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遮荫对短梗大参苗木光合作用及生长的影响

梁文斌1,聂东伶2,吴思政2**,柏文富2,沈素贞1   

  1. 1中南林业科技大学生命科学与技术学院, 长沙 410004; 2湖南省森林植物园, 长沙 410116)
  • 出版日期:2015-02-07 发布日期:2015-02-07

Effects of shading on the growth and photosynthesis of Macropanax rosthornii seedlings.

Wenbin1, NIE Dong-ling2, WU Si-zheng2**, BAI Wen-fu2, SHEN Su-zhen1   

  1. (1College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China; 2Hunan Province Forest Botanical Garden, Changsha 410116, China)
  • Online:2015-02-07 Published:2015-02-07

摘要: 以盆栽短梗大参为试验材料,探讨不同遮荫处理(全光日照、70%光日照及40%光日照)对短梗大参苗木叶绿素含量、光合作用和生长的影响,为耐阴植物引种栽培及在园林上的应用提供理论依据。结果表明:在遮荫处理下短梗大参生长良好,叶色浓绿,植株的冠幅和复叶数显著高于全光日照(P<0.05);遮荫处理下叶绿素a、叶绿素b及总叶绿素的含量显著高于全光日照(P<0.05),且随着遮荫程度增强而增加,而叶绿素a/b则呈下降趋势。与全光日照相比,遮荫处理提高了短梗大参表观量子效率(AQY)和最大净光合速率(Pmax),同时明显降低了光饱和点(LSP)和光补偿点(LCP)。遮荫处理提高了PSⅡ原初光能转换效率(Fv/Fm)和潜在活性(F0/Fm),尤其是40%光日照下Fv/FmF0/Fm均显著高于全光日照(P<0.05)。遮荫处理下非光化学猝灭系数(NPQ)显著低于全光日照(P<0.05),并随着遮荫程度的增加而进一步降低,以减少热耗散等途径来提高PSⅡ光能转化效率,但光化学猝灭系数(qP)受遮荫处理影响不大。因此,作为喜阴植物,短梗大参具有较强的弱光利用能力,适宜生长于适度荫蔽的环境。

关键词: 雨水截流, 广州, 湿热地区, 简单式屋顶绿化

Abstract: The effects of shading treatments (full sunlight intensity, 70% sunlight intensity, 40% sunlight intensity) on chlorophyll content, photosynthetic characteristics and growth of Macropanax rosthornii seedlings were examined in a pot-culture experiment. The results showed that shading treatments enhanced the growth performance of the individuals of M. rosthornii with dark green leaves. Both canopy size and the number of compound leaves under shading were significantly greater than those under full sunlight  (P<0.05). The contents of total chlorophyll, chlorophyll a and chlorophyll b in leaves under shading were significantly higher than under full sunlight. The chlorophyll contents increased with the enhanced intensity of shading. On the contrary, the chlorophyll a/b showed a decreasing trend. Under shading, the apparent quantum yield (AQY) and the maximum net photosynthetic rate (Pmax) increased, and the light saturation point (LSP) and light compensation point (LCP) distinctly decreased. The efficiency of primary lightenergy conversion (Fv/Fm) and potential activity (F0/Fm) of PSⅡ were increased by shading, in particular, Fv/Fm and F0/Fm were significantly  higher under 40% sunlight than under full sunlight (P<0.05). The nonphotochemical quenching coefficients (NPQ) were significantly  lower under shading treatments than under full sunlight (P<0.05), and NPQ further decreased with increasing the shading intensity in which heat dissipation was reduced to increase the efficiency of lightenergy conversion of PSⅡ. Meanwhile, the photochemical quenching coefficient (qP) was rarely influenced by shading. Thus, as a shaderequiring plant, M. rosthornii had a rather strong ability to utilize low-intensity light and grew well under appropriate shading.

Key words: rainwater interception, extensive green roof, hot and humid region, Guangzhou