干旱对烤烟团棵期的光合特性影响研究

A Study on the Effects of Drought Stress on Photosynthetic Characteristics in Flue-cured Tobacco at the Resettle Stage

以云烟87为试验材料,采用盆栽防雨棚控水干旱试验,利用Li-6400便携式光合测定仪测定了干旱对烤烟团棵期的光合特性日变化的影响。结果表明,各处理的净光合速率(Pn)、气孔导度(Cond)和蒸腾速率(Tr)日变化均呈单峰曲线,与CK相比,短期干旱(7 d)各指标日均值及峰值下降不明显,分别为CK的91.55%和97.00%、91.12%和86.29%、91.10%和90.06%,而干旱16 d则分别为CK的29.78%和43.57%、18.36%和16.83%、20.22%和18.89%。烤烟叶片胞间CO2浓度(Ci)的日变化与净光合速率日变化基本呈相反趋势,干旱16 d的烟叶胞间CO2浓度日变化最明显,其胞间CO2浓度日较差为226.08%,而CK仅为12.35%,各处理之间水分利用率及叶温日均值均无显著差异,其中胞间CO2浓度稍有下降趋势,而水分利用效率和叶温都随干旱胁迫时间的延长而略有升高,上午水分利用率大,下午水分利用率小,干旱16 d 09:00水分利用率最高,是其他处理利用率的一倍,15:00是其他处理水分利用率的一半。干旱能适当提高烟株的水分利用效率,也会加快叶温升高的速度并使叶温更高,但对烤烟团棵期的光合作用有不利的影响。短期干旱对云烟87的生长影响不大。

An experiment was conducted with potted flue-cured tobacco variety Yunyan87 by controlling irrigation to study the effects of drought stress on diurnal changes of photosynthetic characteristics in flue-cured tobacco at the resettle stage by the Li-6400 portable photosynthesis machine.The results showed that the diurnal changes of the net photosynthetic rates（Pn）,stomatal conductance（Cond） and transpiration rates（Tr） in every treatment all appeared as single peak curves.Compared with CK,the daily average and maximum value of the above mentioned items under short-term drought（7 d） did not decrease obviously,making 91.55% and 97.00%,91.12% and 86.29%,91.10% and 90.06% respectively of CK,while those under the drought stress for 16 days were respectively 29.78% and 43.57%,18.36% and 16.83%,20.22% and 18.89% of CK.The diurnal change of intercellular CO2 concentration（Ci） which was opposite to that of net photosynthetic rate in flue-cured tobacco leaf was the most significant under drought for 16 days,with the appreciation as high as 226.08%,while that of CK was only 12.35%.The daily average of the water utilization efficiency（WUE） and leaf temperature（TL） in every treatment did not show significant differences.The Ci declined lightly,while the WUE and TL ascended slightly when the drought stress time was prolonged.The WUE was high in the morning but low in the afternoon,and that under drought for 16 days it was the highest at 09： 00 am,double of the others treatments,but at 15： 00 pm half of the others.Drought stress could not only improve WUE of flue-cured tobacco appropriately,but also accelerate the rate of increase in leaf temperature and to a higher leaf temperature,but it has an adverse effect on photosynthesis at the resettle stage in flue-cured to-bacco.Short-term drought stress has little effect on the growth of Yunyan87.