基于FvCB模型的几种草本和木本植物光合生理生化特性

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CO₂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.

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

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 fitted by the modified rectangular hyperbolic model and the FvCB model, and the photosynthetic parameters, including maximum net photosynthetic rate (P_{n max}), maximal Rubisco carboxylation rate (V_{c max}), maximal electron transport rate (J_max), day respiration (R_d), and mesophyll resistance to CO₂ transport (r_m), were compared among different woody species, among different herbaceous species, and between woody and herbaceous life-forms, respectively. The results showed P_{n max} of seven woody species descended in the order of Sapium sebiferum and Boehmeria nivea ＞ Machilus pingii and Pittosporum tobira ＞ Cyclobalanopsis glauca, Castanopsis sclerophylla, and Quercus nuttallii. V_{c max} of S. sebiferum, B. nivea, M. pingii, and P. tobira was significantly higher than that of C. glauca and C. sclerophylla. J_max of woody species was in descending order as S. sebiferum ＞ B. nivea and P. tobira ＞ Q. nuttallii, C. sclerophylla, and C. glauca. r_m of M. pingii and C. sclerophylla was higher than that of S. sebiferum, P. tobira and B. nivea. P_{n max} of Phytolacca acinosa was significantly higher than that of Ageratum conyzoides and Achyranthes aspera. There was no significant difference in V_{c max} among 4 herbaceous species. J_max of P. acinosa was higher than that of A. conyzoides. r_m of S. nigrum and A. aspera was higher than that of A. conyzoides. R_d of P. acinosa was higher than that of A. conyzoides and A. aspera. The photosynthetic parameters (P_{n max}, V_{c max}, J_max and r_m) of woody species were significantly higher than those of herbaceous species, but no significant difference was found in R_d 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.