Pre-sowing seed priming is one of the methods used to improve the performance of tomato plants under salt stress, but its effect photosynthesis, yield, and quality have not yet been well investigated. This experiment aimed to alleviate the impact of sodium chloride stress on the photosynthesis parameters of tomato cv. Micro−Tom (a dwarf Solanum lycopersicum L.) plants exposed to salt stress conditions. Each treatment combination consisted of five different sodium chloride concentrations (0 mM, 50 mM, 100 mM, 150 mM, and 200 mM) and four priming treatments (0 MPa, −0.4 MPa, −0.8 MPa, and −1.2 MPa), with five replications. Microtome seeds were subjected to polyethylene glycol (PEG6000) treatments for 48 hours for priming, followed by germination on a moist filter paper, and then transferred to the germination bed after 24 h. Subsequently, the seedlings were transplanted into the Rockwool, and the salinity treatments were administered after a month. In our study salinity significantly affected tomato plants’ physiological and antioxidant attributes. Primed seeds produced plants that exhibited relatively better photosynthetic activity than those grown from unprimed seeds. Our findings indicated that priming doses of −0.8 MPa and −1.2 MPa were the most effective at stimulating tomato plant photosynthesis, and biochemical contents under salinity-related conditions. Moreover, primed plants demonstrated relatively superior fruit quality features such as fruit color, fruit Brix, sugars (glucose, fructose, and sucrose), organic acids, and vitamin C contents under salt stress, compared to non-primed plants. Furthermore, priming treatments significantly decreased the malondialdehyde, proline, and hydrogen peroxide content in plant leaves. Our results suggest that seed priming may be a long-term method for improving crop productivity and quality in challenging environments by enhancing the growth, physiological responses, and fruit quality attributes of Micro-Tom tomato plants under salt stress conditions.

Heat stress is a critical limiting factor in rice production, and a comprehensive understanding of the physiological traits contributing to yield under such conditions remains incomplete. This study evaluated the effects of heat stress on six rice varieties: Nagina22 (N22), NERICA4 (NER), Nipponbare (NPB), IR64, Berenj-I-Mahin (BIM), and Berenj-I-Luk (BIL) exposed to maximum temperatures exceeding 40 °C from flowering to the grain-filling stage. Results demonstrated a strong correlation between the photosynthetic rate and both 1000-grain weight and transpiration rate at the flowering stage across all varieties. Under heat stress, NER, BIM, BIL, and IR64 exhibited elevated levels of malondialdehyde, indicative of oxidative damage, and sustained significant heat injury compared to ambient conditions. Heat stress notably impaired pollen viability and spikelet fertility, reducing crop yields. In contrast, the heat-tolerant variety N22 maintained the highest spikelet fertility rate, effectively regulated transpiration cooling, and significantly enhanced yield by maintaining a lower leaf temperature. The findings indicate that photosynthetic efficiency and oxidative stress during the flowering stage critically influence spikelet fertility and overall yield in rice under heat stress. This research provides valuable insights for rice breeders and agronomists, encouraging the development of heat-tolerant varieties and adaptive strategies to mitigate the adverse impacts of elevated temperatures during critical reproductive stages.

The reproductive stage of rice is vulnerable to heat stress, which reduces spikelet fertility and yield. Auxin significantly influences reproductive development, hence the research aimed to enhance spikelet fertility and grain attributes in rice plants by exploring the application efficiency of Indole-3-acetic acid (IAA) and 1-naphthaleneacetic acid (NAA) under heat stress. This study investigated the effects of IAA (10 μmol L⁻¹) and NAA (100 μmol L⁻¹) on spikelet fertility rate in six rice genotypes during the flowering stage. Compared to the heat stress (HS) treatment, the spikelet production rate and grain yield per plant were higher by 61.16%, 37.25%, and 33.07%, and 72.84%, 44.48%, and 32.71% in control, HS + NAA, and HS + IAA treatments, respectively. In addition, panicle weight, primary branches number panicle⁻¹, and 1000-grains weight were significantly (p < 0.05) improved with HS + IAA and HS + NAA application under heat stress conditions. Auxin application enhanced photosynthetic and transpiration rate, while contrarily, leaf temperature diminished. The higher photosynthetic rate showed positive relationships with spikelet fertility (r = 0.64) and yield plant⁻¹ (r = 0.63). Additionally, leaf temperature had a strongly negative correlation (r = −0.81) with the spikelet fertility rate. The application of auxin increased the number of filled grains panicle⁻¹, which showed a positive relationship (r = 0.75) with grain yield plant⁻¹. The variation of spikelet fertility rate among genotypes was dependent on the variety tolerance rate. Overall, these findings indicate that exogenous auxin application can mitigate the negative impact of heat stress on rice and improve spikelet fertility and grain yield.

The excess presence of calcium carbonate (CaCO₃) in soil poses challenges for production of horticultural crops, including tomatoes. This condition is prevalent in arid and semi-arid regions of Afghanistan. The objective of this study was to evaluate the effects of elevated concentrations of CaCO₃ on growth, physiology, and quality attributes of tomato. Seedlings were exposed to different concentrations of CaCO₃ (0%, 2.5%, 5%, 10%, and 20% w/w) in soil. The results showed that elevated concentrations of CaCO₃ (10% and 20%) significantly increased soil electrical conductivity (EC) and pH, and subsequently affected growth, physiology, and quality of tomato. CaCO₃ effects resulted in an increase in leaf electrolyte leakage, leaf calcium content, root respiration rate, root ethylene production, fruit firmness, total soluble solids, ascorbic acid, and organic acids, as well as a decrease in plant height, leaf length, leaf magnesium content, leaf SPAD value, number of leaves per plant, root weight and length, and root activity. At higher concentrations, CaCO₃ decreased number of flowers and fruit per plant, as well as fruit weight and diameter, consequently affecting yield production. Although elevated concentrations of CaCO₃ is characteristic of soils in Afghanistan, limited information is available about this topic. These findings enhance our understanding of soil conditions in the country and provide valuable insights for farmers.