Water is absorbed by the root hair cell by the process called, Osmosis. Root hairs are made up of epidermal cells, which are present on the surface of the root. they also increase the surface area for absorption SYMPLAST PATHWAY: In this pathway, water and minerals move from the cytoplasm of one cell in to the next, via plasmodesmata eventually reaching the xylem. APOPLAST PATHWAY: In this pathway, water and dissolved minerals travel through the cell walls that surround plant cells.

1. TRANSPORT OF WATER

2. TWO STEPS
• ABSORPTION OF WATER
• ASCENT OF SAP

3. ROOT STRUCTURE

4. • WATER IS ABSORBED BY THE ROOT HAIR
CELL BY THE PROCESS CALLED, OSMOSIS.
• ROOT HAIRS ARE MADE UP OF
EPIDERMAL CELLS, WHICH ARE PRESENT ON
THE SURFACE OF THE ROOT.
• THEY ALSO INCREASE THE SURFACE AREA
FOR ABSORPTION

5. PATHWAYS OF WATER TRANSPORT
• SYMPLAST PATHWAY:
• IN THIS PATHWAY, WATER AND MINERALS
MOVE FROM THE CYTOPLASM OF ONE CELL
IN TO THE NEXT, VIA PLASMODESMATA
EVENTUALLY REACHING THE XYLEM.
• APOPLAST PATHWAY:
• IN THIS PATHWAY, WATER AND DISSOLVED
MINERALS TRAVEL THROUGH THE CELL
WALLS THAT SURROUND PLANT CELLS.

6. APOPLAST PATHWAY
• WATER MOVEMENT THROUGH CELL
WALL OR INTERCELLULAR SPACES
• WATER DOES NOT CROSS THE
MEMBRANE, IT MEANS IT DOES NOT
BECOME PART OF THE CELL
• WATER ROOT HAIR
INTERCELLULAR SPACES
PASSAGE CELLS XYLEM
• COMPARATIVELY QUICK
SYMPLAST PATHWAY
• WATER MOVEMENT THROUGH THE
CYTOPLASM VIA PLASMODESMATA
• WATER BECOMES PART OF THE
CYTOPLASM OR CELL SAP
• WATER ROOT HAIR
CELL SAP PASSAGE CELLS
XYLEM
• TIME CONSUMING PATHWAY

7. WATER THROUGH ENDODERMIS
• THE ENDODERMIS IS THE INNERMOST LAYER OF THE CORTEX OF PLANTS.
• CASPARIAN STRIP: WATER IMPERVIOUS DUE TO SUBERIN
• THE PASSAGE CELLS: UNSUBERINISED CELLS IN ENDODERMIS
• ALLOW THE PASSAGE OF ELEMENTS BETWEEN THE VASCULAR TISSUES AND THE
CORTEX.

8. • ENDODERMIS ALLOWS SYMPLAST ONLY.
• WHEN WATER ENTERS THE PASSAGE CELLS, IT HAS TO MOVE THROUGH THE
CELL SAP.
• AFTER CROSSING PASSAGE CELL IT AGAIN SHOWS APOPLAST MOVEMENT AND
REACHES XYLEM.
• NOTE:
MAX MOVEMENT OF WATER IN PLANT OCCURS THROUGH APOPLAST
PATHWAY.

9. VACUOLAR PATHWAY

10. VIDEO

11. ASCENT OF SAP

12. FACTORS RESPONSIBLE FOR ASCENT OF SAP
• ROOT PRESSURE
• ADHESION / COHESION
FORCES
• CAPILLARY ACTION
• TRANSPIRATION

13. ROOT PRESSURE
• ROOT PRESSURE IS A FORCE GENERATED IN THE ROOTS THAT HELP IN DRIVING
THE FLUIDS AND OTHER IONS FROM THE SOIL IN UPWARDS DIRECTIONS INTO
THE PLANT’S VASCULAR TISSUE – XYLEM.
• THIS PROCESS IS PRODUCED BY OSMOTIC PRESSURE IN THE CELLS OF THE
ROOT.

14. • PASSIVE MOVEMENT OF WATER THROUGH ROOTS.
• IF ABSORBANCE OF WATER CONTINUES AND TRANSPIRATION STOPS DUE TO CLOSURE
OF STOMATA.
• IF STOMATA CLOSES THE ABSORPTION AND MOVEMENT OF WATER INSIDE THE PLANT
CONTINUES AND CREATES A PRESSURE IN XYLEM.
• THIS IS ROOT PRESSURE.
• IT CAN PUMP WATER A FEW INCHES FAR.
• SO IT CAN MOVE WATER IN SMALL PLANTS (HERBACEOUS PLANTS).
• NOT SIGNIFICANT IN HIGHER PLANTS
• MOVEMENT OF WATER IN PLANTS IS UNIDIRECTIONAL.

15. AN EXPERIMENT TO DEMONSTRATE ROOT
PRESSURE

16. GUTTATION
• GUTTATION OCCURS WHEN A PLANT OOZES
WATER AND MINERALS OUT FROM
PERFECTLY HEALTHY LEAVES, STEMS, AND
SOMETIMES EVEN FLOWER PETALS.
• LOSS OF WATER AS LIQUID THROUGH
HYDATHODES.
• HYDATHODES: SECRETORY TISSUES PRESENT
IN THE LEAVES SECRETE WATER DROPS
THROUGH PORES IN THE EPIDERMIS IN LEAF
MARGINS.
• TAKES PLACE AT NIGHT OR EARLY
MORNING.
• OCCURS WHEN WATER COLUMN IS BUILT
DUE TO ABSORPTION OF WATER AND WHEN
TRANSPIRATION IS NEGLIGIBLE.

17. SEASONAL FLUCTUATIONS IN ROOT
PRESSURE
• IN SPRING:
TRANSPIRATION IS SLOW BECAUSE NEW LEAVES ARE COMING OUT. SO IT IS
HIGHEST IN SPRING.
• IN SUMMER:
TRANSPIRATION RATE IS VERY HIGH SO ROOT PRESSURE IS VERY LOW.

18. NO ROOT PRESSURE IN GYMNOSPERMS
• IT IS ABSENT IN GYMNOSPERMS AS THEY ARE MOSTLY TALL PLANTS AND ROOT
PRESSURE IS NOT EFFICIENT MECHANISM TO TRANSPORT WATER UPTO TO
GREAT HEIGHTS IN THESE PLANTS.
• THESE PLANT TRANSPORT WATER MAINLY BY THE TRANSPIRATIONAL PULL
MECHANISM.

19. COHESION AND ADHESION OF WATER

20. • DUE TO ADHESIVE FORCE BETWEEN WATER MOLECULE AND LIGNIN, ONE
WATER MOLECULE GETS ATTRACTED OR PULLED TOWARDS LIGNIN.
• WHEN THIS WATER MOLECULE MOVES, IT TAKES OTHER WATER MOLECULES
ALONG WITH IT DUE TO COHESIVE FORCES.
• SO THESE FORCES HELP IN MAINTAINING CONTINUOUS WATER COLUMN IN
XYLEM.

21. EXTRA INFO

22. CAPILLARY ACTION IN PLANTS
DUE TO THESE PROPERTIES OF WATER, TWO PROCESSES OCCUR IN THE XYLEM
VESSEL.
1. THE FIRST PROCESS IS THAT THE WATER MOLECULES AT THE WATER SURFACE
IN THE XYLEM VESSEL ARE ATTRACTED TO THE WALLS ABOVE IT
IMMEDIATELY. THIS IS DUE TO ADHESION THUS THE WATER WILL BE
ATTRACTED UPWARDS.
2. THE SECOND PROCESS IS THAT WATER MOLECULES NEXT TO THESE WATER
MOLECULES ARE ATTRACTED TO THEM BY COHESION. THUS, THESE WATER
MOLECULES ARE ALSO PUSHED UPWARD AND THEREFORE MOVING UP THE
XYLEM VESSEL AS A CONTINUOUS WATER COLUMN.
THESE TWO PROCESSES MAKES UP THE CAPILLARY ACTION, WHICH AID IN THE
MOVING OF WATER UP THE XYLEM VESSEL.

25. TRANSPIRATION
• TRANSPIRATION PLAYS A VITAL ROLE IN THE BODY OF THE PLANTS.
• IT HELPS IT TO TRANSPORT WATER AND MINERALS TOWARDS THE LEAVES FROM THE
ROOTS IN THE UPWARD DIRECTION AGAINST THE GRAVITATIONAL PULL.
• IT COOLS DOWN THE PLANT DURING SUMMERS.
• IT REMOVES EXCESS WATER.
• ALSO WHEN WATER IS ELIMINATED FROM THE PLANT IT URGES THE ROOTS TO PULL
MORE WATER AND ALONG WITH THEM MINERALS ARE ALSO ABSORBED WHICH IS
BENEFICIAL FOR THE PLANT.

26. TRANSPIRATIONAL PULL
• WHEN WATER GETS EVAPORATED FROM THE SURFACE OF THE LEAVES, IN ORDER TO
MEET THE REQUIREMENTS OF THE PLANT
• THE WATER IS SUCKED UP FROM THE SOIL BY THE ROOTS OF THE PLANT
• AND IS TRANSPORTED THROUGHOUT THE PLANT BODY I.E. FROM THE ROOTS OF
THE PLANT TILL THE LEAVES.
• CONTINUOUS EVAPORATION FROM STOMATA OF LEAVES CREATES SUCTION WHICH
PULLS UP WATER THROUGH XYLEM VESSELS .
• THIS PROCESS OF SUCKING OF WATER FROM THE SOIL, BY THE ROOTS OF THE PLANT
MAY BE TERMED AS TRANSPIRATION PULL.

27. • IT IS A BASIC PROCESS NEEDED FOR THE MAINTENANCE AND THE GROWTH OF
THE PLANT.
• THIS TRANSPORTS THE WATER AND ALL THE ESSENTIAL NUTRIENTS FROM THE
SOIL TO THE VARIOUS PARTS OF THE PLANT WHICH ARE NEEDED FROM ITS
GROWTH AND MAINTENANCE.