Kong Ricky S, Henry Hugh A L, Smith Nicholas G
Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B7, Canada.
Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.
Oecologia. 2025 Sep 12;207(10):156. doi: 10.1007/s00442-025-05794-1.
Plants are likely to experience multiple cycles of drought. However, physiological acclimation and stress memory may play key roles in reducing the detrimental effects of successive droughts. We investigated drought acclimation in cotton (Gossypium hirsutum) fertilized with low or high nitrogen (N) in a greenhouse factorial experiment. The cotton plants were subjected to one of four drought treatments applied during two 15-day periods, where plants were withheld water or were fully watered. We assessed CO assimilation (A) and stomatal conductance (g), maximum rates of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (RuBisCO) carboxylation (V), maximum rates of electron transport for RuBP regeneration (J), and biomass at the time of harvest. Droughted and well-watered plants had similar rates of A, g, V, and J during the first drought under low N. High N plants were larger in size than low N plants, which suggests that the additional N likely increased the severity of the drought, causing stomatal closure and a decline in photosynthesis. However, there were increases in both V and J for high N plants during the first drought. There was no evidence of drought memory, and plants exposed to both droughts responded similarly to plants exposed to only the second drought. Overall, our results indicate that cotton can acclimate under drought, and additional fertilization may result in severe drought stress.
植物可能会经历多个干旱周期。然而，生理适应和胁迫记忆可能在减轻连续干旱的有害影响方面发挥关键作用。我们在温室析因实验中研究了低氮或高氮施肥条件下棉花（陆地棉）的干旱适应性。棉花植株在两个15天的时间段内接受四种干旱处理之一，即不给水或充分浇水。我们评估了收获时的二氧化碳同化率（A）、气孔导度（g）、核酮糖-1,5-二磷酸羧化酶/加氧酶（RuBisCO）羧化的最大速率（V）、核酮糖-1,5-二磷酸再生的电子传递最大速率（J）以及生物量。在低氮条件下的第一次干旱期间，干旱处理和充分浇水的植株的A、g、V和J速率相似。高氮植株比低氮植株更大，这表明额外的氮可能增加了干旱的严重程度，导致气孔关闭和光合作用下降。然而，在第一次干旱期间，高氮植株的V和J均有所增加。没有干旱记忆的证据，经历两次干旱的植株与仅经历第二次干旱的植株反应相似。总体而言，我们的结果表明棉花能够在干旱条件下适应，额外施肥可能导致严重的干旱胁迫。
