Life Processes- Transportation in Plants Flashcards
why would a process of teansportation with organs be necessary
For plants,
the soil is the nearest and richest source of raw materials like nitrogen,
phosphorus and other minerals. The absorption of these substances
therefore occurs through the part in contact with the soil, namely roots.
If the distances between soil-contacting organs and chlorophyllcontaining organs are small, energy and raw materials can easily diffuse
to all parts of the plant body. But if these distances become large because
of changes in plant body design, diffusion processes will not be sufficient
to provide raw material in leaves and energy in roots. A proper system of
transportation is therefore essential in such situations.
why do plants not require much energy
Plants do not
move, and plant bodies have a large proportion of dead cells in many
tissues. As a result, plants have low energy needs, and can use relatively
slow transport systems. The distances over which transport systems
have to operate, however, can be very large in plants such as very tall
trees.
what are the 2 transporting tubes
These two pathways are constructed as
independently organised conducting tubes. One, the xylem moves water
and minerals obtained from the soil. The other, phloem transports
products of photosynthesis from the leaves where they are synthesised
to other parts of the plant.
how is ionic difference and root pressure important for transport of water through xylem
At the roots, cells in contact
with the soil actively take up ions. This creates a difference in the
concentration of these ions between the root and the soil. Water, therefore,moves into the root from the soil to eliminate this difference. This means
that there is steady movement of water into root xylem, creating a column
of water that is steadily pushed upwards.
how is water transported throughthe xylem
In xylem tissue, vessels and tracheids of the roots, stems and leaves are
interconnected to form a continuous system of water-conducting
channels reaching all parts of the plant.
explain the importance of transpiration in transportation of water
Provided that the plant has an adequate
supply of water, the water which is lost through the
stomata is replaced by water from the xylem vessels
in the leaf. In fact, evaporation of water molecules from
the cells of a leaf creates a suction which pulls water
from the xylem cells of roots. The loss of water in the
form of vapour from the aerial parts of the plant is
known as transpiration.
Thus, transpiration helps in the absorption and
upward movement of water and minerals dissolved
in it from roots to the leaves. It also helps in
temperature regulation.
define translocation
v\This transport of soluble products of photosynthesis
is called translocation and it occurs through a vascular tissue called as phloem.
where are the products transported to?
These substances are
especially delivered to the storage organs of roots, fruits and seeds and
to growing organs.
\where does transolaction occur
The translocation of food and other substances takes
place in the sieve tubes with the help of adjacent companion cells both
in upward and downward directions.
how is the food translocated along the phloem
The translocation in phloem is achieved by utilising
energy. Material like sucrose is transferred into phloem tissue using
energy from ATP. This increases the osmotic pressure of the tissue
causing water to move into it. This pressure moves the material in the
phloem to tissues which have less pressure. This allows the phloem to
move material according to the plant’s needs. For example, in the spring,
sugar stored in root or stem tissue would be transported to the buds
which need energy to grow.
