Vegetative development and content of calcium, potassium, and sodium in watermelon under salinity stress on organic substrates

Abstract

-The objective of this work was to evaluate the vegetative development and determine the concentration of sodium, potassium, and calcium in watermelon (Citrullus lanatus) grown on two organic substrates and under increasing saline concentrations. The substrates were soil + earthworm humus (S 1 ) and soil + bovine manure (S 2 ), and the saline treatments consisted of irrigation water with different electrical conductivities: 1.36 (control), 3.56, 5.76, and 7.96 dS m -1 . The experimental design used was a randomized complete block in a 2×4 (substrate × conductivity) factorial arrangement with five replicates. Main branch length, root length, stem diameter, leaf number, leaf area, and fresh matter mass of shoots and roots, as well as the sodium, potassium, and calcium contents in the plants, were determined. All phenological parameters interacted with the substrates, and S 1 improved plant performance. Substrates interacted significantly with: leaf area; leaf number; stem diameter; main branch length; root length; fresh matter mass of shoots and roots; and the contents of sodium, potassium, and calcium, in both shoots and roots of watermelon irrigated with saline water for up to 27 days after emergence. There are also interactions between substrates and salinity for stem diameter, main branch length, fresh matter mass of roots, and calcium contents in both shoots and roots, and potassium and sodium contents in the roots.Index terms: Citrullus lanatus, bovine manure, humus of earthworm, salt stress.Desenvolvimento vegetativo e conteúdo de cálcio, potássio e sódio em melancieira sob estresse salino, em substratos orgânicos . Utilizou-se o delineamento experimental de blocos ao acaso, em arranjo fatorial 2×4 (substratos × condutividade), com cinco repetições. Foram determinados comprimento do ramo principal e da raiz, diâmetro do caule, número de folhas, área foliar e massa fresca da parte aérea e da raiz, bem como o conteúdo de sódio, potássio e cálcio nas plantas. Todos os parâmetros fenológicos apresentaram interação com os substratos, e S 1 promoveu melhor desempenho das plantas. Os substratos interagiram significativamente com: área foliar; número de folhas; diâmetro do caule; comprimento do ramo principal; comprimento de raiz; massa de matéria fresca da parte aérea e da raiz; e teores de sódio, potássio e cálcio na parte aérea e nas raízes de melancieiras irrigadas com água salina, até 27 dias após a emergência. Os substratos também interagiram com a salinidade para diâmetro do caule, comprimento do ramo principal, massa de matéria fresca de raiz, e teores de cálcio na parte aérea e raiz, e de potássio e sódio na raiz.Termos para indexação: Citrullus lanatus, esterco bovino, húmus de minhoca, salinidade.

Effect of phosphorus application on substrate and use of saline water in sugar-apple seedlings

“…Consequently, the adoption of techniques that enable the use of this water is essential. Some producers use biofertilizers, perform substrate drainage and dilute the salt water to employ the hydric resources available to them (Mesquita et al 2015, Silva Júnior et al 2017.…”

“…According to Silva Júnior et al (2017), salinity reduces the osmotic potential, decreasing the availability of water in the soil, what compromises the crops yield. K + and Ca +2 interact positively during the development of several plant species, and one of the positive effects of these ions occurs under salt stress conditions (Diniz Neto et al 2014, Wu et al 2014.…”

Citrullus lanatus morphophysiological responses to the combination of salicylic acid and salinity stress

“…There is a diversity of literary works contemplating the effects of salinity on the cultivation of watermelon (Cheng et al, 2015;Sousa et al, 2016;Silva Júnior et al, 2017). These authors reported that salinity stress significantly affects the following variables: main branch length, stem diameter, leaf number, leaf area, root length, shoot dry mass, root dry mass, net CO 2 assimilation, transpiration rates, stomatal conductance and water use efficiency.…”

Initial development of watermelon in fuction of substrates and irrigation with saline water

“…The addition of organic matter to the substrate reduced the harmful effects on the melon (Cucumis melo L.) development under saline stress [10]. The use of humus in the substrate promoted high watermelon development under saline stress up to 27 days after emergence (DAS) [11].…”