ruangbelajar - Biologi XII SMA - Pertumbuhan dan Perkembangan Tumbuhan

Summary

This educational video explains the growth and development of plants, starting from seeds. It covers key concepts like germination, where seeds break dormancy, absorb water, and activate hormones like gibberellin to begin sprouting. The video explains the two types of germination—epigeal and hypogeal—and describes the stages of growth, including primary and secondary growth. Primary growth occurs at the tips of roots and stems, while secondary growth causes the plant to grow thicker. The video concludes with a discussion on plant maturation, where flowers and fruit appear, marking the completion of the plant's life cycle.

Takeaways

• 😀 Growth in plants refers to the increase in the number, size, or volume of cells, leading to a larger plant over time.
• 😀 Development in plants refers to the maturation process, such as when plants produce fruits, indicating that their reproductive organs are mature.
• 😀 Germination (perkecambahan) begins when a dormant seed absorbs water, which activates processes that allow the seed to sprout and grow.
• 😀 The process of imbibition occurs when water enters the seed, kickstarting the germination process.
• 😀 Gibberellin, a hormone in plants, is activated during germination and helps trigger enzymes that break down stored food in the seed for energy.
• 😀 Two types of germination are distinguished: hypogeal (where cotyledons stay underground) and epigeal (where cotyledons rise above the soil).
• 😀 Hypogeal germination is seen in plants like corn, rice, and peas, where the cotyledons stay beneath the soil after sprouting.
• 😀 Epigeal germination is seen in plants like beans and soybeans, where the cotyledons are lifted above the soil surface during sprouting.
• 😀 Primary growth occurs at the tips of roots and shoots, causing the plant to grow in length due to apical meristem activity.
• 😀 Secondary growth leads to the thickening of the plant, especially in stems and roots, and occurs due to the activity of the cambium layer.

Q & A

What is the process of seed germination?

Seed germination is the process where a dormant seed becomes active, starting with imbibition (the absorption of water). This process activates hormones like gibberellin, which then activate enzymes to break down stored food in the seed to provide the energy necessary for the seedling to grow.

What is the role of gibberellin in seed germination?

Gibberellin is a plant hormone that plays a key role in seed germination. It activates enzymes that break down stored food in the seed, providing energy for the seedling to grow and begin the process of sprouting.

What is dormancy in seeds, and how does it relate to germination?

Dormancy is a state in which a seed is inactive, typically due to lack of water. Once water is absorbed (imbibition), the seed exits dormancy, and the germination process can begin.

What are the two types of seed germination, and how do they differ?

The two types of seed germination are hypogeal and epigeal. In hypogeal germination, the cotyledons remain below the soil surface (e.g., corn, rice), while in epigeal germination, the cotyledons are raised above the soil (e.g., beans, soybeans).

What happens during the primary growth of a plant?

Primary growth in plants occurs at the tips of roots and shoots, resulting in an increase in the length or height of the plant. This growth is driven by the activity of the apical meristem, which continuously divides cells at the tips of roots and stems.

How does secondary growth in plants differ from primary growth?

Secondary growth results in an increase in the girth or thickness of the plant, particularly in stems and roots. This growth occurs through the activity of the cambium, which produces secondary xylem and phloem, contributing to the widening of the plant.

What is the role of the apical meristem in primary growth?

The apical meristem is a region of active cell division at the tips of roots and stems. It is responsible for the primary growth of the plant, contributing to the elongation of the plant by producing new cells at these growing tips.

How does the cambium contribute to secondary growth in plants?

The cambium is a layer of cells that lies between the xylem and phloem. During secondary growth, the cambium divides to produce secondary xylem and phloem, leading to an increase in the diameter of stems and roots.

What signifies the maturity or development of a plant?

A plant reaches maturity when its reproductive organs, such as the flowers, are fully developed and capable of producing seeds or fruit. The production of flowers and fruit indicates the plant has reached its developmental stage.

What is the difference between growth and development in plants?

Growth in plants refers to the increase in size, number, and volume of cells, while development refers to the plant reaching maturity, often signified by the ability to produce flowers, fruits, and seeds. Growth is more about physical size, whereas development involves functional and reproductive maturation.