Research On The Photosynthetic Characteristics And Color-emerging Mechanism Of Several Colored-leaf Trees Of Red Series

With the development of landscape architecture in China, colored-leaf tree has been paid much more attention and increasingly applicated in the landscape planning and greening for its brilliant leaf. As a special type of foliage tree, although the apparent colors of leaves are different, photosynthetic pigments of colored-leaf tree are changing, and its photosynthetic characteristics and ability is likely to be affected, which then directly impacting the growth rate and growth of whole plant, further impacting the production cycle and commodity quality of colored-leaf seedlings. In view of this, it has important theoretic value and practical significance to study the photosynthetic physiological characteristics and color-emerging mechanism of colored-leaf tree. This research on several colored-leaf trees of red series(Photinia serrulata,Lorpetalum chinense (R.Br.) Oliv.var. rubrum Yieh, Berberis thunbergii cv.Atropurpurea,Prunus ceraifera cv. Pissardii,Populus×euramericana cv. zhonghuahongye)in Anhui Agricultural University and Anhui Academy of Agricultural Science, studied systematically the influence on the change of pigment content of each colored-leaf tree leaf from the external environment factors like light, temperature, humidity and so on,and observed and compared the difference of photosynthetic characteristics of colored-leaf trees and ordinary green-leaf trees with LI-6400portable photosynthesis instrument. The main conclusions are as follows:1. The leaves of colored-leaf tree are more red than chlorosis, because the anthocyanin content of leaves is higher than chlorosis.2. In different seasons,the pigment content and photosynthetic characteristics in leaves of colored-leaf tree will change a lot,mainly due to various environmental factors such as light,temperature,humidity and so on.3. In different light conditions,the chlorophyll content in leaves of colored-leaf tree will have significant differences,mainly because light influences the synthesis of chlorophyll,and glare can cause the decline of chlorophyll content.4. The anthocyanin contents in leaves of colored-leaf tree all rose in order from the bottom to the top,mainly because the light accepted by the upper leaf was stronger, which caused the rise of the anthocyanin contents in upper leaves.5. Different colored-leaf trees have differences in photosynthetic pigment content and photosynthetic characteristics,mainly due to the differences in genetic factors and biological habits between different colored-leaf trees.6. The photosynthetic capacity of some colored-leaf trees,such as Prunus ceraifera cv. Pissardii, is lower than which of green-leaf trees,primarily because the accumulation of photosynthesis products in leaves of colored-leaf tree has feedback inhibition effect on leaf photosynthesis.7. When there is photosynthetic ‘nap’ in leaves of some colored-leaf trees, such as Populus×euramericana cv. zhonghuahongye, stomatal conductance of leaves drops, which confirms that stomatal limitation directly causes photosynthetic ‘nap’.