Plant Soil Environ., 2018, 64(5):240-246 | DOI: 10.17221/15/2018-PSE

Root architecture and nitrogen metabolism in roots of apple rootstock respond to exogenous glucose supply in low carbon soilOriginal Paper

Dongmei LANG, Zitan ZHU, Sijun QIN^*, Deguo LYU^*

Shengyang Agricultural University, Shengyang, P.R. China

To investigate the response of root architecture and nitrogen metabolism of apple rootstock to glucose supply in low-carbon (C) soil, Malus baccata (L.) Borkh. in gravel soil was treated with glucose C equal to the soil microbial biomass carbon (MBC)-C value (G₁), five times the soil MBC value (G₂), or with no glucose (CK). The roots samples were harvested after treatments for 7, 15 and 30 days. The roots tended to become larger, more dichotomous and showed a larger link branching angle in G₁ and G₂ than in CK, especially in the G₁ treatment for 30 days. Plant height and biomass were increased by G1. Nitrate (NO₃^--N) and nitrite (NO₂^--N) contents were increased, but ammonium (NH₄⁺-N) concentration was decreased in the roots treated with G₁ and G₂ in all treatment periods. Also, the activities and transcript levels of nitrate reductase, glutamine synthetase, glutamate dehydrogenase, glutamate synthase were generally increased in roots treated with glucose, especially under G₁. The activities of glutamic oxalacetic transaminases and glutamic-pyruvic transaminase were higher under G₁ than under either G₂ or CK. Exogenous carbon source that equals to the native MBC effectively regulated the root architecture and supported increasing nitrogen absorption and metabolism in plants growing under carbon-restricted conditions.

Keywords: external carbon source; nitrogen uptake and assimilation; root morphology and topology; transcript levels

Published: May 31, 2018  Show citation