鹽分對五梨跤(Rhizophora stylosa)苗木形質生長之影響

Abstract

This study examined the effects of salinity on morphological growth of the mangrove Rhizophora stylosa seedlings. The viviparous seedlings were grown in various concentrations of salinity containing 0, 0.75, 1.5, and 3.0% NaCl each for 60, 120, and 150 days. The overall morphological parameters including sprout height, diameter at root collar, dry weight of various components, total dry weight and relative growth rate (RGR) were higher for seedlings that cultivated in 0.75 and 1.5% NaCl. The seedling quality index for seedlings that cultivated in 0.75% NaCl was the highest, indicating that the 0.75% NaCl was the optimum salinity for seedling growth of this species. All morphological parameters of seedlings grown in 0 and 3.0% NaCl were significantly decreased. The results also implied that the growth reduction in R. stylosa was primarily a result of a lower RGR. The leaf numbers, total leaf area, leaf expansion rate, leaf succulence, leaf area ratio (LAR), specific leaf area (SLA) and leaf weight ratio (LWR) of the seedlings cultivated in 0.75 and 1.5% NaCl were also higher. However, all leaf morphological parameters for seedlings cultivated in 0 and 3.0% Nacl were significantly decreased, which indicated that leaf morphology and carbon allocation were altered by salinity.