Effects Of Light Quality On Choloropyll Fluoresense Spectral And Its Kinetic Characters Of Cucumber Leaves

The paper focused on the production of greenhouse cucumber leaves of different layers of light quality of the photosynthesis process to full utilization, this study not only QE65000 fiber spectrophotometer Determination of viability of the fluorescence were analyzed, and the study of white North cucumber as material, the use of blue, green and red light emitting diode (LED) for monochromatic light treatment, the use of optical spectroscopy (QE65000, Spectrometer Ocean Optics, Inc. USA) measured the light quality Fp₆₈₅, Fp₇₃₅, Fp₆₈₅/Fp₇₃₅, F₆₈₅, F735, F₆₈₅/F735, Y (II)′, the process of de-etiolated cotyledons of light absorption. Determination of atrazine on PSII to PSI electron transport inhibition.Using UV-2450 Spectrophotometer light quality on photosynthetic pigment content; while taking advantage of chlorophyll fluorescence imaging instrument (MINI-IMAGING-PAM) for cucumber leaves chlorophyll fluorescence parameters determined. Analysis of the cucumber green light quality on chlorophyll fluorescence and light quality induced de-etiolation in cucumber cotyledons in light absorption and activity of PSâ…¡.With the relevant system, IPSMT and later phase of chlorophyll fluorescence under a variety of light qualities can be obtained by QE65000, the 200 900nm in the spectra also can be quickly scanned by it.With the increase of light intensity, the P in OJIP of chlorophyll fluorescence curve showed a fast rising. Fp₆₈₅ were in the order of red>blue>green, but Fp₇₃₅ were in the order of green> red≈blue. However, the order of blue> green≈red were observed for the ratio of Fp₆₈₅/ Fp₇₃₅.Under Blue light the F₆₈₅ fluorescence value higher than F735, under green or red fluorescence the F735 fluorescence value is higher than the F₆₈₅; P point appeared under blue required minimum PAR, followed by green, red the most. The point of P appeared earlier under the mixed light than under single light, and Pmix≥Psingle. The ratios of F₆₈₅/ F735 always lower under the mixed lights than under single light. The order of Y(II)′green> Y(II)′red> Y(II)′blue were observed for the yield of PSII by single light. Conclusion: In cucumber the photosynthetic capacity of the strongest is under green.Atrazine treatment will prevent transmission of electrons from PSII to PSI. Infrared radiation back help accelerate the use of electronic in PSI; the back of the light green leaves beneficial use of the Blue light.With the increase of light intensity, the absorption coefficient, chlorophyll content, carotenoid content, minimum fluorescence yield (Fo) and maximum fluorescence yield (F_m) of de-etiolated cotyledons of cucumber seeding showed a rising and saturated trend, which were in the order of red > blue > green. However, the order of red≈blue > green and no irradiated light > red > green > blue were observed for the ratio of chlorophyll a/b and relative absorbance, respectively.Furthermore, with increase of irradiation intensity and time, the maximum photochemical efficiency of PSII (F_v/F_m) was firstly decreased and then increased, as well as the effective quantum yield of PSII (Y(II)) was persistent rose. The trends of F_v/F_m for different light qualities in the de-etiolated cotyle dons of cucumber seeding were in the order: blue > red > green for 3 hours of photosynthetically active radiation (PAR) from 0.5 to 1.0μmol·m^-2·s^-1, red > blue > green for 3 hour of PAR from 1.5 to 3.0μmol·m^-2·s^-1, green≈blue > red for 1 hour of 0.5μmol·m^-2·s^-1PAR, and blue>red>green for 2 to 4 hours of 0.5μmol·m^-2·s^-1 PAR.The etiolated cotyledons of cucumber seeding had little carotenoids and chlorophyll accompanied with 1 for quantum yield of non-regulated energy dissipation of PSII (Y(NO)) and 0 for quantum yield of regulated energy dissipation of PSâ…¡(Y(NPQ)) and Y(â…¡) before the start of light qualities treatment, which indicated that regulatory mechanism of energy dissipation of etiolated cotyledons had not been established. This may be related to function, epoxidation and de-epoxidation of xanthophyll cycle not establish. After etiolated cotyledons of cucumber seeding were irradiated by different light qualities, the Y(â…¡) and Y(NPQ) not only significantly increased, but also Y(NO) gradually reduced. It revealed that the photosynthetic apparatus and regulated mechanism for heat dissipation were constructed in de-etiolated cotyledons after induced by light, and eventually exerted function cooperating with non-regulated heat dissipation mechanism in the balance and distribution process of energy flow.Through analysis of the results of this study and research, a preliminary understanding of the leaves under different light quality, chlorophyll fluorescence, light absorption and other physiological indicators of the impact on agricultural production for future facilities to provide some new theoretical basis. The chlorophyll and carotenoid contents, Fo and F_m under red light are higher; pure blue light and red light of pure Y (â…¡) is high when under blue and red light. blue light on positive and green or infrared light on negative at the same time reduce the leaves of the fluorescence Emission. Therefore, the use of light energy from the blade angle, the when the cucumber grow in greenhouse need irradiation, in addition to red and blue light, the leaves on the back while a certain amount of green light or infrared light can increase the chlorophyll Energy use.