Plant Tissue Flashcards
Two types of cell tissues in plants
-Meristematic -Non-meristematic
Features of Meristematic tissues
- Actively divide
- Six-sided, box-like, similar in shape and size
- With tiny or no vacuole (bcuz they don’t need it as they keep on dividing actively/ the organelle is not needed/ no need to store food or water)
Groups of Meristematic tissues
(a) Apical meristems (root/shoot)
(b) Lateral meristems
(c) Intercalary meristems
—————— Found in tip of roots and shoots, responsible for increase in length as they form new cells (primary growth)
Apical meristem
Primary meristems = ———- + ———–
apical meristems + meristems in buds and embryo leaves.
only primary growth meaning no lignin in the cell wall
Apical meristem is divided to (1)——— (2)——- (3) ———
(1) protoderm (2) ground meristems (3) procambium
————– Increase the girth (width) of roots and stems and give the secondary growth
Lateral meristems
Lateral meristems made of
(1) Vascular cambium
(2) Cork cambium
——————- it present a long the length of
roots and stems of perennial plants and many
herbaceous annuals. and gives xylem and phloem
Vascular cambium
—————— thin cylinder that runs along the root
and stem of woody plants outside the vascular
bundles and produces the bark.
Cork cambium
give cork cells
—————- it present in nodes (leaf
attachment areas), develop at intervals along the stem
and so add to stem length
Intercalary meristems
Grasses and most annuals have neither a ——– cambium nor a ——– cambium but still have —– and ——— meristems
vascular cambium nor a cork cambium
apical and intercalary meristems
Non-meristematic tissues can be:
(1) simple (one kind of cells)
(2) Complex (2 or more cells)
simple Non-meristematic tissues are divided into three types
Parenchyma
Collenchyma
Sclerenchyma
Features of Parenchyma
-The most abundant in plants, have thin and flexible primary wall
-spherical but could flattened at the point of contact with adjacent cells forming relatively large intercellular spaces.
-have large central vacuole which may contain starch, oil, tannins and crystals.
-The least specialized, carry out most of plant metabolism, can divide to repair damage and may live for long time up to 100 years as in cactus.
-synthesize & store various organic products (fleshy fruit, stem, root, petiole)
Types of parenchyma:
-Aerenchyma: in aquatic plant has extensive
intercellular spaces
-Chlorenchyma: leaf parenchyma
(photosynthesis)
-Transfer parenchyma; produce cells with
extensive extensions to transfer dissolved
substances (nectaries and carnivore plants).
—————– in aquatic plant has extensive
intercellular spaces
Aerenchyma
————— leaf parenchyma
(photosynthesis)
chlorenchyma
————- produce cells with
extensive extensions to transfer dissolved
substances (nectaries and carnivore plants).
Transfer parenchyma
Features of Collenchyma
- Have living cytoplasm and can live for long time
- Thicker uneven walls, strong but still pliable.
- No secondary walls (not lignified).
- Often beneath the epidermis
- Give flexible support for both growing organs and
mature organs (leaves and floral parts). - Like parenchyma, the are capable to resume
meristematic activity as in the formation of cork
cambium and response to wounding
Features of Sclerenchyma
- Thick, tough secondary walls (lignin)
- They are non-living at maturity
- Support other plant tissues and organs
- Two Kinds:
(1) Sclereids (stone cells), as long as they are wide
and irregular in shapes (found in seed coat, nut shell
and gritty texture of fruits (pear and apple)
(2) Fibers: much longer than they are wide, slender
and tapered cells, have a tiny cavity (lumen) in the
center of the cells. - Commercial use (since 10,000 years ago) from more
than 40 different families to produce textile goods,
ropes, string, canvas
Complex tissues include:
- xylem
- phloem
- epidermis
-periderm
Some complex tissues are produced by ——————- but others by ———————-
apical meristems, vascular cambium (so called vascular tissues).
———– conduct water and dissolved substances throughout all organs.
xylem
Characteristics of Xylem:
- conduct water and dissolved substances throughout all organs.
- Consists of parenchyma cells, fibers, vessels, tracheids, and ray cells.
- In certain non-flowering plants the xylem is entirely tracheids.
The Xylem consist of: (5)
parenchyma cells, fibers, vessels, tracheids and ray cells.
————- long tube made of vessel elements (each one represents a cell) that are open at each end. The cells are joined end to end forming a tube.
Vessels
———— long tubes tapered at each end. The ends overlapping with other ——— . Most have spiral thickening
Tracheids
Booth vessels and tracheids are —— at maturity and have ———.
dead
secondary walls.
—- allow water to pass as they are without secondary
walls
Pits
—— are always in pairs and could be 1-2 up to several
thousands per cell
Pits
—- could be swelling out like doughnut (bordered
— ) or not (simple —).
Pits
——– function in lateral conduction of water and
food storage. They are long-lived parenchyma cells
that are produced in horizontal rows by special ray
initials of the vascular cambium
Rays
——- Conducts dissolved food materials throughout plant organs.
Phloem
Characteristics of Phloem:
-Conducts dissolved food materials throughout plant organs.
- Derived from parent cells of cambium
- its composed of sieve tubes (made up of cells called sieve tube members), companion cells, parenchyma, ray cells and fibers.
- Sieve tube members relatively larger and wider than companion cells and laid end to end.
- Unlike xylem vessels, sieve tube members have no large openings, instead, the end walls have small pores called sieve plate
- Despite its cytoplasm is very active in food conduction, sieve tube members have no nuclei at maturity. Which means that the companion cell may contribute.
- Callose (1-3 glucan) aids in plugging injured sieve tubes (i.e. by aphids).
- In ferns and conifers, sieve cells, which have overlapping end walls and adjacent albuminous cells take the place of sieve tube members and companion cells
Phloem is composed of (5)
sieve tubes (made up of cells called sieve tube
members), companion cells, parenchyma, ray cells and fibers.
——— The outermost layer of cells of all young plant organs.
Epidermis
The epidermis may include:
(1) guard cells that border pores called stomata
(guard cells have chloroplasts)
(2) root hairs, which are tubular extensions of single
cells; other hairs that consist of one to several cells.
(3) glands that secrete protective substances.
(4) Or modified as hairs that either reduce water loss
(desert plants) or repel insects and animals.
In ———– the epidermis is sloughed out
and replaced by ——– after the cork
cambium starts producing new tissues (girth)
woody plants, periderm
Periderm consists of: (2)
cork cells and loosely arranged
groups of cells comprising lenticels involved in
gas exchange.
Cork cells are dead at maturity, while the
cytoplasm is still functioning, it secretes a fatty
substance called ——- into the walls
Suberin
Cork oak used commercially to produce ——— and ——-
bottle corks and gaskets
—————— May function individually or as part of a secretory tissues.
Secretory cells and tissues
Secretory tissues occur in various places in plants; they
secrete substances such as:
-nectar (flowers)
-oils (citrus, mint, etc.)
-mucilage (glandular hairs of insect–trapping plants)
-latex and resins (Coniferous plants)
———– a thick fluid that is white, yellow, orange or red
in color and consists of gums, proteins, sugars, oils,
salts, alkaloids, enzymes and others, some of them are
commercially produced e.g. rubber
Latex
Epidermis is usually one cell thick, but epidermis with several cells thick is found in some plant roots (e.g. orchids) which produce ———–, ——— of some tropical figs and ———- of pepper family.
This aids in ——————- .
velamen roots, leaves of some tropical figs and members of pepper family.
This aids in preventing desiccation.
Epidermis Secretes —— which form the cuticle, with wax (secreted also by epidermis). Resistant to —— and prevent ————.
cutin
Resistant to pathogens and prevent desiccation.
Cutin consists of ————– and their derivatives
which are interlinked via ———, forming a polyester polymer of indeterminate size
hydroxy-fatty acids
ester bonds
