| Chrysanthemum grandiflorum Ramat is one of the four important cut flower around the world and the ten famous traditional flowers in China, it is also one of the main flower species in flower market around Europe, America and Japan etc. In recent years, China’s export industry of cut chrysanthemum is developing rapidly, the yield branch reached1221million in2012year. There have not systemic technical management system for faclilties of cut chrysanthemum, the qualified rate of production obviously fell behind the foreign enterprises. Light quality is one of the main factors of regulating growth and quality of chrysanthemum, there were more studies on the effect of temperature, photoperiod, radiation and other factors on the growth and development of chrysanthemum, but there was few studies on the effect of Light quality on the growth and development of chrysanthemum, especially the effect of red and far-red ratio (R/FR). In this study, aiming at improving the product quality of cut chrysanthemum, meeting the needs of international market, based on the effects of R/FR on chrysanthemum development, using LED light with two wavelength (660nm±10nm and730nm±10nm (25℃)), designing four different R/FR value of0.5,2.5,4.5,6.5. Experiment with the photosynthesis, chlorophyll fluorescence parameters and senescence on the different stages of cut chrysanthemum leaves during2010to2012in Nanjing University of Information Science and Technology expermental greenhouse. It can provide scientific basis regulating cut chrysanthemum growth and quality in different light.1. The effect of R/FR ratio on photosynthetic of chrysanthemum leaves in greenhouseThe results showed that during the period from short-day treatment to harvest, the photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of cut chrysanthemum leaves reached a peak in breaking bud stage and decreased afterwards, content of chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Cx.c) and SPAD value reached a peak in completely open stage. The R/FR ratio of2.5led to a maximum Pn, maximum photosynthetic rate (Pmax), Chl a, Chl b, SPAD value, however the Gs and Tr in this treatment were second only to the R/FR ratio of4.5. The effects of R/FR ratio on photosynthesis of chrysanthemum could be attributed to the regulation of R/FR ratio to photosynthetic pigments and activity of PSII. The photosynthetic capacity of chrysanthemum leaves were not linear correlated to R/FR ratio, but presented a parabola relation between them, the R/FR ratio of2.5was most helpful for activity of PSII and photosynthetic capacity of chrysanthemum. In the four development stage, under a certain concentration of photosynthetically active rative radiation(PAR) and CO2, The R/FR ratio of2.5led to a maximum value of Pn, apparent quantum efficiency (Aq), apparent quantum efficiency(Ce), Maximum assimilation rate(Amax), and were second only to the R/FR ratio of4.5. It showed that the capability of using light and CO2of R/FR ratio in2.5of chrysanthemum leaves was best.2. The effect of R/FR ratio on dynamic parameters of chlorophyll fluorescence about chrysanthemum leaves in greenhouseThe results showed that during the period from short-day treatment to harvest, the maximum photochemical efficiency(Fv/Fm), photochemical quenching(qP) and lectron transfer rate(ETR) showed a trend of first increase and then decrease, the overall performance of different R/FR ratio was2.5>4.5>ck>0.5>6.5, the Fv/Fm, qP, ETR value of R/FR ratio in2.5,4.5and6.5were maximum in breaking bud stage, least in short day treatment period, the Fv/Fm, qP, ETR value of R/FR ratio in0.5were maximum in budding stage, less in short day treatment and completely open period. The chlorophyll fluorescence value of R/FR ratio in2.5were maximum, it showed that activity of PSII of R/FR ratio in2.5was strongest, then the ratio in4.5, the weakest activity of PSII was in0.5and6.5. The Fv/Fm, qP, ETR value of chrysanthemum leaves were not linear correlated to R/FR ratio, but increaseed first and then dereaseed with increase of R/FR ratio.The Pn of chrysanthemum leaves were significantly correlated to SPAD, Chl a, Fv/Fm, qP and ETR, the correlation coefficients betwween Pn and SPAD reached0.995,and0.999betwween Pn and Chl a. The Gs were significantly correlated to Ci.3. The effect of R/FR ratio on aging characteristics of chrysanthemum leaves in greenhouseThe results showed that during the period from short-day treatment to harvest, the SOD was showed a tread of increase, in all treatments the R/FR ratio of6.5resulted in highest value of SOD, lowest in2.5; the POD was increased first and then dereased in all treatment, the R/FR ratio of4.5resulted in highest value. In all treatments the R/FR ratio of0.5resulted in lowest value of POD.In all treatment, the POD reached a peak in breaking bud stage and decreased afterwards. With the different development stages, the SOD of the R/FR ratio of6.5was showed a tread of steady growth, the rest treatment were showed a high peak first then a low peak. The MDA of the R/FR ratio of6.5was showed a tread of steady growth, and resulted in highest value in all treatment, it indicated that the free radical activity were highest in R/FR ratio of6.5, the chrysanthemum membrane suffered the furthest damage, than ratio of4.5, and the lowest damage in ratio of0.5,2.5. the soluble protein content showed a trend of first decrease and then increase, in the R/FR ratio of4.5and2.5were higher than others, the treatmengs could slow down aging process of chrysanthemum leaves,. But were lower in R/FR ratio of6.5. |
PDF Full Text Request