Flowering in Peas: Effect of the Gene Hr on Spectral Sensitivity1
- J. B. Reid2
A differential flowering response to fluorescent and incandescent light has been observed among different lines of peas (Pisum sativum L.). The present study set out to find the genetic basis for this response and to ascertain whether the response was due to an effect on the spectral sensitivity of the pigment system involved. The flowering node and time of flowering of homozygous lines carrying the gene Hr (in combination with gene Sn) is substantially delayed when an 8-hour photoperiod is extended with 8 hours of light from a fluorescent source compared to plants where the extension comes from a mixed fluorescent-incandescent source. On the other hand, lines homozygous for the gene hr (in combination with gene Sn) are only marginally delayed under these conditions. Flowering in all four lines examined is significantly delayed by an 8-hour photoperiod with no photoperiod extension. These results show that the gene Hr is responsible for the differential response. However, both genotype Sn Hr and Sn hr show typical phytochrome red-far-red reversibility and similar response patterns to broad band red, far-red, and blue light. Therefore, the gene Hr is unlikely to have a direct effect on spectral sensitivity. Rather, the differential response reported is probably an artifact of the threshold nature of the process of flower initiation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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