The effect of silicon supply on photosynthesis and carbohydrate metabolism in two wheat (Triticum aestivum L.) cultivars contrasting in response to phosphorus nutrition

Transcriptome analysis of Pennisetum americanum × Pennisetum purpureum and Pennisetum americanum leaves in response to high-phosphorus stress

Excessive phosphorus (P) levels can disrupt nutrient balance in plants, adversely affecting growth. The molecular responses of Pennisetum species to high phosphorus stress remain poorly understood. This study examined two Pennisetum species, Pennisetum americanum × Pennisetum purpureum and Pennisetum americanum, under varying P concentrations (200, 600 and 1000 µmol·L- 1 KH2PO4) to elucidate transcriptomic alterations under high-P conditions. Our findings revealed that P. americanum exhibited stronger adaption to high-P stress compared to P. americanum× P. purpureum. Both species showed an increase in plant height and leaf P content under elevated P levels, with P. americanum demonstrating greater height and higher P content than P. americanum× P. purpureum. Transcriptomic analysis identified significant up- and down-regulation of key genes (e.g. SAUR, GH3, AHP, PIF4, PYL, GST, GPX, GSR, CAT, SOD1, CHS, ANR, P5CS and PsbO) involved in plant hormone signal transduction, glutathione metabolism, peroxisomes, flavonoid biosynthesis, amino acid biosynthesis and photosynthesis pathways. Compared with P. americanum× P. purpureum, P. americanum has more key genes in the KEGG pathway, and some genes have higher expression levels. These results contribute valuable insights into the molecular mechanisms governing high-P stress in Pennisetum species and offer implications for broader plant stress research.

Impact of silicate fertilizer on soil properties and yield of bread wheat in Nitisols of tropical environment

Purpose

Soil acidity and depletion of essential plant nutrients are among the major abiotic stresses that constrained wheat productivity in Ethiopia. Silicates and silicate by-products can be used as alternative source for amendment of soil acidity and improvement of crop yields. Surface application of water-soluble silicate fertilizer alone and the integrated application with full does of recommended N and P from mineral fertilizers can reduce the extent of soil acidity and improve phosphorous availability in the soil, soil pH and exchangeable acidity and can enhance the yield attributes and yield of bread wheat. A field experiment was conducted under rain-fed condition from July to December of 2020 to evaluate the role of soil and foliar application of water-soluble silicate fertilizer without and with reduced or full doses of recommended nitrogen (N) and phosphorus (P) (RNP) from mineral fertilizers on soils chemical attributes, yield components and yield of bread wheat sown under moderately to strongly acidic condition in southeastern Ethiopia.

Methods

The experiment comprised sole silicate (40 kg + 18 L/ha-1), and its integration with full dose of RNP (92-30 kg N-P ha-1), three quarters dose of RNP (69-23 kg N-P ha-1) and half dose of RNP (46-15 kg N-P ha-1) from mineral fertilizers. Full dose of RNP from mineral fertilizers and a negative control with no silicate and mineral fertilizer inputs included as controls, resulting in a total of six treatments. The experiment was laid out in randomized complete block design, replicated three times.

Results

The combined application of silicate with mineral fertilizers significantly influenced soil properties, yield attributes and yield of bread wheat. Integrated applications of silicate fertilizers and full dose of RNP increased grain yield, biomass yield, and available soil P by 108, 115, and 23 % respectively relative to untreated soil.

Conclusions

Integration of silicate with mineral fertilizers can be considered as a viable and alternative option for acid soils amendment. Generally, the result of the current study revealed that combined application of water soluble granular and liquid silicate at the rate of (40 kg + 18 L)/ha with full dose of recommended nitrogen (92 kg ha-1) and phosphorus (30 kg ha-1) significantly reduced exchangeable acidity, tended to increase soil reaction, increased available soil phosphorus content and boosted yield of bread wheat compared to their sole applications. Thus, application of water-soluble silicate fertilizer with recommended rate of nitrogen and phosphorus is better in enhancing plant nutrition and yield of bread wheat in the highlands of Ethiopia and other similar agro-ecologies.

Effects of exogenous zinc (ZnSO4·7H2O) on photosynthetic characteristics and grain quality of hybrid rice

Rice is an important food crop and zinc (Zn) is a beneficial microelement. However, there are few reports on the effect of zinc on yield and physiological characteristics of rice. In this study, exogenous zinc (ZnSO4·7H2O) was applied on plant to explore the effects of zinc on rice yield, quality and photosynthetic capacity. The results showed that appropriate concentration of zinc could increase the net photosynthetic rate (Pn) of rice leaves, and Zn2 (2 mg/L ZnSO4•7H2O) treatment was the most significant. However, the Zn treatment had no positive effect on rice yield except under the concentration of Zn2. Meanwhile, the result showed that Zn treatment could increase chalkiness degree (CD) and chalky grain rate (CGR), decreased amylose content (AC), increased protein content and changed protein composition of rice. The above indexes were most significant in Zn2 treatment. In addition, the Zn2 treatment significantly increased rapid viscosity analyzer (RVA) of rice. In conclusion, the results of this study suggested that Zn treatment could enhance the photosynthetic capacity of rice leaves, and improve the processing quality, taste quality and nutritional quality of rice. However, it will have a negative impact on the appearance quality of rice and cannot be used to increase rice production. This study will provide a basis for the application of zinc in rice production.

Integrated Analysis of Metabolome and Transcriptome Reveals Insights for Low Phosphorus Tolerance in Wheat Seedling

Low phosphorus (LP) stress leads to a significant reduction in wheat yield, primarily in the reduction of biomass, the number of tillers and spike grains, the delay in heading and flowering, and the inhibition of starch synthesis and grouting. However, the differences in regulatory pathway responses to low phosphorus stress among different wheat genotypes are still largely unknown. In this study, metabolome and transcriptome analyses of G28 (LP-tolerant) and L143 (LP-sensitive) wheat varieties after 72 h of normal phosphorus (CK) and LP stress were performed. A total of 181 and 163 differentially accumulated metabolites (DAMs) were detected for G28CK vs. G28LP and L143CK vs. L143LP, respectively. Notably, the expression of pilocarpine (C07474) in G28CK vs. G28LP was significantly downregulated 4.77-fold, while the expression of neochlorogenic acid (C17147) in L143CK vs. L143LP was significantly upregulated 2.34-fold. A total of 4023 differentially expressed genes (DEGs) were acquired between G28 and L143, of which 1120 DEGs were considered as the core DEGs of LP tolerance of wheat after LP treatment. The integration of metabolomics and transcriptomic data further revealed that the LP tolerance of wheat was closely related to 15 metabolites and 18 key genes in the sugar and amino acid metabolism pathway. The oxidative phosphorylation pathway was enriched to four ATPases, two cytochrome c reductase genes, and fumaric acid under LP treatment. Moreover, PHT1;1, TFs (ARFA, WRKY40, MYB4, MYB85), and IAA20 genes were related to the Pi starvation stress of wheat roots. Therefore, the differences in LP tolerance of different wheat varieties were related to energy metabolism, amino acid metabolism, phytohormones, and PHT proteins, and precisely regulated by the levels of various molecular pathways to adapt to Pi starvation stress. Taken together, this study may help to reveal the complex regulatory process of wheat adaptation to Pi starvation and provide new genetic clues for further study on improving plant Pi utilization efficiency.

Application of Silicon, Zinc, and Zeolite Nanoparticles-A Tool to Enhance Drought Stress Tolerance in Coriander Plants for Better Growth Performance and Productivity

Drought stress in arid regions is a serious factor affecting yield quantity and quality of economic crops. Under drought conditions, the application of nano-elements and nano-agents of water retention improved the water use efficiency, growth performance, and yield quantity of drought-stressed plants. For this objective, two field experiments were performed and organized as randomized complete block designs with six replications. The treatments included kaolin (5 t. ha-1) bentonite (12.5 t. ha-1), perlite (1.25 t.ha-1), N-zeolite (1.3 L.ha-1), N-silicon (2.5 L.ha-1), and N-zinc (2.5 L.ha-1). The current study showed that the application of silicon, zinc, and zeolite nanoparticles only positively influenced the morphological, physiological, and biochemical properties of the drought-stressed coriander plant. Exogenous application of N-silicon, N-zinc, and N-zeolite recorded the higher growth parameters of drought-stressed plants; namely, plant fresh weight, plant dry weight, leaf area, and root length than all the other treatments in both seasons. The improvement ratio, on average for both seasons, reached 17.93, 17.93, and 18.85% for plant fresh weight, 73.46, 73.46, and 75.81% for plant dry weight, 3.65, 3.65, and 3.87% for leaf area, and 17.46, 17.46, and 17.16% for root length of drought-stressed plants treated with N-silicon, N-zinc, and N-zeolite, respectively. For physiological responses, the application of N-zeolite, N-silicon, and N-zinc significantly increased leaf chlorophyll content, photosynthetic rate, water use efficiency, chlorophyll fluorescence, and photosystem II efficiency compared with the control in both seasons, respectively. Similar results were observed in antioxidant compounds, nutrient accumulation, and phytohormones. In contrast, those treatments markedly reduced the value of transpiration rate, nonphotochemical quenching, MDA, ABA, and CAT compared to control plants. Regarding the seed and oil yield, higher seed and oil yields were recorded in drought-stressed plants treated with N-zeolite followed by N-silicon and N-zinc than all the other treatments. Application of N-zeolite, N-silicon and N-zinc could be a promising approach to improve plant growth and productivity as well as to alleviate the adverse impacts of drought stress on coriander plants in arid and semi-arid areas.

Effect of Fertilization Regime of Common Wheat (Triticum aestivum) on Flour Quality and Shelf-Life of PDO Tuscan Bread

The shelf-life of bread is influenced by flour components, such as starch, composed of amylose and amylopectin. The aim was to test the effect of different balances of N (45, 90, 135 kg/ha) and P (48, 96 kg/ha) fertilizers on the flour characteristics and consequently the shelf-life of PDO Tuscan bread, stored in different modified atmosphere packaging (Ar, N₂, Air). The amylose and phytochemical compounds were increased by N and decreased by the addition of P, but excessive doses of N (135 kg/ha) had a negative effect on flour quality. In the bread, the study highlighted the tendency of N₂ and Ar, as storage filler gases, to reduce water loss, slow down the staling process, and prolong shelf-life. However, the most significant influence on shelf-life was related to the different fertilizations of wheat. In fact, when N was present in equal dose to P (90/96 or 45/48 kg/ha) or slightly higher (90/48 kg/ha), the bread tended to last longer over time. Instead, when these ratios were unbalanced in favor of N (135/48 or 135/96 kg/ha) and in favor of P (45/96 kg/ha), the shelf-life decreased considerably.