Cooley D R, Manning W J
Department of Plant Pathology, University of Massachusetts, Amherst, MA 01003, USA.
Environ Pollut. 1988;49(1):19-36. doi: 10.1016/0269-7491(88)90011-5.
Alfalfa (Medicago sativa L.) were exposed to O(3) concentrations varying between 118 x 10(-6) microg cm(-3) (0.06 ppm) and 157 x 10(-6) microg cm(-3) (0.08 ppm) for 6 h per day 5 days per week for several weeks. Typical plants were sacrificed weekly, and growth parameters were measured. O(3) reduced overall growth, relative growth rates and unit leaf rates in alfalfa before it was cut, indicating that O(3) had reduced photosynthesis. However, after the alfalfa was cut, these same parameters indicated that in some cases, O(3)-stressed plants had greater photosynthetic rates than controls during regrowth. O(3) also altered dry matter partitioning. Roots were most affected, followed by leaves and stems, respectively. In general, O(3) reduced photosynthate production and reduced the proportion of photosynthate partitioned to roots relative to leaves and stems. This could reduce starch reserves in alfalfa, and be detrimental to stand longevity. However, the post-cutting study indicated that at least some alfalfa cultivars may be able to acclimate to O(3)-stress, though plants did not fully recover from pre-cutting differences.
紫花苜蓿(Medicago sativa L.)每周5天,每天6小时暴露于浓度在118×10⁻⁶微克/立方厘米(0.06 ppm)至157×10⁻⁶微克/立方厘米(0.08 ppm)之间的臭氧环境中,持续数周。每周选取典型植株进行采样,并测量生长参数。在紫花苜蓿刈割前,臭氧降低了其整体生长、相对生长速率和单位叶面积生长速率,这表明臭氧抑制了光合作用。然而,在紫花苜蓿刈割后,这些相同参数表明,在某些情况下,受臭氧胁迫的植株在再生过程中的光合速率高于对照。臭氧还改变了干物质分配。根系受影响最大,其次是叶片和茎。总体而言,臭氧减少了光合产物的产生,并降低了光合产物分配到根系相对于叶片和茎的比例。这可能会减少紫花苜蓿中的淀粉储备,并对植株的寿命产生不利影响。然而,刈割后的研究表明,至少一些紫花苜蓿品种可能能够适应臭氧胁迫,尽管植株并未从刈割前的差异中完全恢复。