Seed Size Effects on Early Seedling Growth and Response to Applied Nitrogen in Annual Ryegrass (Lolium multiflorum L.)

Paul W.  Bartholomew

doi:10.4236/as.2015.610118

Paul W. Bartholomew

Abstract: Use of individual plants as experimental units may be necessary when resources are limited, but inter-plant variation risks obscuring differences among treatments. Experiments were undertaken to measure the effects of seed size on seedling size and response to applied nitrogen of annual ryegrass (Lolium multiflorum L.) harvested six or nine weeks after emergence. In two series of experiments, shoot and root dry weights of seedlings increased respectively at means of 53 - 61 and 29 - 30 mg·mg-1 increase in mean seed weight. Between the largest and smallest seed sizes used in this study, there was 83% difference in shoot weight at harvest six weeks after emergence and 22% difference with harvest nine weeks after emergence. Nitrogen (N) application, in comparison, increased shoot dry weights by averages of 69% and 77% with harvests at six or nine weeks, respectively. Dry mass response to N application was similar across seed size categories in shoots or roots. A mean 30% of total seedling-N was retained in roots. Nitrogen utilization efficiency for shoot growth (increase in shoot growth per unit increase in shoot N capture) ranged from 64 mg·mg-1 with harvest six weeks after emergence to 114 mg·mg-1 with harvest at nine weeks after emergence. Delay in seedling harvest from six to nine weeks post-emergence and use of closely-graded seed can reduce variation in individual seedling size and contribute to reduction in random variation in small-scale experiments.

Keywords: Seed Size, Seedling Growth, Lolium multiflorum

Cite this paper: Bartholomew, P. (2015) Seed Size Effects on Early Seedling Growth and Response to Applied Nitrogen in Annual Ryegrass (Lolium multiflorum L.). Agricultural Sciences, 6, 1232-1238. doi: 10.4236/as.2015.610118.

References

[1] Harkess, R.D. (1965) The Effect of Seed Size on Early Growth of Diploid and Tetraploid Italian Ryegrass. Journal of the British Grassland Society, 20, 190-193.
http://dx.doi.org/10.1111/j.1365-2494.1965.tb00421.x

[2] Arnott, R.A. (1969) The Effect of Seed Weight and Depth of Sowing on the Emergence and Early Seedling Growth of Perennial Ryegrass (Lolium perenne). Journal of the British Grassland Society, 24, 104-110.
http://dx.doi.org/10.1111/j.1365-2494.1969.tb01053.x

[3] Lewis, E.J. and Garcia, J.A. (1979) The Effect of Seed Weight and Coleoptile Tiller Development on Seedling Vigour in Tall Fescue, Festuca arundinacea Schreb. Euphytica, 28, 393-402.
http://dx.doi.org/10.1007/BF00056597

[4] Evans, P.S. (1973) Effect of Seed Size and Defoliation at Three Development Stages on Root and Shoot Growth of Seedlings of Some Common Pasture Species. New Zealand Journal of Agricultural Research, 16, 389-394.
http://dx.doi.org/10.1080/00288233.1973.10421121

[5] Venuto, B.C., Redfearn, D.D., Pitman, W.D. and Alison, M.W. (2002) Seed Variation among Annual Ryegrass Cultivars in South-Eastern USA and the Relationship with Seedling Vigour and Forage Production. Grass and Forage Science, 57, 305-311.
http://dx.doi.org/10.1046/j.1365-2494.2002.00328.x

[6] Sanderson, M.A. and Elwinger, G.F. (2004) Emergence and Seedling Structure of Temperate Grasses at Different Planting Depths. Agronomy Journal, 96, 685-691.
http://dx.doi.org/10.2134/agronj2004.0685

[7] Venuto, B.C., Redfearn, D.D., Pitman, W.D. and Alison, M.W. (2004) Impact of Seeding Rate on Annual Ryegrass Performance. Grass and Forage Science, 59, 8-14.
http://dx.doi.org/10.1111/j.1365-2494.2004.00397.x

[8] Genstat (2008) Genstat for Windows, Release 11.1.0.1575. 11th Edition, VSN International Ltd., Oxford.

[9] Hayes, P. (1976) Seedling Growth of Four Grasses. Journal of the British Grassland Society, 31, 59-64.
http://dx.doi.org/10.1111/j.1365-2494.1976.tb01118.x

[10] Crush, J.R., Easton, H.S., Waller, J.E., Hume, D.E. and Faville, M.J. (2007) Genotypic Variation in Patterns of Root Distribution, Nitrate Interception and Response to Moisture Stress of a Perennial Ryegrass (Lolium perenne L.) Mapping Population. Grass and Forage Science, 62, 265-273.
http://dx.doi.org/10.1111/j.1365-2494.2007.00583.x

[11] Hirose, T. (2012) Leaf-Level Nitrogen Use Efficiency: Definition and Importance. Oecologia, 169, 591-597.
http://dx.doi.org/10.1007/s00442-011-2223-6

[12] Legay, N., Personeni, E., Slezack-Deschaumes, S., Piutti, S. and Cliquet, J.-B. (2014) Grassland Species Show Similar Strategies for Sulphur and Nitrogen Acquisition. Plant and Soil, 375, 113-126.
http://dx.doi.org/10.1007/s11104-013-1949-9

[13] Vasquez de Aldana, B.R. and Berendse, F. (1997) Nitrogen-Use Efficiency in Six Perennial Grasses from Contrasting Habitats. Functional Ecology, 11, 619-626.
http://dx.doi.org/10.1046/j.1365-2435.1997.00137.x

[14] Crush, J.R., Waller, J.E. and Care, D.A. (2005) Root Distribution and Nitrate Interception in Eleven Temperate Forage Grasses. Grass and Forage Science, 60, 385-392.
http://dx.doi.org/10.1111/j.1365-2494.2005.00488.x