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Identifying N sources that affect N uptake and assimilation in Vanda hybrid using 15N tracers

Author:
Panjama, Kanokwan, Ohyama, Takuji, Ohtake, Norikuni, Sato, Takashi, Potapohn, Nuttha, Sueyoshi, Kuni, Ruamrungsri, Soraya
Source:
Horticulture, environment and biotechnology 2018 v.59 no.6 pp. 805-813
ISSN:
2211-3452
Subject:
Vanda, absorption, alanine, ammonium, glutamine, hybrids, leaves, nitrate fertilizers, nitrates, nitrogen, nitrogen content, roots, shoots, stable isotopes, stems, tracer techniques, tyrosine, Thailand
Abstract:
Vanda is an aerial tropical orchid native to Thailand and nitrogen (N) fertilizer is mainly used to promote its growth and quality. However, little is known about the characteristics of N absorption and assimilation in Vanda. The objective of this study was to determine the appropriate source of N for Vanda cultivation. In this experiment, shoots and roots of Vanda ‘Ratchaburi Fuchs-Katsura’ were sprayed weekly with 100 ml of ¹⁵N tracer solution (1) 10 mM of ¹⁵NO₃⁻, (2) 5 mM of ¹⁵NO₃⁻ plus 5 mM of NH₄⁺, (3) 5 mM of NO₃⁻ plus 5 mM of ¹⁵NH₄⁺ and (4) 10 mM of ¹⁵NH₄⁺. The results indicated that plants fed with a combined N fertilizer gave the highest of ¹⁵N use efficiency (¹⁵NUE) of about 21.8%, 30 days after the first feeding (DAF), compared with those fed sole sources of ¹⁵NO₃⁻ (21.0%) and ¹⁵NH₄⁺ (16.6%). However, a sole nitrate fertilizer or combination fertilizer did not significantly affect the total N and labelled N content. Alanine was a major amino acid found in leaves and roots at 7 DAF, whereas glutamine was mainly found in stems. At 30 DAF, tyrosine and alanine became major components in the leaves, and glutamine decreased in stems when plants were fed with a single ¹⁵NH₄⁺source.
Agid:
6240910