摘要
运用开放式气体交换LI-6400便携式光合作用测定系统,研究了梭梭(Haloxylonammodendron)和沙拐枣(Calligonummongolicum)的净光合速率(Pn)、蒸腾速率(E)及水分利用效率(WUE)特征。结果表明:梭梭和沙拐枣在湿润状况下的Pn日变化呈单峰型,梭梭低于沙拐枣,日平均分别为19.60±0.12μmol·m-2·s-1和24.06±0.50μmol·m-2·s-1;E也是梭梭低于沙拐枣,日平均分别为5.53±0.08mmol·m-2·s-1和8.21±0.26mmol·m-2·s-1;WUE则不同,日平均梭梭高于沙拐枣,分别为3.28±0.05mmolCO2·mol-1H2O和2.84±0.06mmolCO2·mol-1H2O。WUE年均值也是梭梭高于沙拐枣,二者最高值都出现在9月,次高值出现在7月,WUE的高低变化与年降水量的高低分布一致。在湿润和干燥两种状况下,梭梭和沙拐枣Pn对光强的响应表明,水分条件好时Pn明显增大,光能利用率提高。从湿润状况时的净光合速率、光饱和点和CO2补偿点,以及干燥状况时也具有低CO2补偿点,确定梭梭和沙拐枣具有C4光合途径。
Desert arid environment was differentiated moist condition and dry condition in the study.An open gas exchange system,LI6400 Portable Photosynthesis System was used to study the characteristics of Haloxylon ammodendron (HA) and Calligonum mongolicum (CM) in photosynthetic rate (Pn),transpiration rate (E) and water use efficiency (WUE).The results showed that the daily changes of net photosynthetic rate of HA and CM appeared as singlepeak curve and Pn of HA lower than CM.Pn on daily average value of HA and CM were 19.60±0.12 μmol·m-2·s-1 and 24.06±0.50 μmol·m-2·s-1 respectively.E of HA was lower than CM,E on daily average value of HA was 5.53±0.08 mmol·m-2·s-1 and \{8.21±\}0.26 mmol·m-2·s-1 in CM.WUE was different from Pn and E,WUE on daily average value of HA was higher than CM and 3.28±0.05 mmol CO2·mol-1 H2O of HA and 2.84±0.06 mmol CO2·mol-1 H2O of CM.WUE on annual average value of HA was also higher than CM and the first peak value of both species appeared in September.The second peak value of WUE on annual average value appeared in July.The annual dynamics of WUE was consistent with annual precipitation curve.Under moist and dry condition,light saturation points of HA and CM were higher when moisture condition was better.The descend reason of Pn is attributed to the non-stomatic factors.CO2 saturation point of HA is higher than CM in this research,CO2 saturation points of HA and CM were also higher when moisture condition was better,but difference is no significance.However,CO2 compensation point of both species are very low.Under moist condition,Pn and light saturation points are higher than dry condition.CO2 compensation point is lower in both moist and dry condition.Base on above these reason,we think that \%Haloxylon ammodendron\% and Calligonum mongolicum were C4 pathway.
出处
《西北植物学报》
CAS
CSCD
2003年第1期11-17,共7页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家重点基础研究发展规划项目(G2000048704)
中国科学院重大项目(KZCX1-09-02)
中国科学院"百人计划"资助
关键词
荒漠植物
梭梭
沙拐枣
光合作用
蒸腾作用
水分利用效率特征
Haloxylon ammodendron
Calligonum mongolicum
photosynthesis
transpiration
water use efficiency
C_4 pathway
desert species
