tugas SPT (bu Sulifah)

a.                  Nodule

Nodule is a small bumps in the root (most of whom are members of the Fabaceae) formed by nitrogen-fixing bacteria infection in mutualistic symbiosis with plants. This cooperation allows the availability of nitrogen for plant symbionts, especially on the state of lack of availability of soluble nitrogen in the soil. Nodule usually found in groups.

Cross section of a root nodule of soybean 'Essex'. The bacteria infect the roots and Bradyrhizobium japonicum symbiosis for nitrogen-free. Visible parts of the cell with asingle bacteroids in simbiosomnya. There are also reticulum endoplasmik, diktiosom, and cell walls.

b.                  Adventitious root

adventitious rooting is the roots growing from every part of the plant and not the primary root. Like roots coming out from the stem tubers, roots out of the trunk (graft).

Figure 2. Wild roots (adventitious) on corn

In addition to sticking from the base of shoots, roots of plants can also exit from the ground. Roots can therefore arise from stem or leaf. We can call the root that grows in parts of this undue called wild or adventitious roots . Wild roots serve as a buffer  and ancillary plants towering stems. Example is the corn plant roots that grow from the trunk.

c.                   Micoriza

Mycorrhizal are fungi  that symbiosis with higher plants (vascular plants, Tracheophyta), especially on the root system. There is also a symbiotic fungi with other fungi, called mycorrhizae but usually is to those that infect the roots.

Mycorrhizal plant roots require to complete its life cycle. Conversely, there are even some plants with mycorrhizal-dependent growth. Some types of plants are not growing or stunted without the presence of mycorrhizae in the roots. For example, pine seedlings usually fail to grow after the removal of tissue if it does not formed mycorrhizae around the roots. Only a few groups of plants that do not become symbionts, such as the Brassicaceae, Commelinaceae, Juncaceae, Proteaceae, Capparaceae, Cyperaceae, Polygonaceae, Resedaceae, Urticaceae, and Caryophyllales.

Endomikoriza: infect the inside of the roots of plants within & between cells of the root apex
Ektomikoriza: infects the outer surface of the roots of plants & between cells of the root apex

d.                  Pneumatophore

Pneumatophore which the root branches that grow straight up so that it appears from the surface of the soil or water where the growth of plants. The roots have many holes or cracks (pneumathoda) to the entrance of air needed in breathing because these plants typically live in a place in the soil is deprived of oxygen, eg in mangroves (mangroove) in plants bogem (Sonneratia sp.) And wood api (Avicennia sp.).

e.                   Cross section dicotyl and monocotyl stem

f.                   Woody stem

Woody Stems are the stems of plants who have been growing for two years or more.  After two years, a plant's stem thickens to accommodate growth and increased circulation in a plant.  Probably the most obvious example of a woody stem is a tree trunk.  Trees are a special woody stem and consequently have unique parts that other woody stems do not.  For example, a tree contains heartwood, sapwood, and cork.  Even so, it is not uncommon for woody stems to start out as a bush or plant and eventually grow into a tree.

g.                  Type of stele

stele is the central part of the root or stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue (pith) and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, which is the innermost cell layer of the cortex.

Protostele

The earliest vascular plants had stems with a central core of vascular tissue. This consisted of a cylindrical strand of xylem , surrounded by a region of phloem. Around the vascular tissue there might have been an endodermis that regulated the flow of water into and out of the vascular system. Such an arrangement is termed a protostele.

There are three basic types of protosteles:

• haplostele - consisting of a cylindrical core of xylem surrounded by a ring of phloem. An endodermis generally surrounds the stele. A centrarch (protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as Rhynia.
• actinostele - a variation of the protostele in which the core is lobed or fluted. This stele is found in many species of club moss (Lycopodium and related genera). Actinosteles are typically exarch (protoxylem external to the metaxylem) and consist of several to many patches of protoxylem at the tips of the lobes of the metaxylem. Exarch protosteles are a defining characteristic of the lycophyte lineage.
• plectostele - a protostele in which plate-like regions of xylem appear in transverse section surrounded by phloem tissue. In fact, these discrete plates are interconnected in longitudinal section. Some modern club mosses have plectosteles in their stems. The plectostele may be derived from the actinostele.

Siphonostele

Siphonosteles have a region of ground tissue called the pith internal to xylem. The vascular strand comprises a cylinder surrounding the pith. Siphonosteles often have interruptions in the vascular strand where leaves (typically megaphylls) originate (called leaf gaps).

Siphonosteles can be ectophloic (phloem present only external to the xylem) or they can be amphiphloic (with phloem both external and internal to the xylem. Among living plants, many ferns and some Asterid flowering plants have an amphiphloic stele.

An amphiphloic siphonostele can be called a:

• solenostele - if the cylinder of vascular tissue contains no more than one leaf gap in any transverse section (i.e. has non-overlapping leaf gaps). This type of stele is primarily found in fern stems today.
• dictyostele - if multiple gaps in the vascular cylinder exist in any one transverse section. The numerous leaf gaps and leaf traces give a dictyostele the appearance of many isolated islands of xylem surrounded by phloem. Each of the apparently isolated units of a dictyostele can be called a meristele. Among living plants, this type of stele is found only in the stems of ferns.

Most seed plant stems possess a vascular arrangement which has been interpreted as a derived siphonostele, and is called a

• eustele - in this arrangement, the primary vascular tissue consists of vascular bundles, usually in one or two rings around the pith. In addition to being found in stems, the eustele appears in the roots of monocot flowering plants. The vascular bundles in a eustele can be collateral (with the phloem on only one side of the xylem) or bicollateral (with phloem on both sides of the xylem, as in some Solanaceae).

There is also a variant on the eustele found in monocots like maize and rye. The variation has numerous scattered bundles in the stem and is called an atactostele. However, it is really just a variant of the eustele