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Variation: Instead of using one cylinder with water and one with food dye, use two different colour food dyes (e.g. blue and red). At first the flower will showtwo separate colours, but as time goes by the whole flower will show both dyes. This is because water can move sideways between xylem vessels through openingsalong their length. The ability of water to move sideways between vessels is useful for when air becomes trapped in a vessel, causing a blockage. If you cutthe stem right up to the base of the flower, this will limit movement between the xylem vessels.

Variation: Try using celery stalks with leaves. Cut open the celery stalk (cross-section) and you will see that the little holes inside are coloured – these arethe vessels.

An example of this experiment with photographs can be found at: http://www.practicalbiology.org/areas/intermediate/cells-to-systems/transport- in-plants/investigating-transport-systems-in-a-flowering-plant,70,EXP.html

Secondary growth

Meristematic tissue

  • Meristematic tissue consists of small cells that are unspecialized. These cells divide by mitosis to form new cells that can differentiate (undergo changes intheir structure) and can become specialized tissue (e.g. xylem, phloem, epidermal cells)
  • Primary meristematic tissue is found in the tips of roots, stems and buds. When it divides new cells are produced which causes the plant to grow longer. Thisis referred to as primary growth.
  • Secondary meristematic tissue originates from permanent tissue, usually parenchyma tissue which divides by mitosis. Cambium is secondary meristematictissue that is found in roots and stems. When these cells divide by mitosis it results in the plant becoming wider. This is called secondary growth.
  • Every growing season the stem of a plant increases in width – this is known as secondary thickening.
  • Towards the end of the first year of growth, the parenchyma cells between the vascular bundles become meristematic and link up with the cambium tissue toform a cambium ring.
  • The cells in the cambium ring start dividing to form secondary phloem (on the outside) and secondary xylem (on the inside).
  • Each year another ring of secondary phloem and secondary xylem is formed, making the stem grow wider.
  • It is not possible to see the layers of secondary phloem but the secondary xylem are visible. These form rings called annular rings which can be used to workout the age of a plant.
  • As new rings are formed each year, the older rings are pushed inward and the xylem vessels collapse due to the pressure. The wood in the centre becomesdenser and harder than the wood at the surface and is called heartwood.
  • The youngest annual rings found on the outside serve its function of transporting water. This wood is not as dense and is called sapwood.
  • The light-coloured rings are called spring wood. They are formed during spring and summer when the growing conditions are favourable. The rings are thereforerelatively thick and light in colour as the xylem cell walls are thin.
  • The dark-coloured rings are called autumn wood. They are formed during autumn and winter when the growing conditions are unfavourable. The rings aretherefore relatively thin and dark in colour as the xylem cell walls are thick.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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why and for what was five kingdom of classification of organisms introduced
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SUBHIKSHA
Comment on the ozone depletion over the period of 1982 to 1996
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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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