PLANTS

Report by Marvin B. Gonzaga

Angiosperms and Gymnosperms

Angiosperms – from the Ancient Greek words angeíon (bottle, vessel) and spermos, (seed)

- plants that produce seeds within an enclosure; they are fruiting plants, although more commonly referred to as flowering plants

Angiosperms And Gymnosperms

Gymnosperms – comes from the Greek word gymnospermo, meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilized state).

- their seeds that are not protected by fruit but are hidden in a woody cone.

Plant Tissues

1. Meristematic tissues or meristem – consists of immature and undifferentiated cells and are regions of active cell divisions.- usually located at the tips of the stems and roots; some are located at the vascular cambium-the cells are usually small, thin walled, approximately isodiametric. Intercellular spaces are generally absent.

Meristematic Tissue

Types of Meristematic Tissues According to Location

a. Terminal or Apical meristems – located at the growing points- occurs at the tips of the stems and roots, and often the leaves of vascular plants.-responsible for the increase in the height of the plant, known as primary growth.a. Intercalary meristems – portion of meristematic tissue found at the internodal region of the stem.-associated with the increase of height of the plant.-ultimately disappear and transformed into permanent tissues.

Types of Meristematic Tissues According to Location

a. Lateral meristems – meristematic tissue found on the side of stems and roots.-responsible for the increase in diameter of the plant body, which is known as secondary growth in plants.-examples: vascular cambium and cork cambium

Plant Tissues

2. Permanent Tissues – consist of mature and differentiated cells performing a specialized function- form the bulk of the plant body.

Types of Permanent Tissues

a. Surface Tissues – found in the outermost layer or covering of the plant body.

- includes the epidermis, cork, and stomata or guard cells.

-primary function is for the protection of the plant.

-stomata or guard cells are responsible for the exchange of gases between the environment and the plant.

Types of Permanent Tissues

a. Fundamental Tissues – basic tissues of plants, which are found in any organ of the plant.

1. Parenchyma cells – cells with primary cell wall with large centrally located vacuole and thin peripheral cytoplasm. Parenchyma cells that contain chloroplast are called chlorenchyma, which serves as the site of food manufacturing and product storage.

1. Collenchyma cells – cells with irregular thickened primary wall that is associated with strengthening and supporting the plants.

2. Sclerenchyma cells – cells with heavily thickened cell wall due to deposition of the substance lignin - commonly forms the skin of fruits and responsible for strengthening and support of the plant.

a. Vascular Tissues – conducting tissues of plants. -complex tissues that consist of several types of permanent tissues.-responsible for the transport of substances inside the plant body.

1. Phloem – responsible for the downward conduction of food. Composed of sieve tube, companion cell, phloem parenchyma and phloem sclerenchyma cells.

2. Xylem – responsible for the upward conduction of water and minerals. Composed of tracheids, vessels, xylem parenchyma and xylem sclerenchyma cells.

Phloem and Xylem

Organs of the Plants

1. Roots – usually subterranean organ used for the anchorage to the soil; responsible for the conduction and absorption of water and minerals from the soil.

Radicle – the first root of the plant, elongates during germination of the seed and forms the primary root.Secondary roots – roots that branch from the primary root.

2. Stems – aerial and upright part of the plant that usually bears the leaves, flowers, and fruits; used for the conduction of food materials inside the plant body; also responsible for food storage and support of the plant.

3. Leaves – flat broad structure responsible for the production of food, transpiration, and respiration; green color is due to chloroplastids that bear chlorophyll capable of absorbing light energy and transform it into chemical energy through photosynthesis.

4. Flowers – reproductive organ of the seed-bearing plants; responsible for the formation of fruits and seed development to carry out sexual reproduction.

5. Fruits – matured ovaries, which hold and protect the seeds.

6. Seeds – developed ovules, which hold and protect the embryo.

Plant Organs

The End!

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