Effects of Different Light Qualities on Activity and Gene Expression of Caspase-like Proteases in Tobacco Leaves

[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yellow, blue and purple films to obtain different light quality, the changes of chlorophyll content, activity and gene expression of caspase-like proteases in the tobacco leaves were studied. [Results] Compared with treatments of white, red and yellow film, blue and purple films delayed the decrease of chlorophyll content and senescence of tobacco leaves at the late growth stage, and relatively lowered the activity and gene expression of caspase-like proteases during growth, development and senescence periods. [Conclusion] Different light qualities exhibited various effects on the growth, development and senescence of tobacco leaves, possibly by affecting the activity and gene expression of caspase-like proteases to some extent.

Monitoring Flue-Cured Tobacco Leaf Chlorophyll Content under Different Light Qualities by Hyperspectral Reflectance

Rapid assessment of foliar chlorophyll content in tobacco is critical for assessment of growth and precise management to improve quality and yield while minimizing adverse environmental impact. Our objective is to develop a precise agricultural practice predicting tobacco-leaf chlorophyll-a content. Reflectance experiments have been conducted on flue-cured tobacco over 3 consecutive years under different light quality. Leaf hyperspectral reflectance and chlorophyll-a content data have been collected at 15-day intervals from 30 days after transplant until harvesting. We identified the central band that is sensitive to tobacco-leaf chlorophyll-a content and the optimum wavelength combinations for establishing new spectral indices (simple ratio index, RVI;normalized difference vegetation index, NDVI;and simple difference vegetation index, DVI). We then established linear and BackPropagation (BP) neural network models to estimate chlorophyll-a content. The central bands for leaf chlorophyll-a content are concentrated in the visible range (410 - 680 nm) in combination with the shortwave infrared range (1900 - 2400 nm). The optimum spectral range for the spectral band combinations RVI, NDVI, and DVI are 440 and 470 nm, 440 and 470 nm, and 440 and 460 nm, respectively. The linear RVI, NDVI, and DVI models, SMLR model and the BP neural network model have respective R2 values of 0.76, 0.77, 0.69, 0.78 and 0.86, and root mean square error values of 0.63, 1.60, 1.59, 2.04 and 0.05 mg chlorophyll-a/g (fresh weight), respectively. Our results identified chlorophyll-a sensitive spectral regions and new indices facilitate a rapid, non-destructive field estimation of leaf chlorophyll-a content for tobacco.

Cultivation of Chlorella sp.HQ in inland saline-alkaline water under different light qualities

Inland saline-alkaline water can be used for the low-cost cultivation of microalgae,but whether algal biomass under various light sources has the potential to produce biodiesel remains to be developed.Herein,the influence of different light-emitting diode(LEDs)light colors(blue,red,white,mixed blue-red,and mixed blue-white LED)on the growth performance,lipid accumulation,and fatty acid composition of Chlorella sp.HQ cultivated in inland saline-alkaline water was investigated.The highest algal density was obtained under blue LEDs at the end of cultivation,reaching 1.93±0.03 × 10^(7) cells/mL.White LEDs can improve biomass yield,total lipid yield,and triacylglycerol yield per algal cell.The main fatty acid components of Chlorella from inland saline-alkaline water were palmitic acid and linoleic acid.The Biodiesel Analyzer software was used to predict algal biodiesel quality by estimating different quality parameters.The cetane number,kinematic viscosity,and density of Chlorella biodiesel were 51.714-67.69,3.583-3.845 mm^(2)/s,and 0.834-0.863 g/cm^(3),respectively.This flirther proved that the Chlorella biomass obtained from inland saline-alkaline water has the potential to be used as a high-quality biodiesel feedstock.

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.

The Effect of the Novel "light fertilizer" on the Environment Factor in High Tunnel and Growth of Brassica Chinensis

[Objective] The aim was to study the properties of novel ＂light fertilizer＂, photo-conversion film, in order to evaluate its effect on the environmental factors and morphogenetic process of crops in the high tunnel. [Method] Photo-conversion film and Iongevous anti-dropping film were compared in terms of light, air and soil temperature utilizing the Facilities of leafy agriculture high tunnel intelligent monitoring system. Verifying the results by farmland experiment. [Result] Photo- conversion film indeed improved the light quality of high tunnel compared with the Iongevous anti- dripping film. The air and soil temperature was raised several degrees. Results of farmland experiment show that the average value of brassica chinensis fresh weight increased 19.15% compared to the control. [Conclusion] Photo-conversion film promotes more crop growth than Iongevous anti-dropping film due to improvement of light quality, air and soil temperature.

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.

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.

Basal internode elongation of rice as affected by light intensity and leaf area

Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.

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 light-emitting diodes on tissue culture plantlets and seedlings of rice (Oryza sativa L.)

Light-emitting diodes(L EDs)are a new light source with low energy consumption and high photoelectric conversion efficiency,and they can satisfy the energy-saving needs of plant culture systems.However,the effects of LED light sources on rice tissue culture and rice seedling cultivation are poorly understood.This study aimed to evaluate the effects of LEDs on the growth of tissue culture plantlets and seedlings of the rice(Oryza sativa L.)cultivar Nipponbare.The best light source for rice tissue culture was different from that for rice seedling cultivation.Blue(B)LED light was the most appropriate light for rice tissue culture.Under a B LED light,the time required for callus proliferation,differentiation and regeneration was the shortest,and the frequency of plantlet ititin,dfferetiation and regeneration was the highest.Ablue:red(B:R)=1:1LED light facilitated the growth of rice seedlings and produced the highest chlorophyll and carotenoid contents and photosynthetic rates in the rice seedlings.Abundant photosynthetic products were more effectively generated in the rice seedlings under the B:R=1:1 LED and R LED lights than under the B LED light.B LED light is the most appropriate light for rice tissue culture plantlets and can be used as an alternative light source for rice tissue culture,and B:R=1:1 LED light facilitated the cultivation of robust rice seedlings and can be used as the primary light source for rice factory seedling cultivation.

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.

Associative learning in plants:light quality history may matter

The possibility of associative learning in plants is a topic of ongoing controversy.In one published study,growing pea plants were reported to associate two stimuli(airflow and light)and thereafter use one(airflow)as an indicator for the other(light),similar to dogs in Pavlov’s famous experiments.However,this observation could not be independently repeated.Here we examine a possible reason for the failure of a published reproduction attempt,which used substantially different light quality during plant cultivation prior to experimental treatments than in the original study.This could have resulted in dramatically different growth characteristics.While the relevance of the original report of plant associative learning remains questionable,greater attention should be paid to good documenting and standardizing the light conditions,in particular spectral quality,not only in studies of plant learning and memory,but also in other areas of experimental plant biology.

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.

Growth of Verticillium tricorpusmA Saprophytic Fungus and Potential Entomopathogen of Cocoa Pod Borer as Affected by the Medium and Light

Cocoa pod borer （CPB） has endangered Indonesian cocoa. Use of entomopathogen in biocontrol of pests is considered to be environmentally friendly approach. Verticillium tricorpus has been reported to be a potential agent for controlling CPB. The aim of this research was to study the possibility in using alternative, easy and cheap media and also the role of intensity and quality of light for mass production of V. tricorpus. The experiments were laid out in split-plot design as factorial, where every combination treatment was replicated three times. Medium, in form of semi-synthetic and natural, was treated as the main plot, while light as sub-plot. Results of this study showed that for the growth and development of fungus V. tricorpus, the use of alternative natural media in form of a mixture of cocoa pod husk and maize was the best. Use of cocoa dextrose agar （CDA） as semi-synthetic medium was more suitable for the growth and development of V. tricorpus compared to potato dextrose agar （PDA）. The semi-synthetic and natural media consisted of cocoa husk and maize are suitable for cocoa production area in Indonesia, where mostly cocoa is planted in lowland area and mostly is also suitable for corn but not for potato growing. Growth of the fungus colony especially on CDA medium reached its optimum condition when using white light with the intensity of 1,000 lux. This study proved that the requirement for light quality was different between growth and development purposes. Development of V. tricorpus until the production of conidia in optimal condition was reached with the use of yellow light with the intensity of 1,000 lux.

Research Progress on the Effect of Light on Plant Growth

Light is one of the important factors affecting plant growth and has an important impact on plant growth and development.In this paper,the effects of light on plant growth,development,and physiological and biochemical functions were reviewed from three aspects:light intensity and light quality on plant biomass,photosynthesis,and chemical components.

Quality Control System for Light Industry

In the next three to five years, China’s light industry will upgrade major product quality generally to world level. This will be done by strengthening quality control and supervision and the improvement in technology. The campaign was announced by Yu Zhen, president of the China National Council of Light Industry at the beginning of this year.

LIGHTING QUALITY AND ACOUSTIC QUALITY IN LEED-CERTIFIED BUILDINGS USING OCCUPANT EVALUATION

Lighting quality and acoustic quality are often not well addressed in the current green building practice,including the Leadership in Energy and Environmental Design(LEED)Green Building Rating System in the US.While the level of LEED certification indicates the level of sustainability,it is not clear if a higher level of LEED certification also implies a more comfortable and productive work environment.The study intended to find the relationship between the level of LEED certification and the level of worker satisfaction and perceived job performance regarding lighting quality and acoustic quality from fifteen LEED-certified buildings.The findings indicate that the LEED Platinum building group tended to provide better lighting quality than the other lower certification groups,while the LEED Gold building group showed lower lighting quality and acoustic quality than the rest of the groups.Workplace designers and organizations should be mindful of the importance of lighting and acoustic qualities in promoting better comfort and productivity as it is easy to overlook these criteria when complying with LEED IEQ guidelines.