Abstract:

Wheat (Triticum aestivum L.) plants were grown under ambient and doubled CO2(plus 350 μL/L) concentration in cylindrical open top chamber to examine their effects on the ultrastructure, supramolecular architecture, absorption spectrum and low temperature (77 K) fluorescence emission spectrum of the chloroplasts from wheat leaves. The results were briefly summarized as follows: (1) The wheat leaves possessed normally developed chloroplasts with intact grana and stroma thylakoid membranes; The grana intertwined with stroma thylakoid membranes and increased slightly in stacking degree and the width of granum, in spite of more accumulated starch grains within the chloroplasts than those in control; (2) The particle density in the stacked region of the endoplasmic fracture face (EFs) and protoplasmic fracture face (PFs) and in the unstacked region the endoplasmic fracture face (EFu) and the protoplasmic fracture face (PFu) was significantly higher than that of control. Furthermore, in some cases many more particles on EFs faces of thylakoid membranes appeared as a paracrystalline particle array; (3) The variations in the structure of chloroplasts were consistent with the absorption spectra and the low temperature (77 K) fluorescence emission spectra of the chloroplasts developed under the doubled CO2 concentration. Results indicate that the capability of light energy absorption of chloroplasts and regulative capability of excitation energy distribution between PSⅡ and PSⅠ were raised by doubled CO2 concentration. This is very favorable for final productivity of wheat.

CO₂浓度倍增对小麦叶绿体超微结构、超分子结构及光谱特性的影响
左宝玉 张 泉 姜桂珍 白克智 匡廷云
（中国科学院植物研究所，北京100093）

摘要： 超薄切片及冰冻撕裂电镜观察、吸收光谱及 77K低温荧光发射光谱的测定结果表明 :CO2 浓度倍增对小麦(Triticumaestivum L .)叶绿体的超微、超分子结构及光谱特性的影响均为正效应。具体反映在 :(1)小麦叶绿体中除了比对照积累有较多的淀粉粒外 ,其基粒和基质类囊体膜发育较好 ;(2 )叶绿体的光合膜系 ,无论是垛叠和非垛叠膜区 ,其镶嵌于内质膜撕裂面 (EFs和EFu)及原生质膜撕裂面 (PFs和PFu)的功能蛋白粒均比其对照的发育良好 ,尤其PFs与EFs面较为突出 ,即它们除了所含蛋白粒的密度较大外 ,在EFs面上有时还呈现出密集有序的阵列结构 ;(3)叶绿体整个吸收谱带 ,尤其红区和蓝区的主峰均较其对照有较大的光吸收 ,表明对光能的捕获能力明显高于对照 ;(4)无论是以 4 36nm还是以 4 80nm波长激发的 ,其叶绿体的F₆₈₄/F _{73 3} (PSⅡ /PSⅠ )的比值均较对照的高 ,表明CO₂ 浓度倍增条件下生长的小麦叶片叶绿体的PSⅡ相对荧光强度有所增强 ,这与叶绿体的超微、超分子结构及吸收光谱的测定结果相一致。以上结果可为小麦在高CO₂  浓度下增产提供理论依据。
关键词： 叶绿体；小麦；CO ₂浓度倍增；超微及超分子结构；吸收光谱；低温荧光发射光谱

Key words: hloroplast, wheat (Triticum aestivum), doubled CO2 concentration, ultrastructure and supramolecular architecture, absorption spectra, low temperature (77　K) fluorescence emission spectra