Page 63 - 《广西植物》2022年第3期
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3 期             黄润霞等: 施氮和短时光辐射变化条件下毛竹幼苗光合限速因子分析                                            4 0 7

    ( 1. Research Institute of Subtropical Forestryꎬ Chinese Academy of Forestryꎬ Qiangjiangyuan Forest Ecosystem Research Stationꎬ State Forestry
          Administrationꎬ Hangzhou 311400 ꎬ Chinaꎻ 2. Zhejiang Jiande Xin Anjiang Forest Cenerꎬ Jiande 311600ꎬ Zhejiangꎬ China )

       Abstract: In order to understand the limiting factors of photosynthesis of Phyllostachys edulis seedlings under nitrogen
       addition and change of short ̄term light irradiance. The light response curve and CO response curve were measured under
                                                                    2
                                                               ̄2   ̄1                  ̄2   ̄1
       different short ̄term light irradiance conditions (high light:1 200 μmolm s ꎬ low light:200 μmolm s )ꎬ and
       an improved FvCB model was used to study the photosynthetic characteristics of P. edulis seedlings with nitrogen
       fertilized. The results were as follows: (1) Biomass of P. edulis seedlings treated with nitrogen fertilized was significantly
       higher than that of controlꎬ and light saturated maximum net photosynthetic rate ( P  )ꎬ carboxylation efficiency
                                                                        Lmax
       (CE)ꎬ maximum carboxylation rate (V  ) and maximum electron transport rate (J  ) were significantly higher than
                                    cmax                              max
       those of control. (2) CO saturated maximum net photosynthetic rate(P  )ꎬ CEꎬ mesophyll conductance (g )ꎬ triose
                          2                                 Cmax                        m
       phosphate utilization rate (T ) and carbon dioxide saturation point (CSP) of P. edulis seedlings under high light level
                            p
       were significantly higher than those of low light level. (3) g has no differences after nitrogen fertilizedꎬ but it reduced
                                                    m
       60.31% while the decrease of short ̄term light irradiance. In conclusionꎬ P. edulis seedlings with nitrogen treatment
       increased the quantity and activity of ribulose ̄1ꎬ 5 ̄bisphosphate carboxylase/ oxygenase ( Rubisco ) protease in
       photosynthesis processꎬ promoted photosynthetic phosphorylation and NADPH synthesisꎬ and improved the reqeneration
       rate of ribulose ̄1ꎬ 5 ̄bisphosphate (RuBP) through higher V  and J  ꎬ in order to fully assimilate photosynthetic
                                                     cmax   max
       carbonꎬ promote the high growth and biomass accumulation. Thereforeꎬ it could be inferred that the content and activity
       of Rubisco and regeneration capacity of RuBP were the limiting factors of the photosynthesis rateꎬ for the control
       P. edulis seedlings with no nitrogen. To sum upꎬ light heterogeneity affect the photosynthetic physiological and
       biochemical changes inside the leaves of P. edulisꎬ the decreasing of light intensity effectively regulate the changes of g
                                                                                              m
       and T ꎬ indicating that the photosynthesis of P. edulis seedlings are mainly limited by g and T . The research shows that
                                                                            p
            p
                                                                       m
       nitrogen fertilized and the change of short ̄term light irradiance affect the photosynthesis and carbon acquisition of
       P. edulis seedlingsꎬ and also affect its growth and regeneration.
       Key words: Phyllostachys edulisꎬ nitrogen treatmentꎬ light irradiance changeꎬ limiting factors of photosynthesisꎬ
       FvCB model


       光合作用是植物生长的基础ꎬ是植物利用光                           广、经济价值高而一直备受人们的青睐( 曹永慧
   能合成有机物的过程ꎬ为植物本身的生长提供能                             等ꎬ2007)ꎬ研究毛竹的光合特征可为将来毛竹林
   量ꎬ还 可 以 维 持 大 气 的 碳 - 氧 平 衡ꎮ Farquhar 等           的经营管理提供理论依据ꎮ 营养和光照条件是影
   (1980) 提出利用 Farquhar ̄von Caemmerer ̄Berry 生        响植物光合和生长的两大重要因素ꎮ 氮素对植物
   物化学光合模型( FvCB 模型) 模拟植物叶片内部                        光合器官的合成和活性具有重要的调节作用ꎬ研
   的光合生理生化反应过程ꎬ分析不同环境条件下                             究表明ꎬ叶片氮含量与叶片 Rubisco 酶含量呈正相
   植物光合系统的内在生理变化ꎮ 研究表明ꎬ影响                            关关系( Yamori et al.ꎬ 2011ꎻXiong et al.ꎬ 2015)ꎬ

   C 植物叶片光合碳反应的主要因素包括 Rubisco                        从而间接影响叶片 Rubisco 酶的羧化能力( Nakano
    3
   酶含量和活性、RuBP 的再生能力以及光合产物—                          et al.ꎬ 1997)ꎮ 此外ꎬ叶片氮含量与 g 呈正相关
                                                                                         m
   磷酸丙糖运出叶绿体的能力(Farquhar et al.ꎬ 1980ꎻ               (Xiong et al.ꎬ 2015)ꎬ因此ꎬ可以推断叶片氮含量
   Manter & Kerriganꎬ 2004)ꎮ 利用 FvCB 模型ꎬ引入植          可能通过调控 g 的变化来影响植物的光合作用ꎮ
                                                                    m
   物叶片的 Rubisco 最大羧化速率 (V              )、RuBP 再      而光照是植物进行光合作用必不可少的要素之
                                    cmax
   生最大速率 (J        )、磷酸丙糖利用率 (T ) 和叶肉                一ꎬ光照强度的变化对植物叶片光合作用具有重
                max                     p
   细胞导度 (g )等光合生理特征参数的变化趋势ꎬ可                         要的影响ꎬ尤其是生活在林下多变光环境中的幼
              m
   以据此判断植物光合能力的变化ꎬ研究植物光合特                            苗ꎮ 不同植物对环境光照强度变化的适应性存在
   征对环境变化的响应(Sageꎬ 1994ꎻEvans & Loretoꎬ              很大差异ꎮ 光照强度较低时会影响植物的光合作
   2000ꎻTholen et al.ꎬ 2012)ꎮ                        用ꎬ影响植物的生长发育ꎬ光照强度过高也可能由
       毛竹作为典型的 C 植物ꎬ因其生长快、用途                         于光抑制而影响植物的光合功能ꎮ 研究光照强度
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