Apparent stimulations of plant growth by air pollutants

Abstract

rnco~rver, Britislr Colrunbia Received Ailgust 16, 1973 BENNETT, J. P., H. M. RESH, and V. C. RUNECKLES. 1974. Apparent stimulations of plant growth by air pollutants. Can. J. Bot. 52: 35-41. A survey of recent literature on the effects of low levels of air pollutants on lants, and the results of our experiments with low levels of ozone ( < 0.1 ppm) on bean (Plraseolos vir?grrris), barley (Horderrti~ vrrlgare), and smartweed (Polygot~rrt~~ Iapntlrifr,lirm~) indicate stin~ulations of various growth parameters when compared with growth in clean, filtered air. Increasing knowledge of the composition of air in various regions of the world has been interpreted by some as evidence of increased air pollution. We argue that such a conclusion may not necessarily be valid, and that the observed levels of individual constituents may be indicative of long-term air composition. The similarity between the ambient levels of pollutants reported from numerous locations and those which result in stimulations of plant growth when compared with clean air, suggests that plants exhibiting such stimulations have adapted to low pollution levels, and hence are at a disadvantage when grown in clean air. We argue that the use of filtered air controls in experiments on the effects of air pollutants on plants is therefore unrealistic and misleading, and should be replaced by the use of ambient levels of pollution.BENNETT, J. P., H. M. RESH et V. C. RUNECKLES. 1974. Apparent stimulations of plant growth by air pollutants. Can. J. Bot. 52: 35-41. Une revue de la littirature rCcente consacrCe aux effets de faibles concentrations de substances polluantes sur les plantes, ainsi que les rksultats de nos expkriences sur les effets de faibles niveaux d'ozone (<0.1 ppm) sur le haricot (Plioseolrrs virlgaris), I'orge (Hordeun~ vulgare) et Polygotrim~ lapatliifolirrm indiquent une stimulation de divers paramktres de croissance par cornparaison avec la croissance dans un alr propre filtre. Certains auteurs ont interprCtC la connaissance accrue que l'on a de la composition de l'air dans diverses regions du globe comme une preuve de l'augmentation de la pollution de l'air. Nous croyons qu'une telle conclusion n'est pas nicessairement valide et que la concentration de certaines substances peut caractkriser la composition de l'air a long terme. La similitude entre les concentrations ambiantes de substances polluantes rapportCes pour nombreuses localites et les concentrations qui produisent une stimulation de la croissance des plantes, par rapport a la croissance dans l'air pur, implique que les plantes presentant de telles stimulations se sont adaptCes a de faibles niveaux de pollution et sont donc desavantagees lorsqu'elles croissent dans l'air pur. Nous croyons donc qu'il est irrialiste et fallacieux d'utiliser un air filtrC dans les expiriences tCmoins lorsqu'on etudie l'effet de la pollution aCrienne sur les plantes; on devrait plut6t utiliser comme tCmoin le niveau ambiant de pollution. [Traduit par le journal]

Arthropods as Indicators of the Effects of Fluoride Pollution on the Succession Following Sand Mining

“…First, low levels of fluoride have previously been noted to cause an increase in plant growth of fluoride-tolerant species (Treshow & Harner 1968;Treshow 1970;Bennett et al 1974;Bruce 1985). This is usually proposed to be the result of a physiological stimulation of plant tissue elongation that is not beneficial to the plant (Bennett et al 1974;Bruce 1985). Decreased competition from fluoride-intolerant species may also result in competitive release of those species that are fluoride-tolerant (Murray 198 la;Ryan 1992).…”

“…Atmospheric fluoride (F) has also been shown to be toxic to some species of plants at levels as low as 0 02 [mol m-3 (Weinstein & Alscher-Herman 1982). However, resistance to fluoride is found to vary widely between species and many studies have found low levels of fluoride to stimulate the growth of fluoride-tolerant plant species (Treshow 1970;Bennett, Resh & Runeckles 1974;Bruce 1985). Decreased survival of intolerant species will produce shifts in plant associations and vegetation structure.…”

Growth and reproduction of vascular plants in polluted environments: a synthesis of existing knowledge

“…Similarly, air pollution was found to frequently disturb reproductive processes, thereby leading to reduced pollen and seed production, size, and viability (Smith 1981;Bonte 1982;Lechowicz 1987;Cox 1988aCox , 1988bCox , 1992. At the same time, several studies found no detrimental effects of industrial pollutants on plant growth and reproduction (Kozlov and Zvereva 2004;Umanova 2004;Elkarmi 2006), and even strong ''positive'' effects have sometimes been recorded (Bennett et al 1974;Chubanov et al 1989;Zvereva et al 1997;Dhir et al 1999;Salemaa et al 1999;Zvereva and Kozlov 2001;Savinov 2003;Kozlov and Zvereva 2007b). The reasons behind this variation in plant responses to pollution, to our knowledge, have not been examined.…”

Does Impact of Point Polluters Affect Growth and Reproduction of Herbaceous Plants?

“…Retarded growth is commonly considered as one of the very general and best known plant responses to industrial emissions including sulphur dioxide, fluorine and heavy metals (Odum 1985;Treshow and Anderson 1989), although 'positive' effects of these pollutants have also been documented (Bennett et al 1974;Lechowicz 1987). Many textbooks and review papers (e.g.…”