土壤pH值对烤烟叶片光合特性和烟碱含量的影响

Effects of Soil pH on Photosynthetic Characteristics and the Content of Nicotine in Flue-Cured Tobacco Leaves

试验研究了土壤pH值对烤烟叶片光合特性和烟碱含量的影响.结果表明:随着烟株的生长发育,不同pH处理的烟叶在光合特性和烟碱含量方面存在差异.从团棵期到现蕾期,pH4.5～7.5各pH处理的叶片内叶绿素含量、光合速率等都随着pH增大而升高,旺长期pH 7.5处理的叶片叶绿素含量最大(1.334mg/g),现蕾期pH 7.5光合速率最高[23.0μmol/(m2·s)],烟碱含量最低(0.71%).而团棵期到旺长期,比叶重增加缓慢,平均增加15%;成熟期各pH处理的烟叶内叶绿素含量、光合速率下降,pH 4.5处理烟叶内叶绿素含量(0.178 mg/g)和光合速率[3.95 μmol/(m2·s)]最低,pH 7.5处理叶片比咔重(6.45mg/cm2)、烟碱含量(1.97%)达到高峰.pH 8.5处理的植株与其它4种处理规律不同,生长后期仍保持较强的生长势,表现为叶绿素含量(1.072mg/g)、光合速率[11.05μmol/(m2·s)]都最高,比叶重(3.59mg/cm2)和烟碱含量(0.68%)最低.

With the growth of tobacco, the photosynthetic characteristics and the content of nicotine of the tobacco leaves treated with various pH values were different. From the rosette stage to the budding stage, with the increase of pH value, the content of chlorophyll and the photosynthesis rate became higher in tobacco leaves when treated with pH value between 4.5 and 7.5. At the vigorous stage, the content of chlorophyll reached the highest （1.334 mg/g ）when treated at pH value 7.5. At the budding stage, the photosynthesis rate of the leaves was the maximum[ 23.0μmol/（m^2. s）], the content of nicotine was the lowest （0.71%）.From the rosette stage to the vigorous stage, the specific leaf weight raised slowly, 15% on average. At the mature stage, the content of chlorophyll and the photosynthesis rate declined in the leaves treated with all pH values, the content of chlorophyll （0.178 mg/g） and the photosynthesis rate [3.95μmol/（m^2·s）] were the lowest when treated at pH value 4.5, the specific leaf weight was 6.45 mg/cm^2 and the content of nicotine of the tobacco was the highest （1.97%） when treated at pH value 7.5. At the later stage of growth, different from other four dealings, the growth tendency of tobacco on pH value 8.5 still remained stronger, which showed the highest chlorophyll content（ 1.072 mg/g） and photosynthesis rate[ 11.05μmol/（m^2·s）] as well as the lowest specific leaf weight（3.59 mg/cm^2） and the content of nicotine （0.68 % ）.