欖李耐鹽性的探討

Salinity Tolerance of Lumnitzera racemosa Willd.

本試驗以台南縣七股鄉頂頭額汕地區之紅樹林植物－－欖李（Lumnitzera racemosa Willd.）為材料，以探討欖李耐鹽分（Na+及Cl-）的機制及無機鹽類在植株的分佈情形。欖李體內累積的Na+及Cl-含量以葉部為最高，其次為根部；葉部又以冠層下部位及老葉含量最高。Na+含量隨葉齡的增加而增加，K+則隨葉齡的增加而降低，Ca2+及Mg2+等則變化不明顯，致使Ca2+/Na+, Mg2+/Na+及K+/Na+的比值隨葉齡增加而下降。欖李適應高鹽分環境方式之一是將鹽分累積於老葉，藉著葉片的脫落，使鹽分排除體外，以減低高鹽分對欖李之傷害。試驗結果亦顯示葉片Na+及Cl-含量與雨量間呈顯著相關。 The objectives of this study were to monitor allocation of Na+, Cl- and the other inorganic nutrients in Lumnitzera racemosa Willd. at Chiguu, Tainan county in order to understand the mechanism of this species survived in high salinity environment. A large amount of Na+ and Cl- are accumulated in leaves and then in roots. The contents of Na+ and Cl- in lower canopy and older leaves are higher than those in upper and younger leaves. The contents of Na+ increase and K+ decrease with increasing leaf age, however the contents of Ca+ and Mg+ are not different significantly. Thus, the ratio of Ca2+ /Na+. Mg2+/Na+, and K+/Na+ decrease with increasing leaf age. It indicated brightly that L. racemosa could survive in high salinity by accumulating salt ions in older leaves and then the old leaves fell off.

The objectives of this study were to monitor allocation of Na+, Cl- and the other inorganic nutrients in Lumnitzera racemosa Willd. at Chiguu, Tainan county in order to understand the mechanism of this species survived in high salinity environment. A large amount of Na+ and Cl- are accumulated in leaves and then in roots. The contents of Na+ and Cl- in lower canopy and older leaves are higher than those in upper and younger leaves. The contents of Na+ increase and K+ decrease with increasing leaf age, however the contents of Ca+ and Mg+ are not different significantly. Thus, the ratio of Ca2+ /Na+. Mg2+/Na+, and K+/Na+ decrease with increasing leaf age. It indicated brightly that L. racemosa could survive in high salinity by accumulating salt ions in older leaves and then the old leaves fell off.