空气CO2增高条件下荔枝叶片光合作用和超氧自由基产率

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23%,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(V_cmax)和最大电子传递速率(J_max)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分压增高趋势下须加强对荔枝霜疫霉病的控制.

Photosynthesis and free radical yield of Litchi chinensis leaves under increased CO2 partial pressure in atmosphere

.The maximum photosynthetic rate of litchi saplings leaves grown under a CO₂ partial pressure of 77?5 Pa was 23% lower than that of 39.3 Pa, and slight decreases in respiration rate in light and CO₂ compensation point excluding of respiration in light were observed. The maximum rates of carboxylation (V_cmax) and photosynthetic electron transport (J_max) were decreased in saplings grown under 77?5 Pa CO₂ partial pressure. It may suggest that there was a lower energy level of photosystem I(PSI) in the saplings leaves under 77?5 Pa CO₂ partial pressure, and free radical yield decreased by 39% in the saplings under 77?5 Pa CO₂, as comparied with that under atmospheric CO₂. The percentage of infection by Peronophythora litchi increased from 1.8% under atmospheric CO₂ to 9.5% under enriched CO₂. It may mean that the decreasing photosynthetic and respiration metabolism would make it lower the production of O₂^-., 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 CO₂ partial pressure will increase continuously.