Location of Repository

The effects of long-day lighting and removal of young leaves on tomato yield

By V. M. Valdes, G. C. Woodward and S. R. (Steven R.) Adams


While low intensity long-day (LD) lighting has been shown to enhance the growth of young plants under low light levels, its effect on the yield of a long-season glasshouse tomato crop has not been previously examined. LD were provided by the use of tungsten lamps (2.8 μmol m-2 s-1 at approx. 0.5 m from the ground) between 04.00 h to sunrise and from sunset until 20.00 h (GMT). LD lighting increased leaf chlorophyll contents, and the numbers of flowers and fruits set per truss when the plants were young. However, this treatment did not affect the total yield of tomatoes. Different leaf removal treatments were applied within each glasshouse compartment. A previous experiment had shown that reducing the leaf area index (LAI) from 5.2 to 2.6, by removing old leaves, did not affect yield. It was also thought that removal of young leaves reduced the total vegetative sink-strength and favoured assimilate partitioning into the fruit. Therefore, removal of young leaves could increase fruit yield. In the present experiments, one-third of the leaves were removed in March (those immediately below each truss) and, subsequently, every third leaf was removed at an early stage of its development. This reduced the LAI from 4.1 to 2.9 and resulted in a loss of yield from 3 – 4 weeks after leaf removal until the end of the experiment, at which point there was an 8% loss of cumulative yield due to a reduction in the average number of fruits set per truss and in mean fruit weight. We postulate that the light which would have been intercepted by young photosynthetically-efficient leaves at the top of the canopy was intercepted instead by older leaves which were less efficient, reducing overall net canopy photosynthesis

Topics: SB
Publisher: Headley Brothers Ltd.
Year: 2010
OAI identifier: oai:wrap.warwick.ac.uk:2912

Suggested articles



  1. (2001). Defoliation of greenhouse tomato plants and its effects on dry matter accumulation and distribution to fruits.
  2. (2005). Effect of leaf area on tomato yield.
  3. (1948). Effects of different chlorophyll concentrations on photosynthesis in foliage leaves. doi
  4. (2006). Efficiency of light energy used by leaves situated in different levels of a sweet pepper canopy.
  5. (1986). Glasshouse crop production. In: The Tomato Crop. A Scientific Basis for Improvement doi
  6. (1973). Long-day effects on growth and flower initiation of tomato plants in low light. doi
  7. (2005). Photoperiod and plant growth: a review.
  8. (1997). Photosynthesis in leaves, fruits, stem and petioles of greenhouse-grown tomato plants. doi
  9. (1991). Photosynthetic and respiratory characterization of field grown tomato. doi
  10. (2007). Plant physiological acclimation to irradiation by light-emitting diodes (LEDs).
  11. (1978). The contribution of leaves from different levels within a tomato crop to canopy net photosynthesis: an experimental examination of two canopy models. doi
  12. (2004). The design and evaluation of a shade screen to overcome within-row variability of tomato crops grown in small experimental glasshouse compartments.
  13. (2002). The effects of leaf removal and modifying temperature set-points with solar radiation on tomato yields.
  14. (2004). Two instead of three leaves between tomato trusses: measured and simulated effects on partitioning and yield.
  15. (2008). Why does low intensity, long-day lighting promote growth in Petunia, Impatiens and tomato?

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.