When does the apical–basal axis first become apparent? a. when the epidermal, ground, and vascular tissues form b. when the cotyledons, hypocotyl, and root form c. when the first cell division produces the apical cell and basal cell d. during the globular stage, when the suspensor is complete

Verified step by step guidance

1. Understand the concept of the apical-basal axis, which refers to the orientation from the top (apical) to the bottom (basal) of a plant.
2. Recognize that the apical-basal axis is crucial for determining the overall polarity and structure of the plant, influencing where specific tissues and organs will develop.
3. Consider the options given: The apical-basal axis needs to be evident early in development to guide subsequent growth and tissue differentiation.
4. Recall that the first cell division in a plant embryo typically results in the formation of an apical cell and a basal cell, which are foundational for establishing the plant's primary growth axis.
5. Conclude that the apical-basal axis first becomes apparent when the first cell division produces the apical cell and basal cell, making option (c) the correct answer.

Key Concepts

Apical-Basal Axis

The apical-basal axis refers to the orientation of plant growth, where one end (the apical end) develops into the shoot and the other end (the basal end) develops into the root. This axis is crucial for establishing the overall body plan of the plant and is first established during early embryonic development.

Plant Embryogenesis

Plant embryogenesis is the process by which a fertilized ovule develops into a mature embryo. This process includes several stages, such as the zygote stage, the globular stage, and the heart stage, during which the apical-basal axis becomes defined, leading to the differentiation of various plant tissues.

Cell Division in Embryos

The first cell division in a plant embryo is critical as it produces two distinct cells: the apical cell, which will give rise to the embryo proper, and the basal cell, which will form the suspensor. This initial division is a key event that establishes the apical-basal axis and sets the stage for further development.