石斛顶叶组物种的碳同化途径类型  

Elucidating the types of carbon assimilation pathways in Dendrobium section Densiflora

作　　者：林雅君 吴宇苇 韦春怡 兰思仁[1] 李明河[1] LIN Yajun;WU Yuwei;WEI Chunyi;LAN Siren;LI Minghe(College of Landscape Architecture and Art,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350002,China)

机构地区：[1]福建农林大学风景园林与艺术学院,福建福州350002

出　　处：《森林与环境学报》2024年第4期441-446,共6页Journal of Forest and Environment

基　　金：国家自然科学基金面上项目“石斛属植物亲缘关系及其碳同化途径的育种潜力研究”(32271957)。

摘　　要：石斛顶叶组(Dendrobium section Densiflora)物种具有重要的观赏和药用价值,为更科学高效地对其进行育种和栽培管理,以该组所有国产的8个原生物种:长苏石斛(D.brymerianum)、鼓槌石斛(D.chrysotoxum)、密花石斛(D.densiflorum)、苏瓣石斛(D.harveyanum)、具槽石斛(D.sulcatum)、球花石斛(D.thyrsiflorum)、小黄花石斛(D.jenkinsii)和聚石斛(D.lindleyi)为研究对象,通过进行稳定碳同位素分馏值(δ^(13)C)、全天CO_(2)净吸收值和早晚可滴定酸值测定,探究其光合碳同化途径类型。结果表明:聚石斛和小黄花石斛的δ^(13) C值大于-20‰,为景天酸代谢(CAM)途径植物;其余6种均小于-20‰,为C_(3)植物。干旱胁迫后,小黄花石斛的整个夜间净CO_(2)吸收速率为正值,聚石斛2/3以上的夜间净CO_(2)吸收速率为正值,聚石斛和小黄花石斛的暗期CO_(2)净吸收量显著高于昼期,同时早晚可滴定酸差值(△H^(+))显著高于C_(3)植物,进一步支持聚石斛和小黄花石斛为CAM植物;C_(3)植物昼期CO_(2)净吸收量均显著高于暗期,其中长苏石斛的△H^(+)小于0,为C_(3)植物中的专性C_(3)物种,而其余5个物种的△H^(+)均大于4 mmol·kg^(-1),为C_(3)植物中的兼性CAM物种。Dendrobium section Densiflora species hold important ornamental and medicinal value.To improve the efficiency of breeding and cultivation,in this study,we aimed to elucidate the types of photosynthetic carbon assimilation pathways in D.brymerianum,D.chrysotoxum,D.densiflorum,D.harveyanum,D.sulcatum,D.thyrsiflorum,D.jenkinsii,D.lindleyi,all of which are known native Chinese species of Dendrobium section Densiflora,by analyzing stable carbon isotope ratios(δ^(13)C),diurnal net CO_(2) assimilation,and titratable acidity.The results showed that theδ^(13)C values of D.jenkinsii and D.lindleyi were greater than-20‰,identifying as crassulacean acid metabolism(CAM)plants,while theδ^(13) C values of other 6 species were less than-20‰,identifying as C_(3) plants.Following drought stress,D.jenkinsii had net CO_(2) uptake during the whole night,and D.lindleyi had net CO_(2) exchange for over two-thirds of the night.The difference in titratable day and night acid level(△H^(+))between these two plants was markedly higher than that of C_(3) plants,providing further evidence that both are CAM plants.All C_(3) species exhibited marked net CO_(2) uptake during the daytime;however,acid accumulation in them was more markedly at night,exceeding 4 mmol·kg^(-1).The only exception was D.brymerianum,which did not show night acid accumulation,indicating that this effect is unique to the obligate C_(3) plants,while the remaining five species were facultative CAM plants.

关 键 词：石斛属 顶叶组 碳同化途径 干旱胁迫 景天酸代谢 

分 类 号：Q945.78[生物学—植物学]