摘要
采用美国Li-COR公司制造的Li-6400便携式光合作用测定系统,研究杨桐苗期的光合特性。结果表明,杨桐叶片净光合速率(Pn)的日变化曲线呈双峰型,具有"光合午休"现象,第1个峰值出现在8:00左右,Pn达到4.76μmol/m2·s;第2个峰值出现在15:00,Pn为3.19μmol/m2·s。造成光合午休的主要原因是受气孔调节。杨桐叶片CO2补偿点为74.0μmol/mol,饱和点为2000μmol/mol;杨桐叶片光补偿点为37μmol/m2·s,饱和点为600～800μmol/m2·s。杨桐的最适光合温度为24～26℃。
The Li-6400 Portable Photosynthesis System of Li-COR was used to study the photosynthetic characteristics of Cleyera japonica Thunb. at its seedling stage. The results showed that the daily variation of net photosynthetic rate in leaves presented a bimodal curve and an obvious 'midday depression' phenomenon occurred. The first peak value was the highest, which occurred at about 8:00 am, the net photosynthetic rate was 4.76 μmol/m^2·s, the second peak value occurred at 14:00 pm, the net photosynthetic rate was (3.19 μmol/m^2·s). The main reason for the midday depression was stomatal factors. At midday, light intensity was the largest, vapor pressure deficit between leaves and air reached maximum but air relative humidity, stomatal conductance and intercellular CO_2 reached minimum hence the photosynthetic midday depression. The CO_2 compensation point was 74.0 μmol/mol and CO_2 saturation point was 2 000 μmol/mol. The light compensation point was 37 μmol/m^2·s and light saturation point was 600～800 μmol/m^2·s, and the most suitable air temperature for the photosynthesis of Cleyera japonica Thunb. at its seedling stage was about 24～26 ℃.
出处
《江西农业大学学报》
CAS
CSCD
2004年第6期896-900,共5页
Acta Agriculturae Universitatis Jiangxiensis
基金
浙江省科技厅基金项目"生态型经济林栽培模式与示范"(013138)
浙江省林业厅招标项目"生态经济树种优选和栽培模式研究"(01A02)
关键词
杨桐
光合特性
气孔导度
蒸腾速率
光合有效辐射
Cleyera japonica Thunb.
photosynthetic characteristics
stomatal conductance
transpiration rate
photosynthesis active radiation
