Effect of Salinity and Potassium on Phytomass and Quality of Guava Rootstocks

Abstract

Potassium fertilization is one of the main techniques that has been studied to mitigateeffects of salt stress in plants, probably because potassium reduces the toxic effect of sodium by competitive inhibition and provides greater tolerance to genotypes of plants to salinity. Hence, this study aimed to evaluate the effect of different salinities of irrigation water in the formation of phytomass and quality of rootstocks of guava cv. Paluma, fertilized with increasing doses of potassium, in an experiment conducted using eutrophic Fluvic Neosol with sandy loam texture under greenhouse conditions, in the municipality of Pombal-PB, Brazil. The experimental design was randomized blocks in 5 × 4 factorial scheme, and the treatments resulted from the combination of five levels of irrigation water electrical conductivity (ECw = 0.3; 1.1; 1.9; 2.7 and 3.5 dS m-1) and four K doses (70, 100, 130 and 160% of K), in which the dose of 100% K corresponded to 726 mg of K dm-3 of substrate, with four replicates and two plants evaluated in each plot. Irrigation with water salinity from 0.3 dS m-1 compromises the total dry matter accumulation and the Dickson quality index of guava rootstocks cv. Paluma at 225 days after emergence (DAE), independent of potassium fertilization. Fertilization with different potassium doses did not promote differences in phytomasses and quality of rootstocks. There was no significant effect of interaction (salt × doses of K) on the studied variables.

Crescimento e Eficiência Fotoquímica em Mudas de Maracujazeiro Submetidas em Níveis de Salinidade e Adubação Foliar

“…Nota-se que o aumento das doses acima do citado proporcionou quedas no crescimento em altura e diâmetro do caule, indicando que acima das doses ótimas para a planta o B C D aumento do fornecimento de nutrientes, podem proporcionar distúrbios nutricionais nas plantas de maracujá (LOPES et al, 2017). Corroborando com Bonifácio et al (2018), que constataram redução no crescimento de porta-enxertos de goiabeira (Psidium guajava L.) em função de doses elevadas de nitrato de potássio e Alvarenga et al (2019) em aceroleira (Malpighia emarginata DC), em que se observaram que a interação entre as doses de N e K aumentaram a pressão osmótica do solo, resultando na redução do diâmetro do caule das plantas.…”

Salt tolerance of Soft and Hard jackfruit varieties in the seedling stage

“…In addition, the absorption of toxic ions, especially chloride and sodium, compromises the synthesis and translocation of hormones between roots and shoots, resulting in reduced leaf area, since these are essential for cell metabolism and, consequently, reduced plant dry matter (Parihar et al, 2015;Machado and Serralheiro, 2017;Sheldon et al, 2017). This also reduces specific leaf area, in addition to inhibition of root system growth, delay in apical buds emission, chlorosis, and leaf edges necrosis (Bonifácio et al, 2018;Wani et al, 2020). The LAR of jackfruit seedlings was high regardless of the genetic material, with higher values for var.…”

“…Soft under higher saline indicates greater photosynthetic efficiency than the var. Hard since there was greater efficiency use of the photosynthetically active leaf area in the biomass synthesis under these conditions (Freitas et al, 2014;Bonifácio et al, 2018).…”

“…High DQI values indicate that the robustness and distribution of plant biomass is adequate, increasing the possibility of seedlings surviving in the field after transplanting (Bonifácio et al, 2018). Saline irrigation water is one of the main causes of quality loss in seedlings (Oliveira et al, 2017) due to osmotic, toxic, and/or nutritional effects caused by salt stress, limiting vital processes, such as nitrogen assimilation and protein metabolism (Parihar et al, 2015;Ahmadi and Souri, 2018;).…”

“…In conditions of prolonged stress, plants absorb toxic ions, mainly sodium and chlorine, causing visual toxicity symptoms of chlorosis and leaf necrosis (Ashraf and Orooj, 2006;Acosta-Motos et al, 2017;Machado and Serralheiro, 2017). Under these conditions, fruit species have their growth and yield compromised (Bonifácio et al, 2018). Despite the adverse effects of salinity on plants, there is scientific evidence of genetic variability of species in lower or higher tolerance to salinity due to morphophysiological defense mechanisms (Ayers and Westcot, 1999;Freitas et al, 2014).…”