The effects of putrescine pre‐treatment on osmotic stress responses in drought‐tolerant and drought‐sensitive wheat seedlings

Abstract

Recent studies have demonstrated that exogenous polyamines have protective effects under various stress condition. A broader understanding of the role of the polyamine pool fine regulation and the alterations of polyamine‐related physiological processes could be obtained by comparing the stress effects in different genotypes. In this study, the impact of pre‐treatment with putrescine in response to osmotic stress was investigated in the drought‐tolerant Katya and drought‐sensitive Zora wheat (Triticum aestivum) cultivars. Photosynthetic performance, in vivo thermoluminescence emission from leaves, leaf temperature, polyamine and salicylic acid levels, contents of osmoprotectants, and activities of antioxidant enzymes in the leaves were investigated not only to reveal differences in the physiological processes associated to drought tolerance, but to highlight the modulating strategies of polyamine metabolism between a drought‐tolerant and a drought‐sensitive wheat genotype. Results showed that the tolerance of Katya under osmotic stress conditions was characterized by higher photosynthetic ability, stable charge separation across the thylakoid membrane in photosystem II, higher proline accumulation and antioxidant activity. Thermoluminescence also revealed differences between the two varieties − a downshift of the B band and an increase of the afterglow band under osmotic stress in Zora, providing original complementary information to leaf photosynthesis. Katya variety exhibited higher constitutive levels of the signaling molecules putrescine and salicylic acid compared to the sensitive Zora. However, responses to exogenous putrescine were more advantageous for the sensitive variety under PEG treatment, which may be in relation with the decreased catabolism of polyamines, suggesting the increased need for polyamine under stress conditions.

PAs Regulate Early Somatic Embryo Development by Changing the Gene Expression Level and the Hormonal Balance in Dimocarpus longan Lour.

“…Previous studies have shown that treatment with the same concentration of different PA compounds may have either positive or negative effects, depending on the PA applied (Put, Spd or Spm), on the mode of PA treatment, on the investigated plant species and on the stress factor, suggesting that “the more PA the better” is not always true [ 48 , 49 , 50 , 51 , 52 ]. Our research results showed that the period between the 9th and 11th days was key for the transformation of EC into GE, in which Put and Spm treatment promoted the transformation, while Spd treatment inhibited it in the early stage, and D-arg, as an inhibitor of PA biosynthesis, also inhibited this process.…”

Exogenous Putrescine Alleviates Drought Stress by Altering Reactive Oxygen Species Scavenging and Biosynthesis of Polyamines in the Seedlings of Cabernet Sauvignon

“…Identifying measures to alleviate drought stress in grapevine is an urgent concern for both grape growers and wine producers. PAs play diverse roles in responses to drought stress stimulation in plants ( Zhang et al, 2018 ; Doneva et al, 2021 ). The effect of exogenously applied Put and its drought tolerance mechanisms were investigated and confirmed in the current as well as the previous study, where the PAs and redox homeostasis mitigated environmental stresses ( Li et al, 2018 ).…”

Response of Some Agronomic, Physiological and Anatomical characters for Some Bread Wheat Genotypes Under Water Deficit in North Delta Region

“…The lowest leaf temperature could be used as an indicator of plant water status and a possible mechanism of stress avoidance. The lowering leaf temperatures could be due to an increased root suction power, allowing plants to absorb water and transpire it, thereby cooling their leaves (El-Gammaal, 2018, Doneva et al, 2021and Takashima et al, 2021. Similar results were reported by Zada et al ( 2020) who stated that drought stress condition considerably reduced the leaf potential and relative water content and transpiration rate with an associated raised in leaf temperature.…”