基于FvCB模型的几种草本和木本植物光合生理生化特性

Photo-physiological and photo-biochemical characteristics of several herbaceous and woody species based on FvCB model

为研究不同生活型植物的光合能力及其叶片光合机构,采用直角双曲线修正模型和C3植物FvCB模型对7种木本植物和4种草本植物的CO_2响应曲线进行拟合,并对不同木本植物、不同草本植物和2种生活型植物的最大净光合速率(P_(n max))、Rubisco酶最大羧化速率(V_(c max))、最大电子传递速率(J_(max))、光合暗呼吸速率(R_d)和叶肉阻力(r_m)等参数进行比较.结果表明:7种木本植物P_(n max)大小顺序为乌桕、苎麻>润楠、海桐>青冈、苦槠、娜塔栎;乌桕、苎麻、润楠和海桐的V_(c max)显著大于青冈和苦槠;J_(max)大小顺序为乌桕>苎麻、海桐>娜塔栎、苦槠和青冈;润楠和苦槠的r_m显著大于乌桕、海桐和苎麻.商陆的P_(n max)显著大于藿香蓟和土牛膝;4种草本植物的V_(c max)无显著差异;商陆的J_(max)显著大于藿香蓟;龙葵和土牛膝的r_m显著大于藿香蓟;商陆的R_d显著大于藿香蓟和土牛膝.木本植物的P_(n max)、V_(c max)、J_(max)和r_m光合参数均显著大于草本植物,但二者的R_d无显著差异.不同物种之间以及2种生活型植物光合能力的差异主要是由叶片内部Rubisco酶羧化能力、电子传递能力和叶肉阻力等差异引起的.

To explore the photosynthetic capacity and the leaf photosynthetic apparatus for plants with different life forms, CO2 response curves of 7 woody species and 4 herbaceous species were fit- ted by the modified rectangular hyperbolic model and the FvCB model, and the photosynthetic pa- rameters, including maximum net photosynthetic rate （P ）, maximal Rubisco carboxylation rate （ Vc max ） , maximal electron transport rate （ Jmax ）, day respiration （ Rd ）, and mesophyll resistance to CO2 transport （rm ）, were compared among different woody species, among different herbaceous species, and between woody and herbaceous life-forms, respectively. The results showed P of seven woody species descended in the order of Sapium sebiferum and Boehmeria nivea 〉 Machilus pingii and Pittosporum tobira 〉 Cyclobalanopsis glauca, Castanopsis sclerophyUa, and Quercus nut- tallii. Vc max of S. sebiferum, B. nivea, M. pingii, and P. tobira was significantly higher than that of C. glauca and C. sclerophylla. Jmax of woody species was in descending order as S. sebiferum 〉 B.nivea and P. tobira 〉 Q. nuttallii, C. sclerophyUa, and C. glauca, r m of M. pingii and C. sclerophylla was higher than that of S. sebiferum, P. tobira and B. nivea. Pn max of Phytolacca acinosa was sig- nificantly higher than that of Ageratum conyzoides and Achyranthes aspera. There was no significant difference in Vc max among 4 herbaceous species. Jmax of P. acinosa was higher than that of A. cony- zoides, rm of S. nigrum and A. aspera was higher than that of A. conyzoides. Rd of P. acinosa was higher than that of A. conyzoides and A. aspera. The photosynthetic parameters （Pn max=, Vc max, Jmax and rm） of woody species were significantly higher than those of herbaceous species, but no significant difference was found in Rd between woody and herbaceous species. In conclusion, the difference in photosynthetic capacity among different species and between the two plant life-forms resulted from the difference in Rubisco carboxylation capacity, electron transport capacity, and mesophyll resistance among these species.