Hydropriming as inducer of salinity tolerance in sunflower seeds

Abstract

A B S T R A C TSunflower is a species with multiple potentialities and its yield can be affected by the presence of soluble salts in the soil, which is common in arid, semi-arid and irrigated regions. The objective of this study was to evaluate the effect of hydropriming as inducer of salinity tolerance in seeds and seedlings of sunflower, hybrid MG305CP. The germination tests were set with four replicates of 50 seeds per treatment, maintained in germinator at 30 ºC for ten days. To simulate salinity, sodium chloride diluted in distilled water was used at electrical conductivities of 0 (control), 4, 8, 12 and 16 dS m -1. On the tenth day, the number of normal seedlings was counted and the length and dry matter of shoots and roots were determined. Seedling fresh matter was used to determine the contents of total chlorophyll, total soluble sugars and proline. The experimental design was completely randomized, in a 2 x 5 factorial scheme (with and without hydropriming and five levels of salinity). Hydroprimed sunflower seeds showed greater vigor expression, with higher number of normal seedlings and faster germination.Hidrocondicionamento como indutor de tolerância à salinidade em sementes de girassol R E S U M O O girassol é uma espécie com múltiplas potencialidades, cuja produtividade pode ser afetada pela presença de sais solúveis no solo, fato comum em regiões áridas, semiáridas e irrigadas. Nesta pesquisa, objetivou-se avaliar o efeito do hidrocondicionamento como indutor de tolerância à salinidade em sementes e plântulas de girassol, híbrido MG305CP. Os testes de germinação foram instalados com quatro repetições de 50 sementes por tratamento, sendo mantidos em germinador a 30 ºC por dez dias. Para simular a salinidade, utilizou-se cloreto de sódio diluído em água destilada nas condutividades elétricas de 0 (controle); 4; 8; 12 e 16 dS m -1. No décimo dia, computou-se o número de plântulas normais, comprimento e massa seca de parte aérea e raiz. A partir da matéria fresca de plântulas foi determinado o teor de clorofila total, açúcar solúveis totais e prolina. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 2 x 5 (com e sem hidrocondicionamento e cinco níveis de salinidade). As sementes de girassol hidrocondicionadas apresentaram maior expressão de vigor com maior número de plântulas normais e germinação mais rápida.

Seed priming improves the germination and growth rate of melon seedlings under saline stress

“…This is because the seed priming can develop different defense mechanisms in seeds against salinity stress (IBRAHIM, 2016). Efficiency of seed priming with water or KNO 3 in improving root dry matter accumulation under stressful conditions was also reported in watermelon in eggplant (NASCIMENTO & LIMA, 2008), tomato (EBRAHIMI et al, 2014, and sunflower (MATIAS et al, 2018).…”

“…BATISTA et al 2015reported that both hydropriming and osmopriming improved germination and seed germination rate index of pepper seeds compared to unprimed seeds. Matias et al (2018) indicated that hydropriming improved tolerance of sunflower plants under saline environments. According to KUBALA et al (2005), the priming can improve germination rate through metabolic activation involving the synthesis of proteins, nucleic acids, and enzymes, and increasing water uptake, respiratory activity, and reserve mobilization.…”

“…Additionally, the osmotic potential of the external medium can affect the enzymatic reactions in the seed; therefore, the delay in germination is due to delay of enzymatic reactions (MARCOS-FILHO, 2015), caused by the break of the imbibition period. The most common responses of plants to the reduction of osmotic pressure are a delay in initial germination and a reduction in the rate and total germination (EBRAHIMI et al, 2014;OLIVEIRA & STEINER, 2017;MATIAS et al, 2018).…”

“…These authors argued that in stressful environmental conditions, such as in saline soils, the use of hydropriming techniques propitiates the maintenance of the viability and vigor of the seeds. Therefore, the hydropriming stands out for its practicality and requires low investments in reagents, compared with the other methods, besides avoiding interference of substances that are harmful to the seeds during soaking (MATIAS et al, 2018).…”

“…Among the strategies used to mitigate the salinity-induced adverse effects, the priming of seeds within organic salt solutions (osmopriming) or water (hydropriming) are cited as the most appropriate, efficient and economic techniques to enhance the rate and the uniformity of germination under saline conditions (SINGH et al, 2015;MATIAS et al, 2018). Research indicates that nitrate-containing compounds may function more efficiently than other salts as priming agents.…”