Question

Vascular cambium and cork cambium are (a) |ateral meristems (b) intercalary meristems (c) primary meristems (d) apical meristems.

Short answer

Vascular cambium and cork cambium are lateral meristems.

Step-by-step solution

Understanding Meristem Definition

Meristems are regions in a plant where cells continuously divide and differentiate into various cell types. Understanding the different types of meristems is crucial for answering this question.

Identifying the Types of Meristems

Apical meristems are found at the tips of roots and shoots and are responsible for the primary growth in length. Intercalary meristems are found at internodes or base of leaves and contribute to the elongation of organ segments. Primary meristems are the direct extensions of apical meristems and contribute to primary growth. Lateral meristems, which include vascular cambium and cork cambium, are responsible for the secondary growth in girth or thickness.

Determining the Correct Option

Knowing that vascular cambium and cork cambium contribute to secondary growth, we can determine that they are lateral meristems. They are not involved in the primary elongation of the plant; therefore, they are not apical, intercalary, or primary meristems.

Key concepts

Vascular Cambium

Imagine the plant as if it were going through a 'growth spurt,' but instead of growing taller, it's growing wider. That's where the vascular cambium steps in. The vascular cambium is a type of lateral meristem, which means it's found around the sides of a plant stem or root.

This lateral meristem is like a cellular superhero, whose superpower is adding layers upon layers to plants, increasing their girth. These layers are made up of xylem and phloem - the vital plant tissues that respectively help in transporting water and nutrients, and food produced by photosynthesis.

As the vascular cambium keeps producing new cells, which pushes the older cells inward and outward, the stem or root gets thicker. It's fascinating to see how plants can adapt and strengthen their structure—much like how we build muscles.

Cork Cambium

Another hero in the plant world is the cork cambium, which creates the protective outer layer that you may know as bark. Interestingly, cork cambium also belongs to the family of lateral meristems, and it has an important role in safeguarding the plant.

Located under the bark, the cork cambium's job is to replace the outer epidermis with a stronger, thicker, and more durable tissue called periderm. This tissue includes the cork, cork cambium, and phelloderm. It's like the plant's own suit of armor, protecting against physical damage and preventing the loss of water. The cork cambium is essential for the survival of many trees, especially those that live for hundreds of years.

Secondary Growth

Secondary growth is like a second phase in a plant's life, which happens after the primary growth of shooting up in height. This is the phase where plants expand their waistline, so to speak. Through secondary growth, plants become thicker and sturdier, as opposed to just taller.

Secondary growth is made possible by the vascular cambium and cork cambium. While they are turning the plant into a more robust version of itself, secondary growth also supports plants in withstanding harsh weather and other environmental stresses. Plants that experience secondary growth tend to live longer because they become more resilient and can store more resources within their expanded tissues.

Meristem Differentiation

Meristem differentiation is a bit like choosing a career path for plant cells. Initially, cells in the meristem are all the same, with the potential to become anything. However, as they differentiate, they get specialized roles. Some will become part of the xylem, carrying water and minerals; others will turn into phloem to transport sugars. And some will join the ranks of either the cork cambium or vascular cambium, thus taking part in the plant's secondary growth. This differentiation is critical because it ensures that each cell contributes effectively to the plant’s life processes, structure, and the ability to adapt to their environment.