Growth of rice plants under red light with or without supplemental blue light

Abstract

The effects of blue light supplementation to red light on growth, morphology and N utilization in rice plants (Oryza sativa L. cv. Sasanishiki and Nipponbare) were investigated. Plants were grown under two light quality treatments, red light alone (R) or red light supplemented with blue light (RB; red/blue-light photosynthetic photon flux density [PPFD] ratio was 4/1), at 380 µmol m −2 s −1 PPFD. The biomass production of both cultivars grown under RB conditions was higher than that of plants grown under R conditions. This enhancement of biomass production was caused by an increase in the net assimilation rate (NAR). The higher NAR was associated with a higher leaf N content per leaf area at the whole-plant level, which was accompanied by higher contents of the key components of photosynthesis, including Rubisco and chlorophyll. In Sasanishiki, preferential biomass investment in leaf blades and expansion of wider and thinner leaves also contributed to the enhancement of biomass production. These morphological changes in the leaves were not observed in Nipponbare. Both the changes in physiological characteristics, including leaf photosynthesis, and the changes in morphological characteristics, including leaf development, contributed to the enhancement of biomass production under RB conditions, although the extent of these changes differed between the two cultivars.

Plant Responses to Extended Photosynthetically Active Radiation (EPAR)

“…In published papers, light treatment is normally mentioned in µmol m -2 s -1 . Further clarifications are usually the type of light source, (white) fluorescent tubes, incandescent lamps, etc., [20][21][22][23][24] which all are just brands or common names with little scientific value. In addition, mentioning the type of light source is complicated by different light sources from various manufacturers.…”

“…Ohashi-Kaneko et al 22 reported that 22 B+R compared with R alone in rice at the same overall PAR increased its net assimilation rate, biomass production, Rubisco, and chl content. Since Rubisco is the most important target to be manipulated for boosting crop photosynthesis 55 being oblivious 55 to the knock-on effect of light quality on photosynthesis does not seem sensible.…”

Differences in plant growth and leaf sesamin content of the lignan-rich sesame variety ^|^#8216;Gomazou^|^#8217; under continuous light of different wavelengths

“…Our study also demonstrated growth reduction under red LED light compared with white fluorescent light (Tables 1, 2). In various plant species, blue-light supplementation to red LED light has been reported to enhance the growth and/or photosynthetic rates of plants compared with those grown under red LED light alone (Goins et al 1997;Hogewoning et al 2010;Matsuda et al 2004Matsuda et al , 2007Ohashi-Kaneko et al 2006;Yorio et al 2001). Sesame plants also seemed to require blue-light supplementation to red LED light for normal growth.…”

Rice yield corresponding to the seedling growth under supplemental green light in mixed light-emitting diodes

“…A number of studies demonstrated that the combination of red and blue light was an effective light source for plant growth (Lian et al 2002, Nhut et al 2003, Matsuda et al 2004, Jao et al 2005, Ohashi-Kaneko et al 2006, Johkan et al 2010). However, it was found that the highest stem width, shoot and root height, dry weight of shoot and root were all observed in RBG 12.5 while not in RB.…”