Improving Chilling Tolerance of Maize Seedlings under Cold Conditions by Spermine Application

Abstract

Low temperature is an important abiotic stress which reduces crops growth and productivity and causes physiological damages to cellular structures. The aim of this study was to investigate the probability of spermine application to improve chilling tolerance of maize under stress conditions. The treatments were included seed priming with spermine (30, 60 and 90 mg/l solutions) and normal and stress condition. Seed emergence was improved by spermine priming on both conditions and mean emergence time (MET) was also decreased with priming. Shoot and root length was highly reduced under stress conditions, but the treated seeds were improved along with increased spermine concentration. Seedling dry weight was also affected by priming and reduced weight of stressful seedlings was alleviated by spermine priming. Decreased relative water content on seedlings under stress was elevated by the treatments and significantly increased. Electrolyte leakage was also recovered by applied treatments while it was adversely decreased on cold conditions. Antioxidative system was highly responded to spermine application. Superoxide dismutase (SOD) activity increased on both normal and stress conditions, but a little decrease was observed on seedlings treated with 90 ppm level and under chilling conditions. Catalase activity was also amplified by spermine treatments. Priming had a great effect on ascorbate peroxidase (APX) activity on both stressful and normal seedlings and increased it compare with non treated seedlings. It is also important to note that with increasing spermine concentration to 90 ppm, no considerable differences were observed. Thus, 60 ppm concentration could be proposed as the appropriate level of spermine in order to improve chilling tolerance of maize seedlings.

Micronutrients (Zn/Mn), seaweed extracts, and plant growth-promoting bacteria as cold-stress protectants in maize

“…Reduced shoot and root growth of maize plants exposed to low temperatures has been attributed to severe oxidative damage induced by cold stress [13,29]. The different isoforms of SO as key enzyme for detoxification of free radicals, strongly depend on Zn, Mn, Cu, and Fe as cofactors and have been implicated in chilling tolerance of higher plants [29].…”

“…Under favorable conditions, short cold periods can be tolerated and later compensated during plant development until final harvest. However, longer stress periods can easily induce irreversible damage already in the seedling stage [13].…”

Effect of seed priming on seed vigor and early seedling growth in maize under optimal and suboptimal temperature conditions

“…The negative effects of suboptimal temperature on maize germination parameters and early seedling growth has been previously reported. Saeidnejad et al (2012) showed that low temperature decreased maize seed germination parameters, seedling emergence and growth. Low temperature had deleterious effect on membrane stability, relative water content, starch metabolism and antioxidant activities (Farooq et al, 2008a).…”

Seed treatment with Penicillium sp. or Mn/Zn can alleviate the negative effects of cold stress in maize grown in soils dependent on soil fertility

“…It is well known that cold stress can reduce shoot and root growth of maize plants due to oxidative damage (Saeidnejad, Pouramir, & Naghizadeh, ). A clear reduction in growth of maize under cold stress was observed for both soils in this experiment (Figure ).…”