Abstract: This paper studied the effects of different dosage of water retaining agent on growth parameters, chlorophyll content, photosynthetic characteristics and chlorophyll fluorescence parameters in tobacco by pot experiments. The results showed that: the application of appropriate amount of water retaining agent could significantly increase the contents of growth index, chlorophyll a, chlorophyll b and total chlorophyll in tobacco. The net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and water use efficiency (WUE) of the treated tobacco increased firstly and then decreased with the application quantity growing of water retention agent. Results showed that the effect of water retaining agent on tobacco photosynthetic characteristics  was obvious, it could improve tobacco photosynthetic capacity, but over usage would be unvaverable for improving   tobacco photosynthetic characteristics. The treated tobacco chlorophyll fluorescence parameters Fv/Fm, ΦPSII and qP increased firstly and then decreased slightly, while the NPQ showed a down trend. Of all treatments, the effect of T2 (3 g/strain) was the best, its photosynthetic capacity was the strongest, and the treated tobacco had better ability of self protection and adjustment.

Key words: water retaining agent, tobacco, photosynthetic characteristics, chlorophyll fluorescence parameters

摘要： 采用盆栽试验，研究了不同保水剂用量对烟草生长指标、叶绿素含量、光合特性和叶绿素荧光参数的影响。结果表明：适量保水剂的施用显著提高了烟草各生长指标、叶绿素a、叶绿素b和总叶绿素的含量；随保水剂用量的增加，各处理烟叶的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和水分利用率(WUE)都呈先上升后下降的趋势，说明保水剂对烟草光合特性影响较大，可以明显提高烟草光合能力，但用量过大时不利于改善烟草光合特性；各处理烟草叶片叶绿素荧光参数Fv/Fm、ΦPSII和qP均表现为先上升后略下降，而NPQ则呈下降趋势。所有处理中以T2(3 g/株)效果最好，其烟株光合能力最强，同时具有较好的自我保护调节能力。

关键词: 保水剂, 烟草, 光合特性, 叶绿素荧光参数