Growth and development in plants
different from animals. In animals, the growth and development occur in
all parts of the body, whereas in plants, growth and development in
certain areas only.
Growth and development in seed plants begins with a meeting between the male and female sex cells, become seeds, germinate, grow into small plants are perfect, and continues to grow and develop into mature plants. Mature plants will be flowering and fruiting.
Growth and development in seed plants begins with a meeting between the male and female sex cells, become seeds, germinate, grow into small plants are perfect, and continues to grow and develop into mature plants. Mature plants will be flowering and fruiting.
1. Growth Terminal
At the end of the roots and stems of seed plants that are actively growing, there are three areas of growth and development. The area is the division, elongation regions, and regional differentiation.
Cleavage areas, is the most tip. In this area, especially the formation of new cells through cell division. Cells in the nucleus of the cell division has a relatively large, thin-walled cells, and actively dividing. The area is also called the cleavage certain areas.
Elongation area, is the result of cell division in the differentiation cell division. The cells of the cleavage results will increase in size to form the elongation region. Cells in this region larger than the cells on the differentiation
Differentiation area, located behind the elongation. The cells in this area have undergone differentiation. This means that the cells have changed shape according to its function. Most cells undergo differentiation into epidermis, cortex, pith, xylem and phloem. Most of the cells had differentiated into a longer parenchymal tissue (basic network), network support such as kolenkim and sklerenkim. With the onset of cell differentiation is formed various plant tissues.
Growth in plants can be divided into primary growth and secondary growth
Primary growth, a growth which is caused by the activities of the primary growing point. Primary growing point located on the tip of the root or stem ends. Primary growing point has been active since the plants are still in embryo. The tip of the root and the stem end is an area where the apical differentiation growth. The growth of the primary causes stem and root length increases.
Based on the growing point of the plant, there are two theories on the growing point of the plant, namely:
1). Histogen Theory
This theory was put forward by Han stein. This theory states that the growth of plant organs formed by three layers of tissue forming, namely:
a). Dermatogen, which forms the outer layer of the epidermis.
b. Periblem, which forms the inner layer of the cortex.
c). Pleuron, which form the inner lining of the stele.
2). Theory tunica corpus
This theory was proposed by Schmidt stating that the growth of plant organs formed two layers forming networks, namely:
a). The tunica, which forms the outer layer of the epidermis and cortex.
b). Corpus, which form the inner lining of the stele.
Secondary growth, a growth which is caused by the activities of the cambium tissue. Meristematic cambium tissue is, the cells are always actively dividing. Cambium is only found in dicotyledonous plants and gymnosperms.
Secondary growth of stem diameter causes a large increase (Figure 1.4). In dicotyledonous woody plants, secondary growth is due to the activity of the meristem cells between the xylem and phloem. Formed xylem inwards and phloem outwards formed. Growth in the inside faster than the growth in the outside, resulting in epidermal and cortical tissue on the outer skin will be damaged (broken)
a). The tunica, which forms the outer layer of the epidermis and cortex.
b). Corpus, which form the inner lining of the stele.
Secondary growth, a growth which is caused by the activities of the cambium tissue. Meristematic cambium tissue is, the cells are always actively dividing. Cambium is only found in dicotyledonous plants and gymnosperms.
Secondary growth of stem diameter causes a large increase (Figure 1.4). In dicotyledonous woody plants, secondary growth is due to the activity of the meristem cells between the xylem and phloem. Formed xylem inwards and phloem outwards formed. Growth in the inside faster than the growth in the outside, resulting in epidermal and cortical tissue on the outer skin will be damaged (broken)
