Photosynthetic and growth responses of Japanese sasabamo (Potamogeton wrightii Morong) under different photoperiods and nutrient conditions |
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Authors: | Munira Sultana Takashi Asaeda M Ekram Azim Takeshi Fujino |
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Institution: | 1. Department of Environmental Science and Human Technology , Saitama University , Saitama, Japan munira.sultana@ymail.com;3. Department of Environmental Science and Human Technology , Saitama University , Saitama, Japan;4. Department of Environmental Science and Human Technology , Saitama University , Saitama, Japan;5. Department of Physical and Environmental Sciences , University of Toronto , Toronto, Canada |
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Abstract: | Controlled laboratory experiments were conducted to examine how photosynthesis and growth occur in Potamogeton wrightii Morong under different photoperiods and nutrient conditions. The experiment was based on a 3×2 factorial design with three photoperiods (16, 12 and 8 h) of 200 μE · m?2·s?1 irradiance and two nutrient conditions, high (90 μmol N · L?1·d?1 and 9 μmol P · L?1·d?1) and low (30 μmol N L?1·d?1 and 3 μmol P · L?1·d?1). After 14, 28, 56 and 70 days of growth, plants were harvested to determine net photosynthesis rate and various growth parameters. Above- and below-ground biomass were investigated on days 56 and 70 only. Plants under low nutrient conditions had greater leaf area, more chlorophyll a, a higher rate of net photosynthesis and accumulated more above- and below-ground biomass than plants in the high nutrient condition. Plants with an 8 h photoperiod in the low nutrient condition had a significantly higher rate of net photosynthesis, whereas 8 h photoperiod plants in the high nutrient condition had a lower rate of net photosynthesis and their photosynthetic capacity collapsed on day 70. We conclude that P. wrightii has the photosynthetic plasticity to overcome the effects of a shorter photoperiod under a tolerable nutrient state. |
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Keywords: | Potamogeton wrightii nutrient dark respiration photoperiod |
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