空气CO_2增高条件下荔枝叶片光合作用和超氧自由基产率

Photosynthesis and free radical yield of Litchi chinensis leaves under increased CO_2 partial pressure in atmosphere.

研究结果表明 ,生长在 77± 5PaCO2 分压下 30d的荔枝幼树 ,其光合速率较大气CO2 分压 (39.3Pa)下的低 2 3% ,光下线粒体呼吸速率和不包含光下呼吸的CO2 补偿点亦略有降低 .空气CO2 增高使叶片最大羧化速率 (Vcmax)和最大电子传递速率 (Jmax)降低 ,表明大气增高CO2 分压下叶片的光系统I(PSI)能量水平较低 ,叶片超氧自由基产率亦降低 39% ,叶片感染荔枝霜疫霉病率则从生长在大气CO2 分压下的1.8%增至 9.5 % .可能较低光合和呼吸代谢诱致较低的超氧自由基产率 ,而使叶片易受病害侵染 .叶片受病害侵染后表现为超氧自由基的激增 .在全球大气CO2

.The maximum photosynthetic rate of litchi saplings leaves grown under a CO 2 partial pressure of 77±5 Pa was 23% lower than that of 39.3 Pa, and slight decreases in respiration rate in light and CO 2 compensation point excluding of respiration in light were observed. The maximum rates of carboxylation ( V c max ) and photosynthetic electron transport ( J max ) were decreased in saplings grown under 77±5 Pa CO 2 partial pressure. It may suggest that there was a lower energy level of photosystem I(PSI) in the saplings leaves under 77±5 Pa CO 2 partial pressure, and free radical yield decreased by 39% in the saplings under 77±5 Pa CO 2, as comparied with that under atmospheric CO 2. The percentage of infection by Peronophythora litchi increased from 1.8% under atmospheric CO 2 to 9.5% under enriched CO 2. It may mean that the decreasing photosynthetic and respiration metabolism would make it lower the production of O 2 -. , and leaves were infected by P.litchi more easily. The controlling of the popularization of P.litchi for litchi plantation must be paid wide attention,as air CO 2 partial pressure will increase continuously.