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

• Published in: Pesquisa agropecuária tropical Vol. 48; no. 2; pp. 190 - 199
• Main Authors: Andrade, Francisco Hélio Alves de, Pereira, Walter Esfrain, Morais, Rafael Ramos, Silva, Anselmo Ferreira da, Barbosa Neto, Miguel Avelino
• Format: Journal Article
• Language: English; Portuguese
• Published: Goiânia Universidade Federal de Goiás - Escola de Agronomia e Engenharia de Alimentos 01.04.2018; Escola de Agronomia/UFG; Universidade Federal de Goiás
• Subjects: AGRICULTURE, MULTIDISCIPLINARY; AGRONOMY; Annona squamosa L; Apples; Attenuation; Calcium ions; Design of experiments; Electrical conductivity; Electrical resistivity; Experimental design; Irrigation; Irrigation water; Leaves; Metabolic disorders; Phosphorus; Saline water; Salts; seedling production; Seedlings; Substrates; Sugar; triple superphosphate; Annona squamosa L; seedling production; produção de mudas; superfosfato triplo; triple superphosphate
• ISSN: 1517-6398; 1983-4063; 1983-4063
• DOI: 10.1590/1983-40632018v4852035

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. RESUMO A salinidade da água de irrigação interfere no crescimento de plantas de pinheira. Relatos indicam que o fósforo interfere no crescimento das plantas, com efeitos positivos na atenuação dos sais. Objetivou-se avaliar os efeitos da condutividade elétrica da água de irrigação (CEai) e doses de superfosfato triplo (SFT), no crescimento e teores foliares de mudas de pinheira (Annona squamosa L.). O experimento foi realizado em ambiente protegido, em delineamento experimental de blocos casualizados, com nove tratamentos, combinando-se doses de fósforo (0,00 g dm-3; 1,10 g dm-3; 3.00 g dm-3; 5,13 g dm-3; e 6.00 g dm-3 de SFT) e condutividade elétrica da água de irrigação (0,50 dS m-1; 1,10 dS m-1; 2,50 dS m-1; 3,91 dS m-1; e 4,50 dS m-1), no crescimento e teores foliares de Na+, K+, Ca+2 e P, em mudas de pinheira. As plantas apresentaram curva crescente de diâmetro caulinar com o aumento do SFT, porém, à medida que aumentou-se a CEai, houve efeito negativo para esta variável. O SFT influenciou positivamente na altura das plantas (2,02 g dm-2/14,50 cm), massa seca (1,25 g dm-2/0,90 g) e massa seca total (2,32 g dm-2/2,00 g). Com o aumento da CEai, houve incremento nos valores de Na+ (16,20 mg g-1), bem como na razão Na+/K+ (1,48 mg g-1), que ocasionam distúrbios metabólicos no meio celular. Doses de SFT melhoram o crescimento das mudas, não sendo fitotóxico; porém, aliados à CEai, reduzem o conteúdo de K+ em plantas de pinheira.