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- Title
Nitrogen uptake and growth responses of seedlings of the brown seaweed <italic>Sargassum hemiphyllum</italic> under controlled culture conditions.
- Authors
Han, Tingting; Qi, Zhanhui; Huang, Honghui; Liao, Xiuli; Zhang, Wenwen
- Abstract
For the purpose of indoor mass culture of seedlings of <italic>Sargassum hemiphyllum</italic> during spring and summer, a series of experiments were designed to evaluate nitrogen (N) uptake, growth performance, and N accumulation of seedlings. Transient uptake rates by N-limited seedlings for nitrate (NO3−), ammonium (NH4+), and urea were more rapid than uptake rates by N-replete seedlings. NO3− uptake revealed a rate-saturating uptake kinetic for both N-limited and N-replete seedlings. Uptake rates of NH4+ and urea for N-limited seedlings were linear, whereas the N-replete seedlings displayed Michaelis-Menten curves. The slope of the linear models or equivalently affinity calculated from Michaelis-Menten curves was highest for NH4+ and lowest for urea, indicating that seedlings were more efficient at taking up NH4+. Tissue N content in seedling increased with increasing N concentrations, with the highest values with all three N sources at 150 μM. The N requirement to support maximum growth varied 2.2-fold from 0.39 ± 0.15% dry weight (DW) in NH4+ to 0.84 ± 0.09% DW in NO3−, and hence, seedlings became more easily N limited at low NO3− availability. The results showed that seedlings cultured in NO3− enrichment (50-100 μM) may be better able to meet their maximum growth than at high NH4+ availability, although seedlings have higher NH4+ uptake capacities.
- Publication
Journal of Applied Phycology, 2018, Vol 30, Issue 1, p507
- ISSN
0921-8971
- Publication type
Article
- DOI
10.1007/s10811-017-1216-1