ABSTRACT

The strawberry (Fragaria ×ananassa Duch.) is a commercially important crop with high water requirements, making strategies that mitigate the influence of water deficits on plant growth necessary. This study aimed to evaluate the effects of shading on the vegetative growth of strawberry cv. Sweet Ann under a water deficit. The treatments consisted of the combination of two levels of shading (light intensity reduced by 47% vs. non-shaded plants) and two levels of water availability (water deficit vs. well-watered plants). The water deficit reduced the leaf water potential from −1.52 to −2.21 MPa, and diminished stomatal conductance, net photosynthetic rate (from 9.13 to 2.5 µmol m⁻² s⁻¹), maximum quantum efficiency of PSII photochemistry (from 0.79 to 0.67), and biomass accumulation, but increased the electrolyte leakage. The shading allowed the water-deficient plants to maintain water potential (−1.58 MPa) and photosystem II efficiency (0.79) and to increase water use efficiency (from 14.80 to 86.90 µmol CO₂/mmol H₂O), net photosynthetic rate (from 2.40 to 9.40 µmol m⁻² s⁻¹) and biomass of leaves, crowns, and roots, as compared to the non-shaded plants without a water limitation. These results suggest, for the first time in strawberry, that a reduction in incident light intensity attenuates the effects of stomatic and non-stomatic limitations caused by a water deficit during vegetative growth in strawberry.

摘要

草莓 ( Fragaria × ananassa Duch.) 是一种重要的商业作物，需水量很高，因此需要采取策略来减轻水分不足对植物生长的影响。本研究旨在评估遮光对草莓品种营养生长的影响。Sweet Ann 缺水。处理包括两个水平的遮荫（光强度降低 47% 与非遮荫植物）和两个水可用性水平（缺水与浇水良好的植物）的组合。水分亏缺使叶片水势从-1.52 降低到-2.21 MPa，气孔导度和净光合速​​率降低（从9.13 到2.5 µmol m ^-2 s ^-1)、PSII 光化学的最大量子效率（从 0.79 到 0.67）和生物量积累，但增加了电解质泄漏。遮荫使缺水植物保持水势 (-1.58 MPa) 和光系统 II 效率 (0.79) 并提高水分利用效率 (从 14.80 到 86.90 µmol CO ₂ /mmol H ₂ O)、净光合速率 (从2.40 到 9.40 µmol m ^-2 s ^-1 ) 和叶、冠和根的生物量，与没有水分限制的非遮荫植物相比。这些结果首次在草莓中表明，入射光强度的降低减弱了草莓营养生长过程中水分不足引起的气孔和非气孔限制的影响。