EFFECTS OF EDAPHIC FACTORS ON SOLUBLE CARBOHYDRATE CONTENT OF ROOTS OF LOLIUM PERENNE L AND TRIFOLIUM REPENS L

In a 33×22 factorial experiment with Lolium perenne L. and Trifolium repens L. grown at three soil moisture tensions, three levels of nitrogen and three levels of phosphorus, there was a wide range of percentage soluble carbohydrate (TSC) in the roots. The significant positive correlations between percentage of TSC and root weight suggest that root growth-rate was proportional to the concentration of TSC in the roots.In other experiments with Lolium perenne grown at five constant soil temperatures and factorial combinations with three soil moisture treatments with and without manure, there was decline in the percentage of TSC with increasing temperature. This implied that the respiration sink strength in the roots did not control the partitioning of photosynthate to the roots.No firm conclusions can be drawn from this work, but it is inferred that there is a dynamic balancing mechanism in the foliage which controls the partitioning of photosynthate between foliage and root growth. This mechanism appears to divert carbohydrate to roots in inverse proportion to root activity. © 1969 OXFORD UNIVERSITY PRESS.