Mechanisms Of Regulating The Bioactive-healthy Compounds In Pak-choi By Illumination And Aritificial Light Quality Applied In Agriculture

Illumination not only affects photosynthesis of plants,but also regulates the physiological and biochemical processes such as their growth,development,secondary metabolism and bio-action.Plant absorbs the spectra ranging from 200 nm to 800 nm,which is more sensitive to the 400-700 nm.The wavelength of this segment is also called the photosynthesis effective energy ragion.Pak-choi（Brassica campestris ssp.chinensis var.communis）is native to China and rich in anthocyanin,flavonoid and individual glucosinolate.These compounds play an important role in anti-cancer-functional food.In this study,the green-and red-leaf pak-choi were used as test materials to select the different supplementary light intensity（energy）and wavelength（signaling）that can effect the growth and phytochemistry of pak-choi significantly.Based on the glucosinolate metabolic network and screening results of the first two experiment,the light treatments which regulate the key genes of light receptor,transcription factor and core structure on regulate network were measured by RT-PCR.For the further research,based on the theory of phytochrome receptor,the red and blue combinational light were also applied in this experiment,which is used to found out how the red and blue combinational light regulate the expression of key genes of glucosinolate.Based on the chosed-light-environment and the mechanism study of bio-active metabolism on pak-choi,artificial illumination for agriculture-functional materials were applied to horticulture.From the macroscopic aspect,rare earth ion doped inorganics were used to construct artificial LED and PC lampshade;From the microcosmic aspect,the fluorescent carbon dots were applied in hydroponic pak-choi,which is used to find how the carbon dots effect the growth and physiological metabolism on pak-choi,and monitor the optical materials in plant by the technology of tissue slice.This experiment is the first attempt to monitoring acritical microcosmic light environment on plant.In summary,this study obtains the results as below:（1）The effect of different supplementary blue light intensity on the growth and quality of two kinds of pak-choi.Four blue light intensities(0,50,100 and 150μmol·m^-2·s^-1 was T0,T50,T100 and T150)were applied 10 days before the harvest under the greenhouse condition,and the light wavelength was 460 nm irradiated for 12 hours.The results showed that under the light intensity of 50μmol·m^-2·s^-1,the two kinds of pak-choi had the highest biomass and chlorophyll content.The contents of antioxidants（Vc,carotenoids）and nutrients（anthocyanins,flavonoids,total phenols）increased with the increase of blue light intensity,while the contents of soluble sugars and nitrates decreased significantly.The content of free amino acids and glucosinolates in two leafy pak-choi increased significantly with the increase of the blue light fill intensity.The content of antioxidant capacity（DPPH and FRAP）of pak-choi supplemented with blue light was higher than that of the control group.（2）The effects of different supplementary light wavelength on the growth and quality of two kinds of pak-choi.The blue-violet light（460,430,400,380 nm）with different wavelengths was continuously irradiated for 10 days before harvest,and the intensity was 100μmol·m^-2·s^-1.The cabbage was continuously irradiated with light for 12 hours.The results indicated that the content of nitrate and mass was significantly decreased with light wavelength decreased.The nutrition-functional compounds（anthocyanin,total phenolics,flavonoid and Vc）significantly increased with light wavelength decreasing.The content of individual glucosinolates and free amino acids have the different changing tendency under radio different light wavelengths.The antioxidant capacity under supplementary light was higher than control group.（3）The molecular regulation mechanism on glucosinolates of pak-choi with light quality.The two species pak-choi were treated with blue-violet light with a wavelength of 430nm.The light intensity was 100μmol·m^-2·s^-1 and was sampled once every 12 hours for a total of three times.The results indicated that the blue light can significantly affect the expression of light receptor,transcription factor and cure structure genes;the above steps were repeated with 430 nm blue-violet light and 630 nm red light combinationally,(the supplementary intensity was 100μmol·m^-2·s^-1,12 h/day).This results not hesitated to conclude that the expression of key genes about regulate glucosinolates’metabolism depends on the different light treatments and cultivation.（4）CaAl₁₂O₁₉:Mn⁴⁺phosphors synthesis,regulate spectra and applied in pak-choi cultivationBased on the results of the light physiology of the Chinese cabbage on the light quality,a kind of phosphors for plant growth LED application was constructed and applied.Mn⁴⁺-activated Ca_1-xY_xAl_12-xMg_xO₁₉（x=0-0.50）solid solutions were prepared by a conventional high-temperature solid-state reaction.The crystal structure transformation via chemical cosubstitution of Y³⁺/Mg²⁺for Ca²⁺/Al³⁺by investigated in detail.Optical properties of the Ca_1-xY_xAl_12-xMg_xO₁₉（x=0-0.50）were reported for the first time by combining techniques of structural refinement and luminescence measurements.Co-doping Mg,Y cations within in the CaAl₁₂O₁₉ host in a controlled manner resulted in the as-prepared samples with red/far-red ratio-tunable luminescent properties.The emission bands are well-matched with the absorption band of phytochrome.Artificial the LED with phosphor applied in pak-choi,which had the higher content of soluble sugars and free amino acids and Gs.Above results indicated that they have tremendous potential as lighting systems for plant growth.（5）Synthesis of CaAlSiN₃:Eu²⁺phosphor doped PC lampshade for pak-choi growth light.In order to achieve the goal of the interchange between traditional white light emitting diodes（WLEDs）and plant growth light,the fluorescent polycarbonate（PC）lampshades with different mass fraction of CaAlSiN₃:Eu²⁺(CASN:Eu²⁺)phosphor were characterized by structural and optical analysis.The results shows a good stability during the preparation process.Meanwhile,the fluorescent PC lampshades were equipped with WLED T8 tubes for plant growth lights.When the color rendering index was from 70.3 to 77.6,the luminous efficiency decreases slightly.The design of combination fluorescent PC lampshades and LED T8 tubes can significantly increase the biomass and soluble sugars in pak-choi.（6）Pollen-carbon dots effect the growth on pak-choi（green-and red-leaf pak-choi）and apply bioimaging on transported via in plant.Carbon dots（CDs）,synthesized from pollen,have attracted attention in hydroponic vegetable due to their low cytotoxicity,water-soluble nature,and biocompatibility.3.5mg/L CDs added to the nutritional solution can significantly increase mass of pak-choi.The pollen-CDs were transported via the vascular system of pak-choi,confirmed by the confocal images.TEM results demonstrated that the pollen-CDs were enriched in the periplasmic space.Above results indicated that nanomaterials applied in agriculture in the future with possibility.