Functions of Nitrogen, Phosphorus and Potassium in Energy Status and Their Influences on Rice Growth and Development

Abstract

Nitrogen (N), phosphorus (P) and potassium (K) are important essential nutrients for plant growth and development, but their functions in energy status remains unclear. Here, we grew Nipponbare rice seedlings in a growth chamber for 20 d at 30°C/24°C (day/night) under natural sunlight conditions with different nutrient regimes. The results showed that N had the strongest influence on the plant growth and development, followed by P and K. The highest nonstructural carbohydrate content, dry matter weight, net photosynthetic rate (Pn), ATP content, as well as NADH dehydrogenase, cytochrome oxidase and ATPase activities were found in the plants that received sufficient N, P and K. The lowest values of these parameters were detected in the N-deficient plants. Higher dry matter accumulation was observed in the K-deficient than in the P-deficient treatments, but there was no significant difference in the ratio of respiration rate to Pn between these two treatments, suggesting that differences in energy production efficiency may have accounted for this result. This hypothesis was confirmed by higher ATP contents and activities of NADH dehydrogenase, cytochrome oxidase and ATPase in the K-deficient plants than in the P-deficient plants. We therefore inferred different abilities in energy production efficiency among N, P and K in rice seedlings, which determined rice plant growth and development.