The effect of seed conditioning, short-term heat shock and salicylic, jasmonic acid or brasinolide on sunflower (Helianthus annuus L.) chilling resistance and polysome formation

Abstract

The aim of this study was to develop the method for increasing resistance of sunflower seedlings 'Wielkopolski' to chilling. Seeds were conditioned at 25°C for 2 days in water to 15, 20 and 25 % moisture content or in salicylic or jasmonic acid in concentration of 10 -2 ; 10 -3 and 10 -4 M or brassinolide in concentration of 10 -6 ; 10 -8 and 10 -10 -15 % moisture content. After 2 days of incubation the conditioned seeds were heat shocked at 45°C for 0, 30, 60, 120 and 240 min and 5 mm seedlings were exposed to chilling at 0°C for 21 days. The effectiveness of the methods was assessed by evaluation of roots growth in Phytotoxkit Microbiotest, changes in the activity of dehydrogenases, the integrity of the cytoplasmic membrane and formation of polysomes after seedling were returned to 25°C for 72 h. Seeds were conditioned at 25°C for 2 days in water to 15 % moisture content and then heat shocked at 45°C for 2 h decreased chilling injury of seedlings expressed by subsequent growth of the roots, electrolyte leakage, dehydrogenases activity and polysomes formation. Application of heat shock of 45°C for 2 h during seed conditioning additionally provided seedling protection against subsequent chilling conditions. Brasinolide, salicylic acid or jasmonic acid applied during seeds conditioning exhibited further beneficial effect on seedling resistance to chilling. The most pronounced effect was obtained due to seed conditioning to 15 % moisture content in solutions of brassinolide in concentration of 10 -8 M. After 2 days of imbibition treated in this way seeds were exposed to heat shock at 45°C for 2 h. The role of physiological events in improvement of sunflower chilling tolerance are discussed.

Application of phytohormones during seed hydropriming and heat shock treatment on sunflower (Helianthus annuus L.) chilling resistance and changes in soluble carbohydrates

“…These species are classified as chilling-sensitive plants (IshizakiNishizawa et al 1996). Sunflower seedlings subjected to prolonged low temperatures exposure exhibited chilling injures manifested by inhibition of roots growth, longer mean emergence time and root damages expressed by external root discoloration as well as lower activities of dehydrogenases (Górnik et al 2014). Hewezi et al (2006) on the basis of an initial characterization of the transcriptome activity also found sunflower as a chilling-sensitive plant under suboptimal temperatures.…”

“…The presented picture were took after 72 h of recovery (25°C) from chilling stress chilling. Our previous results have proved that heat shock applied earlier, before radicles protruded seed coat, may provide beneficial effects on chilling tolerance (Górnik et al 2014). Hydropriming belongs to priming/conditioning techniques which uses only water in the process of controlled seed imbibitions (Grzesik and Nowak 1998).…”

“…Brassinosteroids are the plant steroids which have been implicated in protecting plants from various types of stresses like chilling, heat, drought, salt, heat and heavy metals (Górnik et al 2014). Salicylic acid (SA), a stress-related signaling compound, may directly or indirectly mediate local and systemic defense responses against pathogens and play a role in plant responses to abiotic stresses including drought, low and high temperatures, heavy metals, and osmotic stress (Janda et al 2014).…”

Functions of Jasmonic Acid in Plant Regulation and Response to Abiotic Stress

“…It also plays an important role in the plant response to adverse environmental conditions such as cold [96][97][98], drought [99], salinity [43] and light [100]. Górnik et al [96] reported that treatment of seeds with SA or JA could improve the resistance of seedlings to chilling, while Ilyas et al [97] demonstrated that exogenous application of SA and JA could enhance drought stress tolerance in wheat, although JA was more effective than SA. However, the combined application of SA and JA did not significantly influence plant growth.…”

Seed enhancement: getting seeds restoration‐ready

“…ABA ), or plant protective compounds (e.g. salicylic acid, fungicides) can be used to improve seed germination of dormant species, control germination timing to optimize recruitment, and protect seeds from biotic and abiotic stresses (Carrow & Duncan ; Górnik et al ; Badrakh ; Erickson et al ; Call ).…”