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Annals of Botany 73: 665-669, 1994
© 1994 Annals of Botany Company
Analysis of Dry Matter Partitioning in Dactylis glomerata during Vegetative Growth Using a Carbon Budget Model
Centre d'Ecologie et Physiologie Energétiques--CNRS, 23 Rue Becquerel, 67087 Strasbourg, France
The dry matter partitioning in vegetative plants of Dactylis glomerata was studied from experiments performed in controlled environments. Plants were grown hydroponically in growth chambers, at two constant temperatures (17 and 25 °C). In both experiments the root fraction decreased regularly with time, an effect that was more accentuated in the higher temperature regime. In order to explain the change in dry matter partitioning, the experimental shoot and root growth were analysed using a carbon budget model which includes shoot and root maintenance requirements. The model predicts a relationship between the root specific growth rate and the product of shoot specific growth rate and shoot to root dry weight ratio. In the range of experimental accuracy, this relationship was found to be linear at both temperatures, which should indicate that the partitioning coefficients and the root maintenance coefficient remained constant during vegetative growth. The effect of temperature on the value of these coefficients can be specified from a linear regression analysis. Between 17 and 25 °C, the root maintenance coefficient increased by about a factor of two, whereas the partitioning coefficients did not vary significantly. On the basis of these results, it was shown that the decrease in root fraction during vegetative growth should be mainly attributed to the decrease in net specific activity of shoots.Copyright 1994, 1999 Academic Press
Dactylis glomerata L., vegetative growth, model, partitioning, root:shoot ratio, shoot specific activity, maintenance requirements