Continuous Fluorescent Illumination Enhances Growth and Fruiting of Pepper.

Abstract

Prolonging the photoperiod to continuous illumination (CI) implies a longer photosynthetic period which might be ideal for better plant growth. Pepper (Capsicum annuum L.) were grown in a nutrient culture system under a 12-h photoperiod for 6 weeks. Another group of plants was grown under a 12-h photoperiod for 3 weeks and then grown under a 24-h photoperiod (12/24-htreatment) for 3 more weeks. All seedlings were exposed to a low photosynthetic photon flux (PPF) of 120μmol·m-2s-1. The plants in the 12/24-h treatment gained more shoot dry weight, produced more leaves with heavier specific leaf weight (SLW), and had greater fruit set than those grown under a 12-h photoperiod. In a replicated experiment, the response was enhanced when a third group of plants was exposed to CI for 9 weeks just after germination. The higher shoot dry weight, and lack of further accumulation of starch in new leaves under CI indicate that the extensive carbon fixed under CI at low PPF was utilized effectively for pepper plant growth.