Borrajo Celina I, Sánchez-Moreiras Adela M, Reigosa Manuel J
Departamento de Bioloxía Vexetal e Ciencias do Solo, Facultade de Bioloxía, Universidade de Vigo, Campus Lagoas Marcosende s/n, 36310 Vigo, Spain.
Agricultural Experimental Station Cuenca del Salado of INTA (National Institute of Agricultural Technology), Av. Belgrano 416, Rauch 7203, Argentina.
Plants (Basel). 2022 Jun 10;11(12):1548. doi: 10.3390/plants11121548.
Tall wheatgrass ( (Podp.) Barkworth and D.R. Dewey) is an important, highly salt-tolerant C3 forage grass. The objective of this work was to learn about the ecophysiological responses of accessions from different environmental origins under drought and salinity conditions, to provide information for selecting superior germplasm under combined stress in tall wheatgrass. Four accessions (P3, P4, P5, P9) were irrigated using combinations of three salinity levels (0, 0.1, 0.3 M NaCl) and three drought levels (100%, 50%, 30% water capacity) over 90 days in a greenhouse. The control treatment showed the highest total biomass, but water-use efficiency (WUE), δC, proline, N concentration, leaf length, and tiller density were higher under moderate drought or/and salinity stress than under control conditions. In tall wheatgrass, K functions as an osmoregulator under drought, attenuated by salinity, and Na and Cl function as osmoregulators under salinity and drought, while proline is an osmoprotector under both stresses. P3 and P9, from environments with mild/moderate stress, prioritized reproductive development, with high evapotranspiration and the lowest WUE and δC values. P4 and P5, from more stressful environments, prioritized vegetative development through tillering, showing the lowest evapotranspiration, the highest δC values, and different mechanisms for limiting transpiration. The δC value, leaf biomass, tiller density, and leaf length had high broad-sense heritability (H), while the Na/K ratio had medium H. In conclusion, the combined use of the δC value, Na/K ratio, and canopy structural variables can help identify accessions that are well-adapted to drought and salinity, also considering the desirable plant characteristics. Tall wheatgrass stress tolerance could be used to expand forage production under a changing climate.
高冰草（(Podp.) Barkworth和D.R. Dewey）是一种重要的、高度耐盐的C3饲草。本研究的目的是了解不同环境来源的种质在干旱和盐胁迫条件下的生态生理响应，为高冰草复合胁迫下优良种质的筛选提供信息。在温室中，对四个种质（P3、P4、P5、P9）进行了为期90天的灌溉处理，设置了三个盐度水平（0、0.1、0.3 M NaCl）和三个干旱水平（100%、50%、30%田间持水量）的组合。对照处理的总生物量最高，但中度干旱或/和盐胁迫下的水分利用效率（WUE）、δC、脯氨酸、氮浓度、叶长和分蘖密度均高于对照条件。在高冰草中，钾在干旱条件下起渗透调节剂的作用，受盐度影响而减弱，钠和氯在盐胁迫和干旱条件下起渗透调节剂的作用，而脯氨酸在两种胁迫下都是渗透保护剂。来自轻度/中度胁迫环境的P3和P9优先进行生殖生长，具有较高的蒸散量和最低的WUE和δC值。来自胁迫更大环境的P4和P5通过分蘖优先进行营养生长，表现出最低的蒸散量、最高的δC值以及不同的蒸腾限制机制。δC值、叶生物量、分蘖密度和叶长具有较高的广义遗传力（H），而钠钾比具有中等H。总之，综合利用δC值、钠钾比和冠层结构变量有助于识别适应干旱和盐胁迫的种质，同时考虑理想的植物特性。高冰草的胁迫耐受性可用于在气候变化条件下扩大饲料生产。
