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Selenium (Se) is crucial for both plants and humans, with plants acting as the main source for human Se intake. In plants, moderate Se enhances growth and increases stress resistance, whereas excessive Se leads to toxicity. The physiological mechanisms by which Se influences rice seedlings' growth are poorly understood and require additional research. In order to study the effects of selenium stress on rice seedlings, plant phenotype analysis, root scanning, metal ion content determination, physiological response index determination, hormone level determination, quantitative PCR (qPCR), and other methods were used. Our findings indicated that sodium selenite had dual effects on rice seedling growth under hydroponic conditions. At low concentrations, Se treatment promotes rice seedling growth by enhancing biomass, root length, and antioxidant capacity. Conversely, high concentrations of sodium selenite impair and damage rice, as evidenced by leaf yellowing, reduced chlorophyll content, decreased biomass, and stunted growth. Elevated Se levels also significantly affect antioxidase activities and the levels of proline, malondialdehyde, metal ions, and various phytohormones and selenium metabolism, ion transport, and antioxidant genes in rice. The adverse effects of high Se concentrations may directly disrupt protein synthesis or indirectly induce oxidative stress by altering the absorption and synthesis of other compounds. This study aims to elucidate the physiological responses of rice to Se toxicity stress and lay the groundwork for the development of Se-enriched rice varieties.

RESUMEN

PAM fluorometry showed that the orchid Vanda sp (Gaud ex Pfitzers, Vandeae) had photosynthetic electron transport yields in leaves reaching ≈ 0.617 ± 0.262 at midday. Yield decayed exponentially as irradiance increased (Y½ = 128 ± 12.4 µmol photon m-2 s-1). Optimum irradiance (Eopt) for ETR (Photosynthetic Electron Transport Rate) was ≈ 369 ± 23.3 µmol photon m-2 s-1; the maximum photosynthetic ETR (ETRmax) (on a Chl a basis) ≈ 97.6 ± 3.76 µmol e-g-1 Chl a s-1. Rapid light curves exhibited classic photoinhibition at high irradiances: Vanda sp is a shade plant. Photosynthetic kinetics was strongly diurnal with minimal Eopt and ETRmax in the early morning, reaching a maximum at midday and decreasing in the afternoon. The aerial roots were normally photosynthetically dormant but rapidly activated when wet (homiochlorophyllous) then becoming dormant again after drying. Wet roots deliberately incubated under moist conditions had photosynthetic light curves comparable to leaves (Ymax ≈0.332, Y½ = ≈ 78.3 ± 27.8 µmol photons m-2 s-1, Eopt ≈ 278 µmol photons m-2 s-1 and ETRmax ≈ 317 ± 86.9 µmol e-g-1 Chl a s-1): wetting for only 15 min activated photosynthesis. Leaves showed a small degree of diurnal cycling of titratable acid but acid was accumulated in the early morning, not at night, this is a type of CAM-cycling. Titratable acid was low at sunrise (≈ 54.1 µmol H+g-1 FW), but increased until about 9 a.m. (≈ 137 µmol H+g-1 FW) and then gradually decreased over the course of the day.

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Background: Extensive surveys of several population settlements in different parts of India-covering plains, mountains, valleys, river banks and deeper areas of forests at different altitudes-between 1968 and 2016 demonstrated that the basic vital need of hunger is being fulfilled since antiquity by plants in the wild. Methods: Based on collections, consultations with local population personnel and literature searches, this paper presents many plants that are commonly used as food and focuses on their products, which are rich in alkaloids, polysaccharides, steroids, terpenoids, flavonoids, aminoacids, fatty acids and antibiotics etc. These complex organic compounds are suitable for the production of drugs for many ailments/diseases, including the prevention of cancers. Results: There are more than 100 families including several hundred plant taxa from various plant groups like angiosperms, bryophytes, pteridophytes, gymnosperms and even fleshy fungi, which have offered essential food items to ever-growing human populations since antiquity. Phytochemicals functioning as antioxidants are exceedingly beneficial to the human body but excess consumption of these compounds, adding higher levels of antioxidants, may even be responsible for chronic diseases including aging, cancer, cardiovascular diseases, rheumatoid arthritis, atherosclerosis, etc. These medicines can obviously be taken in small and prescribed quantities but can never be consumed as "food items."

RESUMEN

Jasmonates (JAs) are recognized as essential regulators in response to environmental stimuli and plant development. Carrot is an Apiaceae vegetable with great value and undergoes significant size changes over the course of plant growth. However, JA accumulation and its potential roles in carrot growth remain unclear. Here, methyl JA (MeJA) levels and expression profiles of JA-related genes were analyzed in carrot roots and leaves at five developmental stages. MeJA levels in the roots and leaves were the highest at the first stage and decreased as carrot growth proceeded. Transcript levels of several JA-related genes (Dc13-LOX1, Dc13-LOX2, DcAOS, DcAOC, DcOPR2, DcOPR3, DcOPCL1, DcJAR1, DcJMT, DcCOI1, DcJAZ1, DcJAZ2, DcMYC2, DcCHIB/PR3, DcLEC, and DcVSP2) were not well correlated with MeJA accumulation during carrot root and leaf development. In addition, some JA-related genes (DcJAR1, DcJMT, DcCOI1, DcMYC2, and DcVSP2) showed differential expression between roots and leaves. These results suggest that JAs may regulate carrot plant growth in stage-dependent and organ-specific manners. Our work provides novel insights into JA accumulation and its potential roles during carrot growth and development.

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