Study On The Change Rule Of Populus×euramericana 'Zhonghong'leaf Color And The Effect Of Spurting KH 2 P0 4 On It

Populus×euramericana'Zhonghong'is the bud-mutating cultivar from Aigeiros Populus Linn'2025'. Through spurting 1‰KH₂PO₄, 3‰KH₂PO₄, 5‰KH₂PO₄ and 7‰KH₂PO₄ under the same light intensity and different time, this paper compared the seasonal variations of'Zhonghong'and'2025'leaves(from the sprout), analyzed the quantitative relation between pigment and colored light value, studied the effect of different cultivation measures on leaf color under the same circumstance. The main results are summarized as follows:1. The color of sprout and leaf of'Zhonghong'changed significantly with the seasons. The pigment content and its proportion could directly affect the color generation of'Zhonghong'. the temperature of early April, the frondesce stage, is quite low, which is help for the compounding of anthocyanin; tissue of young leaves developed insufficiently, chloroplast lamella structure was underdeveloped, photosynthetic pigment contents was low, while the anthocyanin content was high, and the ratio of anthocyanin content to chlorophyll content in leaves was 5.27:1, the leaves were in the best red, presenting the highest ornamental value. Early July, temperature rises, light strength increases, the leaf area was the largest, photosynthetic rate and chlorophyll content reached the highest; high temperature goes against the compounding of anthocyanin, so the anthocyanin content was low, the content ratio of anthocyanin to chlorophyll in leaves was 0.11:1, leaves turned green. In the middle of September, temperature drops, the temperature difference between day and night increases, leaves aged, photosynthetic rate and chlorophyll content declined, soluble sugar content increased, which were helpful for the compounding of anthocyanin; the ratio of anthocyanin to chlorophyll in leaves was 0.35:1, leaves turned red, and the ornamental value went up.2. The anthocyanin content of'Zhonghong'shows positive correlation with colored light value in different seasons. Determing L, a, b values of'Zhonghong'leaves in different parts and different seasons using colorimeter, extracting anthocyanin and measuring its content, the relativity between them was analyzed in this paper. Results show: the anthocyanin content of'Zhonghong'shows obviously positive correlation with colored light value; based on the correlation, regression equation between them was set up. Through regression analyses and t-testing, the predicted value was highly conformed to the testing value, so it is feasible to accurately estimate the change discipline of anthocyanin content according to that of colored light value in'Zhonghong'leaves.3. Spurting KH₂PO₄ nutrient solution could efficiently improve the anthocyanin content. In full illumination, spurting KH₂PO₄ of different concentractions on leaves with different interval times, results showed that spurting 7‰KH₂PO₄ nutrient solution with a interval time of 15d improved the contents of anthocyanin and soluble sugar, decreased the contents of chlorophyll and carotenoid, which are in turn reddened the leaf and improve the ornamental value.