Light Intensity and Floral Transition: Chloroplast Says “Time to Flower!”

Abstract

Flowering represents a pivotal developmental transition from the vegetative stage to the reproductive stage. The timing of flowering must be carefully controlled under ever-changing environmental conditions to ensure successful reproduction. Extensive genetic and molecular biological analyses in the model species Arabidopsis thaliana have identified important regulators of flowering time and revealed a complex network of highly interconnected pathways that are regulated by seasonal cues (e.g., light and temperature) and internal factors (e.g., age and nutrient availability) (Bouche et al., 2016). Among the environmental factors that affect plant growth and development, the molecular mechanism underlying the control of flowering time by light is well known. For instance, the photoreceptor phytochrome B perceives changes in light quality (i.e., spectral composition) to modulate flowering time (Cerdan and Chory, 2003). Plants also sense day length to flower under the appropriate inductive conditions. Photoperiodic flowering is regulated by the circadian clock timing system (Johansson and Staiger, 2015), in which LATE ELONGATED HYPOCOTYL (LHY), CIRCADIAN CLOCK ASSOCIATED1 (CCA1), and TIMING OF CAB EXPRESSION1 (TOC1) play an important role. These signals that are perceived by the circadian clock and light signaling systems are eventually mediated by a few floral integrators including FLOWERING LOCUS T (FT) (Pin et al., 2010; Song et al., 2012). However, the effects of changes in light intensity on plant development, particularly flowering time, remain poorly understood.

Apple tree flowering is mediated by low level of melatonin under the regulation of seasonal light signal

“…The sessile plants are directly exposed to the seasonally changed light, which also results in the change of photoperiod and temperature. Accumulated data have confirmed that flowering was triggered by the light alterations . In both annual herbal plants and perennial woody plants, light plays a central role in flowering regulation.…”

“…Accumulated data have confirmed that flowering was triggered by the light alterations. [18][19][20][21][22] In both annual herbal plants and perennial woody plants, light plays a central role in flowering regulation. The well-known mechanism is that light period is measured by the circadian clock in leaves, which controls the release of florigen to the shoot apex for subsequent floral initiation.…”

OFP1 Interaction with ATH1 Regulates Stem Growth, Flowering Time and Flower Basal Boundary Formation in Arabidopsis

“…Previous research has showed that the expression of ATH1 could activate FLC , a flowering repressor [ 16 , 33 , 34 , 35 ]. However, it is not known if OFP1 function in regulation of FLC expression involves an interaction between OFP1 and ATH1.…”

Comparative proteomic analysis of multi-ovary wheat under heterogeneous cytoplasm suppression

“…Chloroplasts are the site of photosynthesis and multiple anabolic reactions essential for growth, development, and reproduction [41]. Signals from chloroplasts can modulate nuclear gene expression and regulate plant development, including flower development [42–44]. An Arabidopsis mutant, lacking the chloroplast-localized rhomboid protease, exhibited either a double stigma or a single stigma with distortions in shape and size [45].…”