What deficiency is characterized by stunted growth and poor reproductive development in plants?

Magnesium deficiency is characterized by stunted growth and poor reproductive development in plants due to magnesium's crucial role in chlorophyll production and enzyme activation. Magnesium is a key component of chlorophyll, the pigment responsible for photosynthesis. When plants lack magnesium, their ability to photosynthesize efficiently is impaired, leading to stunted growth. Additionally, magnesium is involved in the activation of certain enzymes necessary for the synthesis of DNA and RNA, which are vital for cell division and reproduction. Consequently, plants with insufficient magnesium often exhibit poor flowering and fruit set, reflecting inadequate reproductive development.

In contrast, other nutrient deficiencies have different symptoms; for example, iron deficiency typically results in interveinal chlorosis, where leaves turn yellow between the veins but can cause minimal growth impairment compared to magnesium deficiency. Nitrogen deficiency leads to overall yellowing of older leaves and reduced biomass affecting general growth and vigor but with less specific impact on reproductive parts. Potassium deficiency commonly results in marginal leaf burn and poor disease resistance rather than directly stunting growth or reproductive traits. Thus, magnesium's specific roles in plant metabolism and growth processes make it the correct choice for this question.