PHYSIOLOGY OF FLOWERING PLANTS (CHAPTER FIFTEEN) Flashcards
Mineral salts are taken up into plants as
ions
If the concentration of salts in water is high what happens?
plants show symptoms of drought such as witting, reduced growh and colour change.
Soils with high amount of salts are said to be
saline
soils with high sodium levels are said to be?
sodic.
Saline soils occurs when ?
the supply of salts exceeds the normal removal of the salts.
Hygroscopic water passes slowly through the large soil particules by_____ and as such the root hairs cannot absorb it.
percolation
Water available to plants is
capillary water.
What is hygroscopic water.?
This is the water that usually moves downwards in response to gravity and carries with il a lot of nutrients required by the plants.
What is capillary water?
This water is capable of moving through the soil particles by capillary action and therefore it is always available to plants.
When is the soil is said to be saturated ?
When the water fills up the pore spaces so much that no room is available for air
The ability of the soil to retain water is the
water-holding capacity of that soil.
Water in plants acts as a medium for life precesses because of some of its properties which include;
solvent properties, surface tension and capillarity, heat capacity, density of water and gas solubility.
The solvent action of water is generally an effect of
its ability to form hydrogen bonds and of the asymmetrical distribution of its charges.
The membranes through which water passes into and out of the plant cell are
the cell walis, plasma membranes, and the vacuolar membranes.
What is the cytoplasmic membranes?
plasma membranes, and the vacuolar membranes.
Water has at least two modes available for it to move into and out of plant systems which includes
diffusion and osmosis.
Molecules and ions move from regions of higher to lower concentration by
diffusion.
What causes water to move from cell to cell until it gets to the xylem?
Osmotic pressure exerted by cells, along with the transpiration pull
Water moves from the soil into the stele of the root through the cells of the root because?
the water potential of the stele is more negative than the cortex.
What happens to the potential when solutes are added to water?
the potential decreases and becomes negative (i.e. less than zero).
What is the water potential of pure water
Zero
What have the most negative potential in the plant.?
The mesophyll cells of the leaf
What is suction pressure?
The low potential in the mesophyll cells of the leaves creates a pull on the water in the xylem.
What is Transpiration?
This is the loss of water through evaporation in aerial parts of the plant such as the leaves and lenticels.