Article ID Journal Published Year Pages File Type
6407194 Scientia Horticulturae 2014 9 Pages PDF
Abstract

•Effects of continuous light (CL) with or without a DIF were investigated in tomato.•CL and zero DIF initially affected different processes in photosynthetic metabolism.•Thereafter CL and zero DIF had additive negative effects on leaf photosynthesis.•Such negative effects were reflected in dry matter production at the plant level.•Severity of CL-induced injury was correlated with nighttime soluble-sugar turnover.

Effects of continuous lighting (CL) with or without a diurnal temperature difference (DIF) on leaf photosynthesis, plant growth and development, and carbohydrate accumulation were investigated with tomato. Plants were grown for four weeks under a photoperiod of 12 h d−1 or CL of 24 h d−1, each combined with a DIF of 10 or 0 °C. Measurements included: leaf net photosynthetic rates, the maximal quantum efficiency of PSII, growth analysis, and quantification of leaf carbohydrates. Severe and moderate CL-induced injury was found on leaves grown under CL with a DIF of 0 and 10 °C, respectively, while it was not observed for plants under 12 h d−1 photoperiod. On the other hand, the apparent severity of the CL-induced injury was not necessarily correlated with leaf net photosynthetic rates. At the initial treatment phase, CL reduced the light-limited photosynthesis while zero DIF reduced the light-saturated photosynthesis, suggesting that CL and zero DIF independently affected different processes in leaf photosynthetic metabolism. Thereafter, CL and zero DIF additively reduced both the light-limited and -saturated photosynthesis. Net photosynthetic rate of leaves under the respective growth conditions were also lowered under CL and/or zero DIF. Such reductions of leaf photosynthesis were reflected in dry matter production at the whole-plant level through decreases in net assimilation rate. Analysis of leaf carbohydrate contents revealed that apparent severity of the CL-induced injury was associated with the diurnal turnover of soluble sugars, suggesting it to be a factor possibly causing the injury.

Related Topics
Life Sciences Agricultural and Biological Sciences Horticulture
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