Regulation of Flowering Time by Environmental Factors in Plants

Abstract

The timing of floral transition is determined by both endogenous molecular pathways and external environmental conditions. Among these environmental conditions, photoperiod acts as a cue to regulate the timing of flowering in response to seasonal changes. Additionally, it has become clear that various environmental factors also control the timing of floral transition. Environmental factor acts as either a positive or negative signal to modulate the timing of flowering, thereby establishing the optimal flowering time to maximize the reproductive success of plants. This review aims to summarize the effects of environmental factors such as photoperiod, light intensity, temperature changes, vernalization, drought, and salinity on the regulation of flowering time in plants, as well as to further explain the molecular mechanisms that link environmental factors to the internal flowering time regulation pathway.

Keywords: drought; flowering time; light; plants; salinity; temperature.

Figure 1

Regulation of CO activity through CO transcription, protein stability, protein interaction. CO, CONSTAMS; TCPs, TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL NUCLEAR ANTIGEN FACTORs; FBHs, FLOWERING BHLHs; CDFs, CYCLING DOF FACTORs; PHYB, Phytochrome B; HOS1, HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1; COP1, CONSTITUTIVE PHOTOMORPHOGENIC 1; SPA1, SUPPRESSOR OF PHYA-105 1; PHYA, Phytochrome A; PRRs, PSEUDO-RESPONSIVE REGULATORs; FKF1, FLAVIN-BINDING, KELCH REPEAT, F-BOX1; GI, GIGANTEA; CRY2, Cryptochrome 2; BBX, B-BOX TRANSCRIPTION FACTOR; AS1, ASYMMETRIC LEAVES 1; NF-Y, NUCLEAR FACTOR-Y; FT, FLOWERING LOCUS T.

Figure 2

Regulation of flowering time by temperature. Description near arrow indicates detailed regulatory mechanism. Dotted line, weak contribution; solid line, strong contribution. BZR1, BRASSINAZOLE RESISTANCE 1, TCP5, TEOSINTE BRANCHED 1/CYCLOIDEA/PCF 5; PIF4, PHYTOCHROME INTERACTING PROTEIN 4; ELF3, EARLY FLOWERING 3; LUX, LUX ARRHYTHMO; PWR, POWERDRESS; FT, FLOWERING LOCUS T; SVP, SHORT VEGETATIVE PHASE; FLM, FLOWERING LOCUS M; GRP7, GLYCINE-RICH RNA-BINDING PROTEIN 7; CDKG2, CYCLIN-DEPENDENT KINASES G2.

Figure 3

Regulation of flowering time under drought conditions. Drought acts as a positive signal to induce flowering in plants. Drought signal is incorporated into multiple layers of the flowering time regulatory pathway. GI, GIGANTEA; CO, CONSTANS; TSF1, TWIN SISTER OF FT 1; FT, FLOWERING LOCUS T; ABF, ABA-RESPONSIVE ELEMENT (ABRE)-BINDING FACTOR; NF-YC, NUCLEAR FACTOR Y SUBUNIT C; FBH3, FLOWERING BHLH 3; SOC1, SUPPRESSOR OF OVEREXPRESSION OF CO 1; FLC, FLOWERING LOCUS C; OST1, OPEN STOMATA 1; VOZ1, VASCULAR PLANT ONE-ZINC FINGER 1.

Figure 4

Regulation of flowering time through GIGANTEA under salinity conditions. SOS1, SALT OVERLAY SENSITIVE 1; GI, GIGANTEA; FKF1, FLAVIN-BINDING, KELCH REPEAT, F-BOX1; CO, CONSTANS, FT, FLOWERING LOCUS T.