Silva Kalisto Natam Carneiro, Silva Andréa Carvalho da, Borella Daniela Roberta, Carneiro Samuel Silva, Santos Leonardo Martins Moura Dos, Jorge Matheus Caneles Batista, Magosso Beatriz Feltrin, Pizzatto Mariana, Souza Adilson Pacheco de
Institute of Agrarian and Environmental Sciences, Federal University of Mato Grosso, Sinop 78550-728, MT, Brazil.
Postgraduate Program in Agronomy, Federal University of Mato Grosso, Sinop 78550-728, MT, Brazil.
Plants (Basel). 2024 Oct 11;13(20):2850. doi: 10.3390/plants13202850.
In general, young plants in the establishment phase demonstrate sensitivity to changes in environmental conditions, especially regarding water availability. The effects of the seasonality of biophysical processes on plant physiology can trigger differential responses, even within the same region, making it necessary to conduct studies that characterize the physiological performance of the species at different spatial and temporal scales, making it possible to understand their needs and growth limits under water stress conditions. This paper aimed to evaluate the growth, gas exchange and fluorescence in ipê-rosa seedlings subjected to levels of water replacement (LWRs) of 100, 75, 50 and 25% in a greenhouse. The morphometric variables of plant height, diameter at stem height, numbers of leaves and leaflets, root length and volume, plant dry mass and leaf area were evaluated. The potential evapotranspiration of seedlings (ETc) was obtained using direct weighing, considering the water replacement of 100% of the mass variation between subsequent days as a reference; the cultivation coefficients (kc) were obtained using the ratio between ETc and the reference evapotranspiration (ETo) obtained by the Penman-Monteith FAO-56 method. Biomass and evapotranspiration data were combined to determine water sensitivity. Diurnal fluxes of gas exchange (net photosynthesis rate, transpiration rate, stomatal conductance, internal and atmospheric carbon ratio, water use efficiency and leaf temperature) and fluorescence (Fv/Fm, Φ, ETR, Fv'/Fm', NPQ and qL) were evaluated. Water restriction caused reductions of 90.9 and 84.7% in the increase in height and diameter of seedlings subjected to 25% water replacement when compared to seedlings with 100% water replacement. In comparison, biomass accumulation was reduced by 96.9%. The kc values increased throughout the seedling production cycle, ranging from 0.59 to 2.86. Maximum water sensitivity occurred at 50% water replacement, with Ky = 1.62. Maximum carbon assimilation rates occurred in the morning, ranging from 6.11 to 12.50 µmol m s. Ipê-rosa seedlings regulate the physiology of growth, gas exchange and fluorescence depending on the amount of water available, and only 25% of the water replacement in the substrate allows the seedlings to survive.
一般来说，处于定植阶段的幼苗对环境条件变化表现出敏感性，尤其是在水分供应方面。生物物理过程的季节性对植物生理的影响会引发不同的反应，即使在同一地区也是如此，因此有必要开展研究，在不同的空间和时间尺度上表征物种的生理性能，以便了解它们在水分胁迫条件下的需求和生长极限。本文旨在评估在温室中，经受100%、75%、50%和25%水分替代水平（LWRs）的粉花山扁豆幼苗的生长、气体交换和荧光情况。评估了株高、茎高直径、叶片和小叶数量、根长和根体积、植株干质量和叶面积等形态学变量。通过直接称重获得幼苗的潜在蒸散量（ETc），将后续几天之间100%质量变化的水分替代量作为参考；利用ETc与通过Penman-Monteith FAO-56方法获得的参考蒸散量（ETo）的比值来获得作物系数（kc）。结合生物量和蒸散数据来确定水分敏感性。评估了气体交换的日通量（净光合速率、蒸腾速率、气孔导度、内部与大气碳比、水分利用效率和叶片温度）和荧光（Fv/Fm、Φ、ETR、Fv'/Fm'、NPQ和qL）。与100%水分替代的幼苗相比，水分限制使25%水分替代的幼苗株高和直径增加量分别减少了90.9%和84.7%。相比之下，生物量积累减少了96.9%。kc值在整个幼苗生产周期中增加，范围为0.59至2.86。最大水分敏感性出现在50%水分替代时，Ky = 1.62。最大碳同化速率出现在早晨，范围为6.11至12.50 μmol m s。粉花山扁豆幼苗根据可用水量调节生长、气体交换和荧光的生理过程，并且基质中仅25%的水分替代量就能使幼苗存活。
