Browne C L, Fang S C
Department of Agricultural Chemistry, Oregon State University, Corvallis, Oregon 97331.
Plant Physiol. 1978 Mar;61(3):430-3. doi: 10.1104/pp.61.3.430.
Using a whole-plant chamber and (203)Hg-labeled mercury, a quantitative study was made of the effect of environmental parameters on the uptake, by wheat (Triticum aestivum), of metallic mercury vapor, an atmospheric pollutant. Factors were examined in relation to their influence on components of the gas-assimilation model, [Formula: see text]where U(Hg) is the rate of mercury uptake per unit leaf surface, C(a)' is the ambient mercury vapor concentration, C(l)' is the mercury concentration at immobilization sites within the plant (assumed to be zero), r(l.Hg) is the total leaf resistance to mercury vapor exchange, and r(m.hg) is a residual term to account for unexplained physical and biochemical resistances to mercury vapor uptake.Essentially all mercury vapor uptake was confined to the leaves. r(l.hg) was particularly influenced by illumination (0 to 12.8 klux), but unaffected by ambient temperature (17 to 33 C) and mercury vapor concentration (0 to 40 mug m(-3)). The principal limitation to mercury vapor uptake was r(m.hg), which was linearly related to leaf temperature, but unaffected by mercury vapor concentration and illumination, except for apparent high values in darkness.Knowing C(a)' and estimating r(l.hg) and r(m.hg) from experimental data, mercury vapor uptake by wheat in light was accurately predicted for several durations of exposure using the above model.
利用一个全株培养箱和（203）汞标记的汞，对环境参数对大气污染物金属汞蒸气被小麦（普通小麦）吸收的影响进行了定量研究。研究了各因素对气体同化模型各组分的影响，[公式：见原文]其中U（Hg）是单位叶面积的汞吸收速率，C（a）'是环境汞蒸气浓度，C（l）'是植物内固定位点的汞浓度（假定为零），r（l.Hg）是叶片对汞蒸气交换的总阻力，r（m.hg）是一个余项，用于解释对汞蒸气吸收无法解释的物理和生化阻力。基本上所有的汞蒸气吸收都局限于叶片。r（l.hg）特别受光照（0至12.8千勒克斯）影响，但不受环境温度（17至33摄氏度）和汞蒸气浓度（0至40微克/立方米）影响。汞蒸气吸收的主要限制因素是r（m.hg），它与叶片温度呈线性关系，但不受汞蒸气浓度和光照影响，除了在黑暗中明显较高的值。知道C（a）'并根据实验数据估算r（l.hg）和r（m.hg），使用上述模型可以准确预测小麦在光照下几个暴露时间段内的汞蒸气吸收情况。
