Short-term control of root : shoot partitioning

• Published in: Journal of experimental botany 1994-05, Vol.45 (274), p.615-622
• Main Authors: Minchin, P.E.H., Thorpe, M.R., Farrar, J.F.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Barley; Biological and medical sciences; Cooling; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Leaves; Metabolism; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Nitrogen; Nutrition. Photosynthesis. Respiration. Metabolism; Phloem; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology; Plant physiology and development; Plant roots; Plants; Roots of functions; Seedlings
• ISSN: 0022-0957; 1460-2431

We present data showing that the fraction of the available photosynthate partitioned between the root and the shoot of a barley seedling is affected by the supply of photosynthate from the source leaf: an increased fraction of the exported photosynthate goes to the shoot when supply is reduced. Also, if the roots are cooled a short time before reducing the supply of photosynthate, then the effect of a reduced supply upon partitioning is reversed with an increased fraction then going to the root. We conclude that the distribution of available photosynthate between competing sinks is influenced by source supply as well as sink function. The reported source—sink interactions are consistant with the predictions of a recently proposed model of source—sink interaction (Minchin et al., 1993). The concept of marginal partitioning is introduced to describe the distribution, between all of the sinks, of a small change in photosynthate supply.