Effects of potassium application and soil moisture on the growth of Corymbia citriodora plants

Abstract

ABSTRACT:The objective of this work was to evaluate the effects of potassium and soil moisture levels on the growth of Corymbia citriodora plants. Four doses of potassium were applied (0, 40, 80 and 120 mg . dm -3 ) and three soil moisture levels were established (50-80%, 65-80% and 80% of maximum soil field capacity). The experiment was a 4 x 3 factorial arrangement of treatments within a randomized complete design with six replications for each treatment and one pot with two plants for each plot. At 90 days after planting, the plant growth parameters: survival rate, height, stem diameter, leaf area, relative chlorophyll concentration, leaf dry mass, stem and branches dry mass, root dry mass, total dry mass and leaf macronutrient contents were measured. High soil moisture content is necessary for Corymbia citriodora seedlings at nursery stage. Effects of the K doses were not observed in plants, even when they were cultivated in a soil with a low content of this nutrient. EFEITOS DA APLICAÇÃO DE POTÁSSIO E UMIDADES DO SOLO NO CRESCIMENTO DE PLANTAS DE Corymbia citriodora RESUMO:Conduziu-se este trabalho, com o objetivo de avaliar os efeitos de doses de potássio e umidades do solo no crescimento de plantas de Corymbia citriodora. Foram aplicadas quatro doses de potássio (0, 40, 80, e 120 mg . dm -3 ) e promovidas três níveis de umidades do solo (50-80%, 65-80% e 80% do volume máximo de água retido pelo solo em vaso), combinadas em um esquema fatorial 4x3. O delineamento experimental foi inteiramente casualizado com seis repetições, e cada parcela foi composta por um vaso contendo duas plantas. Aos 90 dias após o plantio, foram avaliados: porcentagem de sobrevivência, altura, diâmetro do caule, área foliar, teor relativo de clorofila, massa de matéria seca de folhas, de caule e ramos, de raízes e total, e teor de macronutrientes nas folhas. Mudas de Corymbia citriodora necessitam de alta umidade do solo na fase de viveiro. Não foram observados efeitos das doses de potássio nas plantas, mesmo quando a concentração desse nutriente no solo era baixa.

Growth and physiological responses of cotton plants to salt stress

“…In accordance with this, here the RWC, Ψ 1 and k leaf of cotton plants were significantly reduced by salt stress (Figure 7). Reports have indicated that higher shoot K + concentration and optimum K + /Na + ratio exert pivotal role in adjusting osmotic potential and turgor pressure of guard cells during stomatal movement, thus affecting transpiration rate and hydraulic conductance (Sa et al, 2014;Wang et al, 2013). In the present study, 150 mM NaCl salinity significantly decreased [K + ] leaf and [K + /Na + ] leaf of cotton plants (Figure 6b,c), indicating that salinity-induced decreased in RWC, Ψ 1 and k leaf could be associated with the reduction of [K + ] leaf and [K + / Na + ] leaf .…”

Cell damage, gas exchange, and growth of Annona squamosa L. under saline water irrigation and potassium fertilization

“…The relative water content of custard apple plants also increased linearly in response to potassium fertilization, and according to the regression equation (Figure 1B), there was an increase of 2.196% for each 5 g increment in K 2 O dose. Plants subjected to fertilization with a higher potassium dose (30 g per plant) increased their RWC by 10.74% compared to those receiving the K 2 O dose of 10 g. Potassium supply contributed to osmotic adjustment in plants under low water availability because excess salt in water reduces the water potential (A. F. L. de Sá et al, 2014). Osmotic adjustment is an important characteristic associated with the maintenance of high cell turgor potential and water retention in response to salt stress, being fundamental for the survival of plants under salt stress conditions, highlighting the role of K + in the regulation of turgor within the guard cells during stomatal movement (Wang, Zheng, & Guo, 2013).…”

Metabolic and physiological alterations indicate that the tropical broadleaf tree Eugenia uniflora L. is sensitive to ozone

“…At the end of the exposure period, plant growth was assessed on all plants by measuring plant height, stem diameter (near the base) and total number of leaves. For measurements of height and stem diameter, a measuring tape and a digital caliper (data expressed in cm) (Digimess, São Paulo, Brazil) were used (Sá et al, 2014), respectively.…”