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Title: PREDICTING BEHAVIOR OF PHYLLOSPHERE BACTERIA IN THE GROWTH CHAMBER FROM FIELD STUDIES

Author
item Upper, Christen
item HIRANO, SUSAN

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/1/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Controlled environments facilitate experimental manipulation, diminish environmental variability and provide the means to separate variables and test hypotheses. For many kinds of studies of plant- microbial interactions, results of experiments in controlled environment facitities have been readily applicable to the field. However, controlled environments may not serve particularly well as surrogates for the field for other types of studies. The interaction between Pseudomonas syringae pv syringae (Pss) and snap bean leaflets provides several examples in which the plant-bacterial interaction behaves differently in the field as compared to the laboratory. Field symptoms of bacterial brown spot disease on either leaves or pods are different compared to those on growth chamber- grown plants. Bacterial populations also may differ in the field and growth chamber. For example, numbers of pss on cultivar Eagle may be 1000- fold greater than on Bush Blue Lake 94 in the field, but approximately equal in the growth chamber. These observations indicate that careful field studies are essential if the whole picture of the interaction between the plant and bacteria is to be seen.

Technical Abstract: Use of a controlled environment facilitates experimental manipulation, diminishes environmental variability and provides the means to separate variables and test hypotheses. One common assumption is that results of experiments in such environments should be relevant to the phenomenon of interest in the field. For many kinds of plant-microbial studies,results sof experiments in controlled enviroment facilities have been readily applicable to the field. However, there are some kinds of studies for which controlled environments may not serve particularly well as surrogates for the field. The interaction between Pseudomonas syringae pv syringae (Pss) and snap bean leaflets provides several examples in which the plant- bacterial interaction behaves differently in the field as compared to the laboratory. Symptoms of bacterial brown spot disease on field-grown pods differ from those on growth chamber-grown pods. Numbers of pss on cultivar Eagle may be as much as 1000-fold greater than on Bush Blue Lake 94 in the field, but approximately equal in the growth chamber. When sprayed onto bean leaves in the growth chamber, pss grows, particularly when the plants are reasonably moist. In the field, even when leaves are wet with dew at night, populations of Pss decline or remain static. Occasional bursts of rapid growth, usually triggered by intense rain, give rise to large populations of the bacterium on plants in the field.