The preference of paddy rice for NH4+ rather than NO3‐ is associated with its tolerance to low pH since a rhizosphere acidification occurs during NH4+ absorption. However, the adaptation of rice root to low pH has not been fully elucidated. This study investigated the acclimation of plasma membrane H+‐ATPase of rice root to low pH. Rice seedlings were grown either with NH4+ or NO3‐. For both nitrogen forms, the pH value of nutrient solutions was gradually adjusted to pH 6.5 or 3.0. After 4 d cultivation, hydrolytic H+‐ATPase activity, Vmax, Km, H+‐pumping activity, H+ permeability and pH gradient across the plasma membrane were significantly higher in rice roots grown at pH 3.0 than at 6.5, irrespective of the nitrogen forms supplied. The higher activity of plasma membrane H+‐ATPase of adapted rice roots was attributed to the increase in expression of OSA1, OSA3, OSA7, OSA8 and OSA9 genes, which resulted in an increase of H+‐ATPase protein concentration. In conclusion, a high regulation of various plasma membrane H+‐ATPase genes is responsible for the adaptation of rice roots to low pH. This mechanism may be partly responsible for the preference of rice plants to NH4+ nutrition.

Background Sorghum roots release two categories of biological nitrification inhibitors (BNIs)hydrophilic-BNIs and hydrophobic-BNIs. Earlier research indicated that rhizosphere pH and plasma membrane (PM) H + ATPase are functionally linked with the release of hydrophilic BNIs, but the underlying mechanisms are not fully elucidated. This study is designed to reveal further insights into the regulatory mechanisms of BNIs release in root systems, using three sorghum genetic stocks. Methods Sorghum plants were grown in a hydroponic system with pH of nutrient solutions ranging from 3.0 9.0. Pharmacological agents [(fusicoccin and vanadate) and anion-channel blockers (−niflumic acid (NIF) and

No abstract

No abstract