Effects of Light Quality on Growth and Physiological Characteristics of Neopyropia yezoensis Free Living Conchocelis

[Objectives]To study the differences of growth rate,morphology,ultrastructure,pigment content and antioxidant enzyme activity of free-living conchocelis of cultivated type of Neopyropia yezoensis under different light qualities(white,red,blue,and green light).[Methods]The study was carried out through light quality design and culture,growth rate determination,microstructure and ultrastructure observation,chlorophyll a content and carotenoid content determination,phycobiliprotein content determination,malondialdehyde(MDA)content determination,superoxide dismutase(SOD)activity determination.[Results]After 21 d of culture,the specific growth rate(SGR)and chlorophyll a content of free-living conchocelis of N.yezoensis were significantly increased by white light(WL),followed by red light(RL)and green light(GL),and they were the lowest under blue light(BL).Compared with the WL group,the BL group had the highest content of phycoerythrin(PE),and the RL and GL groups had the highest content of phycocyanin(PC).The algal body of WL group was normal black brown,and the cell wall was the thickest.In RL and GL groups,the algal bodies were green,and their diameters and cell wall thicknesses were similar to those in WL group.In BL group,the algal body was bright red,the diameter was the smallest,the cell wall was the thinnest,and the ultrastructure showed that the number of plastoglobulus on the thylakoid was the largest.After BL irradiation,the highest MDA content and the lowest SOD activity were observed.The results revealed that WL is the most beneficial to the growth of free-living conchocelis,followed by RL and GL,while BL has adverse effects.[Conclusions]This study explored the most suitable light quality conditions for the propagation of free-living conchocelis.It is expected to provide germplasm guarantee for the production and seedling of N.yezoensis.

An Investigation of Lighting Levels and Sleep Quality

Sleep quality in young adults is compromised. Instead of the recommended 7 hours, young adults’ schedule interruptions disturb sleep to a typical six and a half hours, with common disturbances in falling asleep and staying asleep. Recent literature has identified an association between academic performance, negative mood state and low activity level in young adults with sleep disturbances. Young adulthood is a time for the installation of sleep health. Both individual and schedule impositions to the young adults’ sleep schedule are to be modified to obtain Sleep Health. Recent research has identified daytime light effects on sleep such as blue light from electronics as alerting and low level light for relaxation. The aim of this study was to identify sleep quality effects with varying light exposures. It was hypothesized that bright (>450 lux) light conditions would be considered focusing and low light (<220 lux) would be considered calming. We hypothesized that sleep quality would improve by 5% with the introduction of a calm light condition. Undergraduates from a small midwestern university were invited to participate in the study in exchange for a gift card. Six participants completed the study, two males, four females all between 21 - 24 years old. Both hypotheses were supported by qualitative analysis.

I-DCGAN and TOPSIS-IFP:A simulation generation model for radiographic flaw detection images in light alloy castings and an algorithm for quality evaluation of generated images

The intelligent detection technology driven by X-ray images and deep learning represents the forefront of advanced techniques and development trends in flaw detection and automated evaluation of light alloy castings.However,the efficacy of deep learning models hinges upon a substantial abundance of flaw samples.The existing research on X-ray image augmentation for flaw detection suffers from shortcomings such as poor diversity of flaw samples and low reliability of quality evaluation.To this end,a novel approach was put forward,which involves the creation of the Interpolation-Deep Convolutional Generative Adversarial Network(I-DCGAN)for flaw detection image generation and a comprehensive evaluation algorithm named TOPSIS-IFP.I-DCGAN enables the generation of high-resolution,diverse simulated images with multiple appearances,achieving an improvement in sample diversity and quality while maintaining a relatively lower computational complexity.TOPSIS-IFP facilitates multi-dimensional quality evaluation,including aspects such as diversity,authenticity,image distribution difference,and image distortion degree.The results indicate that the X-ray radiographic images of magnesium and aluminum alloy castings achieve optimal performance when trained up to the 800th and 600th epochs,respectively.The TOPSIS-IFP value reaches 78.7%and 73.8%similarity to the ideal solution,respectively.Compared to single index evaluation,the TOPSIS-IFP algorithm achieves higher-quality simulated images at the optimal training epoch.This approach successfully mitigates the issue of unreliable quality associated with single index evaluation.The image generation and comprehensive quality evaluation method developed in this paper provides a novel approach for image augmentation in flaw recognition,holding significant importance for enhancing the robustness of subsequent flaw recognition networks.

Evaluation of Productivity and Light Quality in Two High Density Dwarf Rootstock Apple Orchards in Central China

[Ohjective] The aim of the study is to investigate the productivity and light quality in two high density M26 dwarf rootstock apple orchards in central China so as to provide some management guidance for close planting of dwarf rootstock apples.[Method] The technical parameters of individual trees and group parameters as shoot number and composition and canopy coverage were determined, and the light quality in the canopy, fruit production and quality were investigated. [Result] Slender spindle （SS） orchard has 54 thousands shoots per 667 m^2. Coverage rate is 76%. Leaf area index is 1.9. The ratio of long, medium and spur shoots is 1：1：8. Fruit yield is 3 263 kg/667 m^2 with 85% first grade fruit. Light interception in the canopy is 58% while the ratio of canopy with good light is 65%. Modified slender spindle （MSS） orchard has 93 thousands shoots per 667 m^2 and the coverage is 77%. Leaf area index is 3.3. The ratio cf long, medium and spur shoots is 1：2：7. Fruit yield is 3 931 kg/667 m^2 with 85% first grade fruit. The light interception in the canopy is 73% while the ratio of canopy with good light is 35%. [Conclusion] Apple orchard with M26 dwarf rootstock trained as SS and MSS tree form in medium planting density may be useful to the management of the similar orchards in Central China.

Light Quality-controlled Phytochemicals Biosynthesis in Vegetables and Fruits

Phytochemicals（including proteins, lipids, carbohydrates, vitamins, minerals,phenolic compounds and so on） are one of the most important groups of the bioactive compounds in vegetables and fruits, benefit for human health. The phytochemicals biosynthesis is affected by environmental factors, and light in particular. Light effects can be categorized in photoperiod, intensity and quality. While it is widely known that light intensity can positively affect phytochemicals accumulation, the effects of light quality are more complex and often reported with mixed results. So this review focuses on the currently knowledge about different light quality on the control of phytochemicals biosynthesis. A better knowledge on these regulatory mechanisms will be useful for modifying phytochemicals biosynthesis in vegetables and fruits.

人LIGHT和HSV-TK-EGFP基因共转染的MSCs抗肿瘤免疫的体内研究

目的研究与单纯疱疹病毒的糖蛋白D竞争结合单纯疱疹病毒进入介导物(herpes virus entry mediator,HVEM)的淋巴毒素类似物(homologous to lymphotoxins,exhibits inducible expression,and competes with HSV glycoprotein D for HVEM,a receptor expressed by T lymphocytes,LIGHT)基因和单纯疱疹病毒胸苷激酶(herpes simplex virus thymidine kinase,HSV-TK)基因共转染的骨髓间充质干细胞(mesenchymal stem cells,MSCs)在体内的抗肿瘤免疫功能。方法将pIRES2-LIGHT基因和HSV-TK-EGFP基因共转染小鼠骨髓间充质干细胞(MSCs/LT组),以转染空载体和转染HSV-TK-EGFP基因的骨髓间充质干细胞作对照。流式细胞仪检测LIGHT分子和HSV-TK-EGFP分子在稳定转染的骨髓间充质干细胞上的表达。体内迁移实验观察MSCs/LT在小鼠体内迁移情况。观察更昔洛韦注射前后MSCs/LT对荷瘤小鼠体内肿瘤的治疗作用。ELISA法检测小鼠肿瘤组织中IFN-γ,IL-2和IL-10的水平。结果流式细胞仪检测发现,MSCs/LT能稳定高表达LIGHT分子。MSCs/LT有特异地向肿瘤组织趋化的特性。MSCs/LT和MSCs/T有较好的抑制肿瘤生长的能力,但在更昔洛韦诱导后,MSCs/LT的抗肿瘤效应下降甚至消失。同时,MSCs/LT可促使T细胞进入肿瘤组织,并促进T细胞分泌IL-2、IFN-γ,抑制IL-10分泌(P<0.05)。结论共转染人LIGHT和HSV-TK-EGFP基因的骨髓间充质干细胞能稳定高表达LIGHT分子,能特异性地向荷瘤小鼠体内肿瘤组织趋化并抑制肿瘤的生长,这种体内抗肿瘤功能可能与促进T淋巴细胞IL-2、IFN-γ等细胞因子的分泌,改善局部免疫抑制环境有关。

Crop photosynthetic response to light quality and light intensity

Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light(light quality and light intensity) greatly affect plant photosynthesis and other plant's morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species(ROS) production, antioxidants, and hormone production.

Effect of Light Quality on Photosynthesis and Chlorophyll Fluorescence in Strawberry Leaves

The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showed that the chlorophyll content,maximal photochemical efficiency of PSⅡ(Fv/Fm), Fm/Fo, amount of inactive PSⅡreactioncenters (Fi-Fo) and rate of QA reduction were positively correlated with the red-light/blue-light ratios, but the chlorophyll (a/b) ratios were negatively correlated withthem. Carotenoid content of the leaves was maximum under the blue film, than under greenfilm, red film, white film and yellow film, and negatively correlated with the red/far-red ratios. The apparent quantum yield (AQY), photorespiratory rate (Pr) and carboxylationefficiency (CE) were also strongly affected by light quality. The photosynthetic rate(Pn) in strawberry leaves under green film was significantly lower than under all otherfilm. Our results suggested that light quality is an essential factor regulating thedevelopment of PSⅡ, and phytochrome and an independent blue light photoreceptor,possibly a cryptochrome, can regulate photosynthetic performance.

Systematic Identification of the Light-quality Responding Anthocyanin Synthesis-related Transcripts in Petunia Petals

Previous studies have shown that high light intensity can induce anthocyanin synthesis(AS)in petunia plants.To identifywhich kind of light quality plays a role in inducing such metabolic process,and what transcripts participate in controlling it,we carried out whole-transcriptome sequencing and analysis of petunia petals treated with different light-quality conditions.Among the red and white light treatments,a total of 2205 differentially expressed genes and 15,22,and 20 differentially expressed circRNAs,miRNAs,and lncRNAs,were identified respectively.The AS-related genes,including the structural genes CHSj,F3H,F35H,DFR,and ANS,and the regulatory genes AN4,DPL,PHZ and MYBx were found to be downregulated under red light condition compared with their levels under white light condition.Furthermore,the light photoreceptor Cryptochrome 3(CRY3)and a series of light-dependent genes,such as PIF,HY5,andBBXs,were also determined to respond to the light treatments.The anthocyanin contents in early petunia petals under red light were significantly lower than that under white and blue light.The results of qRT-PCR further confirmed the expression pattern of some AS-related and light-response genes in response to different light quality.Yeast two-hybrid results showed that the key elements in the light signal pathway,HY5 can interact with BBX19,BBX24 and BBX25.And PHZ,the important AS regulator can induce anthocyanin synthesis in response to blue light quality fromtransient expression analysis in petunia petals.These findings presented here not only deepen our understanding of how light quality controls anthocyanin synthesis,but also allow us to explore potential target genes for improving pigment production in petunia flower petals.

Light quality and temperature effects on antirrhinum growth and development

An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19℃, 24℃ and 27℃ in glasshouses. Five different colour filters (i.e. 'Red absorbing', 'Blue absorbing', 'Blue and Red absorbing' and two 'partially Blue absorbing' materials) were tested, with one clear polythene as a control. Plant height, internode length and leaf area were significantly affected by the spectral filters as well as the temperature.Analysis of color filter's effect on presumed photoreceptors to exist indicated that antirrhinum plant height was regulated by the action of a blue acting photoreceptor (BAP) and not the phytochrome. There was no evidence for an effect ofphytochrome or BAP on time to flowering, however, increasing temperature levels effectively decreased the time to flowering. To predict the effects of different spectral qualities and temperature, simple models were created from data on plant height, internode length and time to flowering. These models were then applied to simulate the potential benefits of spectral filters and temperature in manipulation of growth control and flowering in antirrhinum.

Effects of Low Light on Agronomic and Physiological Characteristics of Rice Including Grain Yield and Quality

Light intensity is one of the most important environmental factors that determine the basic characteristics of rice development. However, continuously cloudy weather or rainfall, especially during the grain-filling stage, induces a significant loss in yield and results in poor grain quality. Stress caused by low light often creates severe meteorological disasters in some rice-growing regions worldwide. This review was based on our previous research and related research regarding the effects of low light on rice growth, yield and quality as well as the formation of grain, and mainly reviewed the physiological metabolism of rice plants, including characteristics of photosynthesis, activities of antioxidant enzymes in rice leaves and key enzymes involved in starch synthesis in grains, as well as the translocations of carbohydrate and nitrogen. These characteristics include various grain yield and rice quality components （milling and appearance as well as cooking, eating and nutritional qualities） under different rates of shading imposed at the vegetative or reproductive stages of rice plants. Furthermore, we discussed why grain yield and quality are reduced under the low light environment. Next, we summarized the need for future research that emphasizes methods can effectively improve rice grain yield and quality under low light stress. These research findings can provide a beneficial reference for rice cultivation management and breeding program in low light environments.

Relationships Between the Distribution of Relative Canopy Light Intensity and the Peach Yield and Quality

The aim of the present experiment was to study the relationship between the distribution of relative light intensity in canopy and yield and quality of Wanmi peach. The optimum relative canopy light intensity was judged to be 36.3% for high quality peaches, when canopy volumes of Wanmi peach trees with a relative light intensity 〈 30% accounted for 7.7 and 47.9% of the total canopy volume in June and September, respectively. The canopy volume with a relative light intensity 〉 80% was 27.7 and 3.1% of the total canopy volume in June and September, respectively. Peach canopies were divided into 0.5 m × 0.5 m × 0.5 m cubes, with the relative light intensity being measured at different positions of the canopy during the growing season. Yield and fruit quality were also measured at these positions at harvest. The results showed that the relative light intensity decreased gradually from outside to inside and from top to bottom of the tree canopy. Fruit were mainly distributed in the upper and middle portions of the canopy, 1.5-3.0 m above ground. Regression results showed that single fruit weight and soluble solid content were positively related to relative light intensity.

Effects of Light Quality on Carbon and Nitrogen Assimilation and Root Activity of Eggplant

[Objective] This study was conducted to provide theoretical and data reference for high-quality high-yield production of Shangqie 1 under controlled light quality environment and light quality control of other eggplant varieties. [Method] With Shangqie1 as an experiment material, the effects of red light, blue light, red-blue light, red-blue light and white light(control) on the carbon-nitrogen metabolism and root vitality of eggplant were investigated. [Result] Different light quality significantly affected sugar and starch contents in leaves of eggplant. Under the red-blue light(5∶1) treatment, the sucrose, total sugar and starch contents were the highest, and the values were higher than those under the white light treatment by 3.47%, 13.61% and 33.49%,respectively. The fructose content was the highest under white light. Under red-blue light(3∶1) and red-blue light(5∶1), the nitrate nitrogen contents were higher than that under white light, indicating that compound light affects nitrate content not only by simple superposition of light quality, but also by other type of interaction effect. The free amino acid and soluble protein contents under blue, red-blue(3∶1), red-blue(5∶1) and red light treatments were all higher than those under the white light treatment, and the blue light treatment exhibited the highest values, which were higher than those under white light by 24.89% and 46.62%, respectively, with significant differences. The red-blue light(5 ∶1) treatment exhibited the highest root vitality of eggplant, which was higher than that under the white light treatment by 31.85%. The red light treatment had the second highest root vitality, which was higher than that under the white light treatment by 19.30%, followed by the red-blue light(5∶1) treatment, and the blue light treatment showed the lowest value. [Conclusion] Under red-blue light(5 ∶1) treatment, eggplant had vigorous carbon-nitrogen metabolism and the highest root vitality.

Supplemental blue light increases growth and quality of greenhouse pak choi depending on cultivar and supplemental light intensity

To evaluate the supplementary blue light intensity on growth and health-promoting compounds in pak choi（Brassica campestris ssp.chinensis var.communis）,four blue light intensity treatments（T0,T50,T100 and T150 indicate 0,50,100,and 150μmol m^（-2） s^（-1）,respectively）were applied 10 days before harvest under greenhouse conditions.Both of cultivars（greenand red-leaf pak choi）under T50 had the highest yield,content of chlorophyll and sugars.With light intensity increasing,antioxidant compounds（vitamin C and carotenoids）significantly increased,while nitrate content showed an opposite trend.The health-promoting compounds（phenolics,flavonoids,anthocyanins,and glucosinolates）were significantly higher under supplementary light treatment than T0,so as the antioxidant capacity（2,2-diphenyl-1-picrylhydrazyl and ferric-reducing antioxidant power）.The species-specific differences in photosynthetic pigment and health-promoting compounds was found in green-and red-leaf pak choi.T50 treatment could be used for yield improvement,whereas T100 treatment could be applied for quality improvement.Results showed that blue light intensity can regulate the accumulation of biomass,morphology and health-promoting compounds in pak choi under greenhouse conditions.

Low Light During Grain Filling Stage Deteriorates Rice Cooking Quality, but not Nutritional Value

To investigate the effect of low light （LL, 50% natural light） during grain filling （GF） stage on rice transamination, amino acid （AA） accumulation, nutritional value, and cooking quality in three different rice genotypes, transaminase activities and AA levels in grains during GF stage and the traits that significantly affected rice quality （physical appearance, cooking quality, and nutritional value） were analyzed. LL did not disturb transamination in rice grains during GF stage, as minimal impact was found on alanine and aspartate transaminase activities. Nevertheless, most AAs in caryopses, including lysine and threonine, increased in response to LL, except for sulfur-containing AAs. These results suggest that AA metabolism and accumulation in rice grains were rarely suppressed by LL during GF stage. Rice nutritional ingredients at harvest, such as major protein components including glutelin and most important essential amino acids （EAAs） including lysine and threonine, increased significantly in response to LL, whereas most protein and EAA ratios were rarely affected. However, LL markedly affected physical appearance of rice grains by reducing brown rice rate, milled rice rate, and 1000-grain weight and increasing the chalkiness rate. In addition, cooking qualities decreased in response to LL, while breakdown values and amylose levels decreased and setback values increased. We concluded that LL during GF stage decreased the cooking quality of rice, but could potentially improve the nutritional value of rice.

基于CEEMDAN-VMD-TCN-lightGBM模型的水质预测研究

针对目前水质预测模型中因为数据本身的复杂性、在信号处理过程中存在的噪声干扰以及分解深度不够导致单一分解难以全面捕捉信号非线性特征的问题,提出了一种基于二次分解的水质预测模型。该模型采用完全自适应噪声集合经验模态分解(CEEMDAN)对原始数据进行分解,再利用变分模态分解(VMD)对熵值最高的模态分量进行二次分解,最终将处理后的时间序列输入到TCN-lightGBM多特征预测模型中。同时,采用麻雀算法(SSA)对预测模型进行优化。以山东省玉符河水质为例,本模型的均方根误差(RMSE)是0.1053,平均绝对误差(MAE)是0.0815,决定系数(R2)是0.9471,与GRU、LSTM、LightGBM、TCN等当下较为流行的模型的预测指标进行比较。结果显示,在R2上本模型提升了53.04%、70.41%、66.07%、65.20%等,在RMSE上减少了62.76%、65.50%、64.93%、64.80%等,在MAE上降低了62.76%、66.24%、63.80%、65.24%等。由此可知,基于CEEMDAN-VMD-TCN-lightGBM的模型具有更好的预测性能、泛化能力和捕捉信号非线性特征的能力。

Effects of light quality on growth rates and pigments of Chaetoceros gracilis(Bacillariophyceae)

Light is an important parameter in algal culturing.In this work,the effects of different light qualities on growth of the marine diatom Chaetoceros gracilis are evaluated.The cells were cultured under light quantum flux density of 60μmol photons/(m2·s)with nine light qualities:LED red light(LR),LED blue light(LB),LED red plus LED blue light(LR+LB),LED white light(LW),fluorescent white light(FW),and combinations of LW and FW lights with increased proportions of red or blue light(FW+LR,FW+LB,LW+LR,and LW+LB).Blue light promoted the growth of C.gracilis largely.Three light qualities,FW+LR,LW+LR,and LR,resulted in the lowest growth rate.Both chlorophyll and carotenoids reached the highest level under LB and the lowest level under LR among monochromatic light sources;however,increasing of the proportion of blue or red light in the white light induced an increase of the chlorophyll and carotenoid concentrations.Light absorption ability of microalgae was critical for the growth of these organisms,as we observed a positive correlation between the extinction coefficient at different wavelengths and the specific growth rate.These findings are of importance to improve the culturing of this alga in bioreactors.

The Effect of Supplemental Blue, Red and Far-Red Light on the Growth and the Nutritional Quality of Red and Green Leaf Lettuce

Spectral quality of radiation has a major impact on the growth, development and nutritional quality of crops. The effect of supplemental radiation (blue, red and far-red) on the growth and nutritional quality with regard to health-promoting phytochemical and micronutrient composition of two lettuce (Lactuca sativa) varieties (red leaf “New Red Fire” and green leaf “Two Star”) was studied. Supplemental radiation was provided by blue (450 nm), red (660 nm) or far-red (730 nm) LEDs against a background of white light (fluorescent lighting, PAR;270 μmol/m2/s) in a growth chamber study. All the supplemental radiation treatments increased dry shoot biomass in both varieties. However, supplemental far-red radiation increased both fresh and dry shoot biomass in both varieties. In addition, supplemental far-red radiation produced distinct morphological characteristics in lettuce plants. It produced the largest shoot biomass, bigger and taller plants, fewer leaves but with larger leaf area compared to the control, similar to the shade avoidance response. With regard to the accumulation of phytochemicals, supplemental blue radiation enhanced the total phenolic compound concentration in both varieties. In addition, supplemental blue radiation sharply increased the accumulation of several phenolic compounds in green leaf lettuce including chlorogenic acid, chicoric acid, rutin, kaempferol, luteolin and apigenin. For example, the leaf concentration of rutin in green leaf lettuce increased by 20-fold under supplemental blue radiation. Similarly, supplemental red radiation increased the concentration of many of these phenolic compounds in red leaf lettuce. However, supplemental far-red radiation had an inhibitory effect on the accumulation of chlorogenic acid, chicoric acid, rutin and kaempferol in red leaf lettuce. While supplemental radiation did not affect the accumulation of most of the micronutrients, it had a negative impact on the accumulation of some micronutrients, the response being variety dependent. The results show that supplementing white light with specific spectral quality has a major impact on the biomass accumulation, morphology and on the accumulation of many health-promoting phytochemicals and micronutrients in lettuce. While it had a large positive effect in enhancing the accumulation of several phytochemicals, it also suppressed the accumulation of some micronutrients.

Control of light environment: A key technique for high-yield and high-quality vegetable production in protected farmland

Vegetable crops such as cucumber and tomato are grown widely through the world using not only field but also protected farmland. Sensitive responses of many vegetables have been widely reported to environmental conditions such as light, air temperature, relative humility, and CO2 concentration in the past years. Among these environmental factors, light is considered to be the most important one for vegetable growth and development, especially in protected farmland. Therefore, lots of researches on effects of light environment, including light intensity, light quality, photoperiod, and light direction, on vegetable growth and development have been done in order to optimize the environmental conditions for high-yield and high-quality vegetable production in protected farmland. In this review, recent advances in light environment control for vegetable production in protected farmland have been reviewed and the prospective for the future research has been proposed as well.

Regulation of Reproduction in Delayed Gametophyte of Saccharina japonica (Laminariales, Phaeophyceae): Effects of Light Intensity, Quality and Photoperiod

Saccharina japonica gametophytes can survive a long period under unfavorable environmental conditions,while they also delay in growth and/or reproduction.Although the reproduction in delayed gametophyte of S.japonica was known to be strongly influenced by light intensity,light quality,and photoperiod,no previous studies have evaluated their interactive effects on gametogenesis.To evaluate these effects,we used an orthogonal experiment to expose delayed gametophytes of S.japonica to different light intensities,light qualities,and photoperiods for 12 days.The results showed that changes in light intensity rather than light quality and photoperiod significantly affected the relative growth rates of the delayed gametophytes.Blue light had the greatest promotion on reproduction rate.The optimal light conditions in the early vegetative growth phase in gametogenesis induction for the delayed gametophytes were at 60–80μmol photons m^(−2) s^(−1) with daylength of 12 or 16 hours under white or blue light.When the delayed gametophytes were maintained in a constant light condition from delayed state to gametogenesis,the beneficial photoperiods for vegetative growth and reproductive rate were both 16L(16 hours of light):8D(8 hours of dark).However,when the delayed S.japonica gametophytes achieve the optimal growth state during the first 6 days and then they were cultured at different light conditions for the following 6 days,the reproduction rate increased as the daylength decreased and attained a peak value in group of 8L:16D photoperiod,indicating that photoperiod adjustment at the transition period is crucial in the gametogenesis induction process of delayed gametophyte of S.japonica.