FFA Horticulture CDE General Practice Exam

What condition is indicated by young leaves that exhibit yellowing between the veins?

1. Nitrogen deficiency

2. Chlorosis

3. Manganese deficiency

4. Root rot

The correct answer is: Manganese deficiency

The condition indicated by young leaves exhibiting yellowing specifically between the veins is known as chlorosis. This phenomenon generally occurs due to a deficiency of chlorophyll in the plant and can be caused by various nutrient deficiencies, yet the most common is related to nutrients such as iron or manganese, which are vital for chlorophyll production. In this case, chlorosis often appears in young leaves first because they are more metabolically active and require a higher level of nutrients. While manganese deficiency can lead to interveinal chlorosis (yellowing between the veins), it is a specific type of chlorosis rather than a generalized term for the condition itself. Understanding the broader term 'chlorosis' encompasses various causes, including both nutrient deficiencies and other factors, which can facilitate a better grasp of plant health concerns rather than focusing on a singular cause. In contrast, nitrogen deficiency typically leads to yellowing of older leaves first, as nitrogen is mobile within the plant and is transferred to new growth. Root rot affects the plant's ability to take up nutrients and water but does not directly cause interveinal yellowing. Thus, indicating that chlorosis is the more accurate term that encompasses the condition being observed.