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Effects of soil C:N on growth and distribution of nitrogen and carbon of Malus hupehensis seedlings |
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| Affiliation: | College of Horticulture Science and Engineering, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, China |
| Abstract: | Aims Soil C:N is a sensitive indicator of soil quality and an indicator for assessing carbon and nitrogen nutrition balance of soils. Our objective was to explore the effects of soil C:N on growth and distribution of nitrogen and carbon of Malus hupehensis seedlings. Methods Using the track technology of C and N double mark, we investigated growth parameters (height, stem diameter and dry matter of different organs), 15N parameters (absorption, N derived from fertilizer, distribution and utilization) and 13C parameters (distribution in different organs) of two-year old M. hupehensis seedlings under six different soil C:N treatments (T1-T6 were 4.70, 9.78, 14.70, 19.96, 25.60 and 28.83, respectively). Important findings With increase of soil C:N, dry matter of roots increased significantly, while the height, stem diameter and dry matter of above ground parts and total plant increased at first and then decreased. The highest value appeared in the T4 treatment. There were significant differences in 15N utilization efficiency among the six different treatments. 15N utilization efficiency increased from T1 to T4, and the rate of T4 (18.46%) was 1.73 times than that of T1. But, the 15N utilization efficiency decreased with a further increase of soil C:N, as the rate of T5 and T6 reduced that of T4 by 1.59% and 2.58%, respectively. In the two lower soil C:N treatments (T1 and T2), the order of Ndff value ( 15N derived from fertilizer) in the organs was roots > leaves > stems. With increase of soil C:N, Ndff value in leaves was the highest, followed by roots and stems. 15N distribution ratio in leaves increased, while 13C distribution decreased with increase of soil C:N, but the changes were the opposite in roots. Considering plant growth and utilization of nitrogen, the suitable soil C:N was 21-23 under these experimental conditions. |
| Keywords: | 13C" target="_blank">13C')">13C 15N" target="_blank">15N')">15N distribution growth Malus hupehensis" target="_blank">Malus hupehensis')">Malus hupehensis soil C:N utilization |
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