Abdulrahman Farag Saleh, Williams George J
Department of Botany, Washington State University, 99164, Pullman, Washington, USA.
Oecologia. 1981 Mar;48(3):346-352. doi: 10.1007/BF00346493.
Salicornia fruticosa was collected from a salt marsh on the Mediterranean sea coast in Libya. Growth and gas exchange of this C species were monitered in plants pretreated at various NaCl concentrations (0, 171, 342, 513 and 855 mM). Maximum growth was at 171 mM NaCl under cool growth conditions (20/10° C) and at 342 mM NaCl under warm growth conditions (30/15° C) with minimum growth at 0 mM NaCl (control). Net photosynthesis (Pn) was greatest in plants grown in 171 mM NaCl with plants grown at 513 and 855 mM having lowest rates. Maximum Pn was at 20-25° C shoot temperatures with statistically significant reductions at 30° C in control plants while salt treated plants showed such reductions at 35° C. Salt treatments increased dark respiration over the control at 171 and 342 mM but reduced it at higher concentrations. Photorespiration was reduced by salt treatment and increased by increasing shoot temperature. Greatest transpiration was in 171 mM NaCl treated plants and increasing shoot temperature increased transpiration in all treatments. Stomatal resistance to CO influx was influenced only moderately by temperature while increasing salinity resulted in increased stomatal resistance. In general both temperature and salinity increased the mesophyll resistance to CO influx. The species seems adapted to the warm saline habitat along the Mediterranean sea coast, at least partially, by its ability to maintain relatively high Pn at moderate NaCl concentrations over a broad range of shoot temperatures.
盐角草采自利比亚地中海沿岸的盐沼。在不同NaCl浓度（0、171、342、513和855 mM）预处理的植株中监测了这种C4植物的生长和气体交换。在凉爽生长条件（20/10°C）下，最大生长量出现在171 mM NaCl处理时；在温暖生长条件（30/15°C）下，最大生长量出现在342 mM NaCl处理时，而在0 mM NaCl（对照）处理时生长量最小。净光合速率（Pn）在171 mM NaCl处理的植株中最大，在513和855 mM NaCl处理的植株中速率最低。最大Pn出现在茎尖温度为20 - 25°C时，对照植株在30°C时Pn有统计学意义的降低，而盐处理植株在35°C时出现这种降低。盐处理在171和342 mM时比对照增加了暗呼吸，但在更高浓度时降低了暗呼吸。盐处理降低了光呼吸，而茎尖温度升高则增加了光呼吸。蒸腾速率在171 mM NaCl处理的植株中最大，并且在所有处理中，茎尖温度升高都会增加蒸腾速率。气孔对CO2流入的阻力仅受到温度的适度影响，而盐度增加会导致气孔阻力增加。一般来说，温度和盐度都会增加叶肉对CO2流入的阻力。该物种似乎至少部分地通过其在较宽的茎尖温度范围内、中等NaCl浓度下维持相对较高Pn的能力，适应了地中海沿岸温暖的盐碱生境。
