Degree Name

Master of Science (MS)

Semester of Degree Completion

1978

Thesis Director

Charles B. Arzeni

Abstract

Extensive studies have been reported on the air pollutant sulphur dioxide (SO2), and its effects on vascular and nonvascular plants. It has been shown to interrupt normal physiology, metabolism, reproduction, and alter the plant’s morphology.

Of the cryptogams, lichens have been extensively used as biological indicators of air pollution. More recently, bryophytes have been shown to be as sensitive to contaminates as lichens, and may exhibit responses to the pollutant similar to those of vascular and nonvascular plants. The threshold sensitivity of these cryptogams is about 0.5 ppm over a 12 hour period. However no study to date has investigated the utilization of hepatics as possible pollution indicators.

The intent of this research was to investigate the general responses of selected liverworts to sulphur dioxide. The liverworts used were: Blasia pusilla L., Lophocolea heterophylla (Schrad.) Dum., Scapania nemorosa (L.) Dum. and Jamesoniella autumnalis (D.C.) Steph. The thalli were fumigated under varying SO2 concentrations in an ecological chamber for 8 hours. All thalli exhibited a marked discoloration (chlorosis) which varied directly with the SO2 concentration. Chlorophyll analysis showed a 34-37% decrease in total chlorophyll content at 0.4 ppm SO2 concentration. Numerical data concerning Blasia reflects a conflict with chlorophyll extraction procedures of a plant and an algae. The SO2 caused degradation in chlorophylla whether plant or algal, which did account for the loss in total chlorophyll.

These liverworts exhibit a typical response to SO2 and have a threshold equal to, or slightly less than, other cryptogams.

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