PLANT PHYSIOLOGY , Vol 114, Issue 3 1055-1059, Copyright © 1997 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
Maternal, Single-Gene Regulation of Assimilate Partitioning in Pea
M. O. Kelly and R. M. Spanswick
Section of Plant Biology, Division of Biological Sciences, Cornell University, Ithaca, New York 14853-5908
Assimilate partitioning has been identified as a key process in the control
of yield. Although the role of reproductive structures in this process has
received intensive study, our understanding of the role of the maternal
plant is limited. We suggest that the Sn gene of pea (Pisum sativum L.) is
a potentially valuable genetic tool for studying maternal regulation of
partitioning. In this study, nearly isogenic lines differing at the Sn
locus were compared with respect to seed-filling characteristics and carbon
assimilation. Lines with the Sn gene had a slower rate and shorter duration
of seed growth than the line recessive for this gene, and these traits
could not be ascribed to reduced carbon assimilation. Flowers of the two
nearly isogenic lines were manually pollinated to control the genotype of
the developing embryo independently of the maternal genotype. The final dry
weight of the seed was determined by the genotype of the maternal plant and
not by the genotype of the embryo, supporting the hypothesis that the Sn
gene acts in the vegetative plant to regulate the partitioning of
assimilates between vegetative and reproductive growth. Although the Sn
gene has been noted for delaying apical senescence, it also delayed leaf
senescence in this study; leaves of the Sn line continued to
photosynthesize long past the time that leaves of the recessive line had
senesced and after the seeds and pods were dry.
