Physiological response of greenhouse vegetable crops to supplemental lighting

摘要

In northern regions, the major limiting factor for winter greenhouse production is the low natural light level when CO2, water and nutrients are adequately provided. Current use of supplemental lighting is often restricted to propagation and transplant production. In the province of Quebec, hydro-electricity is not very expensive and can be used by growers during the main crop growth period. Consequently, year-round production of greenhouse vegetables could be maintained and could replace imports of field-grown vegetables from lower latitudes during the winter months. Fifteen years ago, Dr Trudel started an important research program on supplemental lighting of several vegetable crops. The physiological influence of artificial light intensity and photoperiod on seedling production as well as on vegetable crop production has been well studied. Crop management recommendations were made for Quebec growers and nowadays, almost all lettuce growers use artificial lighting. Approximately 10% of cucumber growers and 15% of tomato growers are now producing during winter time with artificial lighting. The demand for high quality products year-round by consumers sustains this technology for the greenhouse industry. This paper will give an overview of the major work conducted at Laval University, Quebec, Canada over the past few years with emphasis on the carbohydrate metabolism of tomato, and conclude on the best strategy for artificial lighting utilization.