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Scientia Silvae Sinicae ›› 2015, Vol. 51 ›› Issue (2): 129-136.doi: 10.11707/j.1001-7488.20150216

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Effects of Shading on Growth and Photosynthetic Characteristics of Distylium chinense Seedlings

Liu Zebin, Cheng Ruimei, Xiao Wenfa, Guo Quanshui, Wang Na   

  1. Key Laboratory of Forest Ecology and Environment, State Forestry Administration Research Institute of Forest Ecology, Environment and Protection, CAF Beijing 100091
  • Received:2013-10-10 Revised:2014-12-01 Online:2015-02-25 Published:2015-03-11

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Abstract:

【Objective】Distylium chinense as a shrub will be inevitably subjected to low light conditions when used in urban landscapes, it is essential to understand how the low light conditions affect the growth of D. chinense. A shading experiment was conducted to study the effects of different shading intensities on growth, photosynthesis and chlorophyll fluorescence parameters of D. chinense seedlings and to analyze the responses of the seedlings to the shading.【Method】Three intensities of artificial shading were installed, full light (Control; CK), moderate shading (25% of full light; L1) and heavy shading (7% of full light; L2), and the growth, photosynthesis and chlorophyll fluorescence parameters of D. chinense seedlings under different shading intensities were measured. 【Result】After shading for 60 d, the increment of basal diameter and specific leaf weight in L1 and L2 were decreased significantly, and leaf length and maximum leaf width in L1 and L2 were increased significantly compared to the CK. The increment of plant height was significantly larger in L1 than in CK, but no significant difference was found between L2 and CK. The shading has led to decline of maximum net photosynthetic rate, dark respiration rate, light compensation point and light saturation point, and the decline gradually intensified with the intensity of shading. Compared to the CK, the maximum net photosynthetic rate, dark respiration rate, light compensation point and light saturation point in L1 decreased by 11.8%,46.3%,48.6%, and 15.5%, respectively, and the maximum net photosynthetic rate, dark respiration rate, light compensation point and light saturation point in L2 decreased by 35.2%,65.7%,64.2%,and 20.4%, respectively. The effect of shading on apparent quantum efficiency was not significant, no significant differences in apparent quantum efficiency were found between the shading treatments (L1 and L2) and the CK after shading for 60 d. Compared to the CK, the shading had resulted in significant increase of the maximal photochemical efficiency in L1 but not in L2, and significant decrease of the photochemical quenching and electron transport rate in L1, significant decrease of the photochemical quenching but not the electron transport rate in L2.Although shading has resulted in decreases of non-photochemical quenching, but not at a significant level compared to the CK. 【Conclusion】Results indicated that D. chinense seedlings had a strongly shade-tolerance. Shading allowed the trees to capture more energy and to improve the efficiency of utilizing low light intensity through regulating the morphological characteristics (such as increasing plant height, leaf length and maximum leaf width and reducing specific leaf weight) and photosynthetic physiological characteristics (such as reducing the light compensation point and the light saturation point and maintain a relatively high apparent quantum efficiency and maximal photochemical efficiency), and also to reduce the consumption of photosynthetic products through reducing the energy distribution for the growth of basal diameter and the dark respiration rate of leaves. Therefore, an attempt might be made to grow D. chinense as a shade-tolerant tree species together with other arbor trees in urban landscapes.

Key words: Distylium chinense, shade, growth, photosynthetic characteristics, chlorophyll fluorescence

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