1 Introduction

Dendrobium officinale is a perennial epiphytic orchid native to subtropical regions of China, and it is recognized both as a traditional Chinese medicinal herb and as a plant with ornamental value (Li et al., 2025). It has long been used in health care and therapy, and its major bioactive constituents include polysaccharides, alkaloids, flavonoids, phenolic compounds, bibenzyls, and related metabolites (Liang et al., 2025). Genomic and phytochemical studies further show that this species possesses a complete inflorescence gene set, expanded pathways related to polysaccharide biosynthesis, and broad adaptive traits associated with symbiosis and stress resistance, which together support both its medicinal importance and its cultivation potential (Yan et al., 2015). In China, D. officinale has become a high-value cultivated crop, but its productivity and quality remain sensitive to environmental regulation, especially temperature and light.

Current utilization of D. officinale has focused mainly on stems, yet recent reviews emphasize that its leaves and flowers are also rich in chemical constituents and have substantial potential for food, medicine, cosmetics, and health products. In particular, the flowers are no longer regarded as by-products alone, because they contain diverse bioactive substances and exhibit antioxidant, neuroprotective, anti-depressive, and learning- and memory-improving activities, supporting their development as natural nutritional resources. Reviews on Dendrobium more broadly also show that the genus combines medicinal, edible, and ornamental functions, and even ornamental Dendrobium taxa can accumulate substantial medicinal metabolites, suggesting that floral organs and ornamental germplasm deserve greater attention in resource utilization research (Li et al., 2023; Peng et al., 2024; Zhou et al., 2025). Moreover, metabolite accumulation in D. officinale varies across growth stages and often peaks during flowering and fruiting, indicating that reproductive development is directly linked to quality formation and resource value.

Light and temperature are among the most important environmental factors controlling plant growth, floral induction, flower development, and final floral quality (Li et al., 2022). Across plant species, these signals regulate the transition to flowering, coordinate developmental timing with seasonal change, and act through integrated signaling networks involving photoreceptors, circadian regulation, phytohormones, and flowering integrators such as FT (González-Suárez et al., 2023). Experimental evidence also shows that the effects of light and temperature extend beyond floral initiation to flowering duration, inflorescence development, floral organogenesis, and flower number. For example, in avocado, only low-temperature-treated buds flowered, and low temperature promoted expression of flowering-time and floral organ identity genes, demonstrating that thermal cues can determine whether reproductive development proceeds at all (Acosta-Rangel et al., 2021). In orchid systems, comparable responses have been reported: in Phalaenopsis, insufficient irradiance delays or prevents flowering, whereas higher light intensity increases spike number and flower quality (van Tongerlo et al., 2021); in potted red firespike, heavy shade delayed first flowering and reduced inflorescence number, while 25℃ promoted inflorescence development and 15℃ or 35℃ prevented it under the tested conditions (Rezazadeh et al., 2018).

For Dendrobium, temperature regulation of flowering appears especially important. In nobile-type Dendrobium, including D. catenatum/D. officinale, sufficient low temperature in winter is required for normal spring flowering, whereas untimely high temperature can delay flowering, induce abnormal flowering phenotypes, or even prevent flowering altogether. Molecular evidence from D. nobile further shows that low temperature activates flowering-related pathways, whereas prolonged high temperature suppresses floral meristem determination, offering a mechanistic basis for temperature-dependent flowering behavior in this orchid lineage (Pan et al., 2023). In D. officinale itself, temperature significantly affects photosynthesis, growth, and metabolite accumulation, with 30℃ favoring photosynthetic performance and stem growth, while 20℃ supports higher polysaccharide accumulation. This species is also highly sensitive to thermal stress: both heat and cold can impair chlorophyll fluorescence parameters, high temperature reduces maximum photosynthetic efficiency, and fluctuating light combined with 4℃ or 42℃ inhibits photosystem performance compared with 25℃ (Sun et al., 2021; Yang et al., 2021). Light likewise alters growth and quality traits in D. officinale, because light intensity and quality affect photosynthetic efficiency, anthocyanin accumulation, and phenolic content, and red-blue composite light has been shown to improve seedling growth and metabolite accumulation. Even after harvest, illumination and temperature continue to shape floral traits, as light accelerates pigment degradation in D. officinale flowers and low-temperature dark storage better preserves chlorophylls, carotenoids, and anthocyanins.

Against this background, studying how light and temperature conditions affect the flowering performance and floral trait characteristics of D. officinale is both scientifically necessary and practically important. Although substantial work has examined its medicinal chemistry, cultivation physiology, and stress responses, direct evidence on how combined light and temperature regimes shape flowering traits in D. officinale remains limited. This article evaluates the effects of different light and temperature conditions on flowering behavior and floral characteristics of D. officinale, so as to clarify how key environmental cues regulate its reproductive performance and floral quality. Such knowledge can provide a theoretical basis for optimized flowering control, high-quality ornamental production, and efficient utilization of floral resources, while also supporting more precise environmental management for this economically important medicinal orchid.

2 Flowering Formation and Floral Trait Characteristics of Dendrobium officinale

2.1 Floral bud differentiation and flowering process of Dendrobium officinale

As a nobile-type Dendrobium, D. officinale follows a flowering pathway in which mature shoots acquire reproductive competence and axillary buds transition from dormancy to floral development under appropriate environmental cues, especially winter chilling (Yan et al., 2015; Li et al., 2025). Genomic and transcriptomic evidence indicates that this species possesses a complete inflorescence gene set and multiple flower-related regulatory modules, providing the molecular basis for floral organ initiation and pattern formation (Chen et al., 2019). During floral transition in D. officinale, several MADS-box genes become upregulated in the reproductive phase, especially DnMADS3, DnMADS8, and DnMADS22, supporting a central role for conserved floral identity regulators in bud differentiation. Broader orchid studies further show that floral patterning in Dendrobium depends on ABCDE-like MADS-box functions and other transcription-factor families that coordinate the differentiation of sepals, petals, lip, and column tissues (He et al., 2024).

Flower development in D. officinale proceeds through distinguishable bud and bloom stages that are accompanied by large transcriptional and metabolic shifts. Comparative analyses between early- and medium-stage flower buds and opened flowers identified thousands of differentially expressed genes and hundreds of differentiated metabolites, with enrichment in phytohormone signaling, phenylpropanoid biosynthesis, zeaxanthin biosynthesis, and pathways related to chlorophyll, carotenoid, flavonoid, and polysaccharide metabolism (He et al., 2020; Ren et al., 2025). Hormonal coordination also appears important, because indole-3-acetic acid and abscisic acid show opposite accumulation trends during flower development, while studies in related nobile-type Dendrobium indicate that low temperature first initiates an invisible Stage 1 inflorescence meristem and then promotes Stage 2 floral meristem determination after continued chilling. Developmental staging work in other Dendrobium orchids further suggests that bud elongation, pigment appearance, meiosis, and the transition to open flowers are orderly landmarks in the flowering process, which provides a useful comparative framework for describing D. officinale floral ontogeny (Lau et al., 2015; Khairul-Anuar et al., 2022).

2.2 Flowering performance and major phenological characteristics of Dendrobium officinale

The flowering period of D. officinale extends mainly from March to June, indicating a spring-to-early-summer blooming habit typical of nobile-type Dendrobium. At the bud stage, flower buds are light green and about 1~2 cm long, while flowers at anthesis are light yellow, 2~4 cm long, curved or folded in shape, and about 1.5~2.0 cm in diameter. Seasonal flowering studies in Dendrobium also indicate that floral initiation can occur several months before visible harvestable spikes are produced, and flowering intensity is shaped by plant age, daylength, and temperature conditions in the months preceding bloom (Paull et al., 1995). This longer pre-anthesis developmental window is consistent with the view that flowering performance in D. officinale depends not only on the immediate flowering environment but also on earlier bud induction and differentiation events (Pan et al., 2023).

Major phenological and performance traits in D. officinale include flowering time, flowering percentage, flower number, inflorescence development, and flower longevity, all of which are sensitive to temperature regulation in nobile-type orchids. Evidence from related Dendrobium species shows that insufficient chilling or untimely high temperature can delay flowering, suppress flower formation, or induce abnormal phenotypes such as non-flowering and floral reversion, whereas optimized induction treatments can improve flowering percentage, flowering duration, and ornamental quality (Ren et al., 2023). In D. nobile, flower buds appeared about 55~60 days after induction treatment and flowering began about 47 days after bud initiation, illustrating the measurable interval between bud differentiation and visible bloom in this genus. For D. officinale, these comparative results suggest that flowering performance should be evaluated through an integrated phenological framework that includes bud emergence, anthesis timing, bloom duration, flower quantity, and the stability of floral display under different environmental regimes.

2.3 Floral morphology and major ornamental traits of Dendrobium officinale

Like other orchids, D. officinale has the typical Dendrobium floral ground plan of three sepals, three petals, and a column formed by fused stamens and pistils, with the inner whorl differentiated into two lateral petals and a specialized median labellum. Its flowers are light yellow at opening and exhibit a small to medium floral size with a curved, folded appearance, traits that contribute to its delicate ornamental character (Yan et al., 2015). Within Dendrobium, floral color, organ size, lip form, and floral longevity are key ornamental traits, and broad phenotypic analyses show that flower width, flower length, petal length, sepal length, lip dimensions, and flower lifespan are positively associated traits useful for selection in breeding (He et al., 2024). The ornamental value of D. officinale is also linked to the fact that its flowers are not only visually attractive but also usable as edible and functional floral resources (Chen et al., 2019; Li et al., 2025).

At the microscopic and molecular levels, floral traits in Dendrobium are shaped by coordinated regulation of pigment biosynthesis, epidermal cell morphology, and organ growth (He et al., 2024). Anthocyanins and other flavonoids are central to flower color formation, and studies in Dendrobium show that MYB regulators can alter pigment intensity as well as organ shape, while changes in flavonoid composition explain visible transitions such as white versus purple flowers (Khairul-Anuar et al., 2022; Qiu et al., 2023; Yin et al., 2026). Floral scent is another important ornamental dimension in the genus, although D. officinale is not considered a strongly scented model species compared with aromatic taxa such as D. chrysotoxum (Du et al., 2022). In addition, the resource value of D. officinale flowers changes with developmental stage and floral part, because the flourishing flowering stage shows the highest polysaccharide and total phenol contents, and the perianth contains higher polysaccharides, flavonoids, and phenols than the gynostemium or ovary, indicating that ornamental traits and utilization quality are closely linked during anthesis (Xin et al., 2019).

3 Analysis of Typical Cultivation Cases and Light-Temperature Environmental Characteristics

3.1 Overview of typical Dendrobium officinale cultivation cases

Typical D. officinale cultivation cases can be grouped into greenhouse, bionic, and wild-simulated systems, which differ mainly in environmental controllability and ecological similarity to the species’ epiphytic habitat (Yuan et al., 2020). Greenhouse production is the dominant artificial mode because wild resources are scarce and cultivated material has become the main source for medicinal and edible use (Figure 1) (Jia et al., 2022). These systems increasingly rely on environment selection, tissue culture, acclimatization, and precise environmental control to stabilize survival, yield, and quality (Silva et al., 2017; Ding et al., 2018; Liu et al., 2025).

Figure 1 The changes in phenotype and anthocyanin content of D. officinale post light- or K-treatment (Adopted from Jia et al., 2022) Image caption: A: The pseudobulbs (P) under natural light were used as the control, light-treated pseudobulbs (PL) were treated with red and blue light in 5:1, and K-treated pseudobulbs (PK) were treated with 3 mM KCl; B: The phenotype of D. officinale pseudobulbs; (C) Anthocyanin extracted from pseudobulb of D. officinale; D: The content of anthocyanins in D. officinale pseudobulbs post light-or K-treatment. The different letters represent significant difference at p<0.05 (Adopted from Jia et al., 2022)

In practical production, case selection usually reflects different goals rather than a single best model. Greenhouse systems favor regulation of light, humidity, and temperature, and are therefore suited to standardized cultivation and experimental manipulation. Bionic and wild-simulated systems retain stronger natural heterogeneity and are often used when resource quality and ecological adaptation are prioritized (Yuan et al., 2020). Across cultivation modes, active-component accumulation changes with ecological context, indicating that any comparison of flowering cases should treat cultivation mode as an integrated environmental package rather than as a background detail (Jia et al., 2022).

3.2 Light and temperature conditions in the cultivation environment of the selected cases

The selected cases show that D. officinale responds best to moderate rather than extreme light, but the practical optimum depends on whether the target is biomass, phytochemical quality, or flowering stability. Under greenhouse conditions in Vietnam, 50% and 70% shading produced the highest growth, biomass, polysaccharide, and alkaloid accumulation, supporting the common use of partial shade in production (Van-Nguyen et al., 2023). A light-gradient experiment in D. officinale found that moderate light at 11 000 lx simultaneously maximized biomass, bioactive compounds, sensory quality, and minimized oxidative stress, whereas extreme high light impaired growth traits and low light reduced some quality dimensions (Guo et al., 2025). Light quality also matters: red light performed best in one greenhouse study, while a red:blue ratio of 2:1 gave the best growth, energy absorption, and phenolic content in tissue-cultured seedlings.

Temperature conditions shape both vegetative performance and flowering competence. In D. officinale, 30℃ supported the highest light-saturated photosynthesis and strongest stem growth, while 20℃ favored higher polysaccharide accumulation, showing a growth–quality tradeoff across thermal regimes. For nobile-type Dendrobium, including D. catenatum/D. officinale, low temperature in winter is required for spring flowering, and about 30~40 days of chilling is often sufficient to initiate the first floral stage before visible bud changes appear. Untimely high temperature can delay flowering, cause non-flowering or floral reversion, and promote vegetative offshoot formation, so successful flowering cases depend on separating the winter induction phase from later warm-growth management.

3.3 Actual flowering performance and floral traits under different light and temperature conditions

Under different light-temperature cases, the most consistent pattern is that moderate light with appropriate temperature control supports better flowering performance than either excessive shade or excessive heat. In Dendrobium orchids, higher morning-to-afternoon light increased bloom number and photosynthesis in most tested cultivars, while less favorable light timing reduced flower opening in some varieties. More broadly, controlling the flowering environment has clear potential to influence flower quality, because flowering in orchids depends on environmental as well as genetic and physiological factors (Farid and Ulinnuha, 2024). In nobile-type orchids, temperature also affects flower number per inflorescence and the size and longevity of individual flowers, not only the date of flowering (Pan et al., 2023).

Floral traits themselves are highly sensitive to light and heat stress. Under natural tropical conditions, full sunlight reduced photosynthetic performance and caused sustained photoinhibition in both leaves and flowers, while flowers were more susceptible than leaves because petals became hotter at midday. Damage became more severe in flowers at 38℃ than at 28℃ under high photon flux, indicating that light and temperature interact directly in determining floral quality. Postharvest evidence from D. catenatum flowers shows the same sensitivity: illumination accelerated pigment degradation, and low-temperature dark storage preserved chlorophylls, carotenoids, and anthocyanins better than room temperature, which implies that floral color expression achieved in cultivation can be quickly lost if light and temperature are not managed after flowering (Gao et al., 2020).

4 Effects of Light Conditions on Flowering Performance and Floral Traits of Dendrobium officinale

4.1 Effects of light intensity on initial flowering and peak flowering periods

Light conditions affect the onset and progression of flowering in Dendrobium officinale, although direct flowering-timing evidence in this species is still limited and much of the mechanistic support comes from other orchids and nobile-type Dendrobium. Light is a key factor affecting growth and quality formation in D. officinale, and different light-quality treatments trigger large transcriptional shifts in light-signal transduction pathways, showing that this species is highly responsive to changes in the light environment (Figure 2) (Li et al., 2026). In a micropropagated Dendrobium hybrid ‘Shuijing’, red-blue-green light at a 4:2:1 ratio has been reported to promote earlier flowering and higher flowering rates, while red-dominant or red-blue composite lights also improve overall growth status in Dendrobium seedlings, suggesting that spectral composition before reproductive transition can shift later flowering behavior (Huo et al., 2024). By contrast, studies in orchid relatives show that the direction, intensity, and spectral composition of light can either advance or delay anthesis, so the effect is not simply “more light is better” (Xue et al., 2025).

Figure 2 Phenotype of D. officinale under different light treatments (Adopted from Li et al., 2026) Image caption: (A-C) show the phenotypes before white, blue and blue polarized light treatments, respectively; (D-F) show the phenotypes after white, blue and blue polarized light treatments, respectively; Bars=10 mm (Adopted from Li et al., 2026)

Evidence from Dendrobium flowering experiments indicates that favorable light exposure tends to accelerate visible flowering progress, whereas insufficient light delays it. In hybrid nobile Dendrobium, darkness during vernalization slightly delayed flowering, and low photon flux of 50~100 μmol·m^-2·s^-1 performed similarly to 200 μmol·m^-2·s^-1 for flowering time, indicating that complete light deprivation is more disruptive than moderate light reduction. In Cymbidium ensifolium, blue light advanced flowering by 18 days relative to the control, whereas red light delayed flowering by 19 days, showing that spectral quality can strongly alter the timing of entry into full bloom in orchids. Under shade-net cultivation, different Dendrobium cultivars required about 14.05 to 19.89 days from inflorescence emergence to full flowering, illustrating that the peak flowering period is plastic under modified light environments, even though genotype remains an important source of variation.

4.2 Effects of light conditions on flower number and flowering duration

Light conditions also regulate flower number and flowering duration, and the clearest pattern across orchid studies is that complete shading or poorly matched light regimes reduce floral output. In hybrid Dendrobium exposed to different sun directions, eastern light increased the number of blooming flowers in several cultivars, whereas flowering declined under the less favorable west-light treatment in some genotypes (Farid and Ulinnuha, 2024). In vernalized nobile hybrids, light during cooling increased flowering-node percentage and total flower number compared with darkness; for example, ‘Sea Mary Snow King’ under light reached 74.9% flowering nodes and 29.7 flowers, whereas darkness reduced flowering performance. These results indicate that adequate illumination during floral induction and early development supports more complete bud activation and higher final floral display.

For D. officinale, the same conclusion is supported indirectly by cultivation and physiology studies showing that moderate shade and optimized light quality improve vegetative vigor and metabolite supply, which likely strengthen the source capacity required for later flowering (Huo et al., 2024). In greenhouse-grown D. officinale, 50%~70% shading produced the highest growth, biomass, and polysaccharide and alkaloid accumulation, while 11 000 lx produced the best combined performance across biomass, bioactive compounds, sensory traits, and oxidative status, arguing against both deep shade and excessive irradiance (Van-Nguyen et al., 2023). Flowering duration appears somewhat less light-sensitive than flower number, but light still matters: darkness during vernalization reduced flower quality in nobile hybrids, and in orchids more broadly red–blue composite light can extend flowering periods, while red light alone slightly prolonged flowering in Cymbidium without a statistically strong effect (Xue et al., 2025). Under shade-net production, Dendrobium cultivars also differed markedly in flower longevity, confirming that the final duration of floral display reflects both environmental regulation and genotype-by-light interaction.

4.3 Effects of light conditions on flower size, color, and floral form

Light conditions influence flower size, color, and floral form through effects on pigment metabolism, floral organ development, and stress physiology. In nobile hybrid Dendrobium, darkness during vernalization produced fewer but larger flowers, and low light mainly reduced flower quality while not improving shape-related traits except flower diameter, showing that size responses can diverge from color and display quality. Studies under shade-net conditions likewise show large cultivar differences in flower length, diameter, spike length, floret number, and longevity, which means light regulation is expressed through several ornamental dimensions rather than a single trait. Because D. officinale flowers are also valuable edible and medicinal resources, light-mediated changes in floral appearance can coincide with shifts in functional compounds, not just decorative quality (Yan et al., 2015; Li et al., 2025).

The evidence is strongest for flower color. In Dendrobium Sonia, low light significantly reduced anthocyanin production throughout flower development and produced paler purple flowers by downregulating the late anthocyanin genes DFR and ANS (Pratama et al., 2023). Other Dendrobium studies show that floral color divergence becomes more obvious as flowers develop, that reduced anthocyanin accumulation underlies white-versus-purple phenotypes, and that MYB regulators such as DhMYB22, DhMYB60, and DntMYB1 control both pigment intensity and aspects of floral organ shape (Khairul-Anuar et al., 2022; Qiu et al., 2023; Yin et al., 2026). In D. officinale, light quality strongly alters secondary metabolism and even visible stem coloration, with blue polarized light inducing a reddish stem and red or red-blue lights promoting metabolite pathways linked to flavonoid accumulation, so comparable light-dependent pigment regulation in floral tissues is biologically plausible (Li et al., 2026). At the structural level, orchid floral form is governed by coordinated developmental regulators, including MADS-box and MYB pathways, and genome-scale evidence confirms that D. officinale possesses a complete inflorescence gene set capable of supporting environmentally responsive ornamental-trait expression.

5 Effects of Temperature Conditions on Flowering Performance and Floral Traits of Dendrobium officinale

5.1 Effects of temperature variation on floral bud differentiation and flowering progression

Temperature variation directly affects floral bud differentiation in nobile-type Dendrobium. In this group, floral induction requires winter chilling, and axillary buds remain vegetative or fail to flower under continuously warm conditions (Liang et al., 2012). Morphological and molecular studies show that low temperature first releases axillary buds from dormancy and initiates inflorescence meristems before visible floral structures appear, indicating that the earliest stages of floral differentiation are already temperature dependent. In D. nobile, about 30~40 days of low temperature is generally sufficient to form Stage 1 floral axillary buds, and prolonged cooling advances the transition to Stage 2, when floral meristem identity becomes more clearly established. Low temperature also upregulates flowering-related genes such as VRN1, FT, SOC1, LFY, and AP1-like regulators, supporting a conserved vernalization pathway in orchid floral initiation (Liu et al., 2016; Wen et al., 2017).

Temperature also controls the rate of flowering progression after induction. Once the chilling requirement is met, warmer forcing temperatures within an appropriate range accelerate development toward anthesis, whereas prolonged cooling delays marketable flowering even if it shortens the interval from the end of cooling to bloom. In nobile hybrids, 3 weeks at 13℃~15℃ appears sufficient to satisfy cooling requirements without unnecessarily retarding subsequent development. By contrast, exposure to 18℃ or higher suppresses or weakens flowering induction in vernalization-dependent materials, and high temperature can divert buds toward aerial shoot formation rather than flower formation. This broader temperature sensitivity is consistent with other species, where both supraoptimal and suboptimal temperatures slow floral bud differentiation and increase malformation risk, suggesting that D. officinale likely also depends on a relatively narrow effective thermal window during reproductive transition.

5.2 Effects of temperature conditions on flowering duration and flowering stability

Temperature conditions affect not only flowering time but also flowering duration and stability. In nobile hybrids, extending low-temperature holding after vernalization can defer flowering by as much as 3 months without markedly reducing most flower-quality traits, showing that post-induction cooling is a practical way to regulate bloom timing. Similar results were found in broader cooling-duration studies, where longer cooling delayed final flowering while accelerating anthesis after plants were returned to forcing conditions. This means that thermal management can shift the calendar date of flowering without necessarily disrupting completion of flowering once development resumes. However, excessive or poorly timed cooling is not neutral, because longer cooling can aggravate defoliation and reduce flower longevity in some cultivars.

Flowering stability declines when temperature departs from the appropriate induction or development regime. Untimely high temperature can cause delayed flowering, non-flowering, floral reversion, and offshoot production, indicating that reproductive development is unstable under warm conditions that counteract vernalization signaling. Mechanistically, prolonged high temperature maintains suppression of DnAPL1 through high DnFCAγ accumulation in axillary buds, thereby delaying floral development (Pan et al., 2023). Stage-specific sensitivity is likely important. In other crops, temperature fluctuations and cold stress cause much more bud abortion once buds have advanced to later phenological stages, and constant control temperatures support normal floral organogenesis (Mirarzgar et al., 2026). A similar principle is plausible for Dendrobium, where flowering progression after bud initiation is described as mainly temperature controlled.

5.3 Effects of temperature conditions on floral organ development and visual quality

Temperature conditions also shape floral organ development and visual quality. In D. nobile seedlings, flowers formed under 25℃ were deformed, whereas a lower day/night regime of 23℃/18℃ for 45 days allowed normal flower development, indicating that moderate cooling is required not only for induction but also for correct organ formation (Wang et al., 2009). In vitro work reached the same conclusion: 18℃ combined with TDZ produced the highest flowering percentage, while warmer treatments were less effective (Nadal et al., 2023). More broadly, low night temperature of 17℃ or below appears conducive to floral initiation, and 10℃ for 30 days can substantially increase floral differentiation rate in Dendrobium (Ren et al., 2023). These findings indicate that temperature affects the completeness, not just the occurrence, of reproductive development.

Visual quality traits such as flower size, longevity, and abortion rate also change with thermal regime. Cooling at 10℃~15℃ generally increases flowering-node percentage and total flower number relative to warmer cooling treatments, while flower diameter and flower number per node vary with the exact temperature–duration combination. Longer cooling can produce larger flowers but may reduce longevity or increase physiological costs depending on cultivar. Temperature history during handling also matters: simulated dark shipping at 10℃~15℃ caused earlier flowering in nobile hybrids, and in one cultivar 10℃ increased flower diameter without harming shelf life (Cinantya et al., 2013). By contrast, temperature stress and fluctuation in other flowering crops produce incomplete sepals, petals, and stamens, floral primordium necrosis, and high abortion rates, reinforcing that stable temperature control is essential for maintaining floral form and ornamental quality.

6 Comprehensive Effects of Light-Temperature Interactions on Flowering Performance and Regulation Strategies

6.1 Effects of light-temperature synergy on flowering regulation

As a nobile-type orchid, D. officinale requires a low-temperature induction phase for normal spring flowering, but the final flowering response depends on how chilling is coordinated with light conditions during and after vernalization. In related nobile Dendrobium, low temperature is the dominant trigger, yet light present during cooling improves the completeness of floral initiation, whereas darkness slightly delays flowering and produces fewer flowers even when chilling is supplied. This interaction is physiological as well as developmental, because favorable light maintains photosynthetic performance and source strength needed to support bud activation, while excessively low or excessively high irradiance destabilizes growth and quality in D. officinale (Guo et al., 2025). Moderate shading or moderate irradiance therefore appears more suitable than either deep shade or strong direct light, with 50~70% shading and about 11 000 lx repeatedly associated with stronger biomass accumulation and better overall plant condition in D. officinale cultivation.

Temperature and light also converge at the molecular level through flowering integrators and stress-response pathways. In Dendrobium, FT-family genes mediate photoperiod and temperature signals, while TFL1-like genes repress floral transition, showing that flowering regulation is intrinsically a signal-integration process rather than a single-factor response (Ahmad et al., 2022; Zhang et al., 2023). In D. nobile, low temperature promotes flowering through the DnFCAβ-DnAGL19 pathway in leaves and the DnFCAγ-DnAPL1 pathway in axillary buds, whereas untimely high temperature maintains suppression of floral development. Light quality likely modifies the efficiency of this temperature-driven transition by changing hormone signaling, carbon allocation, and photoreceptor responses, because red–blue light treatments in Dendrobium alter plant hormone signal transduction and improve physiological vigor (Fan et al., 2022; Jia et al., 2022). Taken together, the evidence supports a flowering-regulation model in which chilling establishes floral competence, while an appropriate light regime determines how efficiently that competence is translated into visible bud emergence and synchronized flowering (Bashir et al., 2025).

6.2 Effects of light-temperature combinations on floral trait formation

Floral trait formation under combined light and temperature conditions is expressed mainly through flower number, color, longevity, and morphological stability. Temperature strongly affects flower number per inflorescence, flower size, and single-flower longevity in nobile-type Dendrobium, and inappropriate warm conditions can cause delayed flowering, non-flowering, or floral reversion. Light then modifies the visible quality of the floral display, because morning-to-afternoon light increased bloom number in several Dendrobium cultivars, while less favorable light exposure reduced blooming performance in some genotypes. This genotype dependence is important, since different Dendrobium types do not respond identically to the same light regime. Even so, the broad consensus across epiphytic Dendrobium is that moderate light favors balanced growth and resource accumulation, which should support more stable floral trait expression than either severe shade or excessive exposure (Yang et al., 2026).

Color and floral form are especially sensitive to light–temperature combinations because pigment biosynthesis and photoprotection are both environmentally responsive. Low light directly decreases anthocyanin production in Dendrobium Sonia by downregulating DFR and ANS, producing paler flowers across developmental stages (Pratama et al., 2023). In D. officinale, light treatments increase anthocyanin and flavonoid accumulation, alter stem coloration, and reshape phenylpropanoid and hormone pathways, indicating that the same regulatory logic likely contributes to floral pigment formation (Jia et al., 2022; Li et al., 2026). Temperature modulates whether these light-driven traits are stably expressed, because under fluctuating light, both 42℃ and 4℃ impose distinct photoprotective demands in D. officinale, and low temperature inactivates the water–water cycle while high temperature can intensify stress on photosystems (Sun et al., 2021). Floral tissues are generally more heat- and light-sensitive than leaves in orchids, so maintaining color saturation, organ expansion, and display quality likely requires avoiding strong light during thermal extremes, especially around visible bud expansion and anthesis.

6.3 Precise light and temperature regulation strategies for flowering of Dendrobium officinale

A practical regulation strategy for D. officinale flowering should separate cultivation into induction, development, and display phases, each with different light–temperature targets. During induction, the evidence supports a low-temperature treatment sufficient to satisfy vernalization, because constant 18℃ suppresses flowering in nobile Dendrobium whereas cooling near 10℃~15℃ promotes flower initiation. During this stage, complete darkness should be avoided, since light during cooling improves flowering completeness and darkness reduces flower number and delays flowering. During vegetative recovery and bud development, moderate light appears most suitable for maintaining carbon gain without excess stress, with 50%~70% shade, around 20% of full light in related Dendrobium, or about 11 000 lx in D. officinale all outperforming more extreme conditions (Van-Nguyen et al., 2023; Yang et al., 2026). Light quality can then be tuned according to production goals, because red light promotes polysaccharide-related gene expression and growth, while mixed red-blue light often improves overall vigor and antioxidant status (Huo et al., 2024).

For high ornamental quality, regulation should prioritize environmental stability over maximal intensity. Low temperature and low light intensity inhibit PLB induction in tissue culture, whereas high temperature and intense light can cause desiccation, showing that extremes at either end reduce developmental quality even outside the flowering stage (Xu et al., 2026). Controlled-environment production therefore benefits from integrating photoperiod, spectrum, and temperature rather than adjusting only one factor, a principle now emphasized broadly in flowering-control research. For D. officinale, the most defensible strategy is winter chilling under non-dark conditions, followed by moderate irradiance, avoidance of heat spikes, and cultivar-specific spectral optimization to balance flowering percentage, floral color, and plant health (Van-Nguyen et al., 2023). Precise flowering regulation in D. officinale depends on coordinated management of light and temperature across developmental stages, not on maximizing either factor in isolation.

7 Conclusions and Prospects

Light and temperature are key environmental factors affecting floral bud differentiation, flowering progression, and flowering stability in Dendrobium officinale. As a nobile-type Dendrobium, D. officinale requires appropriate low-temperature induction for normal flowering, whereas prolonged high temperature or insufficient chilling may result in delayed flowering, failure to flower, or abnormal floral development. Meanwhile, moderate light helps maintain photosynthetic capacity and provides sufficient assimilates for floral bud formation and development, whereas excessively low or high light levels are unfavorable for normal flowering. Overall, suitable winter chilling combined with appropriate light conditions provides an important environmental basis for promoting floral initiation, improving flowering uniformity, and maintaining a stable flowering period.

Light and temperature also influence floral traits such as flower size, color, shape, and longevity. Appropriate light favors the accumulation of anthocyanins, flavonoids, and other metabolites, whereas insufficient light may result in paler flowers. High temperature or large temperature fluctuations can accelerate floral senescence and reduce floral-form integrity and ornamental quality. In addition, the contents of polysaccharides, flavonoids, and phenolic compounds in D. officinale flowers vary among developmental stages and floral organs, indicating that floral traits are closely related not only to ornamental value but also to edible and functional resource potential. Therefore, evaluation of D. officinale flower quality should integrate flowering performance, visual traits, and bioactive-component accumulation.

Future studies should shift from single-factor analyses of light or temperature toward stage-specific and precise regulation of light–temperature interactions. Particular attention should be given to defining suitable chilling duration, day–night temperature differences, light intensity, and spectral combinations during floral induction, bud development, and peak flowering. Environmental monitoring, phenological observation, and molecular regulatory studies can also be integrated to establish flowering prediction and environmental-control systems suited to different cultivars and cultivation regions. In addition, flowering regulation should be more closely linked with floral resource development by jointly evaluating flower color, floral form, flowering duration, and quality indicators such as polysaccharides, flavonoids, phenolics, and aroma compounds, thereby supporting precise flowering control, improved ornamental quality, and high-value utilization of D. officinale floral resources.

Acknowledgments

The author appreciates the open sharing of scientific literature and research illustrations, which supported the comparative analysis of light and temperature effects on flowering and floral traits in Dendrobium officinale.

Conflict of Interest Disclosure

The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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