中文摘要：

以草地早熟禾草坪草为试验材料,采用不同水分梯度（25±2%、15±2%、5±2%）和不同氮素浓度（1.5mM、15mM、30mM）进行交互处理,测定了叶绿素荧光特性和RuBisCO酶的活力。结果表明：同一氮素浓度下,轻度、重度水分胁迫显著（P〈0.05）降低草地早熟禾叶绿素荧光最大量子产量（Fv/Fm）、实际量子产量（Y（Ⅱ））、光化学淬灭系数（qP）及相对电子传递速率（ETR）和RuBisCO酶活力。同一水分条件下,随着氮浓度增大,品种‘Arcadia’和黑龙江草地早熟禾的叶绿素荧光参数Fv/Fm、Y（Ⅱ）、qP、ETR及RuBisCO酶活力先升高后降低,但品种‘Eclipse’的该几项指标一直呈上升趋势。在重度水分胁迫下,与15mM氮处理相比,1.5mM氮处理下‘Arcadia’、黑龙江草地早熟禾、‘Eclipse’的RuBisCO酶活力分别下降47.77%、39.61%、19.08%,表明其光合特性受到严重抑制,适度增加氮素可有效缓解水分胁迫对叶绿素荧光特性和RuBisCO酶活力的影响。25±2%水分和15mM氮交互处理是‘Arcadia’和黑龙江草地早熟禾水氮利用最优选择,而25±2%水分和30mM氮交互处理对‘Eclipse’生长有利。

英文摘要：

The effects of chlorophyll fluorescence characteristics and RuBisCO activity of Kentucky bluegrass under the interactions of different water gradients（25±2% ,15±2% ,5±2% ）and different nitrogen concentrations（1.5mM,15 mM,30mM）were studied.The results showed that：in the same nitrogen concentration,the chlorophyll fluorescence maximum photochemical quantum yield（Fv/Fm）,effective photochemical quantum yield（Y（Ⅱ））,photochemical fluorescence quenching（qP）,relative electron transport rate（ETR）and RuBisCO activity significantly reduced under light as well as heavy water stress.In the same water condition,with the increasing of nitrogen concentration,Fv/Fm,Y（Ⅱ）,qP,ETR and RuBisCO activity increased firstly and then decreased both in ‘Arcadia＇and Heilongjiang Kentucky bluegrass,while‘Eclipse＇kept increasing during the whole process.The RuBisCO activity of‘Arcadia＇,Heilongjiang Kentucky bluegrass and‘Eclipse＇under the heavy water stress and 1.5mM nitrogen treatment decreased by 47.77% ,39.61% ,19.08% respectively compared with the heavy water stress and 15 mM nitrogen treatment,indicated that the photosynthetic characteristics of Kentucky bluegrasses were severely inhibited.Appropriate amount of nitrogen could alleviate the negative effects of water stress on the chlorophyll fluorescence characteristics and RuBisCO activities.Water level at 25±2% with 15 mM nitrogen interactive treatment was the most suitable for‘Arcadia＇and Heilongjiang Kentucky bluegrass,while treatment of water at 25±2% with 30 mM nitrogen was more beneficial to the growth of‘Eclipse＇.