土壤鹽度對欖仁苗木生長、水分狀態及葉綠素濃度之影響

Effects of Soil Salinity on Growth, Water Status and Chlorophyll Concentration of Terminalia Catappa Seedlings

本研究旨在探討0、0.75、1.5及3.0%NaCl等不同土壤鹽度處理，對欖仁（Terminalia catappa）苗木形質生長、水分狀態及葉綠素濃度之影響。試驗結果顯示，鹽分處理90天後，以0及0.75%NaCl處理之苗高、地際直徑、葉片數、總葉面積、葉片大小、葉片伸展速率及各部位乾物累積量較大，顯示欖仁苗木適合生長於無鹽分及低鹽度之環境。以3.0% NaCl高鹽度處理之苗木，所有形態參數則明顯下降。苗木之葉片肉質程度會隨鹽度增加而增加，在處理90天後，3.0% NaCl處理有最大肉質程度。苗木相對生長速率（RGR）、淨同化速率（NAR）、葉面積比（LAR）及比葉面積（SLA）皆隨鹽度增加而降低，但葉重比（LWR）並未受鹽度之影響。處理90天後，1.5及3.0%處理之葉部及莖部含水率明顯降低，惟苗木根部含水率無明顯的差異。成熟葉之相對含水率（RWC）隨著鹽度增加而降低，而1.5及3.0%高鹽度處理葉片之葉綠素濃度較高。 The purpose of this study was to investigate the effect of soil salinity various from 0, 0.75, 1.5 to 3.0% on growth, water status and chlorophyll concentration of Terminalia catappa seedlings. The results indicated seedling height, diameter at root collar, leaf numbers, leaf size, total leaf area, leaf expansion rate and dry matter accumulation of seedlings that cultivated in 0 and 0.75% NaCl were greatly enhanced after 90 days of treatment. This implied that none or low salinity was the optimum environment for seedling growth of this species. All parameters of seedlings that cultivated in 3.0% NaCl were significantly suppressed. Succulence in leaves of seedlings was high when grown in increasing salinity and the highest degree of succulence was obtained at 3.0% NaCl treatments. Salinity significantly reduced relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and specific leaf area (SLA), but leaf weight ratio (LWR) was unaffected. Leaf and stem water content of seedlings that cultivated in L.5 and 3.0% NaCl were decreased after 90 days of treatment. However, salinity level showed less effect on the root water content. The relative water content (RWC) of the fully expanded leaves was decreased, but the total amount of chlorophylls in leaves that cultivated in I .5 and 3.0% NaCI was high.

The purpose of this study was to investigate the effect of soil salinity various from 0, 0.75, 1.5 to 3.0% on growth, water status and chlorophyll concentration of Terminalia catappa seedlings. The results indicated seedling height, diameter at root collar, leaf numbers, leaf size, total leaf area, leaf expansion rate and dry matter accumulation of seedlings that cultivated in 0 and 0.75% NaCl were greatly enhanced after 90 days of treatment. This implied that none or low salinity was the optimum environment for seedling growth of this species. All parameters of seedlings that cultivated in 3.0% NaCl were significantly suppressed. Succulence in leaves of seedlings was high when grown in increasing salinity and the highest degree of succulence was obtained at 3.0% NaCl treatments. Salinity significantly reduced relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and specific leaf area (SLA), but leaf weight ratio (LWR) was unaffected. Leaf and stem water content of seedlings that cultivated in L.5 and 3.0% NaCl were decreased after 90 days of treatment. However, salinity level showed less effect on the root water content. The relative water content (RWC) of the fully expanded leaves was decreased, but the total amount of chlorophylls in leaves that cultivated in I .5 and 3.0% NaCI was high.