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The effectiveness of exogenously applied zearalenone (ZEN) in alleviating water deficiency stress of pea (Pisum sativum L.) and yellow lupine (Lupinus luteus L.) was analyzed in the pot experiment. ZEN was applied in the form of spraying in the flowering phase on the first day of induced drought. The effectiveness of ZEN was evaluated based on physiological (electrolyte leakage, greenness, and photosystem II activity) and biochemical (protein, proline, ascorbic acid contents, and antioxidant enzyme activity) parameters after 14 days of drought. The yield and yield quality defined as yield components, total protein, fats, sugars, and antioxidants (tocopherols and β-carotene) were measured in newly formed seeds. ZEN residue in the seeds was analyzed employing UHPLC-MS/MS to exclude its accumulation. The results showed the possibility of reducing the effects of drought stress through the use of ZEN. It was manifested by increased cell membranes stability and antioxidant enzyme activity and above all ZEN increased crop yield, compared to untreated plants. ZEN modified seed composition by inducing the accumulation of fats and antioxidants. There was no accumulation of exogenous ZEN in seeds.

Ten doubled haploid (DH) lines of winter barley with an increased range of freezing/drought tolerance were used to identify phytohormones involved in plant stress acclimation. Cold hardening and drought stress were applied at the most critical stages of plant development on young seedlings and heading plants, respectively. The level of the phytohormones was significantly higher at heading, more than 5-fold in respect of salicylic acid (SA) and total brassinosteroids (BRs) and 1.7-fold in the case of abscisic acid (ABA). Moreover, the spectrum of detectable BRs increased from one—homocastasterone (HCS)—found in seedlings to four BRs identified in heading plants [HCS, castasterone (CS), teasterone and dolicholide], with the last one detected for the first time in cereal species. To some extent freezing tolerance seems to be determined by native hormonal status as control seedlings of tolerant DH lines contained 1.4- and 2.3-fold lower amount of ABA and HCS and 2.3-fold higher amount of SA in comparison to freezing-sensitive ones. Such dependency was not observed in heading plants as significant variation in CS content was the only detected difference. Under stress treatments, tolerant DH lines accumulated significantly lower (75–81%) amount of ABA, which probably reflected lower stress intensity resulting from another defence strategy. In contrast, stress-induced significant almost 2-fold increase in HCS/CS and 2–3-fold decrease in SA content specific for tolerant DH lines of barley suggest the involvement of these molecules in freezing/drought defence. Detected correlations suggest their interaction with nonspecific peroxidase and low molecular weight antioxidants.

5-Aminolevulinic acid relieves the effects of environmental stresses in plants. Therefore, the aim of our study was to evaluate the effects of 5-aminolevulinic acid (5-ALA) on the activity of the photosynthetic apparatus in spring wheat. Other analyzed parameters involved plant height, relative turgidity, membrane status, and chlorophyll level. The plant material consisted of three genotypes of spring wheat (J × Z, R × K, K × M), subjected to mild and severe drought in the early phase of vegetative development. 5-ALA showed a positive effect on the activity of the photosynthetic apparatus under water stress. The relieving action of 5-ALA on PSII was the most evident in J × Z genotype during severe soil drought. 5-ALA positively influenced the maximum photochemical efficiency of PSII (Fv/Fm), the overall performance index of PSII photochemistry (PI) and the effective quantum field of PSII (φEo). In the same genotype, the investigated acid stimulated light energy absorption (ABS/CSm), and enhanced the amount of excitation energy trapped in PSII reaction centers (TRo/CSm) and the amount of energy used for electron transport (ETo/CSm). Moreover, 5-aminolevulinic acid showed its potential to overcome the adverse effects of water deficit on Triticum aestivum L. by increasing plant growth, relative turgidity, and chlorophyll content and reducing the degree of damage to cell membranes at the early phase of vegetative development.

Soil drought is a major problem in plant cultivation. This is particularly true for thermophilic plants, such as maize, which grow in areas often affected by precipitation shortage. The problem may be alleviated using plant growth and development stimulators. Therefore, the aim of the study was to analyze the effects of 5-aminolevulinic acid (5-ALA), zearalenone (ZEN), triacontanol (TRIA) and silicon (Si) on water management and photosynthetic activity of maize under soil drought. The experiments covered three developmental stages: three leaves, stem elongation and heading. The impact of these substances applied during drought stress depended on the plant development stage. 5-ALA affected chlorophyll levels, gas exchange and photochemical activity of PSII. Similar effects were observed for ZEN, which additionally induced stem elongation and limited dehydration. Beneficial effects of TRIA were visible at the stage of three leaves and involved leaf hydration and plant growth. A silicon preparation applied at the same developmental stage triggered similar effects and additionally induced changes in chlorophyll levels. All the stimulators significantly affected transpiration intensity at the heading stage.

The present study aimed at identifying the regions of triticale genome responsible for cell wall saturation with phenolic compounds under drought stress during vegetative and generative growth. Moreover, the loci determining the activity of the photosynthetic apparatus, leaf water content (LWC) and osmotic potential (Ψ o) were identified, as leaf hydration and functioning of the photosynthetic apparatus under drought are associated with the content of cell wall-bound phenolics (CWPh). Compared with LWC and Ψ o, CWPh fluctuations were more strongly associated with changes in chlorophyll fluorescence. At the vegetative stage, CWPh fluctuations were due to the activity of three loci, of which only QCWPh.4B was also related to changes in F v/F m and ABS/CSm. In the other QTLs (QCWPh.6R.2 and QCWPh.6R.3), the genes of these loci determined also the changes in majority of chlorophyll fluorescence parameters. At the generative stage, the changes in CWPh in loci QCWPh.4B, QCWPh.3R and QCWPh.6R.1 corresponded to those in DIo/CSm. The locus QCWPh.6R.3, active at V stage, controlled majority of chlorophyll fluorescence parameters. This is the first study on mapping quantitative traits in triticale plants exposed to drought at different stages of development, and the first to present the loci for cell wall-bound phenolics.

The reasons for partial recovery after a soil drought are not fully understood and have not been studied so far. This study investigated the physiological and biochemical responses of triticale cultivars with differential recovery ability after soil water deficit. Activity of the photosynthetic apparatus under soil drought followed by rehydration was estimated. Plant antioxidant potential was determined based on the measurement of catalase and peroxidase activity. The levels of hydrogen peroxide and superoxide radical were assessed. Under rehydration, the not fully-recovered cultivar experienced further significant increase in the content of H2O2 and inhibited activity of the photosynthetic apparatus, as compared to the drought period. On 42nd day of the rehydration, the not fully-recovered cultivar showed also a reduced photosynthetic activity in the flag leaves, which resulted in a significant decrease in its grain yield. The first week of a rapid rehydration involved a decrease in total peroxidase and catalase activities. The increased content of H2O2 was compensated only when leaf water content was gradually restored in the first week of the rehydration and no further decrease in the activity of the photosynthetic apparatus was noticed. A destructive effect of the rapid rehydration was manifested in an intensification of the physiological processes associated with reactive oxygen species (ROS) overproduction. An important cause of hydrogen peroxide overproduction seems to be the electron leakage due to overloading of the electron transport chain (ETC) in the PSI and PSII.