Effects of Ammonium, Phosphate,and Salinity on Growth, Gas Exchange Characteristics, and Ionic Contents of Seedlings of Mangrove Kandelia Candel (L.) Druce

氨態氮、磷酸鹽和鹽度影響水筆仔紅樹林幼苗的筆長、氣體交換和組織離子含量等特性之研究

黃元動(Yuan-Hsun Hwang) ； 陳樹春(Shuh-Chun Chen)

《Botanical Bulletin of Academia Sinica》 42卷2期 (2001/04) Pp. 131-139

https://doi.org/10.7016/BBAS.200104.0131

摘要

我們觀察水筆仔紅樹林幼苗在溫室水耕試驗中，其生長、氣體交換和組織離子含量等特徵受水耕溶液中氨態氮、磷酸鹽和鹽度影響。在20ppt NaCl高鹽度下，植株全株的生長速率和葉片CO2交換速率嚴重受到抑制。在鹽度下。高氨態氮(2mM)顯著提高植株的生長速率、葉片的CO2同化速率和呼吸速率。若只增加磷酸鹽含量則不影響植株的生長。但是增加磷酸鹽可提升原本受氨態氮刺激的植株生長速率、葉片CO2同化速率和呼吸速率。在鹽度下，水筆仔葉片和根部組織可維持一定濃度的陽離子總量。在0ppt NaCl鹽度下，鉀離子是組織中陽離子的主要成份；但隨著水耕溶液中NaCl含量增加，鈉離子取代鉀離子成為組織中陽離子的主要成份。在各種鹽度試驗中，水筆紅樹林幼苗筆對水耕溶液中氨態氮的吸取均呈現“奢侈性吸收”的現象，而其中部分氨態氮可能成為組織內調控滲透壓之無機溶質的一部分。本文中亦討論造成水筆仔紅樹林在溫室水耕和野外自然環境由生長差異之可能原因。

關鍵字

生長 ； 水筆子 ； 紅樹林 ； 營養鹽 ； 氨態氮 ； 磷酸鹽 ； 鹽度

並列摘要

The effects of ammonium, phosphate, and salinity on growth, gas exchange characteristics, and ionic content of seedlings of mangrove Kandelia candel (L.) Druce were investigated in solution culture experiments over seven months. High salinity at 20 ppt NaC1 greatly reduced dry matter accumulation in shoots and roots and leaf CO2 assimilation rate. Addition of ammonium-nitrogen (2mM) significantly increased the growth of shoots and roots, leaf CO2 assimilation rate, and respiration rate at low salinity treatments. Phosphate amendment alone did not affect the growth of plants. However, when ammonium-nitrogen was also added, phosphate improved the growth of plants, leaf CO2 assimilation rate, and respiration rate in low salinity treatments. Kandelia candel tended to maintain a constant cation concentration in tissues of leaves and roots at low salinity conditions. Potassium was the major cation in the tissues at the low salinity; however, it was replaced by sodium as the salinity of the culture solution was increased. Kandelia candel absorbed ammonium-nitrogen luxuriously at all salinity treatments and some of the ammonium accumulated in the tissues could be part of cations as the osmotic inorganic solute. Reasons for the difference in optimal growth salinity for K. candel between porewater in the field and the culture solution in the greenhouse are discussed.

並列關鍵字

Ammonium ； Growth ； Kandelia candel ； Mangrove ； Nitrogen ； Nutrients ； Phosphate ； Salinity