大气二氧化碳浓度倍增对闽楠光合性状的影响

The Photosynthetic Response of Phoebe bournei to Doubled CO_2 Concentration in Air

对在照度为5000lx、大气CO2体积分数为700×10-6环境下生长3个月的闽楠PhoebebourneiHemsl.Yang进行了研究.结果表明:大气CO2体积分数倍增将使闽楠植株叶片叶绿素含量降低28.7%,其中叶绿素a、b分别下降了28.6%、19.8%,类胡萝卜素上升2.8%,叶绿素a/b从1.95下降到1.55.长期高体积分数CO2处理使叶片可溶性糖含量降低2.45%,可溶性蛋白含量降低53.91%,暗呼吸速率下降95.6%,光呼吸速率下降43.7%;短期内CO2加倍处理,光合速率上升21.76%;长期处理,则下降89%.这表明,短时CO2体积分数加倍处理使植物的表观光合速率明显增加;长期处理明显抑制了闽楠的光合作用,出现了严重的光合适应现象.闽楠光合作用和呼吸作用的减弱致使整个代谢水平下降.

The photosynthetic response of Phoebe bournei Hemsl. Yang treated with 700×10-6 CO2 for three months was studied under the light of 5 000 lx. The results show that the chlorophyll content of treated leaves decreases compared with the control,the total chlorophyll content decreases 28.7%, of which chlorophyll a decreases 28.6% and chlorophyll b decreases 19.8% and chlorophyll a/b decreases from 1.95 to 1.55 while the content of carotenoid increases 2.8%. The results also show that the contents of protein and solvable sugar decrease by 53.91 and 2.45 respectively in the plants which grow in 700×10-6 CO2; that the net photosynthetic rate of Phoebe bournei is enhanced over 21.7% after being treated with 700×10-6 CO2 for short time, but decreased about 89% after being treated with 700×10-6 CO2 for three months; and that compared with the control, the dark respiration and photorespiration decrease 95.6% and 43.7% respectively and when treated with 700×10-6 CO2 for three months, the dark respiration and photorespiration are restrained seriously. The metabolism fell down because of the decrease of photosynthesis and respiration.