Which structural-functional issue in a plant root would hinder gas exchange but not significantly impact water absorption?

The correct answer is Disrupted stomatal apparatus on aerial organs.

Key Points

• Gas exchange in plants primarily occurs through stomata, which are predominantly located on aerial organs like leaves and stems, rather than roots.
• Roots are not major sites for gas exchange, and the absence of a functional stomatal apparatus on aerial organs would directly hinder the plant's ability to exchange gases (O₂ and CO₂).
• The disruption of stomatal function does not significantly affect water absorption in roots, as water uptake is primarily mediated by root hairs and the epiblema layer.
• Stomatal dysfunction would limit photosynthesis and respiration processes, directly impacting plant growth and metabolism.
• This issue contrasts with other options (e.g., root hairs or epiblema cells), which are more relevant to water absorption rather than gas exchange.

Additional Information

• Stomata: Tiny openings on the surface of leaves and stems that regulate gas exchange and water loss through transpiration. They are controlled by guard cells.
• Root Hairs: Extensions of the epidermal cells in roots, responsible for increasing the surface area for water and nutrient absorption from the soil.
• Epiblema: The outermost layer of root cells that aids in water absorption and sometimes forms root hairs for efficient uptake.
• Suberin in Endodermis: A hydrophobic material present in the Casparian strips of endodermal cells, which regulates water and nutrient flow into the vascular system of roots.
• Photosynthesis and Respiration: Processes that depend on gas exchange (CO₂ for photosynthesis and O₂ for respiration), primarily facilitated by stomata in aerial parts of the plant.