Studies On Effects Of Different Light Intensity On Seedling Growth And Leaf Color Change Of Red Maple Seedling

To explore the effect of different light conditions on red maple seedling growth and leaf color change, this paper selects 1-year-old red maple Acer × freem anii’ Autumn Blaze’ cutting seedlings as test materials. With potted experiment, it sets four light intensity treatment:100% light intensity (natural light),75% light intensity,55% light intensity and 35% light intensity. It studies the situation of plant growth, photosynthetic characteristics, physiological characteristics and leaf pigment changes with different light intensity,and to know the light intensity fertilization of red maple seedlings by using the growth index, photosynthetic characteristics,physiological characteristics and leaf pigment changes.It aims to find the most suitable light intensity which is conducive to the plant growth and the leaf color in autumn of red maple seedlings. The results are as follows:First, this paper explores the effects of different light intensity on seedling growth of red maple. With the decrease of light intensity, height increment and diameter increment of red maple seedlings, it shows the trend of first rising and then falling. Based on comprehensive growth indexes, effects of different light intensities on seedling growth-promoting of red maple, the data shows that 100% light intensity is the strongest, then is 75% light intensity, 55% light intensity,and last is 35% light intensity. Wherein the height of plant under the effect of 75% light intensity is up to 59.73cm,5cm higher than that effected by 100% light intensity. However, other indicators of 75% and 100% light intensity has no significant difference, but there are some differences when compared with 55% and 35% light intensity. Diameter, biomass and leaf area law performance of each group are basically identical. with the weakening of the light intensity decreases, the diameter and biomass of 75% light intensity have a certain inhibition but not significantly. while, there are more significant differences in light intensity of 55% and 100% than 75% and 35% light intensity.Second, this paper probes into the effects of different light intensity on photosynthetic fluorescence characteristics of red maple seedlings. Along with the decrease of light intensity, the maximum photosynthesis photosynthetic rate, light compensation point, light saturation point and dark respiration rate of red maple seedlings have a declining trend.It measures Pmax, Tr, Gs and Ci of red maple under different light intensity, it finds that four light intensity processing photosynthetic rate have a bimodal curve, light intensity of 100%,55% 35% reach the first peak at 10am., while 75% light intensity reaches the first peak at 12am.; the four processes reach their second peak intensity at 16pm. Diurnal variation of stomatal conductance and diurnal variation of transpiration rate are roughly similar,t heir size show as follows 100% light intensity>75% light intensity>55% light intensity>35% light intensity, opposite to the diurnal variation of CO2 concentration changes. Fv/Fo, Fv/Fm values also decrease as light intensity decreases. Among them, in addition to 100% light intensity, the rest of the light intensity under the processing of the red maple seedlings, Fv/Fm values are lower than normal plants.Third, this paper analyses the effects of different light intensity on physiological characteristics of red maple seedlings. With the decrease of light intensity, MDA content is highest under 100% light intensity, their size show as follows 100% light intensity>35% light intensity>55% light intensity>75% light intensity; a specific size of the peroxidase activity (POD) performance show as follows:75% light intensity>100% light intensity>55% light intensity>35% light intensity. However, based on the two sets of data,75% light intensity and 100% light intensity have no obvious differences, but the significant differences exist between 55% and 35% light intensity. With the light intensity decreased, Soluble sugar content is gradually reduced,100% light intensity and 35% light intensity has a significant difference while the other two groups do not differ significantly.Last, this paper shows the effects of different light intensity on the leaf color change aspects of red maple seedlings. Blade changes bright red under 100% natural light, its ornamental is strongest and color changes earliest. With the decrease of light intensity, the total chlorophyll contents of leaves are rising and anthocyanin contents are falling. Anthocyanin contents of 100% light intensity are maximal. It has a great difference when compared with other light intensity processing. With the weakening of light intensity, the change rule of anthocyanin content and soluble sugar content is consistent. a* value and saturation C have a positive correlation with the Anthocyanin content and a negative correlation with the chlorophyll content, and the correlation coefficient reachs a significant level; L* value and anthocyanin content show a negative correlation and have shown a negative correlation with the chlorophyll content; and b* values have no significantly correlation with anthocyanin content and chlorophyll content.According to above analyses, this paper reaches such a conclusion:the red maple in the shade environment is not conducive to plant growth; 75% light intensity has a certain inhibition of plant growth, but not significantly; discoloration of leaves of autumn leaf color intensity processing time to 75% light intensity compared with late in the control group and the poor coloring effect.