摘 要：
用Li-6400XT便携式光合仪对高黎贡山南段3种生境(荒草地、林下、苗圃)中生长的国家Ⅰ级保护植物长蕊木兰幼苗进行连续3d的光合特性测定,为其科学保护提供一定依据。结果显示:(1)3种生境下的幼苗净光合速率、蒸腾速率、气孔导度日变化未见"午休"现象,9:00—11:00所测值为1 d中最高;水分利用率无明显变化规律;胞间CO_2摩尔分数与其他光合参数日变化相反。(2)相关性分析显示,光合有效辐射、相对湿度、空气温度、大气CO_2摩尔分数对幼苗净光合速率的影响为,荒草地幼苗从大到小依次是光合有效辐射、相对湿度、空气温度、大气CO_2摩尔分数;林下幼苗从大到小依次是光合有效辐射、空气温度、相对湿度、大气CO_2摩尔分数;苗圃幼苗从大到小依次是光合有效辐射、相对湿度、大气CO_2摩尔分数、空气温度。(3)荒草地幼苗光饱和点为(1 284.96±48.231)μmol·m~(-2)·s~(-1)、林下幼苗(1 052.31±24.746)μmol·m~(-2)·s~(-1),苗圃幼苗(1 255.62±52.374)μmol·m~(-2)·s~(-1);光补偿点分别为(28.65±1.094)、(17.09±0.828)、(6.75±0.317)μmol·m~(-2)·s~(-1),饱和点后,三者均出现抑制现象。(4)CO_2响应曲线差别较大,其中荒草地幼苗最高,三者CO_2饱和点不明显,补偿点分别为荒草地幼苗(103.75±6.826)μmol·m~(-2)·s~(-1)、林下(102.67±5.081)μmol·m~(-2)·s~(-1)、苗圃(130.1±2.022)μmol·m~(-2)·s~(-1),说明不同生境下的幼苗光合特性存在细微差别,苗圃环境下光合特性最强。
译 名：
Photosynthetic Characteristics of Alcimandra cathcardii Seedlings of Different Habitats in Spring
作 者：
Ma Jiafang;Li Guixiang;Chai Yong;He Liping;Meng Guangtao;Kunming University of Science and Technology;Yunnan Academy of Forestry;
关键词：
Alcimandra cathcardii;;Seedlings;;Different habitats;;Photosynthetic characteristics
摘 要：
Photosynthetic characteristics of protected plant Alcimandra cathcardii seedlings of three habitats(wasteland,underforest,nursery)in Gaoligong Mountains southern section were measured by three successive days using Li-6400XT Portable Photosynthesis System.The results showed that:(1)the diurnal courses of net photosynthetic rate,transpiration rate,stomatal conductance of seedlings under three habitats had no"midday depression",and the highest at 9:00-11:00;the diurnal courses of intercellular CO_2concentration was opposite to the net photosynthetic rate;water use efficiency had no significant change in the law.(2)By correlation analysis,the net photosynthetic rate was influenced by environmental factors:light intensity,relative humidity,air temperature,atmospheric CO_2concentration.According to descending order,seedlings of wasteland:light intensity,relative humidity,air temperature,atmospheric CO_2concentration;seedlings of underforest:light intensity,air temperature,relative humidity,atmospheric CO_2concentration;seedlings of nursery:light intensity,relative humidity,atmospheric CO_2concentration,air temperature.(3)Light saturation point of wasteland seedlings was(1 284.96±48.231)mol·m~(-2)·s~(-1),underforest seedlings was(1052.31±24.746)μmol·m~(-2)·s~(-1),nursery seedlings was(1 255.62±52.374)μmol·m~(-2)·s~(-1),light compensation point were(28.65±1.904),(17.09±0.828),(6.75±0.317)μmol·m~(-2)·s~(-1),after the light saturation point,the three appeared caught inhibition;(4)CO_2response curves varied greatly,the highest was wasteland seedlings,three CO_2saturation point was not obvious,the compensation point of wasteland seedlings was(103.75±6.826)μmol·m~(-2)·s~(-1),underforest seedlings was(102.67±5.081)μmol·m~(-2)·s~(-1),nursery seedlings was(130.1±2.022)μmol·m~(-2)·s~(-1),therefore,there were nuances for the photosynthetic characteristics of seedlings under different habitats,and the nursery environment were the best.
