早春短命植物鸢尾蒜和准噶尔鸢尾蒜的光合途径  

Photosynthetic Pathway of Early Spring Ephemeral Plants Ixiolirion songaricum and Ixiolirion tataricum

作　　者：李岩[1,2] 何学敏[1,2] 张雪妮[1,2] 吕光辉[1,2] LI Yan;HE Xuemin;ZHANG Xueni;LV Guanghui(College of Resource and Environment Sciences,Xinjiang University,Urumqi 830046,China;Key Laboratory of Oasis Ecology,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学资源与环境科学学院,乌鲁木齐830046 [2]新疆大学绿洲生态教育部重点实验室,乌鲁木齐830046

出　　处：《西北植物学报》2020年第8期1339-1346,共8页Acta Botanica Boreali-Occidentalia Sinica

基　　金：新疆维吾尔自治区自然科学基金(2016D01C040)。

摘　　要：该研究以鸢尾蒜属两种早春短命植物准噶尔鸢尾蒜(Ixiolirion songaricum)和鸢尾蒜(Ixiolirion tataricum)为对象,通过解剖结构、光合参数、稳定碳同位素比值(δ^13C)和光合关键酶活性分析二者的光合途径。结果发现:(1)显微结构和超微结构显示,两种短命植物的叶脉维管束鞘细胞1层、排列较紧密,鞘细胞内含有较多叶绿体且多离心分布,类似C4花环结构。(2)准噶尔鸢尾蒜和鸢尾蒜最大净光合速率分别为14.81和15.04μmol·m^-2·s^-1;两者的CO2补偿点较低,分别为3.57和2.54μmol·mol^-1,δ^13C分别为-25.36±0.55‰和-25.76±1.38‰,光合酶PEPC/Rubisco比值分为别0.244和0.322。(3)最大净光合速率、δ^13C和PEPC/Rubisco比值均说明两种植物为C3光合途径,但二者均具有类似C4的维管束鞘结构、较低的CO2补偿点和暗呼吸速率,并具有高于部分C3和C3-C4中间型植物的PEPC/Rubisco比值,表明两种短命植物的光合途径并非典型的C3途径,而是C3-C4中间型。The photosynthetic pathway of two early spring ephemeral plants,Ixiolirion songaricum and I.tataricum in Xinjiang,were investigated by anatomical structure observation,photosynthesis measurement,stable carbon isotope ratio(δ^13C)and photosynthetic enzymes activity determination.The results showed that:(1)the two species had one layer of vascular bundle sheath cells and were closely arranged,the sheath cells contained more chloroplasts and were more centrifugally distributed which were similar to the Kranz structure,revealed by the leaf anatomy and ultrastructure observation.(2)The maximum net photosynthetic rate of I.songaricum and I.tataricum was 14.81μmol·m^-2·s^-1 and 15.04μmol·m^-2·s^-1,respectively.Both of them had a low CO2 compensation point with 3.57μmol·mol^-1 and 2.54μmol·mol^-1,respectively.Theδ^13C value was-25.36±0.55‰and-25.76±1.38‰for I.songaricum and I.tataricum,respectively,and the photosynthetic enzyme PEPC/Rubisco ratio was 0.244 and 0.322,respectively.(3)The maximum net photosynthetic rate,δ^13C value and PEPC/Rubisco ratio indicated that the photosynthetic pathway of the two ephemerals were C3.However,the C4-like vascular bundle sheath structure,relative lower CO2 compensation point and dark respiration,and higher PEPC/Rubisco ratio than some C3 and C3-C4 intermediate plants suggested that the photosynthetic pathways of the two ephemeral species are not typical C3 pathways,but should be defined as C3-C4 intermediate.

关 键 词：光合途径 超微结构 稳定碳同位素比值 CO2补偿点 PEPC 

分 类 号：Q944.56[生物学—植物学] Q945.11