Laboratory of Plant Ecophysiology, Department of Plant Biology and Soil Science, University of Vigo, Campus Lagoas-Marcosende, 36310-Vigo, Spain.
Plant Physiol Biochem. 2011 Aug;49(8):825-34. doi: 10.1016/j.plaphy.2011.05.003. Epub 2011 May 13.
The effects are reported here of Benzoxazolin-2(3H)-one (BOA), an allelopathic compound, on plant water relations, growth, components of chlorophyll fluorescence, and carbon isotope discrimination in lettuce (Lactuca sativa L.). Lettuce seedlings were grown in 1:1 Hoagland solution in perlite culture medium in environmentally controlled glasshouse. After 30 days, BOA was applied at concentration of 0.1, 0.5, 1.0 and 1.5 mM and distilled water (control). BOA, in the range (0.1-1.5 mM), decreased the shoot length, root length, leaf and root fresh weight. Within this concentration range, BOA significantly reduced relative water content while leaf osmotic potential remained unaltered. Stress response of lettuce was evaluated on the basis of six days of treatment with 1.5 mM BOA by analyzing several chlorophyll fluorescence parameters determined under dark-adapted and steady state conditions. There was no change in initial fluorescence (F₀) in response to BOA treatment while maximum chlorophyll fluorescence (F(m)) was significantly reduced. BOA treatment significantly reduced variable fluorescence (F(v)) on first, second, third, fourth, fifth and sixth day. Quantum efficiency of open PSII reaction centers (F(v)/F(m)) in the dark-adapted state was significantly reduced in response to BOA treatment. Quantum yield of photosystem II (ΦPSII) electron transport was significantly reduced because of decrease in the efficiency of excitation energy trapping of PSII reaction centers. Maximum fluorescence in light-adapted leaves (F'(m)) was significantly decreased but there was no change in initial fluorescence in light-adapted state (F'₀) in response to 1.5 mM BOA treatment. BOA application significantly reduced photochemical fluorescence quenching (qP) indicating that the balance between excitation rate and electron transfer rate has changed leading to a more reduced state of PSII reaction centers. Non photochemical quenching (NPQ) was also significantly reduced by BOA treatment on third, fourth and fifth day. BOA had dominant effect on C isotope ratios (δ¹³C) that was significantly less negative (-26.93) at 1.0 mM concentration as compared to control (-27.61). Carbon isotope discrimination (Δ¹³C) values were significantly less (19.45) as compared to control (20.17) at 1.0 mM. BOA also affect ratio of intercellular to air CO₂ concentration (ci/ca) that was significantly less (0.66) as compared to control (0.69) when treated with 1.0 mM BOA. Protein content of lettuce leaf tissue decreased under BOA treatment at 1.5 mM concentration as compared to control.
苯并恶唑啉-2(3H)-酮（BOA）是一种化感化合物，本研究报道了其对生菜植物水分关系、生长、叶绿素荧光成分和碳同位素分馏的影响。生菜幼苗在环境控制玻璃温室中的珍珠岩培养基中的 1:1 Hoagland 溶液中生长。30 天后，以 0.1、0.5、1.0 和 1.5 mM 的浓度和蒸馏水（对照）施加 BOA。在（0.1-1.5 mM）范围内，BOA 降低了茎长、根长、叶和根鲜重。在该浓度范围内，BOA 显著降低了相对水含量，而叶片渗透势保持不变。通过用 1.5 mM BOA 处理 6 天，分析在暗适应和稳态条件下测定的六个叶绿素荧光参数，评估生菜的应激反应。对照处理下，BOA 处理对初始荧光（F₀）没有影响，而最大叶绿素荧光（F(m)）显著降低。BOA 处理显著降低了第 1、2、3、4、5 和第 6 天的可变荧光（F(v)）。暗适应状态下 PSII 反应中心开放量子效率（F(v)/F(m)）对 BOA 处理的响应显著降低。由于 PSII 反应中心激发能捕获效率降低，PSII 电子传递的量子产率显著降低。光适应叶片中的最大荧光（F'(m)）显著降低，但光适应状态下初始荧光（F'₀）没有变化。1.5 mM BOA 处理显著降低光化学荧光猝灭（qP），表明激发速率和电子传递速率之间的平衡发生变化，导致 PSII 反应中心更还原。非光化学猝灭（NPQ）也被 BOA 处理显著降低，第 3、4 和第 5 天。BOA 对 C 同位素比值（δ¹³C）的影响明显，在 1.0 mM 浓度下明显负值（-26.93）低于对照（-27.61）。碳同位素分馏（Δ¹³C）值也明显低于对照（19.45），在 1.0 mM 时为 20.17。BOA 还影响胞间与空气 CO₂浓度比（ci/ca），当用 1.0 mM BOA 处理时，其值明显低于对照（0.66）。当用 1.5 mM BOA 处理时，生菜叶片组织中的蛋白质含量与对照相比降低。
