Effects of potassium in Myracrodruon urundeuva, Libidibia ferrea and Mimosa tenuiflora seedlings under a short-term water déficit

Abstract

This study aimed to evaluate the effects of potassium fertilization on Myracrodruon urundeuva, Libidibia ferrea and Mimosa tenuiflora seedlings submitted to a short period of water deficit. Three doses of K (0, 150 and 300 mg dm-3 KCl) and three water regimes (without water deficit, moderate water deficit and severe water deficit) were evaluated. The plants were kept in black plastic bags containing soil from the Caatinga and, 30 days after the beginning of the water regimes, the relative water content (RWC), transpiration (E), stomatal conductance (gs) and photosynthesis (A) were evaluated. High moisture content in the soil was unfavorable to plants, promoting reduction in RWC and gas exchange. The water deficit increase E, gs and A, but the intensity of these responses was variable between species. The water deficit favored L. ferrea, with elevated RWC and reduced alterations in gas exchange, demonstrating its greater tolerance in relation to the others species evaluated, however it was the species most benefited by K. The supply of 300 mg dm-3 of KCl positively influenced the water status and gas exchange of the studied species with an increase in the water deficit. We suggest the development of research subjecting the plants to a longer period of time, in order to establish a better relationship between potassium and the increased tolerance of these plants to water deficit.

Gas Exchange of Oiticica Seedlings in Response to Potassium Fertilization and Water Turning

“…). Similar results were obtained in Mimosa tenuiflora, when submitted to 100% and 25% of vessel capacity (cv), in which the gs reduced with the increase of the amount of K [22]. In contrast, Costa, Carvalho and Pinto [29] reported that the highest dose of potassium contributed to greater stomatal conductance, adding that it provided a greater balance between the turgor of the guard cells and the control of the osmotic potential of the plant.…”

“…With this, the plant guarantees the maintenance of an adequate state of hydration and, consequently, of activities vital to its growth. Stomatal closure due to water deficit was also reported by Albuquerque et al [33], França et al [34], Campelo et al [35] and Almeida et al [22], among others. The increase in water turning and consequent decrease in soil moisture content may have resulted in the production of abscisic acid (ABA) in the roots and its transport to the leaves, resulting in the closing of the stomata [36,37].…”

“…Reduction in RWC due to water deficit has been reported in other studies [19,20,21,22]. However, in aroeira (Myracrodruon urundeuva Fr.…”

“…Allem) and jucá (Libidibia ferrea (Mart. ex Tul) under moderate and severe water deficits, Almeida et al [22] found an increase in RWC when they supplied potassium to the plants. Presented by plants, when supplied with K, demonstrates its ability to provide drought tolerance, helping to carry out photosynthesis and transport carbohydrates from leaves to roots [23], and the osmotic effect exerted on plants.…”

O potássio atenua os efeitos do déficit hídrico em mudas de pereiro (Aspidosperma pyrifolium Mart. & Zucc.)

“…CT: controle; EM: déficit hídrico moderado; ES: déficit hídrico severo.O comportamento da fotossíntese é reflexo dos efetios verificados na condutância estomática (Tabela 1) e transpiração (Tabela 2), com reduções à medida que o déficit hídrico se acentuou, independentemente da quantidade de K fornecida, e aumento com a elevação na dose desse nutriente, além do efeito positivo da interação entre os tratamentos 50%cp x 100 mg dm 3 K.Reduções na condutância estomática, taxa de transpiração e de fotossíntese devido o déficit hídrico têm sido relatadas em diversas espécies, a exemplo de Tabebuia aurea (OLIVEIRA, GUALTIERI e BOCCHESE, 2011), Khaya ivorensis A. Chev (ALBUQUERQUE et al, 2013),. Myracrodruon urundeuva(ALMEIDA et al, 2020), Handroanthus impetiginosus(DOMBROSKI et al, 2014; PESSOA, FREIRE e COSTA, 2017), Mimosa tenuifloraALMEIDA et al, 2020) e Cnidoscolus phyllacanthus (RAMOS; FREIRE, 2019), sendo que a resposta variou com a espécie estudada, bem como com a intensidade do estresse hídrico imposto.…”