Pré-condicionamento in vitro de plantas de cana-de-açúcar (Saccharum spp.) para tolerância ao estresse salino

Abstract

RESUMO Avaliou-se a capacidade de adaptação à salinidade de mudas de cana-de-açúcar da variedade RB98710 após pré-condicionamento (priming) in vitro com cloreto de sódio (NaCl). O experimento foi conduzido no período de maio a outubro de 2013. Plantas foram micropropagadas em biorreatores de imersão temporária, com tratamentos de priming caracterizados pela adição de 25 mM de NaCl, durante 0, 12, 24 e 36 horas. Concluídos os períodos de priming, as plantas foram cultivadas em meio de enraizamento sem NaCl, aclimatizadas e submetidas a tratamento salino gradativo: S0 = sem NaCl; S1 = regas com 20→40→60 mM de NaCl acrescido à solução nutritiva, durante 30 dias. Procedeu-se à supressão do NaCl e avaliaram-se as plantas 15 dias depois. As variáveis foram: matéria seca da parte aérea (MSPA) e radicular (MSR), número de perfilhos, estimativa de clorofila (Chl), conteúdo hídrico relativo e dano de membrana. As plantas pré-condicionadas não reduziram a MSPA quando submetidas ao NaCl. O efeito do estresse salino sobre a MSR foi anulado nas plantas submetidas ao priming por 24 h. O priming favoreceu o perfilhamento das plantas dos tratamentos por 24 ou 36 h. A recuperação após o estresse, avaliado 15 dias após a supressão do NaCl, não diferiu entre plantas submetidas ou não ao priming. De acordo com os resultados, o priming utilizado na variedade RB98710, pode favorecer a tolerância à salinidade.

Effect of <i>seed priming</i> with NaCl on the induction of salinity tolerance in <i>Myracrodruon urundeuva</i> Allemão <i>in vitro</i>

“…The authors emphasized the increase in biomass production, decrease in membrane damage, electrolyte leakage, and increase in leaf area. Preconditioning with NaCl favored the maintenance of biomass production in sugarcane plants and induction of tolerance when they were exposed to salinity(MELO et al, 2014).In the case of M. urundeuva in the present research, the excess of salts was not favorable to the accumulation of fresh root biomass, which is probably linked to the osmotic effect of the saline media solutions, caused by the decrease in the free energy of water, directly influencing the cellular water status (AMANIFAR; TOGHRANEGAR, 2020). Despite the eliciting effect of the H 2 O 2 in attenuating the harmful effects of salinity, a decrease in seedling growth of M. urundeuva under salinity conditions was observed(RODRIGUES et al, 2020) The seedlings from the seed priming treatment kept the mean leaves number (LN) similar regardless of the saline concentration (Figure| Effect of seed priming with NaCl ... 2208…”

Genotypic variation of sugarcane for salinity tolerance: Morphological and physiological responses

“…Thus, the deleterious effects of salinity will be observed at the last level, as noted for some cultivars. A study by Melo et al (2014) indicate that the pre-conditioning of plants for 24 -36 hours in 25 mM NaCl prevented the reduction of plant growth for the cultivar RB98710 when subjected to gradual salt stress up to 60 days, which could be an interesting line of research.…”

“…is considered an important agricultural commodity (Picoli;Machado, 2021) and the interest in this culture has increased because of its importance in the production of renewable energy (Hammer;Sentelhas;Mariano, 2020;Walter et al, 2014). However, it is classified as glycophyte and moderately sensitive to salt stress (Melo et al, 2014). Its cultivation has been expanding to semiarid regions (Begcy et al, 2019), and the success of this expansion depends, in part, on the cultivars that tolerate the adverse conditions of those places such as salinity.…”