Nitrogen source determined significant for inflorescence development in Phalaenopsis
Tuesday, April 22, 2014
Research shows importance of ample nitrogen fertilization at all growth stages
TAIPEI, TAIWAN--The Phalaenopsis orchid, also known as the
moth orchid, is the most important pot flower in terms of market value
in the world's major floriculture markets. Because nitrogen
significantly affects the growth and flowering of Phalaenopsis,
nitrogen needs during flowering are of particular interest to growers.
Researchers Hadi Susilo, Ying-Chun Peng, and Yao-Chien Alex Chang from
the Department of Horticulture and Landscape Architecture at National
Taiwan University published a study in the Journal of the American Society for Horticultural Science that determined the importance of providing Phalaenopsis with ample nitrogen fertilization at the its various growth stages.
"To our knowledge, the relative contributions of stored nitrogen (N)
and recently absorbed fertilizer N to the developing inflorescence had
not been studied in Phalaenopsis," the authors said. "The
relative contributions to the stored N pool of N accumulated during the
different growth stages during the long vegetative period of Phalaenopsis cultivation were also unknown. The objective of our study was to bring answers to these unknowns."
The team used N-labeling--a powerful research tool for accurately
determining the fate of nitrogen in the environment--to compare the
contributions of fertilizer N, applied before or after spiking, to the
developing inflorescence, and compared the relative contributions of
fertilizer N absorbed during various stages of the vegetative period to
the stored N pool. "The nutritional study of Phalaenopsis is
difficult with traditional methods because it has a strong buffering
capacity against nutrient deficiency, but we used 15N-labeling with the
enrichment method to accurately trace the absorption and partitioning of
fertilizer N in Phalaenopsis," the scientists said.
The results of multiple experiments showed that inflorescence is a major N sink during the reproductive stage of Phalaenopsis. "Fertilizer applied during the reproductive stage is a significant N source for the inflorescence development of Phalaenopsis,
whereby current fertilizer application supplies 57% of the N required
for inflorescence development. Therefore, providing sufficient
fertilizer N is important during the reproductive stage to ensure the
quality of flowering," the authors said.
Further experiments showed that, even when ample fertilization was
provided during the reproductive stage, 6-8% of the nitrogen accumulated
during growing Stage I (small plant in 4.5-cm pot for 5 months), Stage
II (medium plant in 8.5-cm pot for 5 months), and Stage III (large plant
in 10.5-cm pot for 5 months) ended up in the inflorescence at the
visible bud stage. At the "two-third flowers open" stage, 12-16% of the N
accumulated in the plant during these three stages ended up in the
inflorescence. The scientists concluded that these results indicated the
importance of providing Phalaenopsis with ample N fertilization at all growth stages.
The complete study and abstract are available on the ASHS J. Amer. Soc. Hort. Sci. electronic journal web site: http://journal.ashspublications.org/content/139/1/69.abstract
Founded in 1903, the American Society for Horticultural Science
(ASHS) is the largest organization dedicated to advancing all facets of
horticultural research, education, and application. More information at ashs.org
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Nitrogen Source for Inflorescence Development in Phalaenopsis: I. Relative Significance of Stored and Newly Absorbed Nitrogen
Hadi Susilo, Ying-Chun Peng, and Yao-Chien Alex Chang
J. Amer. Soc. Hort. Sci. 139:69-75. [Abstract]
Corresponding author. E-mail: email@example.com