Hardening Pretreatment by Drought and Low Temperature Enhanced Chilling Stress Tolerance of Cucumber Seedlings

Abstract

Chilling stress is of major limiting factors influencing the growth and development of warm-season crops like cucumber. In this research, the possibility of chilling tolerance of cucumber seedlings was investigated through employing the drought and low-temperature pretreatments. The factorial experiment consisted of two factors including cucumber cultivars (i.e. ‘Super Dominos’ and ‘Super Star’) and hardening treatments (control, low temperatures at 10°C, and 15°C and drought simulated by 10% and 20% PEG) based on completely randomized design (CRD) in 3 replications. After applying treatments and providing them 48 h opportunity to be recovered, the seedlings were subjected to 3°C for a six-day period and 6 h for each day. All hardening treatments improved seedlings’ growth, chlorophyll content, total phenol (TP) and antioxidant enzyme activities, while reducing chilling injury index and malondialdehyde (MDA) content. Comparing to temperature hardening, the drought pretreatment showed to have a better effect on inducing the chilling tolerance into cultivars. Overall, the results of this experiment showed that employing drought and low-temperature pretreatments enabled cucumber seedlings to mitigate the harmful effects of chilling.

Effects of the Protein Hydrolysate Pretreatment on Cucumber Plants Exposed to Chilling Stress

“…Lower biometric parameters (Table 1), reduced leaf protein content (Table 2), and enhanced lipid peroxidation rate (Table 4) were indicators of this damage in cucumber plants exposed to chilling stress. ese results agree with earlier data on the effects of chilling stress on cucumber plants (Borowski, 2009;Ghanbari & Kordi, 2019;Shibaeva et al, 2018). In addition, our study demonstrated that the pretreatment of the cucumber plants with the biostimulant Naturamin WSP alleviated, to some extent, the negative effects of chilling stress on plant growth (Table 1) and affected several biochemical parameters (Table 2-Table 5).…”

“…Currently, two main approaches are used to increase the tolerance of cucumber plants to chilling stress: (i) graing on rootstocks from more chilling tolerant plant species such as pumpkin (Fu et al, 2021;Xu et al, 2017) and (ii) application of different products such as plant growth promoters, plant growth regulators, and biostimulants, with anti-stress properties (Borowski, 2009;Ghanbari & Kordi, 2019;Zhao et al, 2017).…”

Circular drought‐hardening confers drought tolerance via modulation of the antioxidant defense system, osmoregulation, and gene expression in tobacco

“…In this study, circular drought‐hardening treatments T2 and T3 improved the activities of the antioxidant enzyme, particularly POD, APX, and GR, thus conferring drought tolerance to the two tobacco varieties. The findings of this study in terms of enhanced drought‐hardening‐induced antioxidant enzyme activities (Figure 5) are in line with Wang et al (2020), Ghanbari and Kordi, (Ghanbari & Kordi 2019) and Zhang et al (2018). In conclusion, the results indicate that various circular drought‐hardening treatments in the two tobacco variety seedlings exhibit less cellular damage due to their greater ability to reduce the oxidative damage caused by MDA and ROS by improving the antioxidant enzyme activities.…”

Recent Advances in PGPR and Molecular Mechanisms Involved in Drought Stress Tolerance

“…Similarly, the specific enzyme activity of numerous ROS-quenching enzymes comprising APX, CAT, and SOD was found escalated in PGPR primed plants (48). A similar correlation of drought endurance and CAT profile was shown in cucumber (49) , maize (50), and wheat (51). However, some other studies focused on the assessment of enzymatic antioxidants to investigate the ROS damage that occurred during drought conditions.…”