Problem 42 - Objective Biology for NEET

Question

Phloem parenchyma stores (a) Resins (b) Latex (c) Mucilage (d) All of these

Step-by-Step Solution

Answer

The correct answer is (d) All of these.

Step 1: Understanding phloem parenchyma

Phloem parenchyma, also known as transfer cells and border parenchyma, are responsible for loading and unloading sugars into the sieve elements. However, they also serve as a storage space for various substances.

Step 2: Analyzing the substances

Resins, latex, and mucilage - all of these are substances that are stored by the parenchyma. Resins are complex chemical substances produced by plants, latex is a milky fluid found in many plants that contains alkaloids, glycosides, and proteins while mucilage is a viscous secretion or bodily fluid.

Step 3: Conclusion

Drawing from what we understand about the function and capacity of phloem parenchyma, it is evident that it is capable of storing resins, latex and mucilage.

Key Concepts

Plant Storage

Plants, like any living organisms, need mechanisms to store essential compounds for survival. Within a plant, phloem parenchyma plays a crucial role in storing various substances including resins, latex, and mucilage. These cells act as reserve tanks, ensuring the plant has the necessary resources to thrive under varying environmental conditions.
Imagine they are like storage units that keep these substances until the plant needs them. This storage capability aids in sustaining the plant during tough times, such as drought or damage, by supplying important compounds from these reserves. The efficient storage of substances is vital for a plant’s growth and defense.

Transfer Cells

In the fascinating network of plant tissues, transfer cells are specialized forms of phloem parenchyma. These cells are rich in wall ingrowths, which increase their surface area for transport processes.

• They help in the active transport of nutrients like sugars and amino acids.
• Transfer cells play a significant role in moving substances into sieve elements, ensuring efficient distribution throughout the plant.

This increased surface area allows for more effective movement, actively loading and unloading nutrients into the phloem. These functions make transfer cells essential for the plant's nutrient management.

Sieve Elements

Sieve elements are the conduits of the phloem, facilitating the flow of nutrients. These elongated cells help in the transport of products from photosynthesis, especially sugars, all over the plant.

• The main purpose of sieve elements is to conduct these nutrients efficiently.
• Unlike other plant cells, sieve elements lose their nuclei at maturity to allow easy passage of substances.

Sieve elements work closely with companion cells for support and regulation, underscoring their importance in keeping plants nourished and healthy.

Resins

Resins are sticky substances produced by plants, often as a response to injury. They serve multiple purposes:

• Protection against pathogens and pests
• Healing and sealing of plant wounds
• Storage medium for eventual secondary metabolite release

Resins can harden upon exposure to air, providing a barrier to further infection. This protective function helps plants maintain their health by isolating and addressing damaged areas effectively.

Latex

Latex is a milky plant fluid that contains a mix of chemicals including alkaloids, glycosides, and proteins. This substance plays a crucial role in plant defense, warding off herbivores and pathogens.

• It acts as a chemical deterrent, being toxic or distasteful to many animals.
• Latex can help plants heal by sealing wounds and preventing further damage.

Found in thousands of plant species, latex serves as an essential line of defense, showcasing nature's efficiency at protecting itself.

Mucilage

Mucilage is a viscous, jelly-like substance produced by many plants. It serves several important functions:

• Retention of water and prevention of dehydration by holding moisture in plant tissues.
• Facilitating seed germination and aiding in seed dispersal.
• Acting as a means of intracellular lubrication and adherence.

This gooey substance not only helps plants retain moisture but also assists in many critical physiological processes, ensuring constant adaptability to their environment.