Tag Archives: Triticum aestivum

Indices of antioxidant and osmoprotective systems in seedlings of winter wheat cultivars with different frost resistance

T. O. Yastreb1, Yu. E. Kolupaev1,2*, A. I. Kokorev1, B. E. Маkaova2,
N. I. Ryabchun1, O. A. Zmiievska1, G. D. Pospielova2

1Yuriev Plant Production Institute, National Academy of Agrarian Sciences of Ukraine, Kharkiv;
2Poltava State Agrarian University, Ukraine;
*e-mail: plant_biology@ukr.net

Received: 02 January 2023; Revised: 27 January 2023;
Accepted: 13 April 2023; Available on-line:  27 April 2023

The functioning of the stress-protective systems of wheat under the action of cold at the early stages of plant development remains poorly studied. The aim of this work was a comparative study of antioxidant activity and the content of sugars and proline as indicators of osmoprotective activity during cold adaptation of seedlings of seven winter bread wheat (Triticum aestivum L.) cultivars that differ significantly in frost resistance. The 3-day-old etiolated seedlings were hardened at 2°C for 6 days and then frozen for 5 h at -6 or -9°C. Two days after freezing, the survival of seedlings was assessed by their ability to grow. A decrease in ROS content, an increase in the activity of antioxidant enzymes catalase and guaiacol peroxidase and accumulation of sugars in the shoots of high-frost-resistant cultivars during hardening were detected. The absolute values of catalase and guaiacol peroxidase activity correlated positively with the frost resistance of seedlings. The negative correlation between the frost tolerance of the cultivars and the accumulation of proline in the seedlings during hardening was recorded. The possibility of using the studied biochemical indices for frost resistance screening of winter wheat varieties at the seedling stage was stated.

Hydrogen peroxide as a signal mediator at inducing heat resistance in wheat seedlings by putrescine

Yu. E. Kolupaev1,2, A. I. Kokorev1, T. O. Yastreb1, E. I. Horielova1

1Dokuchaev Kharkiv National Agrarian University, Ukraine,
e-mail: plant_biology@ukr.net;
2Karazin Kharkiv National University, Ukraine

Received: 27 May 2019; Accepted: 18 October 2019

Polyamines are multifunctional stress metabolites of plants. However, information on the effect of exo­genous polyamines on plant resistance to high temperatures is contradictory, and it remains unclear which signal mediators are involved in the realization of their physiological effects. The possible involvement of hydrogen peroxide as a mediator under the action of exogenous diamine putrescine on the resistance of etiolated wheat seedlings (Triticum aestivum L.) to hyperthermia (10-minute heating at 46°C) and the functioning of antioxidant system was investigated. It was established that the treatment of seedlings with putrescine in 0.25–2.5 mM concentrations caused a significant increase in their heat resistance. In response to the putrescine effect, a transient increase in the H2O2 content occurred in the root cells. This effect was eliminated by treatment of seedlings with a diamine oxidase inhibitor aminoguanidine and an NADPH oxidase inhibitor imidazole. These inhibitors, as well as the scavenger of hydrogen peroxide dimethylthiourea (DMTU), mitigated the effects of increased heat resistance of seedlings and increased activity of superoxide dismutase and catalase caused by putrescine. Under the influence of DMTU and imidazole, but not aminoguanidine, the effect of increasing the activity of guaiacol peroxidase in the roots of seedlings treated with putrescine was eliminated. The conclusion was made about the role of hydrogen peroxide and the possible participation of diamine oxidase and NADPH oxidase in its formation during the implementation of the stress-protective effect of putrescine on wheat seedlings.

Phenylalanine ammonia-lyase activity and content of flavonoid compounds in wheat seedlings at the action of hypothermia and hydrogen sulfide donor

Yu. E. Kolupaev1,2, E. I. Horielova1, T. O. Yastreb1, Yu. V. Popov3, N. I. Ryabchun3

1Dokuchaev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@ukr.net;
2Karazin Kharkiv National University, Ukraine;
3Yuryev Рlant Production Institute, National Academy of Agrarian Sciences of Ukraine, Kharkiv

At present hydrogen sulfide (H2S) is considered as one of the signal mediators in plant cells. However, its role in formation of plant resistance to low temperatures and, in particular, in regulation of secondary metabolism under stress conditions remains poorly understood. The influence of H2S donor sodium hydrosulfide (NaHS) on phenylalanine ammonia-lyase (PAL) activity and content of flavonoids in wheat seedlings at normal temperature (21 °C) and under cold hardening conditions (7 days at 3 °C) was studied. After 2 days of the hardening temperature, a transient increase in PAL activity was noted. Also, activity of the enzyme was increased by treatment of plants with 0.1 or 0.5 mM NaHS under normal temperature conditions and especially at the background of cold hardening. By themselves, the cold hardening and the action of H2S donor caused an increase in total content of flavonoids and amount of anthocyanins. With the combination of hypothermia and treatment of seedlings with NaHS, this effect enlarged and the total content of flavonoids increased by 3.8, and anthocyanins increased by 1.8 times in comparison to the control. Treatment with the H2S donor caused a decrease in content of the lipid peroxidation product malonic dialdehyde in seedlings after the action of hardening temperature, and especially after their freezing at –5 °C. Also, under the influence of NaHS, survival of hardened and unhardened seedlings after cryostress increased. It was concluded that one of the mechanisms of the positive influence of the H2S donor on resistance of wheat seedlings to hypothermia is the PAL-dependent accumulation of flavonoid compounds, which have a high antioxidant activity, and a decrease in effects of secondary oxidative stress.