Which symptom is indicative of phosphorous deficiency in corn?

The symptom indicative of phosphorus deficiency in corn is a dark green appearance with reddish-purple leaf tips. This specific coloration is a key indicator of phosphorus deficiency, as it reflects the plant's inability to adequately utilize phosphorus for growth and development. When corn plants experience a lack of phosphorus, they may exhibit stunted growth and a darkening of the leaf color as they attempt to conserve resources. The reddish-purple tint, particularly visible on the leaf tips, arises due to the accumulation of sugars that are not properly metabolized in the absence of sufficient phosphorus.

In contrast, other symptoms mentioned in the choices refer to different nutrient deficiencies or plant stresses. For example, yellow leaves with brown centers often suggest issues like potassium deficiency or leaf burn, while rapid wilting and stunted growth can be associated with water stress or other nutrient deficiencies. Pale leaves with no growth might indicate broader nutrient deficiencies or adverse environmental conditions, rather than the specific effects of phosphorus deficiency. Understanding these specific symptoms helps in identifying the right nutrient management practices for corn.