光合单位的周转率与叶片光合速率的关系  

Relationship Between the Rate of Photothesynthetic Unit Turn-Over and that of Leaf Photosynthesis

作　　者：邱国雄[1] 李德耀[1] 郭保杰 

机构地区：[1]中国科学院上海植物生理研究所,上海200032

出　　处：《植物生理学报（0257-4829)》1993年第3期209-215,共7页Acta Phytophysiologica Sinica

基　　金：国家自然科学基金

摘　　要：利用闪光技术,测得若干高等植物叶片的光合单位为 1450～2050 Chl/CO_2。在含O_2 2％及CO_2浓度和光通量密度都饱和的条件下,测得叶片的连续光合速率为25～70μmol CO_2 m^(-2) s^(-1)。从上述数据及叶片叶绿素含量计算,得叶片光合单位的周转率已达80～160次/s。这样的周转速率与Emerson当初用改变闪光间暗间隔而测到的光合单位周转时间相似(即<10 ms/次,或>100次/s),从而证实了光合单位的周转与光合速率直接有关。这样的速率可称之为叶片光合的理论速率。The turn-over rate of photosyn-thetic unit (PSU) observed by Emer-son et al. (1932) in flash experimentexceeded 100 times per second. Such arate implies that leaf could have amuch higher rate of photosynthesisthan those normally observed. The dis-parity between actual and calculatedfigures is due to the limiting rate ofcarboxylation under normal air as veri-fied by Malkin et al. (1981). TheCO_2-saturataed rate of leaf photosyn-thesis they measured could reach 86umol m^(-2) s^(-1), which was 5～6 timesof that the rate in normal air. They al-so measured the PSU of leaves, but theturn--over rates of PSU calculated bythem were only 30 times per second. This paper reported that the PSUsizes of higher plants measured withflash technique were in the range of1450～2050 (Chl/CO_2) and the turn-over rates of PSU calculated from theirphotosynthetic rates measured undersaturating CO_2 concentration and lightintensity and low oxygen air were inthe range of 80～160 s^(-1) (Table 1)which were in agreement with the re-sult of Emerson's flash experiment.Since the rate of leaf photosynthesisunder such condition equals the prod-ucts of PSU density of leaf and itsturn--over rate, it can be taken as thetheoretical maximum rate of leaf pho-tosynthesis.

关 键 词：光合单位 光合作用 光合速率 

分 类 号：Q945.11[生物学—植物学]