Upload
nat
View
40
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Exercise 5. Plant Cell Types and Tissues. Tissue – group of cells that perform a specific function. 2 kinds of tissues (state of development): 1. Meristematic tissues/ meristerms - responsible for the production of new cells 2. Permanent tissues - perform specific functions. - PowerPoint PPT Presentation
Citation preview
Exercise 5Plant Cell Types and Tissues
Tissue – group of cells that perform a specific function
2 kinds of tissues (state of development):1. Meristematic tissues/ meristerms
- responsible for the production of new cells2. Permanent tissues
- perform specific functions
Kinds of meristems based on their position or location:1. Apical meristem – responsible for the increase in
length of stems or roots- at tips or apices of stems and roots- with very small or no vacuole at all- very thin-walled and isodiametric
Includes:a. Protodermb. Ground meristemc. Procambium
2. Lateral meristem3. Intercalary meristem – at bases of young
leaves and internodes
- for further lengthening of stems and leaves far away from the tips of stems
Kinds of Permanent Tissues:
1. Simple permanent tissues- consist only of one kind of cella. Epidermis – outermost tissue of leaves, stems and roots of all monocots and herbaceous dicot- has a layer of cuticle made up of waxy substance called cutin to prevent excessive evaporation of water- uniseriate when young, multiseriate when old
b. Parenchyma – uniformly thin-walled
- Function: for food storage
- Examples: cassava pith, tomato fruit pulp, Spanish flag petiole
c. Collenchyma – with unevenly thickened walls
- function: for strengthening & support and sometimes for storage
- examples: lotus petiole, celery petiole, coleus petiole
d. Sclerenchyma – with heavily thickened walls because of the presence of lignin
- function: for strengthening & support
- Examples: mungbean seed coat, peanut pericarp, pineapple leaf
e. Cork – outermost tissue of leaves and roots of woody dicot plants
- function: for protection
2. Complex Permanent Tissue
Sieve tubes Companion cellsArranged end to end Shorter, narrower, vertically
elongatedDenucleated when matured Nucleated even when matured
1. Phloem – conducts dissolved organic food materials
2. Xylem – conducts water
a. Tracheids – without perforations
b. Vessel elements – with perforations
Accessory cells – participate in osmotic changes involved in movements of the guard cells
Closed Stomata Open Stomata
Exercise 6 Absorption
1. Tap Root2. Fibrous Root
Specialized RootsSpecimen Modification & functionCamote Enlarged fleshy root for food
storage
Radish Enlarged fleshy root for food storage
Carrot Enlarged fleshy root for food storage
Rhizophora Brace roots for supportPandan Prop roots for support
*brace roots – aerial roots arising from the main stem which penetrates the ground
*prop roots – aerial roots arising from the branches which penetrate the ground
Exercise 7 Transport & Nutrition Origin of the stem: from the epicotyl and
partly from the hypocotyl of the embryo
Shoot – a stem with leaves
Shoot system – all the stems and leaves of a plant
General Features of the Stem:
1. Node – where leaves, branches & buds arise2. Internode – portion between 2 consecutive nodes3. Leaf sheath
- in some monocotyledons (Poaceae/ Gramineae/ grass family), a distinct petiole is lacking. Instead, the blade is supported by a flattened structure called the leaf sheath, which clasps the stem.
4. Petiole – or leaf stalk- holds the blade upright
5. Leaf scar – mark left on the stem by a fallen leaf
6. Bundle scar – cut end of vascular bundles seen within each leaf scar
7. Leaf axil – angle formed by the leaf stalk and the stem
8. Axillary bud – located at the leaf axil9. Terminal bud – located at the tip of the stem10. Bud scale – protective scale that covers
the bud11. Lenticels – tiny raised pores on dicot stems
for gaseous exchange
Modified Stems:Plant Specimen Modification
Fern plant, Ginger Rhizome for food storage
Gabi Corm
Potato (Solanum tuberosum)
with “eyes” = budsTuber for reproduction
Bermuda Grass Runner/StolonBougainvillea Thorn for protectionDilang-baka Cladophyll
Vine TendrilCycas Spines for protection
Exer 7 Leaf
Important Terms:1. Phyllotaxy – system of leaf arrangement on the
stem:a. Alternate or spiral – only 1 leaf develops at each
nodeb. Opposite – 2 leaves develop opposite each other
at a nodec. Whorled – 3 or more leaves develop equidistantly
around the node
2. Blade or lamina – thin, flattened, green structure
3. Leaf stalk or petiole – holds the blade upright; to provide maximum exposure
*sessile – leaf without petiole4. Stipules – a pair of outgrowths at base of
some dicotyledonous leaves*exstipulate – without stipules
Petiolule – stalk of each leaflet Stipels – outgrowths in pairs found at the
base of petiolule Rachis – continuation of the petiole
5. Nature of leaf blade
a. Simple leaf – blade consists of only 1 pieceb. Compound leaf – blade is divided into
separate segments called leaflets or pinna
6. Venation – arrangement of vein of a leaf blade
a. Netted or reticulate venation – veins branch profusely and form a network over the blade; commonly found in dicot leaves
b. Parallel venation – veins do not form a network; commonly found in monocot leaves