Auxins (IAA) and cytokinins (CKs) are the most influential phytohormones, having multifaceted roles in plants. They are key regulators of plant growth and developmental processes. Additionally, their interplay exerts tight control on plant development and differentiation. Although several reviews have been published detailing the auxin-cytokinin interplay in controlling root growth and differentiation, their roles in the shoot, particularly in leaf morphogenesis are largely unexplored. Recent reports have provided new insights on the roles of these two hormones and their interplay on leaf growth and development. In this review, we focus on the effect of auxins, CKs, and their interactions in regulating leaf morphogenesis. Additionally, the regulatory effects of the auxins and CKs interplay on the phyllotaxy of plants are discussed.

The hormonal imbalances, including abscisic acid (ABA) and brassinosteroid (BR) levels, caused by salinity constitute a key factor in hindering spikelet development in rice and in reducing rice yield. However, the effects of ABA and BRs on spikelet development in plants subjected to salinity stress have been explored to only a limited extent. In this research, the effect of ABA and BRs on rice growth characteristics and the development of spikelets under different salinity levels were investigated. The rice seedlings were subjected to three different salt stress levels: 0.0875 dS m⁻¹ (Control, CK), low salt stress (1.878 dS m⁻¹, LS), and heavy salt stress (4.09 dS m⁻¹, HS). Additionally, independent (ABA or BR) and combined (ABA+BR) exogenous treatments of ABA (at 0 and 25 μM concentration) and BR (at 0 and 5 μM concentration) onto the rice seedlings were performed. The results showed that the exogenous application of ABA, BRs, and ABA+BRs triggered changes in physiological and agronomic characteristics, including photosynthesis rate (Pn), SPAD value, pollen viability, 1000-grain weight (g), and rice grain yield per plant. In addition, spikelet sterility under different salt stress levels (CK, LS, and HS) was decreased significantly through the use of both the single phytohormone and the cocktail, as compared to the controls. The outcome of this study reveals new insights about rice spikelet development in plants subjected to salt stress and the effects on this of ABA and BR. Additionally, it provides information on the use of plant hormones to improve rice yield under salt stress and on the enhancement of effective utilization of salt-affected soils.

Non-nutritive metals, especially cadmium (Cd), are present in P fertilizers; the long-term application of these P fertilizers leads to Cd build-up in the soil. The current study aims to evaluate the impacts of P sources and rates on the growth of maize (Zea mays L.) and the bioavailability of Cd. Twelve treatments including rock phosphate 4 g kg⁻¹ (RP1); 8 g kg⁻¹ (RP2); 12 g kg⁻¹ (RP3)); single super phosphate 333 mg kg⁻¹ (SSP1); 444 mg kg⁻¹ (SSP2); 555 mg kg⁻¹ (SSP3); di-ammonium phosphate 130 mg kg⁻¹ (DAP1); 174 mg kg⁻¹ (DAP2); 218 mg kg⁻¹ (DAP3); mono-ammonium phosphate 115 mg kg⁻¹ (MAP1); 154 mg kg⁻¹ (MAP2); 193 mg kg⁻¹ (MAP3) in two soil textures (sandy and clayey) were assessed. Results revealed that all P sources significantly influenced the plant growth and yield characteristics of maize (p ≤ 0.05). In both soil textures, P in soil and plant, plant growth and yield characteristics were maximized by MAP and DAP. Cadmium build-up in soil and uptake was also significantly (p ≤ 0.05) affected by P sources, levels, and soil texture. It was observed that Cd build-up in soil and uptake by plants boosted with increasing P levels. Maximum Cd concentration in plant root and shoot was found with SSP3, and its concentration in soil increased with MAP3, whereas the concentration was higher in sandy texture. The study concludes that type of P fertilizer should be determined based on texture and human consumption of the crop to avoid Cd toxicity.

The current study aimed to improve the nitrogen recovery efficiency (NRE) of maize under the application of balanced proportions of ammoniacal-nitrogen (NH₄⁺-N) and nitrate-nitrogen (NO₃⁻-N) (1:1), as well as to determine economic impacts of such fertilizers on maize productivity. A 3-year field study was carried out in Sahiwal, Punjab, Pakistan during the 2018–2020 growing seasons with autumn maize. In parallel, multi-location field experiments were conducted at farmer’s fields in Sahiwal during the same growing seasons with autumn maize. The trials compared the effects of different fertilizers like urea, calcium ammonium nitrate (CAN), Sarsabz nitrophos (NP), nitrphos plus (NP Plus), and di-ammonium phosphate (DAP) on maize growth and yield, as well their economic efficiency. The results revealed that the application of Sarsabz NP and CAN increased the maize grain yield by 30%, 13%, 15%, 19%, 15%, and 9% as compared to the control, NP + urea, NP Plus + CAN, NP Plus + urea, DAP + urea, and DAP + CAN, respectively. In addition, the combined application of NP and CAN increased the total N and NO₃⁻-N concentrations, whereas it decreased the NH₄⁺-N concentrations in the soils. By contrast, NP + CAN increased the NH₄⁺-N concentrations in maize leaves as compared to NO₃⁻-N concentrations. Overall, the NRE of maize plants and the net return were higher under combined application of NP and CAN. In conclusion, CAN fertilizer increased the soil NO₃⁻-N concentrations, which thus assimilated in the plants as NH₄⁺ and improved the NRE of maize. Improved NRE thus enhanced maize yield and resulted in the maximum net return as compared to all other fertilizer combinations.