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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。
The turfgrass was treated with different moisture gradient (25 ± 2%, 15 ± 2%, 5 ± 2%) and different nitrogen concentrations (1.5mM, 15mM, 30mM) Fluorescence properties and RuBisCO enzyme activity. The results showed that under the same nitrogen concentration, mild and severe water stress significantly decreased the maximum chlorophyll fluorescence yield (Fv / Fm), actual quantum yield (Y (Ⅱ)), photochemical quenching coefficient (qP) and relative electron transfer rate (ETR) and RuBisCO enzyme activity. Under the same water condition, the chlorophyll fluorescence parameters Fv / Fm, Y (Ⅱ), qP, ETR and RuBisCO activities of ’Arcadia’ and Heilongjiang bluegrass increased first and then decreased with the increase of nitrogen concentration, Eclipse ’s several indicators have been on the rise. Under severe water stress, compared with 15mM nitrogen treatment, the enzyme activity of RuBisCO in ’Arcadia’, Heilongjiang bluegrass and ’Eclipse’ decreased by 47.77%, 39.61% and 19.08% respectively under 15mM nitrogen treatment, indicating that photosynthetic characteristics were affected Severe inhibition and appropriate increase of N could effectively alleviate the effects of water stress on chlorophyll fluorescence and RuBisCO activity. Interaction of 25 ± 2% moisture and 15mM nitrogen was the best choice for water use of ’Arcadia’ and Heilongjiang grassland, while interaction of 25 ± 2% moisture and 30mM nitrogen benefited the growth of ’Eclipse’.