McLaughlin S B, McConathy R K
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830.
Plant Physiol. 1983 Nov;73(3):630-5. doi: 10.1104/pp.73.3.630.
A series of laboratory exposures of two varieties of bush bean (Phaseolus vulgaris L., var 274 and var 290) was conducted to determine the sensitivity of [(14)C]photosynthate allocation patterns to alteration by SO(2) and O(3). Experiments with the pollution-resistant 274 variety demonstrated short-term changes in both (14)C and biomass allocation to roots of (14)CO(2)-labeled plants but no significant effect on yield by up to 40 hours of exposure to SO(2) at 0.50 microliters per liter or 4 hours of O(3) at 0.40 microliters per liter. Subsequent experiments with the more sensitive 290 variety demonstrated significant alteration of photosynthesis, translocation, and partitioning of photosynthate between plant parts including developing pods. Significant increases in foliar retention of photosynthate (+40%) occurred after 8 hours of exposure to SO(2) at 0.75 microliters per liter (6.0 microliters per liter-hour) and 11 hours of exposure to O(3) at 0.30 microliters per liter-hour (3.3 microliters-hours). Time series sampling of labeled tissues after (14)CO(2) uptake showed that the disruption of translocation patterns was persistent for at least 1 week after exposures ceased. Subsequent longer-term exposures at lower concentrations of both O(3) (0.0, 0.10, 0.15, and 0.20 microliters per liter) and SO(2) (0.0, 0.20, and 0.40 microliters per liter) demonstrated that O(3) more effectively altered allocation than SO(2), that primary leaves were generally more sensitive than trifoliates, and that responses of trifoliate leaves varied with plant growth stage. Altered rates of allocation of photosynthate by leaves were generally associated with alterations of similar magnitude and opposite direction in developing pods. Collectively, these experiments suggest that allocation patterns can provide sensitive indices of incipient growth responses of pollution-stressed vegetation.
对两种菜豆（菜豆属普通菜豆，品种274和品种290）进行了一系列实验室暴露实验，以确定[(14)C]光合产物分配模式对二氧化硫（SO₂）和臭氧（O₃）变化的敏感性。对耐污染的274品种进行的实验表明，在每升0.50微升的SO₂中暴露长达40小时或在每升0.40微升的O₃中暴露4小时后，(14)C和生物量向(14)CO₂标记植物根系的分配出现短期变化，但对产量没有显著影响。随后对更敏感的290品种进行的实验表明，光合作用、光合产物在包括发育中的豆荚在内的植物各部分之间的转运和分配发生了显著变化。在每升0.75微升（每升·小时6.0微升）的SO₂中暴露8小时和在每升0.30微升·小时（3.3微升·小时）的O₃中暴露11小时后，光合产物在叶片中的滞留量显著增加（+40%）。在吸收(14)CO₂后对标记组织进行的时间序列采样表明，暴露停止后，转运模式的破坏至少持续1周。随后在较低浓度的O₃（每升0.0、0.10、0.15和0.20微升）和SO₂（每升0.0、0.20和0.40微升）下进行的长期暴露实验表明，O₃比SO₂更有效地改变了分配模式，初生叶通常比三出复叶更敏感，并且三出复叶的反应随植物生长阶段而变化。叶片光合产物分配速率的改变通常与发育中的豆荚中类似幅度但相反方向的改变相关。总体而言，这些实验表明，分配模式可以为受污染胁迫植被的初期生长反应提供敏感指标。
