| As one of the world famous ornamental woody flower with high merchantability, Rhododendron hybridum has the greatest varieties, the longest florescence, four seasons blossom, flowers relatively larger, bright colors.The blossom period cultivation and management measures of regulation of Rhododendron hybridum is to achieve the goal of anniversary for flowers.Therefore, Rhododendron hybridum has extremely development potential, by forcing culture of regulation of flowering, can provide flowers on Christmas, new year’s day, which can greatly improve the ornamental and economic value of the flowers. This study used Rhododendron hybridum ’Pink’ as the material, the effects of different light intensity (shading30%, shading60%, shading80%), different temperature (5℃,8℃,11℃,25℃), and different concentrations of GA3 (0,500,1000,1500,2000mg/L) on florescence, flower diameter, flowering rate, physiological and biochemical index were studied during flowering, and other correlation index which directly impact ornamental characteristics of Rhododendron hybridum were compared and analyzed, and try to use light intensity, temperature, GA3 on flowering, and explore the adaptation mechanism of the physiological response for different treatment, which provide scientific theoretical basis and technical support for the anniversary production of Rhododendron hybridum.The main results are as follows:1、The treatment of shading30%, shading60%, shading80% had a significant role in the regulation of flowering and blossom quality of Rhododendron hybridum.Compared with shading 60%, the florescence was advanced about 15d with shading 30% treated, and length, width, flower diameter, and flower rate increased 12.96%,14.86%,2.39%,10.91% and 80%; the florescence was delayed about 8d after treated with shading 60%, and length, width, flower diameter and flower rate decreased 7.41%,12.12%,5.01%, 60%,9.53%. The analysis of variance showed that the bloom quality and flowering of Rhododendron hybridum cultivars all reached significant difference among different light (P<0.05).2、The treatment of shading 30% shading 60% shading 80% had showed shading30%< shading60% < shading80%on chlorophyll a, chlorophyll b and chlorophyll a+b contents of Rhododendron hybridum with the light intensity enhancement, and chlorophyll a/b showed the opposite trend. Photosynthesis diurnal changes of Rhododendron hybridum after treated with different light intensity were measured by using LCpro+ portable photosynthetic systems. The treatment of shading30% and shading60% showed "Shuangfeng" curve on the diurnal variation of net photosynthetic rate of Rhododendron hybridum, the first peak appeared at 12pm, respectively5.62μmol·m-2·s-1、4.93μmol·m-2·s-1, the second peak appeared at 15pm respectively3.38μmol·m-2·s-1、3.μmol·m-2·s-1, and the treatment of shading80% showed a "peak" curve on the diurnal variation of net photosynthetic rate, the peak which is about 4.25μmol·m-2·s-1, appeared at 12 pm. The treatment of three light intensity, net photosynthetic rate, stomatal conductance, transpiration rate, water use efficiency and stomatal limitation value were highest in shading30%, the second was shading 60% and the lowest was shading80%, and intercellular CO2 concentration showed shading 30%< shading 60%< shading 80%. Analysis of variance showed that each index of Rhododendron cultivars all had significant difference among different light intensity(P<0.05), and Photosynthesis diurnal changes of Rhododendron hybridum can be evalued nicely after treated with different light intensity.3、With SPSS software, analysis the correlation between net photosynthetic rate and physiological ecology factors in different light intensity. Net photosynthetic rate positively correlated with stomatal conductance, transpiration rate, temperature (P<0.01), the correlation coefficients were:0.938,0.956, 0.915; negatively correlated with intercellular CO2(P<0.01), the correlation coefficients was-0.965; positively correlated with photosynthetic active radiation(P<0.05), the correlation coefficient was 0.826; negatively correlated with air relative humidity (P<0.05), the correlation coefficient was 0.865.4、With the increase of the light intensity, the PSII efficiency of primary conversion of light energy Fv/Fm, the actual photochemical efficiency Yield, photochemical quenching coefficient QP showed shading30%< shading 60%< shading 80%; chemical quenching coefficient QN showed the opposite trend.The treatment of shading30% was lower than the other two shading treatment Fv/Fm and Fv/Fo, which is not significant.among each shading treatment.5、Compared with 25℃, the florescence was advanced after treated with 5℃,8℃,11℃ for the completion of flower bud differentiation of Rhododendron’Pink’ cultivar, respectivelyl3d, 11d,7d. In a certain temperature range, with temperature decreasing, flower diameter and flower formation rate were increased.The treatment of 5℃ was best for flower induction, which make flower diameter and flower formation rate increase, respectively 5.36%,3.03%, significantly advance the flowering and improve the quality of blossom. Florescence was advanced about 11d and flower diameter and flower formation rate were increased by 4.09%,2.74% after the treatment of 10℃. Analysis of variance indicated that, after thirty five days of low temperature, the flower diameter and flower formation rate of Rhododendron hybridum had significant difference between different temperature treatment (P<0.05).6, Treated by different low temperatures, the obvious trend can be found on relative with water content、soluble protein、soluble sugar、SOD、POD、CAT、MDA and Proline of Rhododendron hybridum ’Pink’cultivars, and the overall trend whole showed a rising trend with temperature decreasing.Seven days of low temperature treatment had significant different from zero days. The analysis of variance showed that, each index of Rhododendron cultivars had reached significant difference among temperature and processing time (P<0.05), and the changes of the intrinsic physiological characteristics of the Rhododendron hybridum can be evalued nicely under different temperature treatments. Integrated the various indicators, it is concluded that the treatment of 5℃had significant positive concentration.7, Compared with the contrast, the florescence was advanced six days on average of Rhododendron hybridum’Pink’cultivar throughout the flowering period under the treatment of 0、500、1000、1500、 2000mg/LGA3. After the treatment of different concentration of GA3, Rhododendron hybridum had better flowering quality、flowering rate、flower induction. The treatment of 1500 mg/LGA3 was the best for bud length、width、flower diameter、a rate significantly, respectively increased by 10.30%、8.89%、3.66%、 21.15%, which were higher than the contrast; The treatment of 1000 mg/LGA3were increased by 6.06%、 6.67%、3.01%、14.77%. Analysis of variance showed that, flower bud length、width、flower diameter, a rate significantly were higher than control (P<0.05).8、Treated by different concentrations of GA3, the obvious trend can be found on relative with chlorophyll content、anthocyanin content、soluble protein、soluble sugar、SOD、POD of Rhododendron hybridum’Pink’cultivars, and the overall trend whole showed a rising and then decreased trend with concentration decreasing, while MDA was presented a rising trend after the first reduction. Analysis of variance showed that, each index of Rhododendron cultivars had reached significant difference among concentration and processing time (P<0.05), and the changes of the intrinsic physiological characteristics of the Rhododendron hybridum leaves and petals can be evalued nicely under different concentrations treatments. Integrated the physiological index of leaves and petals, it is concluded that the treatment of 1500 mg/L GA3 had significant positive concentration, followed by the treatment of 1000mg/LGA3. |
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