【作者】 刘张栋； 曹声海； 仇硕； 罗靖； 赵健； 李秀娟； 王彩云；

【Author】 LIU Zhang-dong;CAO Sheng-hai;QIU Shuo;LUO Jing;ZHAO Jian;LI Xiu-juan;WANG Cai-yun;Key Laboratory of Horticultural Plant Biology,Ministry of Education,Huazhong Agricultural University;Guangxi Institute of Botany,Guangxi Zhuang Autonomous Region and the Chinese Academy of Sciences;

【机构】 华中农业大学园艺植物生物学教育部重点实验室； 广西壮族自治区·中国科学院广西植物研究所；

【摘要】 石斛兰是重要的兰科观赏和药用植物。已有报道表明,石斛兰中存在专性C₃、专性CAM和C₃/CAM中间型3种类型的植物,然而C₃到CAM途径转变过程中的机理目前尚不明确。本研究以6种具有不同光合类型的石斛属植物为材料,在充分供水和干旱胁迫后测定苹果酸、柠檬酸、可溶性糖和淀粉等代谢物质的变化。结果表明,几种石斛属植物中柠檬酸含量均很低,且干旱胁迫不影响柠檬酸的积累;充分供水条件下,CAM型美花石斛和秋石斛‘索尼亚’苹果酸、碳水化合物和淀粉含量均表现出一定程度的净积累,干旱胁迫下,积累量显著增加;对于C₃型玫瑰石斛和流苏石斛,充分供水条件下,苹果酸净积累分别只有0.12±0.03和0.02±0.01,并且干旱胁迫下,苹果酸等有机物积累呈一定程度的下降趋势。金钗石斛在充分供水条件下,苹果酸含量仅为0.25士0.04,表现出一定的C₃植物特性,而在干旱胁迫下,苹果酸含量几乎增加一倍,达到0.48±0.03,暗示了金钗石斛是一个C₃/CAM中间型植物,干旱胁迫促进光合途径从C₃到CAM的转变,并且苹果酸含量变化在这一转变过程中起到关键作用。更多还原

【Abstract】 Dendrobium nobile are important orchid flowers for their ornamental and medical value.It was reported that there were not only obligate C₃,obligate CAM plants,but also C₃/CAM plants in Dendrobium,however,the mechanism is still not clear during the transition from C₃ to CAM.In this work,six Dendrobium nobile with different photosynthetic pathways were chosen,and the contents of malic acid,citric acid,soluble sugar,and starch under well- watered and drought stress condition were analyzed.The results showed that the citric acid content was low in all six cultivars,and drought stress did not affect the accumulation of citric acid.Under well- watered condition,CAM tpye D.loddigesii and D.hybrida’ Sonia’ showed accumulation of malic acid,soluble sugar,and starch with certain degree,and drought stress increased their content further.For C₃ type D.crepidatum and D.fimbriatum,the accumulation of malic acid was only 0.12 ±0.03 and 0.02 ±0.01 under well- watered condition,respectively,and droped in some degree under drought stress.In D.nobile,the content of malic acid was only 0.25± 0.04 under well- watered condition,which showed feature of C₃ plant,however,under drought stress,the malic acid content increased to 0.48 ±0.03,which was almost doubled,suggesting that D.nobile was a facultative C₃/CAM plant,drought stress promoted the transition form C₃ to CAM,and the change of malic acid content was important during this transition.更多还原