以美洲黑杨杂交子代2年生的高(H4)、低(L3)生长势无性系及父本(F)为试验材料,比较其净光合速率(Pn)日变化及对有效光辐射(PAR)和CO2响应等生理特征差异.结果表明:H4,L3,F的Pn日变化曲线没有显著的双峰现象,H4的光合优势主要集中在6:00-12:00之间；光响应曲线数据分析表明:3个系号除暗呼吸速率(rd)外,最大光合速率(Pnmax)、表观光合量子效率(AQY)、光补偿点(LCP)、光饱和点(LSP)等存在显著差异,H4的Pnmax最大,为21.47 μmol·m-2s-1,超过L3达39.42％,其LCP最小,仅15.09 μmol·m-2s-1,LSP值又最大,分别超过L3和F值的17.03％和10.35％；CO2响应曲线数据分析表明:各系号间仅Pnmax有显著差异,羧化效率、CO2补偿点(CCP)、光呼吸速率等差异均不显著,H4的羧化效率略高于L3和F,而CCP则稍低于L3和F,表明高生长势植株在CO2的转化效率和利用效率上稍有优势.高生长势无性系H4利用弱光的能力较强,且能在强光下进行相对高效的光合作用,其光合速率的优势主要集中在上午,日积累的优势更加明显,但对于CO2的吸收利用能力仅略有优势.%Two 2-year-old hybrid clones with high (H4) and low ( L3 ) growth vigor of Populus deltoides and their paternal parent ( F) were used as the experimental materials to illustrate their difference of diurnal changes of photosynthesis, light response curves and C02 response curves. The result showed that diurnal changes of the net photosynthetic rate of H4, L3 and F all displayed a single peak curve H4 started its efficient photosynthesis significantly earlier than L3 and F. The analysis of light response curves indicated that the maximum net photosynthetic rate (P nmax ) , apparent quantum yield (AQY) , light compensation point (LCP) and light saturation point (LSP) expect dark respiration rate (Rd) all exhibited significant differences over the clones. The P nmax of H4 was largest, reaching to 21. 47 μmol·m-2 s-1 , and 52. 8% higher than L3 , and the LSP was also largest and 17. 03% and 10. 35% higher than L3 and F respectively, but the LCP was the lowest, only 15.09 μmol·m-2s-1. The result of CO2 response curves showed that there were no significant differences in the carboxylation efficiency, the CO2 compensation point (CCP) and photorespiration rate except Pnmax. The carboxylation efficiency and CCP of H4 were slightly higher and lower than L3 and F respectively, which revealed the clone with high growth vigor had a little advantage in the utilization of CO2. In a word, the clone with high growth vigor had a stronger ability to make use of low light and performed relatively efficient photosynthesis in strong light, only with a little advantage in the absorption and utilization of CO2.
展开▼
