芸薹属两个亚种间杂种光合作用优势及其机理  

The Photosynthetic Heterosis and Its Mechanisms of an Inter-Subspecific Hybrid Between Brassica campestris ssp. chinensis and B. campestris ssp. rapifera

作　　者：董德坤[1] 师恺[1] 曹家树[1] 

机构地区：[1]浙江大学蔬菜研究所,杭州310029

出　　处：《中国农业科学》2007年第12期2804-2810,共7页Scientia Agricultura Sinica

基　　金：教育部高等学校博士学科点专项科研基金(20030335117);浙江省重大科技项目(2005C12019-2)

摘　　要：【目的】探讨芸薹属作物杂种是否具有光合作用优势及其机理。【方法】利用气体交换和叶绿素荧光技术系统地研究了‘矮脚黄’白菜和‘白蔓菁’芜菁及其正反交杂种的叶片光合作用的特性,并对卡尔文循环中的关键酶核酮糖1,5-二磷酸羧化/加氧酶(RuBisCO)进行了相对定量研究。【结果】在整个试验期间,杂种F1的净光合速率(Pn)显著高于双亲,具有较强的杂种优势。杂种气孔导度(Gs)也高于亲本,但其胞间CO2浓度(Ci)和气孔限制值(l)与亲本间没有明显的差异。杂种总叶绿素含量介于双亲之间,仅表现出微弱的中亲优势。杂种PSII光合电子传递量子效率(ΦPSII)及光合电子传递速率(ETR)显著高于亲本,其变化趋势和PSII反应中心开放程度(qP)一致。RuBisCO最大羧化速率(Vcmax)、最大电子传递速率(Jmax)和RuBisCO蛋白含量在杂种中均有所增加。【结论】气孔导度、叶绿素含量和光呼吸均不是杂种光合优势产生的主要原因。光合优势的产生很可能是由于碳固定效率的增加反馈上调了光合电子传递速率引起的。【Objective】The aim is to investigate whether hybrid of Brassica crops has heterosis in photosynthetic capacity and reveal the mechanisms involved. 【Method】The reciprocal inter-subspecific hybrids between Brassica campestris ssp. chinensis Aijiaohuang and B. campestris ssp. rapifera Baimanjing, and their parents were used to analyze photosynthetic characteristics by simultaneous measurement of leaf gas exchange and chlorophyll fluorescence parameters. The ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO), a key enzyme in the Calvin cycle was also investigated accordingly. 【Result】 The net CO2 assimilation rates (Pn) of hybrids were significantly higher than that of their parents in the experiment, leading to strong heterosis in photosynthesis. Hybrids also showed increased stomatal conductance (Gs) but had no influence on intercellular CO2 concentration (Ci) and stomatal limitation (l). The concentrations of total chlorophyll in the hybrids were between their parents with only a weak mid-parent heterosis. Hybrids were detected to have significantly increased quantum efficiency of PSII photochemistry (ΦPSII) and electron transport rate (ETR), which were accompanied by a similar increase in photochemical quenching (qP). Additionally, the hybrids also had evident heterosis in the maximum carboxylation rate of RuBisCO (Vcmax), maximum electron transport rate (Jmax), and the RuBisCO protein content. 【Conclusion】 It was concluded that the increase of photosynthesis in the hybrids were not accounted by the changes in stomatal conductance, chlorophyll content or photorespiration. The photosynthetic heterosis might be mainly attributed to the improved efficiency of photosynthetic carbon fixation in the Calvin cycle which resulted in an up-regulation of electron transport.

关 键 词：芸薹属 亚种间杂种 光合作用 叶绿素荧光 杂种优势 核酮糖1 5-二磷酸羧化/加氧酶 

分 类 号：S634[农业科学—蔬菜学] S631.3[农业科学—园艺学]