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  1. What was the difference in longitudinal growth between seedlings B and F?
  1. What was the difference between the longest and the shortest seedling?
  1. Describe the way in which a seedling's longitudinal growth occurs.

Assessment: Graph

Were you able to answer the questions?

[LO 2.3]

Assessment

LO 2: Constructing Science Knowledge:

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

This is evident when the learner:

  • recalls meaningful information;
  • categorises information;
  • interprets information;

2.4 applies knowledge.

Memorandum

Plant organs: Stems

Activity

Assignment 1

  • As you have indicated, the functions of the plant stem include bearing the leaves, flowers and eventually also the fruit, in such a way that they are exposed to sunlight, pollinating agents and fruit distributors respectively.
  • In the case of large trees, the stem, in time, becomes the trunk, which is greatly thickened and strengthened with bark and other structures.
  • Plant stems need to have channels for conducting the main products that have to be moved up and down. If you understand that water has to be conducted from the lowest tip of the roots to the highest tip of the uppemost leaf, you will realise that we need a conducting channel for such water and for mineral salts.
  • The leaves produce starch and sugar, which have to be conducted to all the cells, even to those that are at the furthest tips of the roots, but cannot be conducted along the same channels as the water, because this would lead to confusion. The special channel for these nutrients is known as the PHLOEM.
  • Further variations occur on the outer surfaces of stems.
  • Herbaceous stems are green and fleshy, but woody stems are brown and hard.
  • The annual monocotyledon usually has fleshy, green herbaceous stems and the perennial dicotyledon, e.g. a fruit tree, has hard, woody stems.
  • As we are mentioning fruit trees – they are deciduous, which means that they lose their leaves in autumn.
  • If you know that leaves are the most important part of the plant (and therefore of fruit trees) when it comes to respiration, and that deciduous trees are without leaves during winter, you might ask what they do about respiration. We should actually ask how gas exchange takes place.
  • Examine the brown, woody twigs that you have collected. There is a good chance that you will notice fine white specks on these brown twigs. These are LENTICELS. Lenticels are pores (openings) that facilitate gas exchange during the wintry season.

Assignment 2

DIFFERENT PARTS ON THE TIP OF STEM

Terminal bud : end bud of a stem, where the growing tip is situated.

Apical meristem : growth tip tissue at the end tip.

Internodes: regions of the stem between nodes.

Nodes : region on stem where buds, leaves and lateral shoots will develop.

Leaf nodes : marks on stems where previous leaves have fallen off.

Axil: region in a node where bud growth will take place.

Scale leaves : Protective leaves for the terminal bud and other growth tips.

1. different types of twig – a green, herbaceous type and a brown, woody type.

Main functions of stems:

to carry leaves in such a way that photosynthesis can take place;

to carry flowers in such a way that they can be pollinated;

to carry fruit in such a way that they can be dispersed;

to conduct water and nutrients between leaves and the roots.

Assignment 3:

  • The following column graph shows the longitudinal growth of six different sunflower seedlings (A, B, C, D, E, F) during the first week after germination.

1. histogram have spaces inbetween

2. M – highest growth

3. approximately 6 mm

4. L and N

5. 8-7=1mm

6. 12-6= 6mm

7. cells divide – cells lengthen and differentiate = growth

Questions & Answers

what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
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.
Virgil
is Bucky paper clear?
CYNTHIA
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
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Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
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