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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

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
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
give the ans as fast as possible
Comment on the ozone depletion over the period of 1982 to 1996
Mpho Reply

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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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