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

Francisco Hélio Alves De Andrade,Rafael Ramos Morais,Miguel Avelino Barbosa Neto,Anselmo Ferreira Da Silva,Walter Esfrain Pereira

doi:10.1590/1983-40632018v4852035

Francisco Hélio Alves De Andrade, Rafael Ramos Morais + Show 3 more

Open Access

https://doi.org/10.1590/1983-40632018v4852035

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Abstract

ABSTRACT The irrigation with saline water affects the growth of sugar-apple plants. Some reports indicate that phosphorus affects the plants growth, with positive effects on the salts attenuation. This study aimed to assess the effects of the irrigation water electrical conductivity (iwEC) levels and triple superphosphate (TSP) doses in the growth and leaf levels of sugar-apple seedlings (Annona squamosa L.). The experiment was conducted in a protected environment, in an experimental design of randomized block, with nine treatments that combined phosphorus doses (0.00 g dm-1, 1.10 g dm-1, 3.00 g dm-1, 5.13 g dm-1 and 6.00 g dm-1 of TSP) with irrigation water electrical conductivity (0.50 dS m-1, 1.10 dS m-1, 2.50 dS m-1, 3.91 dS m-1 and 4.50 dS m-1), to evaluate the growth and leaf levels of Na+, K+, Ca+2 and P of sugar-apple seedlings. The increased curve for stem diameter presented by plants was proportional to the amount of TSP. Nevertheless, the iwEC levels were inversely proportional to this variable. The use of TSP directly affected the plant height (2.02 g dm-2/14.50 cm), dry mass (1.25 g dm-2/0.90 g) and total dry mass (2.32 g dm-2/2.00 g). The increase in the iwEC levels was directly proportional to the Na+ values (16.20 mg g-1), as well as to the Na+/K+ ratio (1.48 mg g-1), which cause metabolic disorders in the cellular environment. The TSP doses improve the seedlings growth, proving to be not phytotoxic; however, in combination with the iwEC, they reduce the amount of K+ in sugar-apple seedlings.

Highlights

The sugar-apple tree (Annona squamosa L.), known as sweetsop tree, belongs to theAnnonaceae family
The greatest diameter of 3.93 mm corresponded to the dosage of 0.125 g dm-3 of triple superphosphate (TSP) on the plants irrigated with a water sample of lower salinity, a sample of 0.5 irrigation water electrical conductivity (iwEC) (Figure 1a)
Sá et al (2015) reported that the stem diameter was inversely proportional to the salinity level, in sugar-apple seedlings. This reduction may be a response to the nutritional unbalance caused by the salt complex, and due to the specific ionic effect of Na+ and Cl, which are the components in greater proportion in all water samples used in the seedlings irrigation (Table 2) and which induced plant toxicity, even in plants with ascending P doses. Another important fact: the daily irrigation was greater in the treatments with more concentrated iwEC and TSP levels, since the build-up of salts in the substrate was inversely proportional to the water absorption, due to the greater concentration of solutes in the substrate

Summary

Introduction

The sugar-apple tree (Annona squamosa L.), known as sweetsop tree, belongs to theAnnonaceae family. According to León (1987), the sugar-apple tree originated from the lands of Central America, entered Mexico, and was introduced to the Middle East through the Philippines. From the Annonaceae trees, the sugar-apple and the soursop trees are the most important ones in the Northeastern Brazilian region. This region has the greatest producers of the country, especially in the states of Bahia, Pernambuco and Ceará, while, in the Southeast region, the greatest producing states are São Paulo and Minas Gerais (Lemos 2014). Effect of phosphorus application on substrate and use of saline water in sugar-apple seedlings

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