ACTIVITY 5 PLANT TISSUES

root; shoot

Plants are eukaryotic, photoautotrophic organisms. Common to all plants are cells with rigid cellulosic walls and chloroplasts containing chlorophylls a and b together with accessory pigments.

All plants are multicellular, the cells organized into tissues and organs. Their bodies consist of two organ systems: the ________ system and ________ system.

meristematic; permanent; Meristematic

apical meristems

All plant tissues can be categorized into ___________ and ___________ tissues. ___________ tissues are composed of immature cells undergoing active mitotic division. They are largely confined to the root and shoot apices, hence, they are referred to _______________.

apical meristems

They are responsible for the primary growth, the increase in length of the plant body.

lateral meristems

Another group of meristematic tissues, the _____________, run along the length of the shoot to the root. They are responsible for the secondary growth or the increase in girth of woody plants.

permanent

dermal tissues; ground tissues; vascular tissues

Meristematic tissues ultimately differentiate into ___________ tissues.

These, on the other hand, are composed of matured or differentiated cells. These are further classified into three tissue systems: _______________, ______________, and __________________.

epidermis; periderm

Dermal tissues (i.e., ___________ and _____________) provide the surface or protective tissues of the plant body.

parenchyma; collenchyma; sclerenchyma

Ground tissues perform various functions, namely photosynthesis and storage (___________) and mechanical support (_____________ and _____________).

xylem; phloem

Vascular tissues (i.e., ____________ and ____________) function in conduction and transport of substances throughout the plant body.

root cap

A. Meristematic Tissue

Obtain a slide of the longitudinal section of the root tip of Zea mays and focus it under the scanner. Locate the apex. Notice the mass of cells forming a dome-shaped protective structure. This is the __________.

protoderm; ground meristem; procambium

The protoderm gives rise to the epidermis, the ground meristem produces cells of the fundamental tissue, while the procambium gives rise to the primary xylem and phloem.

A. Meristematic Tissue

Above the root cap is the region of active cell division. This is the root apical meristem which gives rise to the three primary meristems: the ___________, the _______________, and the ______________.

elongation; maturation

A. Meristematic Tissue

Above the region of cell differentiation is the region of __________. Focus on this region and describe the cells.

The uppermost region is the region of ___________ where the cells have differentiated into the three tissue systems, i.e., dermal, fundamental and vascular.

mesophyll layer; chlorenchyma

Fundamental Tissues

Parenchyma

Note that the top and bottom surfaces of the leaf are each formed by a single layer of epidermal cells. The middle portion of the leaf is the _______________, which is filled with parenchyma tissue.

Parenchyma cells in the leaf contains numerous chloroplasts and are properly called _____________.

collenchyma

Fundamental Tissues

The ____________ cells form a layer of tissue just below the epidermis. Note the uneven thickening of the cell walls and the presence or absence of intercellular spaces.

Fundamental Tissues

sclerenchyma

Just below the epidermis is the cortex, made up of several cell layers. Note the mass of red stained cells forming a cap on top of each vascular bundle. In Eleusine stem, ____________ tissue forms an unbroken wavy band several layers beneath the epidermis.

parenchyma; sclerenchyma

Vascular tissues are complex tissues since they contain more than one type of cell. Aside from the conducting cells, the xylem and phloem, it also contains ____________ and _____________.

The vascular tissue

In the flowering plants these tissues are arranged in discrete bundles

metaxylem vessels

The vascular bundle

The two large vessels are called ______________. These are primary xylem vessels, which differentiate slowly and thus are large and thick-walled

protoxylem; lacuna

The vascular bundle

In between and below the two metaxylem cells may be one or two smaller __________ cells, which differentiate faster and thus have smaller diameters and thin walls. Often these are broken and missing and what is left of the protoxylem is an air space or _________.

sieve tube elements; companion cells

The vascular bundle

Now, locate the phloem tissues. This is situated above the xylem. Closely examine the two distinct types of cells in the phloem --- the large _____________ and the smaller ___________.

sieve plates

The vascular bundle

The sieve tube elements possess _____________ at the end of each cell. When mature, the cells lose their nucleus and only the cytoplasm remains. Lying next to the sieve tube elements are the companion cells.

bundle sheath

The vascular bundle

Take note of the layer of sclerenchyma fibers enclosing the entire vascular bundle. This is the ____________ and may be present only in some monocots like grasses and in a few dicot species.

collateral

Vascular tissue arrangement

The xylem and phloem tissue may be arranged in different ways depending on the species of plant examined. If both the xylem and phloem tissues are located along the same radius of the stem, the vascular arrangement is described as _____________. This is typical of the stems of gymnosperms and angiosperms.

radial

Vascular tissue arrangement

The root generally shows a ________ (alternate) arrangement.

bicollateral; concentric

Vascular tissue arrangement

In some dicots, the xylem tissue is sandwiched between two phloem tissues; hence the vascular tissue arrangement is described as ___________.

Some vascular bundles are __________, such that one tissue completely surrounds the other.

amphivasal; amphicribral

Vascular tissue arrangement

In the ___________ vascular bundle arrangement, the xylem surrounds the phloem while in the __________, the phloem surrounds the xylem.

epidermis; cortex; endodermis

Tissue organization in a dicot root

Obtain a slide with a cross section of the root of Ranunculus sp., a dicot, and focus it under LPO. The outer most layers of cells is the __________. Inner to the epidermis is the _________.

The innermost layer of the cortex consists of a distinct, single layer of cells known as the _________, which encloses the vascular tissue.

upper epidermis; lower epidermis

Tissue organization in a dicot leaf

Since the leaf has two surfaces, it has two layers of epidermis: the _____________ and the ______________. Note that the epidermal cells do not contain chloroplasts.

mesophyll; palisade mesophyll; spongy mesophyll

Tissue organization in a dicot leaf

In between the upper and the lower epidermis is the ___________, which in dicots forms two distinctive layers: the ____________________ and the ______________________. Interspersed in the mesophyll are the vascular bundles.

Parenchyma
Collenchyma
Sclerenchyma

List all the Fundamental Tissues.