Harmens Harry, Hayes Felicity, Sharps Katrina, Radbourne Alan, Mills Gina
Centre for Ecology & Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK.
Plants (Basel). 2019 Jul 12;8(7):220. doi: 10.3390/plants8070220.
Ground-level ozone (O) pollution is known to adversely affect the production of O-sensitive crops such as wheat. The magnitude of impact is dependent on the accumulated stomatal flux of O into the leaves. In well-irrigated plants, the leaf pores (stomata) tend to be wide open, which stimulates the stomatal flux and therefore the adverse impact of O on yield. To test whether reduced irrigation might mitigate O impacts on flag leaf photosynthesis and yield parameters, we exposed an O-sensitive Kenyan wheat variety to peak concentrations of 30 and 80 ppb O for four weeks in solardomes and applied three irrigation regimes (well-watered, frequent deficit, and infrequent deficit irrigation) during the flowering and grain filling stage. Reduced irrigation stimulated 1000-grain weight and harvest index by 33% and 13%, respectively (when O treatments were pooled), which compensated for the O-induced reductions observed in well-watered plants. Whilst full irrigation accelerated the O-induced reduction in photosynthesis by a week, such an effect was not observed for the chlorophyll content index of the flag leaf. Further studies under field conditions are required to test whether reduced irrigation can be applied as a management tool to mitigate adverse impacts of O on wheat yield.
已知地面臭氧（O₃）污染会对诸如小麦等对臭氧敏感的作物产量产生不利影响。影响程度取决于臭氧进入叶片的累积气孔通量。在灌溉良好的植株中，叶片气孔（气孔）往往会充分张开，这会刺激气孔通量，进而导致臭氧对产量产生不利影响。为了测试减少灌溉是否可以减轻臭氧对旗叶光合作用和产量参数的影响，我们在日光温室中将一个对臭氧敏感的肯尼亚小麦品种暴露于30和80 ppb的臭氧峰值浓度下四周，并在开花期和灌浆期采用了三种灌溉方式（充分灌溉、频繁亏缺灌溉和不频繁亏缺灌溉）。减少灌溉分别使千粒重和收获指数提高了33%和13%（合并臭氧处理时），这弥补了在充分灌溉植株中观察到的臭氧诱导的降低。虽然充分灌溉使臭氧诱导的光合作用降低提前了一周出现，但旗叶叶绿素含量指数并未出现这种效应。需要在田间条件下进行进一步研究，以测试减少灌溉是否可以作为一种管理工具来减轻臭氧对小麦产量的不利影响。
