Abstract
In a glasshouse experiment, single plants of ten-weeks old white clover (Trifolium repens L.) were subjected to two levels of shading and two levels of defoliation. Nodulation and nitrogen fixation parameters were measured at six sequential harvest over four weeks.
Changes in nodule number and hence nodule dry weight per plant were due to nodule decay, sloughing off and non-production and were closely related to losses in root dry weight.
Severe defoliation caused degradation of leghaemoglobin, an effect which was seen in less than three days from treatment. It led also to a temporary but marked decrease in the nitrogen fixation capacity of the nodules as measured by the acetylene reduction assay. Recovery of normal activity by the nitrogenase system took about ten days.
The effects of shading and defoliation on the pattern of nodulation have been described briefly.
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Chu, A.C.P., Robertson, A.G. The effects of shading and defoliation on nodulation and nitrogen fixation by white clover. Plant Soil 41, 509–519 (1974). https://doi.org/10.1007/BF02185812
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DOI: https://doi.org/10.1007/BF02185812