Moderate application of nitrogen augments the growth of Taxodium hybrid ‘Zhongshanshan 406’ plants in coastal soils

Abstract

In plants, nitrogen (N) is known to affect photosynthesis and induces resistance to abiotic stresses by influencing physiological processes. In this study, we investigated the influence of low (50 kg ha−1), moderate (150 kg N ha−1) and high (250 kg ha−1) N application on the physiology, photosynthesis and mineral element contents of Taxodium hybrid ‘Zhongshanshan 406’ (T. 406) plants grown with salt stress (low, moderate and severe) or without (non-saline control, CK). T. 406 plants showed poor growth and gradually died under severe salt stress (EC=12.3 dS·m−1). The biomass of T. 406 plants was reduced by 44.3%, on average, in low salt (EC=1.99 dS·m−1) treatment compared with plants grown in control conditions. Moderate N application conspicuously improved photosynthesis and growth of plants in the low-salt treatment group, thus alleviating the adverse effects of salt stress compared with low and high N application treatments. The results showed that moderate N increased the contents of N and cations in T. 406 plants, leading to an increased efficiency of photosynthetic N use. These findings indicated that excessive N fertilization did not promote N uptake in reclaimed soils and that moderate N application may be used as a potential tool for the alleviation of salt stress in T. 406 plants in coastal soils.