Influence of distinctive Osmoprotectnats foliar spray in alleviating the harmful effects of water stress at sensitive growth stages of Maize (Zea mays L.)

Water availability is becoming a significant concern for crop production worldwide. In light of this, a study was conducted in maize crop to explore the effectiveness of various osmoprotectants including sodium nitroprusside nanoparticles (SNP NP) at a concentration of 90 ppm, melatonin (MEL), at 25 ppm and salicylic acid (SA) at 100 ppm in mitigating the adverse effects of drought, by evaluating their impact on morpho-physiological, biochemical and yield attributes of maize (Zea mays L.). Drought stress was induced by withholding irrigation during both the vegetative and reproductive stages of maize and then drought-stressed plants were foliar sprayed with different osmoprotectants. Results revealed that among the osmoprotectants tested, foliar application of salicylic acid at 100 ppm exhibited the most substantial improvement in morpho-physiological parameters (plant height, stem diameter, leaf number, root length, leaf area index, relative water content, leaf chlorophyll and carotenoid content) as well as biochemical parameteters like proline and soluble protein content increased, and enhanced membrane stability under drought conditions. The use of SA proved outstanding as it led to a remarkable 75% higher biological yield than plants subjected to drought stress. On the other hand, the SA foliar spray was successful, resulting in a 78.8% in grain yield. However, the extent of improvement varied depending on the growth stage at which the osmoprotectants were applied. While the foliar application of osmoprotectants showed promising results during the vegetative phase than the reproductive phase of maize. Nonetheless, the osmoprotectants' foliar spray exhibited a yield advantage by preserving photosynthetic pigments and the maize plants' ability to produce seeds under drought stress

Standardization of optimum melatonin concentration for drought tolerance at germination and early development stage in rice (CO-54)

Drought stress poses a serious threat to production and nutritional security. In recent years, foliar application of plant growth regulators (PGRs) and nutrients are increasingly employed to overcome physiological constraints resulting in enhanced crop production. Melatonin is a new biomolecule recently found to ameliorate the effect of biotic and abiotic stresses in crop plants. Hence, the present experiment was conducted to assess the optimum concentration of melatonin to mitigate the adverse effect of drought stress on germination and growth components in rice variety CO-54. In this experiment, PEG-mediated drought stress (-0.5 MPa) was imposed with different concentrations of melatonin (at doses of 50, 100, 150, 200, and 250 µM) seed treatments. Together, these results indicated that 200 µM melatonin-treated seeds showed a greater germination percentage (60%), root length (12.23cm), shoot length (8.23cm), fresh and dry weight (0.126g and 0.095g), high vigor index (1910.22), promptness index (64.83), and germination stress index (100) respectively. The result of this experiment provides a shred of strong evidence suggesting that seed treatment of 200 µM melatonin could be considered an effective technique for mitigating the detrimental effects of drought by promoting seed germination and thereby increasing the growth components of seedlings in rice. The study demonstrates that melatonin can shield rice seedlings from the effects of drought stress

Effect of phosphorus activators on soil legacy phosphorus availability and its uptake by maize hybrid COH(M) 6 in calcareous soil

Continuous application of phosphatic fertilizers in association with its low recovery results in the insoluble legacy P buildup in agricultural soils. In this study, a field experiment was conducted with maize hybrid COH(M) 6 to know the effect of different P activators (Farmyard Manure, Humic acid, Phosphorus Solubilising Bacteria, and Phytase) on increasing the legacy phosphorus (P) availability. The P activators were combined and applied along with the different doses of P fertilizer (100%, 75%, and 50% soil test dose of P fertilizer). The results showed that the application of Farmyard manure (FYM) and Humic acid (HA) significantly (p < 0.05) increased the soil available P (18.54 kg ha-1) and notably reduced the calcium P fraction (93.08 mg kg-1). The application of FYM and HA with 100% soil test dose of P showed a similar grain (9.98 kg ha-1) and stover P uptake (12.67 kg ha-1) response as that of FYM and HA with 75% soil test dose of P. The study suggested that FYM and HA application has activated the fixed calcium phosphorus in soil and increased its availability for crop utilization. The findings have illustrated that even the reduced dose of P fertilizer application can support the nutrient uptake if they are applied along with P- activators such as FYM and HA. This could promote soil health by reducing the P overload and further P loss in soil

Melatonin mediated high-temperature tolerance at seedling stage in green gram (Vigna radiata L.)

Global warming is predicted to have a generally negative effect on food grain production. The emergence of seedlings, blooming, pod-filling stages and yield of the mung bean are affected by high-temperature stress. Melatonin is a multifunctional signaling molecule with antioxidant properties that plays a vital role in plant stress defense mechanism. With this knowledge, the experiment was conducted to identify the optimum melatonin concentration to mitigate the adverse effects of high temperature in green gram var CO 8 with a completely randomized design (CRD). The treatments consisted of soaking seeds with different melatonin concentrations, viz., 20, 40, 60, 80 and 100 μM. Seeds were sown in a pertidish and allowed to germinate. After 5 days, the seedlings were exposed to two different high-temperature stress following the temperature induction response (TIR) protocol in the growth chamber viz., Ambient + 2°C (40°C) and Ambient + 4°C (42°C). After stress period, the seedlings were allowed to recover at room temperature for 2 days. At the end of the recovery period, observations on temperature tolerance-related traits viz., survival percentage, per cent reduction of shoot and root growth, cell viability, mortality per cent, malondialdehyde content, superoxide dismutase and catalase activity of green gram seedlings were assessed. Seeds pre-treated with melatonin of 100 and 80 µM exhibited higher survival percentage, shoot and root growth, cell viability and antioxidant enzyme activity (like superoxide dismutase and catalase) with reduced mortality per cent and malondialdehyde content under high-temperature stress at both 40°C and 42°C. The results revealed that seeds treated with different melatonin concentrations significantly improved green gram germination and seedling health.               

Influence of rice husk ash-derived silica nanoparticles on sweetcorn (Zea mays L. sachharata) seed germination

In agriculture, the utilization of nanomaterials has garnered significant global attention. This research adopts a pioneering approach to investigate the influence of nanosilica on the germination dynamics of sweetcorn seeds. The present study aimed to synthesize and analyze an amorphous nano-silica material using rice husk ash (RHA) and its impact on the germination of sweetcorn seeds (Zea mays L. sachharata). The extracted nano-silica particles dispersed into six rates of suspensions (0, 100, 200, 300, 400 and 500 ppm) were used to study their effects on seed germination. The synthesized amorphous nano-silica was  determined for size, shape, and elemental content. The amorphous nature of the silica sample was confirmed by transmission electron microscopy-selected area electron diffraction (ED) patterns and X-ray diffraction (XRD), whereas siloxane and silanol groups were mainly detected by Fourier-transform infrared (FT-IR) spectroscopy. Image obtained using scanning electron microscopy (SEM) revealed the presence of original nanoparticles alongside secondary microparticles, probably due to agglomeration. Particles in the extracted amorphous silica had an average diameter of 35 nm. Nano-silica powder was amorphous, according to XRD. As per the EDS analysis, the extracted silica sample is 96.87 % pure. The amorphous nano-silica significantly boosted germination metrics such as germination percentage, germination index, vigour index, and mean germination time of sweetcorn. With the addition of 300 ppm nano-silica, the germination percentage increased by 40.1%, the germination index by 96%, and the vigor index by 120% over control seeds. The improvement of seed germination by amorphous nano-silica in sweetcorn implies a potential application of nano-silica in seed germination