为研究土壤中Pb污染对烤烟（Nicotiana tabacum）叶片光合特性、烟叶品质及其产量的影响，对烤烟主栽品种‘云烟85’进行了盆栽条件下的Pb污染实验，实验浓度为0 、150、300、450、600、750和1000 mg·kg-1（以纯Pb2+计），分别于团棵期、现蕾期和采收期测定叶片光合特性的变化，并在采收期测定烟叶产量和烤后烟叶的品质变化。结果表明：在 3个生育时期，Pb污染下供试烤烟品种叶片净光合速率（Pn）和气孔导度（Gs）均随Pb浓度的升高而下降，而胞间CO2浓度（Ci）随Pb浓度的升高先增加后下降；PSⅡ活性(Fv/Fo)、最大光能转换效率(Fv/Fm)、光化学猝灭系数（qP）、非光化学猝灭系数（NPQ）、电子传递的量子产率（ΦPSⅡ）、表观电子传递速率（ETR）和烟叶产量均随Pb浓度的升高而下降，不利于烟叶充分地利用捕光色素所吸收的光能，降低其光能利用效率，从而降低了光合速率；烤烟烟叶品质指标糖/碱比和氮/碱比升高，糖/碱比和氮/碱比分别为9.52～11.96 和1.05～1.23，分别大于7（优质烟叶标准）和1（优质烟叶标准），不利于烟叶香吃味的形成。
In order to examine the effects of Pb pollution on photosynthesis, quality, and yield of tobacco cultivar, pot experiment was carried out at the Research Station of Henan Agricultural University during 2002-2004. Cultivar of `Yunyan 85‘ was treated with seven concentration levels of Pb2+ (0, 150, 300, 450, 600 , 750 and 1 000 mg·kg-1) applied with (CH3COO)2 Pb after transplanting. Twenty leaves were saved after topping. The net photosynthetic rate (Pn), intercellular CO2 concentration (Ci), and stomatal conductance (Gs) of three identical functional leaves from the same position were measured during rosette, budding, and harvest stages respectively using a Li_6400 Portable Photosynthesis System. Maximal fluorescence (Fm)，fixed fluorescence (Fo), and steady fluorescence (Fs) were determined in the dark (for 30 min) and maximal fluorescence in the light (Fm′) with a Hansatech FMS2 photo_fluorometer. PSⅡ activity (Fv/Fo), PSⅡ maximum light energy transformation (Fv/Fm), chemical quenching coefficient (qP), non_photochemical quenching coefficient (NPQ), apparent photosynthetic electron transport rate(ETR), and the ratio of photochemical quantum yield of PSII (ΦPSⅡ) were calculated．The reductive sugar, total N, nicotine, Kalium contents of tobacco leaves and yield per plant were investigated.The results showed that Pn, Gs, and Ci occurred at the Pb concentrations of 300 mg?kg-1 in budding stage and the Pb concentrations up to 150 mg?kg-1 in rosette and harvest stages. Fv/Fo, Fv/Fm, qP, NPQ, ETR, andΦPSⅡ decreased with increasing Pb concentrations, resulting in declining ability of photosynthetic pigments assimilating light, photosynthetic light use efficiency, and Pn of tobacco leaves. Higher Pb concentrations led to increases in the ratios of reductive sugar/nicotine (9.52-11.96) and total_N/nicotine (1.05-1.23), which are used as the quality indexes of tobacco leaves, above the standards (7 and 1) of high quality of tobacco leaves, and then deteriorated the fragrance of tobacco leaves.