摘要
以美花石斛、春石斛和铁皮石斛为材料,对它们的叶片进行光合作用、叶绿素含量和叶绿素荧光等参数的测定。结果表明:3种石斛的光饱和点都低于300μmol.m-2.s-1,且美花石斛具有较高的净光合速率和较低的光饱和点,容易引起光抑制;美花石斛的羧化效率高于春石斛和铁皮石斛,其净光合速率随着CO2浓度的升高而迅速升高,并在CO2浓度达到500μmol.m-2.s-1时达到最大值;美花石斛的非循环电子传递速率(ETR)、实际光化学反应量子效率(Yield)和光化学猝灭系数(qP)都明显高于铁皮石斛和春石斛,而春石斛具有较高的非光化学猝灭系数(qN),其光合机构的自我保护能力较强;美花石斛的叶绿素a、叶绿素b以及总叶绿素含量都较低。研究发现,3种石斛的光饱和点均比较低,具有石斛喜阴的生活习性,都表现出对密林和悬崖等独特生长环境的适应,并以美花石斛的这种特性更为突出。
The photosynthetic parameters,chlorophyll contents and chlorophyll fluorescence characteristics of three Dendrobium species were comparatively studied.The results showed that light saturation points（LSP） of three Dendrobium species were lower than 300 μmol·m-2·s-1 and Dendrobium loddigesii Rolfe has the highest net photosynthetic rates（Pn） and lowest LSP.Pn of D.loddigesii increased rapidly with the increase of CO2 concentration and then stopped increasing as CO2 concentration increased to 500 μmol·m-2·s-1.The results of chlorophyll fluorescence showed that quantum yield of electron transport（Yield）,apparent photosynthetic electron transport rate（ETR） and the photochemical quenching coefficient（qP） of D.loddigesii was higher than those of D.candidum and D.nobile,while Dendrobium nobile had the highest non-photochemical quenching coefficient（qN） values.Chlorophyll a（Chl a） content and chlorophyll b（Chl b） content of D.loddigesii was lower than the other two Dendrobium species.This study showed that D.loddigesii had a higher value in Pn and lower value in qN and chlorophyll content.Thus,it could be concluded that the low LSP of these species indicated that they had the particular acclimatization of Dendrobium living in underwood and cliff.
出处
《西北植物学报》
CAS
CSCD
北大核心
2010年第10期2067-2073,共7页
Acta Botanica Boreali-Occidentalia Sinica
基金
江苏省自然科学基金(BK2006045)
江苏省常熟市科技项目
关键词
美花石斛
春石斛
铁皮石斛
光合速率
叶绿素荧光
Dendrobium loddigesii Rolfe
Dendrobium nobile
Dendrobium candidum
photosynthetic
chlorophyll fluorescence
作者简介
沈宗根（1962-），男（汉族），教授，主要从事结构与发育植物学研究。E—mail：zonggenshen@cslg．cn
通讯作者：吕洪飞，教授，主要从事植物发育生物学与中药学研究。Email：luhongfei0164@163．com
