摘要
补增UV -B辐射的香蕉叶片光下呼吸速率 (Rd)和不包括光下呼吸的CO2 补偿点 (г ) ,分别为0 .33μmol·m- 2 ·s- 1 和 46.5μl·L- 1 ,较对照植株分别高 5.6%和 1 0 .0 %。在较高CO2 浓度 (>340 μl·L- 1 )条件下的An/θp关系最初直线部分斜率 ,即表观量子产率 (αA)为 0 .0 2 3± 0 .0 0 7,而补增UV B辐射处理的植株则降低 1 3.0 % ,光能转换效率 (δ)亦降低 2 8.6% ,表明UV B辐射明显降低αA 和δ。在高θp(1 1 0 0 μmol·m- 2 ·s- 1 )和Ci<2 0 0 μl·L- 1 条件下 ,对照植株的An/Ci关系为An =0 .0 2 8Ci+1 .44,补增UV B辐射处理的植株则为An =0 .0 2 1Ci+1 .0 1 ,UV B辐射降低羧化限制速率。最大羧化速率 (Vcmax)和电子传导速率的光饱和值 (Jmax)亦较低 ,补增UV B辐射的叶片 ,叶氮在Rubisco的分配系数 (PR)和叶氮在生物力能学组分的分配系数 (PB)分别较对照低 8.1 %和 3.0 % ,叶氮分配到类囊体膜捕光色素蛋白组分的则略见增高 ,UV
Respiration rate in light (Rd) and the CO 2 compensation point in absence of Rd (г *) were 0.33μmol·m -2 ·s -1 and 46.5μl·L -1 in leaves of Musa paradisiaca exposed to UV B radiation (4.8μW·cm -2 ) respectivty. They were higher than those in control plants by 5.6% and 10%, respectively. The initial slope of light response curves, the apparent quantum yield (α A) in leaves of control plants was 0.023±0.007 while the relative value was decreased by 13.0% in plants exposed to UV B radiation. A parameter related to the efficiency of light energy conversion (δ) was also decreased by 28.6% for plants exposed to UV B radiation in comparison with that of control plant. The partial An/Ci curves measured under θp 1100μmol·m -2 ·s -1 , was An=0.028Ci+ 1.41 for leaves of control plants and An=0.021Ci+1.01 for leaves exposed to UV B radiation. Maximum carboxylation rate (Vcmax) and electron transport rate in saturated θp in leaves exposed to UV B treatment were also lower than those of controls considerably. The partitioning coefficients for leaf nitrogen in Rubisco (P R) and in bioenergetic (P B) in leaves exposed to UV B radiation were lower than those of controls by 8.1% and 3.0%, respectively. And the fraction of leaf nitrogen in thylakoid light harvesting component (P L) increased finely in plant exposed to UV B radiation as compared to that of controls. The results imply that supplementary UV B radiation cause the decrease of nitrogen partition in the components of photosynthetic carbon cycle and decrease photosynthetic rate.
出处
《植物学通报》
CSCD
2000年第5期450-456,共7页
Chinese Bulletin of Botany
基金
国家自然科学基金!( 39899370 )
广东省自然科学基金!( 980 952 )
中国科学院 95重大项目!(KZ951 B1 1 1 0 )
关键词
香蕉
UV-B辐射
光合速率
叶氮分配
Musa paradisiaca
UV B radiation
Photosynthesis
Partition for leaf nitrogen
