A new practical tool for deriving a functional signature for herbaceous vegetation

Hypothesis: For any one time and place a ‘functional signature’ can be derived for a sample of herbaceous vegetation in a way that concisely represents the balance between the different clusters of functional attributes that are present among component species. Methods: We developed a spreadsheet‐based tool for calculating functional signatures within the context of the C‐S‐R system of plant functional types. We used the tool to calculate and compare signatures for specimen British vegetation samples which differed in management regime and location in time. Conclusion: The integrative power of the ‘C‐S‐R signature’ is useful in comparative studies involving widely differing samples. Movements in the signature can be used to indicate degree of resistance, resilience, eutrophication and dereliction. Systems of plant functional types other than C‐S‐R might also be approached in this way. Availability: The tool can be downloaded free of charge from the first author's web pages or from the journal's electronic archive.     

Nodulation of Hydroponically Grown Soybean Plants and Inhibition of Nodule Development by Nitrate

A procedure is described for obtaining a large number of nodules(approximately 1000) on a hydroponically grown soybean plantafter a brief exposure to Rhizobium japonicum. This procedurewas used to study the effect of medium nitrate upon nodulationof the soybean plant. It was found that nitrate, at concentrationsequal to or greater than 2.0 mM, restricted nodule developmentbut did not inhibit appreciably the activity or synthesis ofnitrogenase in those few nodules that were formed. Key words: Soybean, Rhizobium japonicum, Nodulation