Final answer:
Interveinal chlorosis in younger leaves is typically caused by nutrient deficiencies, particularly of micronutrients like iron, manganese, or zinc, which are essential for chlorophyll synthesis, leading to yellowing between the veins.
Step-by-step explanation:
Interveinal chlorosis in younger leaves is primarily caused by nutrient deficiencies, in which the leaf loses its green color and turns yellow between the veins while the veins remain green. The term interveinal chlorosis indicates that chlorophyll is not being produced or maintained in the areas of the leaf between the veins.
This condition is often associated with a deficiency of certain micronutrients, such as iron, manganese, or zinc, which are crucial for the synthesis of chlorophyll. When these nutrients are lacking, the plant cannot produce enough chlorophyll in the younger leaves, resulting in the characteristic yellowing.
Other potential causes of interveinal chlorosis can include a plant's inability to uptake nutrients due to poor soil pH, or damage to the root system which affects the plant's nutrient absorption. It is also possible that a plant pathogen causing leaf spots and discoloration can lead to symptoms of chlorosis.