many other chemicals besides water.
b) Xylem elements in a plant / tree form a CONTINUOUS system of water pipes through out . It forms an interconnected network with in the plant / tree. It is because of this , there is a continuous water column
(even though highly branched) within the plant body.
c) Due to the ‘Transpiration Pull ‘ this water column is constantly pulled in the direction of the leaves like a massive rope being winched UPWARDS!
d) This water column will not break no matter what the height of the tree is . This is because the cohesive force of water molecule will require more than 120 atmospheric pressure to break it!

e) Thus water can rise easily to a height of 400 feet.
f) The tallest tree in the world, the Red wood giant or Sequoia semiperviens is about 384 feet!


4) Force of Adhesion between water and the walls of the xylem elements—Xylem elements are made up of lignin . There exists a force of attraction between it and the water . This is the force of adhesion.
( i. e. attraction between to dissimilar things.)
This leads to the capillary action and makes the water column continuous and stronger.
Only capillary action cannot account for the rise of water to great height . As Taller trees have wider Xylem ( It is contrary to the expectation.).


Solid manures as such are not taken up by the roots/plants. The salts from them which are dissolved in water are absorbed along with water in their ionic forms only. For example Potassium nitrate (KNO3) is absorbed in the form of K+ ions and NO3 - ions independently.

Answer 3

From ground to roots - Osmosis

From Root to Leaf - Capillary action combined with Transpiration.

Answer 4

Capillary effect in the xylem (small tubes that carry the fluids and nutrients upward). You can calculate the capillary tension versus gravity and understand why the tallest trees can only be at about 180 feet high.

Answer 5

there R 2 Mechanisms:
1- Root hairs pressure (osmosis)
2- Transpiration ( from stomata pulls the water up like in mercury column )

Answer 6

Capillary action.

Answer 7

BE sure to use "vegan" fertilizers... usiing raped/murdered manures will only be bad for you, there is a scientific equation for teh scale of pain associated and teh uptake tha t teh plant spirit KNOWS all to well. ~Transfer~


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Answer 8

Capillary action.