Tillering and leaf area index in grasses in the vegetative phase

The relationship between tillering of a vegetative grass stand and Leaf Area Index (LAI) has been studied during sward establishment of perennial ryegrass and Italian ryegrass with different seedling densities and nitrogen fertilizer rates and on established swards of tall fescue during winter and early spring after different dates of last cut in autumn. The different experiments on different species led to the conclusion that in every instance the tillering rate slows down as soon as the LAI reaches a value of 3 and terminates rapidly at higher LAI, which corresponds with the almost complete extinction of light at the level of the tiller buds. The results confirm the direct role of light on morphogenesis previously demonstrated by several authors. The existence of such a limit of LAI helps to explain some contradictory effects of temperature or nitrogen on tillering.

[1]  H. Thomas,et al.  The influence of light and temperature during winter on growth and death in simulated swards of Lolium perenne , 1981 .

[2]  A. Davies,et al.  Regrowth of perennial ryegrass as affected by simulated leaf sheaths , 1983, The Journal of Agricultural Science.

[3]  J. Casal,et al.  Variations in Tiller Dynamics and Morphology in Lolium multiflorum Lam.Vegetative and Reproductive Plants as affected by Differences in Red/Far-Red Irradiation , 1985 .

[4]  J. Casal,et al.  Effects of Light Quality on Tiller Production in Lolium spp. , 1983, Plant physiology.

[5]  M. Robson.  The Effects of Temperature on the Growth of S.170 Tall Fescue (Festuca arundinacea). II. Independent Variation of Day and Night Temperatures , 1973 .

[6]  M. Robson.  The Effect of Temperature on the Growth of S170 Tall Fescue (Festuca arundinacea). III. Leaf Growth and Tiller Production as Affected by Transfer Between Contrasting Regimes , 1974 .

[7]  K. Mitchell.  Influence of Light and Temperature on the Growth of Ryegrass (Lolium spp.) II. The Control of Lateral Bud Development , 1953 .

[8]  S. Kays,et al.  The regulation of plant and tiller density in a grass sward , 1974 .

[9]  A. Davies,et al.  Rates of Leaf and Tiller Production in Young Spaced Perennial Ryegrass Plants in Relation to Soil Temperature and Solar Radiation , 1983 .

[10]  A. Davies.  Leaf tissue remaining after cutting and regrowth in perennial ryegrass , 1974, The Journal of Agricultural Science.

[11]  A. Davies,et al.  Changes in growth rate and morphology of perennial ryegrass swards at high and low nitrogen levels , 1971, The Journal of Agricultural Science.

[12]  J. Simon.  Evolution de l'indice foliaire d'un peuplement de ray-grass d'Italie (Lolium multiflorum Lam.) en phase d'implantation , 1985 .